This PDF file contains the front matter associated with SPIE Proceedings Volume 11190, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

Dynamic optical contrast imaging (DOCI) is a novel optical imaging technology that rapidly generates image contrast from measurements of aggregate endogenous fluorescence lifetime in a clinically meaningful field of view. Recently, our use of this system in both human ex-vivo and in-vivo specimens generated statistically significant contrast between tumor and adjacent normal tissue in biopsies taken from patients undergoing surgery for head and neck squamous cell carcinoma and primary hyperthyroidism. In this work we evaluated the components and resolution of our next-generation DOCI system. We also standardized the quantitative output of our system against the fluorescence lifetime values of three dye standards with monoexponential decay using a commercial Leica two-photon fluorescence lifetime imaging microscope. Significantly, our system continued to demonstrate clinically meaningful contrast between tissue samples with multiexponential decay in near real-time.

Coronary heart disease is the fatal cardiovascular disease, as well as the leading killer threatening people’s health. Coronary atherosclerosis is the main cause of coronary heart disease, the accurate identification of the coronary atherosclerotic plaques is of great importance for the judgement of the pathological conditions of the vascular and the guidance of subsequent treatment. Due to its extremely high imaging resolution, intravascular optical coherence tomography (IVOCT) has been widely used in the clinical diagnosis and treatment of coronary heart disease, of which one of the important functions is to judge the type of plaque in the diseased vessels. The purpose of this paper is to study an algorithm of the IVOCT plague image automatic recognition, which assists the doctors to analyze the images, so as to improve the accuracy of the plaque recognition.

Distributed sensing based on Optical Backscattering Reflectometry (OBR) is a promising solution for medical applications, such as thermal ablation. OBR working principle is based on the change in pattern of small reflections from non-homogeneities inside the fiber as a response to applied strain and temperature. The advantage of OBR is its high resolution and sensitivity. However, since the scattering level is the same for standard single-mode fibers, OBR is unable to discriminate the pattern of different fibers when they are connected in parallel to a single channel. As a result, OBR detection is limited to a single sensing fiber and does not allow multiplexing. This work proposed a method to overcome the aforementioned limitation by the use of high-scattering fibers. Such fibers are achieved by doping their core with magnesium oxide particles, which size varies from 20 to 100 nm. The backscattering level of nanoparticles doped fiber (NPDF) is 50 dB higher than of the standard fibers. Four NPDFs have been spliced to the standard single-mode pigtails with different length to achieve four sensing regions located at different distances from pigtails. The NPDF sensors have been connected to the OBR equipment by the use of optical couplers and the backscattered pattern has shown four high-scattered sensing regions separated by low-scattering regions from standard fibers. The proposed setup has been applied in the thermal ablation experiments and the 2-dimensional map of temperature change with time has been obtained.

CARS is the one of most exciting and actively developed techniques for real-time monitoring of processes occurring in biological tissues. We present a fiber optical parametric oscillator pumped by specially designed MOPA fiber laser to get time-synchronized optical signals with a frequencies difference of 2800-3000 reverse centimeters. We utilize the fourwave mixing effect in a photonic-crystal fiber to build narrowband tunable fiber optical parametric oscillator. A complex optimization of each part of the source has been performed.

Lymph nodes are an important secondary lymphoid organ in the lymphatic system. It is the major site of B cells, T cells and other white blood cells, leading to the function of identifying and fighting infection. To observe the structure of the lymph node, it is necessary to label it with dyes or fluorescent probes. Multi-color labeling are required to label various cell types and structures, which may be difficult under conditions such as in vivo labeling. Stimulated Raman scattering microscopy (SRS) is a burgeoning label-free biological imaging technique that has been used in many areas, such as tumor detection, pharmacokinetics, and neuroscience. Here, we developed a method of label-free imaging of various cell types and structures in lymph nodes with SRS. Collagenous fibers in the lymph node capsule, subcapsular sinus macrophages, B cells, blood vessels and white blood cells were observed in fresh lymph nodes. Based on the visualization of lymph node structure, we prospected its applications in cancer research, aging research and extracellular matrix research.

This paper describes detailed study of single human platelet and can be used for rapid and early structure changes and biomarkers identification in individuals with cardiovascular decease (CCD) pathology in vitro. The obtained data include analyzed Surface-enhanced Raman spectra (SERS) of human platelets taken from healthy individuals and individuals with cardiovascular pathology. Paper describes characteristic maxima of different cell components and its changes in platelets.

Mast cell (MCs) researches have received worldwide attention and achieved great achievements. Degranulation of MCs is not only related to anaphylaxis, but also plays an important role in the formation and progression of tumor. The existing detection methods could not fully reflect the degree of cell degranulation. In this paper, surface-enhanced Raman scattering (SERS) was used to detect and analyze the degranulation degree of MCs treated with different concentrations of C48/80 (compound 48/80, a mast cell activator). The culture supernatants of cells treated with different concentrations of C48/80 (0 μg/mL, 2 μg/mL and 10 μg/mL) were mixed with Ag colloids and high quality SERS spectra were acquired. The assignment of SERS bands combined with differential spectra analysis indicated that biomolecules associated with cell degranulation in the C48/80 treated groups were changed compared with the control group, including a decrease in the percentage of lipid content and an increase in the relative contents of collegen and phosphatidylserine. Furthermore, principal component analysis (PCA) and linear discriminant analysis (LDA) diagnostic algorithms were employed to analyze and distinguish the SERS spectra of different cell degranulation groups with high sensitivity, specificity and accuracy. The larger value of the integration area under the ROC curve also suggested the greater forecast accuracy. This exploratory work demonstrates that the combination of SERS technology and PCA-LDA algorithm has great potential for developing a label-free, comprehensive and accurate method for detecting cell degranulation.

Optical coherence tomography (OCT) is a noninvasive, non-contact imaging technique, which is an indispensable diagnostic tool in ophthalmology. However, light attenuation in opaque tissues of the eye limits the imaging depth of OCT. In this study, the imaging depth of rabbit eye in vitro was extended by reduction of multiple scattering by using tissue optical clearing (TOC) agents. Results showed that with the application of glycerol in anterior segment, boundaries of ciliary muscle could be obviously differentiated. For posterior segment, the retina, the choroid, the sclera and even the eye container were also clearly imaged. All the physiology change by glycerol was recovered by a direct wash of saline in a short time.

Super-resolution localization microscopy (SRLM) techniques overcome the diffraction limit, making possible the observation of sub-cellular structures in vivo. At present, the spatial resolution of ~20 nm in x-y axis has been achieved in SRLM. However, the localization accuracy for the longitudinal axis (i.e., the z-axis) still need be improved. Although some methods have been proposed to implement 3-D SRLM, these methods are computationally intensive and parameter dependent. To overcome these limitations, in this paper, we propose a new method based on deep learning, termed as dl- 3D-SRLM. By learning the mapping between a 2-D camera frame (i.e., the experimentally acquired image) and the true 3-D locations of fluorophores in the corresponding image region with a convolutional neural network (CNN), dl-3D-SRLM provides the possibility of implementing 3-D SRLM with a high localization accuracy, a fast data-processing speed, and a little human intervention. To evaluate the performance of dl-3D-SRLM, a series of numerical simulations are performed. The results show that when using dl-3D-SRLM, we can accurately resolve the 3-D location of fluorophores from the acquired 2-D images, even if under high fluorophores densities and low signal-to-noise ratio conditions. In addition, the complex 3-D structure can also be effectively imaged by dl-3D-SRLM. As a result, dl-3D-SRLM is more beneficial for 3D-SRLM imaging.

In this paper, beam-shifting optical coherence tomography (BSOCT) is presented for speckle reduction and flow rate measurement. The sample beam is rotated about the optical axis of the objective lens to modulate the incident angle on sample; 17 and 3 incident angles are respectively performed for speckle reduction and flow rate measurement. The performance of the proposed technique is investigated on both phantom and in vivo experiments. By combining a 2D micro-electro-mechanical system (MEMS) and a zigzag scanning protocol, the frame rates of 45.2 Hz for speckle reduction and 25.6 Hz for flow rate measurement are achieved. With beam-shifting angle of 4.76º, the speckle noise reduction of 91% and the flow rate measurement precision of 0.0019 μl/s are achieved.

With the development of super-resolution fluorescence microscopy, complex dynamic processes in living cells can be observed and recorded with unprecedented temporal and spatial resolution. Single particle tracking is the most important step to explore the relationship between the spatio-temporal dynamics of subcellular molecules and their functions. Although previous studies have developed single particle tracking algorithms to quantitatively analyze particle dynamics in cell, traditional tracking methods have poor performance when dealing with intersecting trajectories. This can be attributed to two main reasons: 1) They do not have point compensation process for overlapping points; 2) They use inefficient motion prediction models. In this paper, we presented a novel Fan-shaped Tracker (FsT) algorithm to reconstruct the trajectories of subcellular molecules in living cells. We proposed a customized point compensation method for overlapping points based on the fan-shape motion trend of the particles to solve the merging trajectory problem. Furthermore, we compared the performance of our Fan-shaped Tracker with five state-of-the-art tracking algorithms in simulated time-lapse movies with variable imaging quality. Our results showed that the Fan-shaped Tracker achieves better performance than other reported methods as we systematically evaluated using a set of standard evaluation parameters. We anticipate that our FsT method will have vast applications in tracking of moving objects in cell.

Cancer incidence and mortality are rapidly growing worldwide, resulting in heavy social and economic burdens. Early detection as well as precise intraoperative diagnosis of cancers is crucial to improving the prognosis and thus significantly decreasing the mortality. Two-photon excitation fluorescence lifetime imaging microscopy and spectroscopy not only shows the outstanding capability of label-free, intravital, high-resolution, three-dimensional imaging but also allows the quantitative biochemical characterizing of live tissues. Benefiting from these advantages, this technology is promising for early detection and demarcation of malignant tumors. However, its full potential has not been extensively evaluated in clinical settings. Here, we assess the feasibility of using two-photon excitation fluorescence lifetime imaging microscopy and spectroscopy to identify various cancers, including esophageal cancer, gastric cancer, and brain cancer. In terms of esophageal cancer, we compared the fresh human esophageal mucosal tissues of normal, squamous cell carcinoma, and adenocarcinoma. For gastric cancer, we performed a systematic investigation on fresh human gastric mucosal specimens at typical stages of gastric carcinogenesis. In addition, by developing a mouse chronic cranial window, we carried out a preliminary study on glioma margin identification in vivo. By extracting fluorescence spectrum and lifetime information of endogenous fluorophores, qualitative and quantitative indicators which are found to have the potential to discriminate normal, premalignant and different malignant lesions are derived. This study may shed new light on the early detection, precise intraoperative diagnosis, and classification of digestive tract cancers and brain cancers. With advances in endoscopy, two-photon excitation fluorescence lifetime imaging microscopy and spectroscopy has the potential to become a noninvasive, label-free, real-time histological and functional cancer detection tool in the future.

Two novel thiadiazolo[3,4-g]quinoxaline (TQ) derivatives, 6,7-bis(4-(hexyloxy)phenyl)-[1,2,5]thiadiazolo[3,4- g]quinoxaline (TQs-1) and 4,9-dibromo-6,7-bis(4-(hexyloxy)phenyl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline (TQs-2) were synthesized and fully characterized by 1H-NMR, 13C-NMR and HR-MS spectra. Their photo-physical and photo-chemical properties, including UV-Vis spectra, fluorescence spectra, photostability and singlet oxygen quantum yield were comprehensively studied. Compared to TQs-1, TQs-2 exhibited a higher singlet oxygen quantum yield and a broader absorption spectrum due to the introduction of two bromine atoms. Furthermore, TQs-2 based nanoparticles (TQs-2 NPs) was obtained via a simple co-assembly strategy using a biocompatible amphiphilic polymer DSPE-mPEG2000 to encapsulate TQs-2. In vitro photodynamic therapy (PDT) experiments to three tumor cells (4T1, MCF-7 and HeLa) and normal cells (L929) were carried out using TQs-2 NPs as photosensitizers. The results showed that TQs-2 NPs possessed negligible dark cytotoxicity to these cells at a high concentration of 50 μg mL-1, but exhibited high light cytotoxicity to them, especially to three tumor cells, under a 532 nm laser illumination at the same concentration, indicating that TQs-2 NPs has a promising potential for PDT applications.

Early studies suggest that some PDT photosensitizers can be used as sonosensitizer for sonodynamic therapy (SDT). In this study, sonodynamic effects of a novel water soluble chlorin YLG-1 were evaluated. SDT of YLG-1 solution was carried out using an ultrasound transducer of 450 KHz at 2.0 W/cm² for 0 – 600 s. Comparison of spectroscopic profiles of YLG-1 before and after SDT demonstrated that sonification could cause the reduction of YLG-1 absorbance and fluorescence emission but did not cause obvious change of the Raman spectrum. No significant by-products were identified from spectroscopic study. Nevertheless, this study demonstrated that the sonification mediated sensitizer fluorescence bleaching effect could be partially blocked by the addition of NaN3, which suggests a possible involvement of singlet oxygen in the process of sonification of YLG-1 compound.

Stem-cell therapy is showing great potential in regenerative medicine for their inherent ability to self-renew and differentiate. Biochemical and genetic methods and 3D materials/structures have been developed and making great progress in controlling the development and differentiation of stem cells. One of the major remaining concerns is the invasion of those technologies. In this study, we demonstrate an all-optical and noninvasive approach to precisely induce the differentiation of adipose-derived stem cells (ADSCs) and cerebellar granule neuron progenitor (GNP) cells. We show that the single-time fast-flash of photostimulation by a tightly-focused femtosecond laser, without any optogenetics, can activate endogenous signaling pathways for stem-cell differentiation directly by multiphoton excitation. The significant upregulation of differentiation regulator RUNX2 and Osterix in ADSCs 7 days after photostimulation indicates the osteogenic differentiation of ADSCs. The differentiation was finally confirmed by Alizarin red staining 28 days after photostimulation. The differentiation of GNP cells in vitro and in vivo can also be induced by this method. This noninvasive optical technology hence provides an encouraging advance to activation of signaling pathways in cells and alternative to classic biochemical methods for stem-cell differentiation. This result also provides an optical choice with promising potential for clinical regenerative applications.

Photodynamic therapy (PDT) employs light activation of tissue-localized photosensitizer in an oxygen-dependent process which initiates oxidative stress, inflammation, and cell death. Laser systems, which are mostly used in PDT as light sources can be costly and oversized. light-emitting diodes (LEDs) equipment has a high potential to simplify technical part of phototriggered therapies and to reduce its costs. We develop the LED-based system that includes the control and irradiation units. The system provides the same power density at any irradiation point. Among the advantages of the device is a possibility to change the irradiation area and tune the irradiation dose. PDT experiments with cancer cells in vitro treated with two different photosensitizers demonstrated a possibility to use the developed LED-based system as a low-cost light source in PDT.

Gas in scattering media absorption spectroscopy shortly called GASMAS, is a tunable diode laser spectroscopic technique developed for the measurement of gas present in turbid media. The technique relies on the sharp and specific absorption lines of gases which enables sensitive measurements of gas concentrations in the presence of a scattering solid medium with much broader absorption features. The Biophotonics laboratory at Tyndall National Institute (Biophotonics@Tyndall) is currently exploring the clinical translation of GASMAS technology into the respiratory healthcare of neonates. In this study, we use computational tools to assess the potential gain in gas absorption signal. One of the challenges in the development of the GASMAS technique is to obtain a sufficiently good signal in the measurements, as the light attenuation is high in tissue and the lungs are interior organs. To have an estimation of the capabilities and limitations in this specific application of gas spectroscopy, we model the transmission of near infrared (NIR) light in tissue when a 760 nm source and a set of 68 detectors are placed in different locations over the thorax. We segmented the main organs of the thorax from anonymized DICOM images of a neonate. This is followed by the creation of 3D computational models to solve light propagation with the diffusion equation, and the modelling of light propagation through the thorax of an infant including optical properties of lung, heart, arteries, bone, muscle, trachea, fat and skin. Finally, we calculate a map of the optimal light source – detector configurations to obtain the highest signal from oxygen gas imprint in the lungs. The use of computational tools such as NIRFAST Slicer 2.0 for investigation and further understanding of the advantages and limitations of the technology is fundamental.

Such simulations enable the recreation of different clinical scenarios and identification of the minimum requirements necessary to further improve the application and develop a bedside clinical device that can potentially be used for continuous monitoring of lung function and control of ventilator settings. The potential capability of measuring non-invasively oxygen, water vapour and carbon dioxide in the lungs, would reduce the need for intubation and extracorporeal membrane oxygenation, as well as lower the incidences of chronic lung disease.

As an emerging optical imaging modality, photoacoustic imaging provides optical absorption contrasts and ultrasonic high resolution. Artifacts appearing in photoacoustic computed tomography (PACT) always deteriorate image quality and resolution, and result in confusion of biological information. On the basis of different causing reasons, they are roughly classified as split artifacts and streak artifacts. Here we present an innovative Feature-Coupling (FC) method to weaken split artifacts with joint reconstruction of speed of sound and a new reconstruction algorithm, termed Contamination-Tracing Back-Projection (CTBP), is proposed for the mitigation of streak artifacts. The utility, effectiveness and robustness of our methods were demonstrated using numerical, phantom, and in vivo experiments.

Nuclear Ca²⁺ regulates many signaling pathways including NFAT, CREB, MEF that are essential to cell immunity, development and differentiation. In current stage, there is no specified biochemical drugs to regulate nuclear Ca²⁺ individually. The existence of nuclear Ca²⁺ store remains unknown. In this study, we show the femtosecond-laser stimulation can precisely regulate nuclear and other subcellular Ca²⁺ stores exclusively. The stimulated Ca²⁺ store can be released but other subcellular Ca²⁺ stores are not interfered by femtosecond laser. By using this method, we present the evidence of the endogenous Ca²⁺ store inside nucleus. The nuclear Ca²⁺ store volume and release mechanism are clarified. By photostimulation, nuclear Ca²⁺ store can be released and impact the calcium in endoplasmic reticulum (ER), suggesting a Ca²⁺ transmission channel between nucleus and ER. The permeability of nuclear pore complex (NPC) to Ca²⁺ at different Ca²⁺ levels is also found different. This study indicates the existence of nuclear Ca²⁺ store and the final mapping of subcellular Ca²⁺ stores. This result thus is of great significance to the cell calcium theory, Ca²⁺ signaling, Ca²⁺-related cell processes, and further other Ca²⁺-related fields.

Stage IA endometrial cancer is the only candidate for conservative management. Therefore, early diagnosis of endometrial cancer is very important. Co-registered photoacoustic (PA) and ultrasonic (US) imaging system is available to detect early endometrial cancer (EEC) based on a cylindrical diffuser. To correctly detect and diagnose EEC from FIGO stage IA and stage IB by co-registered PA and US imaging system, a convolutional neural network (CNN) classifier of EEC for co-registered PA and US images was proposed. Activation function ReLU and the dropout technique were used in the CNN classifier. The experiment results show the area under the receiver operating characteristic curve of the proposed algorithm is 0.9998 with a sensitivity of 98.75% and specificity of 98.75%. The CNN classifier could be used in the computer-aided diagnosis for early endometrial cancer of the co-registered PA and US imaging system.

Fluorescence spectroscopy has been extensively investigated for disease diagnosis. In this framework, optical tissue phantoms are widely used for validating the biomedical device system in laboratory environment outside clinical procedures. Moreover, it is fundamental to consider that there are several scattering components and chromophores inside biological tissues and the interplay between scattering effects and absorption can result in a distortion of the emitted fluorescence signal. In this work, the photophysical behaviour of a set of liquid tissue like phantoms containing different compositions was analysed: phosphate buffer saline (PBS) was used as background medium, low fat milk as a scatterer, India ink as an absorber and PpIX dissolved in dimethyl formamide (DMF) as fluorophore. We examined the collected data in terms of the impact of surfactant Tween-20 on the background medium, scattering effects and combination of scattering and absorption within a luminescent body on PpIX. The results indicated that the intrinsic emission peaks are red-shifted by the scattering particles or surfactant, whilst the scatterer and absorber can alter the emission intensity substantially. We corroborated that phantoms containing higher surfactant content (< 0.5% Tween 20) are essential to prepare a stable aqueous phantoms.

Leukemia is a worldwide malignant tumor with high morbidity and mortality. Developing screening methods for leukemia cells is of great significance for clinical diagnosis. Traditional biochemical and immunohistochemical detection methods that usually require fluorescence labeling are time-consuming and labor-intensive. Here we report a deep learning based 2D light scattering cytometric technique for high-precision, automatic and label-free identification of lymphocytic leukemia cells. A deep convolutional neural network (CNN) is used for learning the biological characteristics of 2D light scattering patterns. The Inception V3 network can identify different label-free acute lymphocytic leukemia cells with a high accuracy. The results show that the deep learning based 2D light scattering microfluidic cytometry is promising for early diagnosis of leukemia, and has the advantages of label free, high efficiency and high automation.

We demonstrate a cost-effective time-gated fluorescence imaging system based on an opto-mechanical method to achieve high signal-to-background ratios (SBRs). Time-gated capability is realized by using a 405-nm continuous wave diode laser for excitation and an optical chopper to mechanically synchronize phases of both excitation and detection beams, which circumvents the use of typically expensive pulsed light sources and image intensifier. A commercial CMOS camera is used to collect bright filed imaging, non-time-gated fluorescence imaging, and time-gated fluorescence imaging. To demonstrate time-gated imaging capability of the system, silicon quantum dot nanoparticles (SiQDNPs), with long fluorescence lifetime of about 16 μs, is used as biocompatible probes to help remove background autofluorescence usually with shorter lifetime in the order of nanoseconds. Compared with non-time-gated fluorescence imaging mode, the time-gated fluorescence imaging mode achieves over 300-fold enhancement in SBR by imaging of a phantom of SiQDNPs with FITC as background. For in vivo imaging, zebrafish embryos and GFP transgenic zebrafish larvae microinjected with SiQDNPs are imaged. Nearly all background autofluorescence signal emitted from the embryo and the larvae is suppressed in the time-gated mode, which yields great improvement in SBR. Furthermore, signals emitted from the SiQDNPs probe can be separated from the undesired fluorescence emitted from the yolk sac and the transgenic zebrafish larvae through the proposed time-resolved method. By virtue of high price-performance ratio, the proposed time-gated fluorescence imaging system has potential for its more widespread uses to benefit biomedical research and clinical applications.

Intravascular photoacoustic imaging (IVPA) can obtain specific inflammation information and lipid composition in vivo, which is a new method for the diagnosis of atherosclerotic plaques. Numerous IVPA systems have been proposed and pushed towards clinical application. But imaging speed hinders their final clinical translation, considering necessary blood flush or balloon blood blockage operations during the intravascular intervention. In this study, we developed a high-speed IVPA system based on a 1064 nm pulsed laser, with the imaging speed of 60 round/second, about twice speed of the fastest IVPA system. In this system, a 0.9 mm outer diameter catheter was used for simultaneous IVPA and IVUS imaging. A plastic tube with an outer diameter of 1.3 mm was wrapped on the outside of the imaging catheter for protection and blood flushing channels. Firstly, the capability of high-speed imaging was verified by the imaging of a manually moving metal needle. Photoacoustic and ultrasonic images of the needle were obtained. No artifacts were found during the real-time imaging of the needle, which was unavoidable in the low-speed imaging system. Then, an artery excised from abdominal aorta of a New Zealand rabbit was sealed and a certain frequency of flowing water was injected from the one end to simulate the pulsation of blood vessels with a frequency of about 4.5 Hz, which was a typical heart rate of a rabbit. The high-speed IVPA-US imaging of pulsed blood vessels was successfully performed, which proved the feasibility of the system in vivo and even further clinical application.

The back-projection method is mostly used in the circular or spherical scanning based photoacoustic tomography for its computational efficiency and robustness. However, it models the transducer as a point detector, which leads to the “finite aperture” problem. To solve this, here we for the first time propose to calculate the time delay and weighting factor in the back-projection method with a forward linear model. Compared with the conventional back-projection method, our proposed method can almost completely resolve the “finite aperture effect”, which was validated with simulation and experimental results. Results also show that by improving the tangential resolution in the off-center regions, our proposed new method can provide clearer details when imaging complicated targets. However, results also imply that it’s still important to try making all the targets effectively detected at each position when scanning the transducers.

Infrared laser had been proved their effectiveness on injury repairing, synchronize embryos and neural regulation etc. Pulsed laser with wavelengths < ~1.5 μm was used in controlling nerves in vitro, such as stimulation or block action potentials. Theoretical analysis demonstrated that whether enhancement or inhibition could be ascribed to the thermal effect induced by the pulsed laser. A membrane capacitance mediation mechanism had been proved to act as a chromophore in the mediation this thermal effect with the cell function. Here, we explored a continuous infrared laser irradiation situation, which was a case in clinic. A continuous near infrared laser with a wavelength centered at 980nm was employed to irradiate a neuron cell in vitro. And a patch clamp technique was employed to record a whole cell current. The whole cell current was formed by a compensated capacitance current, a rapid voltage-dependent inward sodium current, and a slowly voltage-dependent outward-rectifier potassium current. After a 36s irradiation, the potassium current was changed not that much, but the sodium current was decreased in its peak current. We analyzed the compensated capacitance current and found that the infrared irradiation decreased the membrane capacitance also. Analysis demonstrated that this can also be related to temperature raising gradient. Our results support that a near infrared continuous laser change neurons activities by reducing its membrane capacitance.

Cell observations and analysis are often required in biological and medical fields for cell condition evaluations and disease diagnostics. Compared to classical methods such as bright/dark field microscopy and fluorescent microscopy, quantitative interferometric microscopy as one of the quantitative phase microscopic techniques is able to provide high contrast image of label free samples thus can be potentially using in live cell imaging. While it often suffers from the low processing speed often due to the heavy computational load in phase unwrapping. In order to accelerate the imaging speed, we design a rapid cell phase imaging technique relying on the fast shearing phase unwrapping method. It can extract the sample information from a single-shot interferogram showing that it can capture live cell images. Moreover, the phase unwrapping process is significantly reduced with accelerated speed. Considering the system can provide quantitative and high-contrast live cell imaging in label free mode with high accuracy, fast speed and large field of view, it can be a potential tool for cell observations and measurements in biological and medical applications.

Cerebral blood flow (CBF) is the main basis for clinical diagnosis of cerebrovascular diseases such as cerebral infarction and cerebral hemorrhage. The local cerebral blood flow (rCBF) detection method based on optical heterodyne detection (OHD) is expected to achieve high-precision detection of rCBF. The purpose of this study is to study the polarization state distribution characteristics of polarized light in the scattering medium by Monte Carlo simulation method, and to guide the optimization of measurement position and source-detector separation when OHD method is used to detect rCBF, and improve the measurement sensitivity. The Monte Carlo simulation result shows that the proportion of photons maintaining polarization state in the weak scattering medium is greater than in the strong scattering medium, and the proportion of photons maintaining polarization state is inversely proportional to the source-detector separation. Among them, The photon ratio that maintains the polarization state is best when the scattering angle is 0 or π. This study is of great significance for optimizing the source-detector separation and improving the sensitivity of OHD method for detecting rCBF.

Determination of blood glucose characteristic absorption wavelengths is one of most important steps in the photoacoustic measurement of diabetes mellitus. In this paper, a kind of custom-built photoacoustic measurement system of glucose solutions based on OPO pulsed laser and ultrasonic detector with central frequency of 10MHz was established. The photoacoustic peak-to-peak values of glucose solutions with six different concentrations were obtained under the scanning wavelengths from 1300 nm to 2300nm. To obtain the characteristic wavelengths of glucose, the differential spectrals between the photoacoustic peak-to-peak spectrals with different concentrations and that of the pure water were firstly gotten. Then, the synergy interval partial least square (siPLS) algorithm was used to optimally choose the characteristic wavelengths of glucose. The mean method was used to pre-process the photoacoustic peak-to-peak data. The photoacoustic peak-to-peak spectrals of glucose were divided into different sub-intervals, and different components and different segments were chosen. In addition, different synergies of sub-intervals were test to get the maximum correction coefficients for the calibration samples. After computing and compare with each other, 30 sub-intervals, 7 components, 4 segments, and 3 synergies sub-intervals were chosen because the root mean square error of cross validation (RMSECV) and the prediction bias are least. Finally, combined with the differential spectral, the optimal characteristic absorption wavelengths of glucose were determined.

In this article, we have studied the feasibility of using Raman spectroscopy and multivariate statistical algorithms to distinguish human hepatoma cells from normal human liver cells with the aim to explore a label-free and non-invasive method for detecting and screening hepatoma cells. High-quality Raman spectra were obtained from 50 normal liver cells (Lo2 cell line) and 50 hepatoma cells (HepG2 cell line) in the range of 500-1750 cm-1. There are significant differences in Raman spectra between normal liver cells and hepatoma cells, which indicated special changes in the content of biomolecules including nucleic acids, proteins and lipid in different cell lines. Principal component analysis (PCA) and linear discriminate analysis (LDA) were used to classify the Raman spectra obtained from hepatoma cells and normal liver cells, and the discrimination sensitivity and specificity were 98% and 100%, respectively. In addition, PCA in conjunction with support vector machine (SVM) (with a Gaussian radial basis function) was also employed to classify the same Raman spectra dataset, and the sensitivity and specificity could be improved to 100% and 100%, respectively, indicating that the classification performance of PCA-SVM is superior to that of PCA-LDA. This exploratory study demonstrated that Raman spectroscopy technique combined with multivariate statistical algorithms as a clinical cell-based biosensor has great potential for noninvasive cancer cell detection and screening.

Accurate wavelength calibration is necessary to maximize imaging resolution and sensitivity in the spectral domain optical coherence tomography (SD-OCT) systems, which is the process of determining the wavelength distribution on a line-scan CCD. We present a novel method of calibrating the wavelength distribution of a spectrometer based on the broadband source spectral in SD-OCT system. This method uses the extreme points of the source spectrum and the corresponding CCD pixel points to establish a functional map. Therefore, additional calibration source with narrow spectral lines is not required. Third-order polynomial fitting function is obtained to fit the relationship between the CCD pixel number and the characteristic wavelength. As a comparison, this paper firstly tests the mercury-based argon lamp calibration method, analyzes its performance, and then tests the source-based calibration method. After comparing the curve parameters, we verify that the performance of the source-based spectral calibration method is as good as the mercury argon lamp calibration method. The feasibility and accuracy of the new method are verified by fitting results, sensitivity map and imaging. With the new calibration method, the sensitivity of the system roll-off of 2.163 dB / mm and high quality two-dimensional (2D) imaging of rubber tube is realized. This method is much simpler and reduces the cost because no additional calibration source is required.

Polarization-sensitive optical coherence tomography (PS-OCT) is an extension of OCT and provide the polarization information of biological tissues. Generally, the polarization-diversity detection of PS-OCT is free-space type, which is usually very complicated and reduces Signal to Noise Ratio (SNR). We built a polarization depth-encoding PS-OCT system with fiber-based polarization-diversity detection unit. The PS-OCT system was based on swept source OCT operating at 1310 nm, which has 100 kHz axial scan rates. The polarization depth-encoding was implemented by polarization-dependent spectral delay by combining of a polarization beam splitter (PBS) and two quarter-wavelength plates. The fiber-based polarization-diversity detection unit was implemented by the combination of fiber based polarization beam splitters and polarization controllers, which was used to calibrate the input light polarization of the fiberbased polarization beam splitters (FPBS). The acquired spectral signals were processed with standard Fourier domain OCT procedure including background subtraction, numerical dispersion compensation, zero padding and Fourier transforming. Jones Matrix Measurement method was adopted to process the Fourier transformed complex-valued OCT signals to compute the information of polarization properties of sample. And we measured zero-order, quarter-wave plate at 1310nm wavelength and zero-order, half-wave plate at 514nm wavelength to verify the accuracy of the system. We also obtained the image of human’s skin of fingertip. This PS-OCT system with fiber-based polarization-diversity detection unit can be obtained from standard swept source OCT easily, and can be further widely used in biomedical applications such as correlating burn depth and measuring the birefringence of the retinal nerve fiber layer.

Microfluidic cytometry has led to great progress in the field of single cell analysis. Here a light scattering microfluidic cytometer with dual-channel three-dimensional (3D) hydrodynamic focusing is developed, which potentially enables single cell or particle measurements with high-throughput. The light sheet illumination is introduced to provide a uniform excitation. Two dimensional (2D) light scattering patterns of label-free single cells or particles are imaged by a CMOS sensor via an objective lens (10x). The focusing effect of our dual-channel 3D hydrodynamic focusing unit is visualized. Simultaneous measurements of standard beads with different concentrations and sizes are performed. Our results demonstrate that the light scattering microfluidic cytometer with dual-channel 3D hydrodynamic focusing is promising for parallel, label free analysis of various cells with an enhanced throughput.

Cancer cells secrete copious amounts of secretory granules, exosomes, proteases. Recently, studies reviewed that mast cells (MCs) play crucial roles in the growth, spread and metastasis of tumor. MCs are one of the earliest cell types to infiltrate developing tumors. MCs undergo degranulation in response to various stimuli and rapidly release diverse bioactive mediators, such as histamine, tryptase, serotonin, tumor necrosis factor α (TNFα), which will tremendously affect the tumor microenvironment (TME). However, the mechanisms between the secretion of MCs degranulation and tumor remain unclear. Therefore, we developed a nanobiosensor based on fluorescence resonance energy transfer (FRET) for the determination of P815 mast cells and HeLa cells by secretagogues. With the pep-FITC as an energy donor and reduced grapheme oxide (rGO) as an energy acceptor, the two parts assemble an efficient FRET biosensor through electrostatic and stacking interaction (- interaction). Sensitized secretory cells can produce tryptase which would hydrolyze the specific cleavage site of the peptide, leading to ruin FRET system and then yield intensive fluorescence (FL) recovery of quenched FITC. Results showed that P815 cells are more sensitive and intense secretory than HeLa cells owing to more amount secretory mediators of P815 can change the microenvironment and further exacerbate the degree of degranulation in return. Our findings suggest that FRET biosensor have the ability to detect the extracellular dynamics of the cancer cells microenvironment. In addition, targeting mast cells may serve as a novel therapeutic scheme for cancer treatment and that inhibiting mast cell function may lead to tumor regression.

Vascular-targeted photodynamic therapy (V-PDT) has been demonstrated to be an effective treatment modality for nonmalignant diseases such as capillary malformations port wine stains (PWS). V-PDT treatment of PWS involves a complex interaction of light, photosensitizer (PS), oxygen and biological tissue. A three-dimensional (3D) model of PWS with a Y-bifurcation blood vessels was proposed for mathematical simulation of the spatial and temporal distribution of singlet oxygen (¹O₂), which related to the distribution of light, PS and oxygen. A graphics processing units (GPU)-based method, Monte Carlo eXtreme (MCX), was applied to calculate the light deposition in the PWS, and a set of differential equations were utilized to describe the photochemical reactions involved in V-PDT. Using the obtained light energy deposition and the distributions of the PS and oxygen, a dynamic change model of the cumulative concentration of ¹O₂ ([¹O₂]) was estimated. The data show that the smaller vessels are more likely to acquire more [¹O₂].

The visualization of embryonic development is important for the study of basic physiological development. It is also indispensable for evaluating the effects of modification and editing of genetic engineering. Compared with traditional invasive methods of monitoring embryo development, optical coherence tomography (OCT) has its great advantages, such as high resolution, real time and non-invasive. These characteristics of OCT make it possible to observe a living embryo in its whole growth development. In this paper, we use OCT to monitor the embryonic development of locusts noninvasively and reconstruct the two-dimensional and three-dimensional image of the embryo at different development stages. The phenomena of anatrepsis, revolution and katatrepsis are observed. The in-vitro observations of the prior studies with invasive methods are confirmed by the in-vivo experimental results. We hope OCT is a useful tool for the understanding of the embryonic development of insects.

Melanoma is a malignant tumor whose circulating tumor cell (CTC) count has been shown as a prognostic marker for metastasis development. Therefore detection of circulating melanoma cells plays an important role in monitoring tumor metastasis and prevention after diagnosis. In Vivo Photoacoustic Flow Cytometry (PAFC) is established here to achieve in vivo melanoma inspection, meanwhile guarantees non-invasive and real-time detection.Accurate tumor cell detection is of great significance to achieve highly specific diagnosis and avoid unnecessary medical tests.However, the amount of data detected by PAFC is large and original photoacoustic signal is mixed with various noises.The traditional triple mean square deviation method has lower accuracy and consumes a lot of time in data processing. Here, a classification approach in photoacoustic is proposed, which could discriminate signals and noises based on features extracted from photoacoustic waves compared to normal cells using Support Vector Machines algorithm. Due to similar shape and structure of cells, the photoacoustic signals usually have similar vibration mode. By analyzing the correlations and the signal features in time domain and frequency domain, we finally choose the continuity, amplitude, and photoacoustic waveform pulse width as the features to characterize the signal.More than 600,000 samples were selected as the training set (normalized in advance), and a classifier with a precision of 85% accuracy to filter out the photoacoustic signals rapidly was trained by the support vector machine method.The classifier introduced here has proved to optimize the signal acquisition and reduce signal processing time, realizing real-time detection and real-time analysis in PAFC.

The current，infrared thermal imaging technology provides a new method for the detection of various soft tissue parts in human body, but the research on soft tissue lesion of ankle joint by infrared thermography is not very extensive. With the maturity of this technology and the improvement of pattern recognition and digital image processing algorithm, the analysis of infrared thermal image has been improved. The principle of infrared thermal imaging technology is to display the infrared signal sent by human body in the form of temperature distribution, and the change of temperature will cause the pathological changes of human tissue. In this paper, by taking a large number of infrared thermal images under appropriate conditions, the infrared thermal image is preprocessed by de-noising and other operations, and the temperature information on the infrared thermal image is converted into data sequence information. Since the discrete cosine transform (DCT) has a relatively mature fast algorithm, it can effectively solve the problem of large computational complexity. Therefore, the discrete cosine transform is used to reduce the dimensionality of the infrared thermal image. Then, using the feature extraction process of Fisher linear discriminant analysis (LDA) algorithm, we seek a best projection direction to compress high-dimensional features into one-dimensional features, and then use Fisher's linear discriminant analysis algorithm to obtain the discriminant function after the projection of the training samples. The experimental results determine whether the test sample belongs to the damaged ankle soft tissue or not. Then, the soft tissue damage site of the sample is judged.

Degranulation in mast cell is usually characterized by the release of tryptase. We developed a fluorescence resonance energy transfer (FRET) probe based on graphene oxide (GO) to detect tryptase released from mast cells. The GO based FRET probe is composed of GO and a self-assembled complex of tryptase-specific recognition peptide chains labeled with isothiocyanate fluorescein. The fluorescence intensity around the mast cells increased when the mast cells were stimulated with C48/80, a kind of reagent promoting degranulation. The fluorescence distribution is inhomogenous. The fluorescence intensity was dependent on the concentration of C48/80 and the stimulation time. These results demonstrate that GO-base FRET probe could be used to study degranulation in mast cells.

Ultrasound (US) is one of the major medical imaging models and has been widely applied in clinical practice. However, the spatial resolution of US is limited to approximately half-wavelength of sound wave. To address this problem, super-resolution ultrasound (SR-US) imaging technique based on single molecule localization has been proposed, which can achieve a ten-fold resolution improvement compared with the conventional US imaging techniques. But, the temporal resolution of SR-US is low. Inspired by super-resolution optical microscopy, recently, a super-resolution optical fluctuation imaging (SOFI) method has been applied in SR-US to improve temporal resolution. However, in the previous work, SOFI is used to process B-mode US sequence (i.e., the image domain), which may affect the obtained imaging performance of SR-US. To further improve the spatial resolution of SR-US, in this work, we propose an alternative method, termed as RF-SOFI, where SOFI is used to process data in radio-frequency (RF) domain. Further, to reduce data acquisition time, here, US data are acquired by plane wave (PW) scan. To evaluate the performance of the proposed RF-SOFI method, numerical simulation experiments were performed. The results indicate that compared to the previous reported SOFI method (i.e., SOFI applied in image domain), the imaging performance of SR-US can be improved by using RF-SOFI (i.e., SOFI applied in RF domain). As a result, RF-SOFI provides the potential in fast SR-US imaging.

Objective: To investigate the feasibility of Mueller optical coherence tomography (OCT) imaging of myocardial fiber structures at different locations. METHODS: A pig heart was taken as a sample, and the Mueller OCT system was used to perform two-dimensional scanning on different positions of the pig heart test sample, and the collected image data was processed by digital image processing method to observe the basic structure of the myocardium at different positions. RESULTS: The images of the isolated pig heart after scanning by the OCT system were processed by the relevant algorithm. The images of 16 elements in the Mueller matrix of the myocardial structure at different locations were also observed. It can also be seen that there is some different of the myocardial fiber structures in different depth directions. Conclusion: Mueller Optical coherence tomography (OCT) can be successfully used to image myocardial fiber structures at different locations.

X-ray luminescence optical tomography (XLOT) is a promising in vivo noninvasive imaging technique. By using x-rays to irradiate nanophosphors (NPs) in imaged region, XLOT can achieve better imaging depth and higher imaging sensitivity than the widely used optical molecular tomographic imaging techniques, e.g., bioluminescence tomography (BLT) or fluorescence molecular tomography (FMT). However, compared with the anatomical imaging techniques, e.g., x-ray computed tomography (XCT), XLOT has the disadvantage of low spatial resolution limited to millimeters. To overcome the limitation, recently, many efforts have been dedicated to optimize the data acquisition schemes and improve reconstruction methods. Nevertheless, challenges remain in XLOT due to the light scattering in biological tissues and the severely ill-condition and ill-posed of the inverse problem of XLOT. To improve the spatial resolution of XLOT, inspired by super-resolution localization optical microscopy, in this work, we propose a novel imaging method, termed as SR-XLOT, which is achieved by locating the position of NPs in each frame by using the single emitter localization methods (e.g., Gaussian fitting method). After reconstructing the positions of NPs in each frame, a super-resolution XLOT image can be generated by superimposing the identified positions of NPs from all frames into one image. To evaluate the performance of the proposed SR-XLOT method, a series of numerical simulation experiments were performed. The experimental results indicate that when using SR-XLOT method, the spatial resolution of XLOT can be significantly improved, compared with the conventional reconstruction methods. As a result, the method makes it possible to implement a super-resolution XLOT imaging, which is attractive for medical diagnostic and drug research.

Macrophages are at the center of the invasion and play a protumoral role in the tumor microenvironment. They can facilitate angiogenesis, extracellular matrix remodeling, invasion and migration of cancer cells, while inhibit the antitumoral immune surveillance. Tumor-associated macrophages are a major component of malignant tumors, which can stimulate the progress of tumors. In many human cancers, the presence of macrophages in tumor microenvironment has been correlated with unfavorable prognosis. Therefore, visual diagnosis of macrophages in tumor microenvironment is great significance for us to comprehend the occurrence and progress of tumor. Multiphoton microscopy (MPM) with subcellular resolution based on second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) is very suitable for real-time detecting morphological and structural changes in biological tissues without tissue staining and exogenous probe molecule. In this study, we describe the use of label-free MPM for analyzing the intratumoral distribution and morphological changes of macrophages in breast tumor microenvironment. Our results indicated that MPM can accurately identify macrophages in breast tumor tissues. MPM images were well consistent hematoxylin and eosin (H&E) stained images. This work would provide the basis for further quantifying these changes using MPM. With the development of miniaturized imaging devices, MPM may be a promising imaging technique for clinicians to study various structural features in tumor microenvironment.

Pleomorphic invasive lobular carcinoma (pILC) is a distinct morphological variant of invasive lobular carcinoma (ILC), which is more aggressive than classic invasive lobular carcinoma (cILC) with worse overall prognosis. It is critical to distinguish between pILC and cILC for management and treatment of patients. Multiphoton microscopy (MPM),based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG), produces subcellular resolution images to show detailed information on structure and cell morphology of tissue sections without staining. In this work, MPM was introduced for label-free identification of normal breast lobules, pILC and cILC, which is consistent with haematoxylin and eosin (H&E) staining. Furthermore, analysis of nuclear area is used to quantitatively reflect their cytological characteristic. These results demonstrate that, MPM has the ability to distinguish between normal breast lobules, cILC, and pILC by histopathological features, which can provide additional indicators to determine adequate treatment strategies of patients with pILC for pathologists and surgeons. In the future, MPM may be used as a diagnostic tool of lobular cancer into routine clinical use.

Perineural invasion (PNI) is the process of neoplastic invasion of nerves. The nerve sheath includes three layers, that is, the epineurium, perineurium and endoneurium from the outside to the inside. Any one of them is invaded by malignant tumor cells, or more than 33% of the circumference of the nerve should be surrounded by tumor cells, then it can be defined as perineural invasion (PNI). Perineural invasion is another way of tumor cell metastasis, which not only indicates the poor prognosis of patients but also indicates the decline of survival rate. In this study, multiphoton microscopy (MPM) which is based on the intrinsic nonlinear optical signals—two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) was applied to identify the perineural invasion in breast cancer patients, including the recognition of normal nerves and tumor cells infiltrating into the nerve. Our aim is to determine the potential feasibility of using this microscopy to identify tumor invasion around the nerves. The results mean that it is feasible to detect perineural invasion with multiphoton microscopy, and to provide a new auxiliary tool for pathologists to quickly and effectively diagnose perineural invasion.

On the design methods and traditional micro system structures in multiple configurations, there are some certain limitations. In order to resolve the problems of the conventional multiple structures present in the system, new sensors and components are applied in the development of the design method and system configuration. Micro lens, as a kind of typical components, are developing the methodology in research advanced multiple configuration systems. The effect of system evaluated criterion that Modulation Transfer Function (Modulation Transfer Function, the MTF), Energy concentration (Radial Energy Analysis, REA), diffusion (Spot Diagram, RMS) can support our issue qualitatively. Results showed that can not only change systems weight, size and structural stability, but also increase freedom in these kinds design. While improving the implementation of existing multiple path configuration from traditional complex.

Carotid arteries are important channels delivering blood and oxygen to brain. Atherosclerosis plaque in carotid arteries hinders blood delivery, and plaque rupture causes stroke, leading to high morbidity and motility. Extensive preclinical and clinical studies showed that atherosclerosis inflammation activities are highly related to plaque vulnerability. Thus, visualizing the inflammation of atherosclerosis plaques is important in atherosclerosis vulnerability assessment. In this study, photoacoustic imaging modality was applied for carotid atherosclerosis inflammation identification of mouse in vivo. Deficient apolipoprotein E (ApoE-/-) mice with high-fat diet and normal diet for 16 weeks were employed as atherosclerosis models and control models, respectively. Photoacoustic molecular probes with optical absorption at nearinfrared wavelength and specifically target cluster of differentiation 36 (CD36) were employed to mark inflammation cells in carotid atherosclerosis plaques of mouse in vivo. Noninvasive imaging of atherosclerosis inflammation cells marked by molecular probes was performed by point-to-point scanning with a custom-built acoustic-resolution photoacoustic imaging system. Considering low scattering of near-infrared light in tissues and mature commercialization of laser, excitation wavelength in this research is chosen at 1064 nm. Carotid arteries with and without atherosclerosis plaques have been noninvasively imaged and distinguished. Furthermore, carotid atherosclerosis with different inflammation severity has been analyzed by photoacoustic imaging and immunohistochemistry staining. Photoacoustic signal from atherosclerosis arteries showed high relativity with inflammation severity defined by immunohistochemistry staining, evidencing the reliability of the novel imaging technology in atherosclerosis inflammation identification. This study paves the way for photoacoustic imaging technology to atherosclerosis inflammation identification, severity quantification and even further atherosclerosis therapy.

Cryptococcus neoformans is an encapsulated fungus that widely exists in the environment through the world. It can enter the human body through the respiratory tract, causing inflammation of the lungs and even causing serious infectious diseases in patients with impaired immune function. Those serious infectious diseases can be avoided if the cryptococcal pneumonia can be early detected and accurately assessed. However, due to less clinical symptoms, cryptococcal pneumonia is easily misdiagnosed as lung cancer, tuberculosis, etc., and the rate of misdiagnosis is high. Therefore, a rapid, accurate and non-invasive method is urgently needed to make early diagnosis and precise assessment of cryptococcal pneumonia, in which timely and appropriate treatment can be implemented and the cure rate is expected to be significantly improved. In this study, surface enhanced Raman spectroscopy (SERS) was served as the diagnostic tool to identify cryptococcal pneumonia, in which the blood serum SERS spectra are collected from cryptococcal pneumonia mice and uninfected mice. The multivariate curve resolution alternating least squares (MCR-ALS) and support vector machine (SVM) are employed to quantify the biochemical composition changes in serum microenvironments. The excellent results have demonstrated that the serum SERS has significant potential in early diagnosis and accurate assessment of cryptococcal pneumonia.

Fluorescence lifetime imaging (FLIM) can reveal information about the spatial distribution of a fluorescent molecule together with information about its microenvironment, which makes FLIM find wide applications in biomedical research. In this paper, we implemented time-correlated single-photon counting-based fluorescence lifetime imaging microscopy (TCSPC-based FLIM) in skin cancer diagnosis, including malignant melanoma (MM), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). The fluorescence lifetime images and two-dimensional vector analysis of normal and several cancerous skin tissue sections stained with hematoxylin-eosin (H&E) were mapped and the results showed that cancerous skin tissue has a relatively shorter fluorescence lifetime compared with normal skin tissue. Moreover, the fluorescence lifetime of skin cancer tissue sections with different clinical stages was measured, and the quantitative relationship between fluorescence lifetime and pathological stage of skin cancer was explored.

Singlet oxygen (¹O₂) is widely considered as the major cytotoxic species generated during Type-II photochemical reaction of photodynamic therapy (PDT), and its production is crucial for the treatment outcome of PDT. However, it is still a challenging task for direct detection of ¹O₂ by using an optical system as its extremely weak luminescence at 1270 nm. In previous study, a high-sensitivity optical fiber detection system has been developed to measure the time-resolved ¹O₂ luminescence spectra. In this study, an optical phantom of skin tissue has been built to simulate the skin optical properties for research in photodynamic therapy (PDT). The phantom consists of an absorber (ink) and a scatterer (Intralipid) and phosphate buffer saline (PBS). Rose Bengal (RB) was utilized as the model photosensitizer to generate ¹O₂. The time-resolved ¹O₂ luminescence spectroscopy were measured by using a ¹O₂ luminescence detection system with a fiber prober in tissue phantom. Furthermore, the effect of absorption coefficient (μ_a) and scattering coefficient (μ_s) on the photosensitizer triple state lifetime (τ_T) and ¹O₂ luminescence lifetime (τ_D) was investigated as well. The results indicated that the integrated intensity of ¹O₂ luminescence decrease with the increase of μ_a and μ_s. μ_a has no significant effect on τ_T and τ_D. τ_T increase with the increase of μ_s, and it finally stabilized around 1.6 μs. Meanwhile, τ_D decrease firstly and then increase slowly, and it finally stabilized around 14 μs. This result indicates that this system for ¹O₂ luminescence have a potential for clinical applications in PDT dosimetry.

Cardiovascular disease, especially coronary heart disease (CHD) caused by coronary atherosclerosis, has been a leading cause of death world-wide. Traditional methods of diagnosing CHD, including coronary CT angiography and histopathological examination, are limited either by the low image resolution or time-consuming sample preparation. Spectrum- and time-resolved multiphoton microscopy has the potential to circumvent this problem because it can not only interrogate the three-dimensional structure of coronary arterial intima but also reveal its biochemical components at subcellular resolution. However, its clinical utility hasn’t been thoroughly assessed. Here, we adopted a spectrum- and timeresolved multiphoton microscope to characterize unstained human coronary atherosclerotic plaque ex vivo. According to the fluorescence spectra, the collagen fibers and elastic fibers in the coronary arterial intima can be separated clearly. We also analyzed the changes in the relative content of collagen fibers and elastic fibers by calculating the ratio of these two kinds of fibers in normal and diseased coronary arterial wall and found that the coronary atherosclerotic plaque regions has a higher ratio compared to that of normal tissue. Finally, we assessed the biochemical variations in coronary atherosclerotic tissues by measuring the fluorescence lifetime and found a lower mean fluorescence lifetime in coronary atherosclerotic plaque. This study indicates that the spectrum- and time-resolved multiphoton microscopy has the potential to distinguish atherosclerotic plaque on the coronary arterial wall from normal tissues.

Renal artery occlusion is an unavoidable process during operations such as nephrectomy, carcinoma resection, kidney transplantation and so on. For minimizing the kidney injury, the optimal renal ischemia time was experimentally investigated. Optical coherence tomography (OCT) is a high resolution imaging modality can non-invasively image biotissue in vivo and in real time. In order to study the relationship between tubular injury and the renal ischemia time, OCT images of Wistar rat kidneys endured various ischemia time were obtained throughout the whole ischemia-reperfusion procedure. The tubular density and the average diameter of uriniferous tubules were considered as biomarker of kidney activity, and the quantitative results well described the degree of kidney injury.

The number of neuronal cells is fundamentally important for brain functions. However, it can be difficult to obtain the accurate number of neuronal cells in large-scale brain imaging, which is nearly inevitable with traditional image segmentation techniques due to the low contrast and noisy background. Here, we introduce a Docker-based deep convolutional neural network (DDeep3M) for better counting neurons in the stimulated Raman scattering (SRS) microscopy images. To reconcile the memory limit of computational resource, a high-resolution 2D SRS image of whole coronal slice of mouse brain is divided into multiple patch images. Each patch image is then fed into the DDeep3M and predicted as a probability map. A higher contrast image targeting neurons (i.e. the predicted image) can be acquired by stitching the patches of probability map together. With this routine segmentation method applied in both raw SRS image and the predicted image, the DDeep3M achieves the accuracy of over 0.96 for cell counting which is much better than the result of traditional segmentation methods. Compared with the U-Net, which is one of the most popular deep learning networks for medical image segmentation, DDeep3M demonstrates a better result when handling such large-scale image. Thus, DDeep3M can be really helpful for large-scale cell counting in brain research.

Cellular mechanical properties are an important indicator for assessing and analyzing the functions of cells. However, the structure and compositions of the cell are complex. In order to analyze the effects of different components on the mechanical properties of cells, a multi-structured 3D model of cancer cells considering the cytoskeleton, cytoplasm, nucleus and cell membrane was established by finite element method. And the tensegrity structure-finding algorithm was used to analyze the cytoskeletal distribution and the pre-stress of each component. First, the model was verified by comparing numerical results with force-indentation curve obtained by atomic force microscopy in Ho-8910 cells. Then, the elasticity modulus of cell were obtained via applying a load to the established model.Computational simulation showed that cytoskeleton are the major component targeted in resisting compression.In addition, this model can provide useful guidance for the measurement and analysis of single cell through atomic force microscopy.

Osteoporosis is a bone disease associated with aging. As the population ages, osteoporosis has become a significant public health problem that threaten life quality of most countries in the world. Adequate vitamin D is able to improve intestinal calcium absorption, promote bone mineralization, maintain muscle strength, enhance balancing ability, and reduce fall risks, whichplays a vital role in bone metabolism. Moreover, vitamin D is mainly produced by ultraviolet (UV) light. The serum levels of 25(OH)D3 is the tools for estimating of the osteoporosis.It is known that vitamin D deficiency is ubiquitous in the elderly population, hence, we adopted UV light-emitting diode (UV-LED) instruments to generate narrow-range wavelengths of UV and determined its capability for producing vitamin D. The osteoporosis SD rats are our research subjects. The study was to investigate the effects of UV-LEDs of different power densities on vitamin D production. There are 4 groups：0.1, 0.2, 0.4, 0.8mW/cm2 and the rats (n = 6 per group) were irradiated with different power densities twice a week for a total of 8 weeks. The results showed that serum 25(OH)D3 levels rapidly increased in all irradiated groups compared with those in the control group (P < 0.001 in all groups), and 25(OH)D3 level of the rats in groups of both 0.4 and 0.8 m W/cm2 were able to return to the initial level at the fourth week after irradiation, besides, the group of 0.4 mW/ W/cm2 can achieve and maintain the highest25(OH)D3 level and so as the group of 0.8 m W/cm2 as the continuing irradiation. We demonstrate that the proper irradiation density of UV-LED irradiation can increase the production of vitamin D in rats and does not adversely affect the skin of rats.

In laser speckle imaging methods, speckle correlation coefficient analysis (SCCA) shows great potential in blood flow monitoring because of its high sensitivity to slow flows than laser speckle contrast imaging (LSCI). But the published SCCA usually depends on short exposure times and high frame rates to preserve the autocorrelation. Differently, in this paper we use SCCA at normal exposure time (20 ms) to evaluate the performance of skin optical clearing (SOC) and demonstrate that SCCA with long exposure time also significantly improves the ability to image large range of flow speeds over LSCI.

Here, a doxorubicin (Dox)-Cu complex is prepared and used as thiols-cleavable Dox prodrug in FLIM imaging studies. The Dox-Cu complex has no fluorescence and its absorption spectrum shows a significant red shift as compared to the raw Dox. When the complex is mixed with biothiol compound, the fluorescence of Dox is restored. In this paper, both Dox and Dox-Cu complexes are used in the fluorescence lifetime analysis, cell incubation and FLIM imaging studies. The way of intracellular transport and the changes in fluorescence lifetime of two compounds are basically the same. This indicates that the Dox-Cu complex has been decomposed into free Dox molecules and Cu-biothiol complex inside the cell. This research provides a valuable example for the study of Dox prodrug by FLIM technique, promoting the application of FLIM technique in drug research.

We present a sparse-sampled camera for compressed sensing spectral domain optical coherence tomography (CS SD-OCT), which is mainly composed of a novel mask with specially designed coating and a commercially available CCD camera. Compared with conventional SD-OCT system, the CS SD-OCT system equipped with the sparse-sampled camera has better fall-off and SNR performance.

Super-resolution localization microscopy (SRLM) breaks the diffraction limit, making possible the observation of sub-cellular structures. Challenges remain in SRLM due to a long data acquisition time. To overcome the limitation, the methods based on compressed sensing (CS) have been proposed. However, at the current stage, the widely used sparsity-based localization methods, e.g., interior point method (IPM), is computationally intensive. To address the problem, in this paper, we introduce an alternative CS reconstruction method to super-resolution imaging model, which is achieved by using gOMP (generalized Orthogonal Matching Pursuit). A series of numerical simulations with varying emitter densities and signal-to-noise rations (SNRs) are performed to evaluate the performance of gOMP method. The results show that whatever gOMP or IPM is used in SRLM, the obtained localization accuracy is similar. But, the data-processing time of gOMP can be significantly reduced (< 100 times) than the previous reported IPM method. As a result, gOMP provides the potential for reducing the computational cost while maintaining a desired spatial resolution, which is beneficial for SRLM imaging.