This PDF file contains the front matter associated with SPIE Proceedings Volume 11651, including the Title Page, Copyright information, and Table of Contents.

Recently, various nanomaterials have been used to develop nanotechnology‐based rapid diagnostic tests. Due to their unique optical properties, gold nanoparticles (AuNPs) have been employed to design and develop modern biosensors for the rapid and real-time detection of various diseases or pathogen‐specific biomolecules/markers, such as DNA, RNA, proteins, and whole cells. Optical biosensors offer great advantages over conventional analytical techniques. Specifically, they can provide multiple capabilities such as user-friendly operation, real-time analysis, rapid response, high sensitivity and specificity, portability, label-free detection and cost-effectiveness. As a result, this diagnostic approach possesses suitable features to develop point‐of‐care (POC) diagnostics and monitoring technologies. This study implemented the use of surface plasmon resonance (SPR) biosensing to monitor biomolecular interaction between biorecognition element covalently immobilized on a gold-coated glass substrate and an analyte. A custom-built Kretschmann configuration SPR optical biosensing setup was used to measure angle shift to monitor the biomolecular interaction events on the biosensing layer. To amplify the differences in SPR biosensing due to biomolecular binding events, AuNPs were used and successfully conjugated to the anti-TB antibodies and confirmed using ultraviolet–visible (UV-vis) spectroscopy. Mycolic acids were successfully immobilized on gold-coated substrates and were able to bind to the anti-TB antibodies that were introduced on the substrates, therefore enabling the detection of the captured anti-TB antibodies. As a result, mycolic acids have been realized to be efficient biomarkers to specifically react with anti-TB antibodies and produce a detectable signal for the purpose of TB diagnosis.

Optical spectroscopy offers a potential non-invasive, label free and rapid method to assist clinicians to diagnose diseases for which biomarkers are known. Neonatal respiratory distress syndrome (nRDS) diagnosis in preterm infants is known to be correlated with the lecithin/sphingomyelin ratio (LS ratio) in gastric aspirates, with a ratio less than 2.2 indicating that surfactant replacement therapy is needed. Currently no widespread method exists that can give clinically relevant answers in less than 2 hours from the point of sample collection as it is difficult to identify those who could benefit from prompt surfactant treatment. Various LS ratios were generated using pure dipalmitoylphosphatidylcholine (DPPC) and sphingomyelin (SM) dissolved in dichloromethane and infrared spectra generated using Attenuated Total Reflection (ATR) assisted Fourier Transform InfraRed spectrometry (FTIR). Subsequent analysis obtained the LS ratio using the spectra alone. Further, we demonstrate the application of principal component regression (PCR) and partial least squares (PLS) fits to measured spectra to assist in the determination of the LS ratio using a model trained with multiple runs of the different batches of the same concentration.

The infectious disease COVID-19 emerged in a province on the Chinese mainland and ended up spreading to other continents, in a pandemic effect, including Brazil. In this work we present a investigation concerning saliva samples of 200 patients diagnosed with COVID-19 attended in the Clinics Hospital of University of Sao Paulo, Brazil. Fourier-Transform Infrared Absorption (FTIR) and Raman spectroscopy on the saliva samples. The main spectral variations and details concerning the quantitative analyses of the spectral data and its biochemical correlations will be presented and discussed.

Lateral flow immunoassays (LFAs) are widely used platforms for point-of-care detection of target analytes; however, these rapid tests are not very sensitive and offer only binary results. In this study, highly sensitive thermo-photonic LFA readers were developed for the sensitive detection and quantification of tetrahydrocannabinol (THC) in oral fluids and the antibodies (IgM and IgG) developed against SARS-CoV-2 virus in human blood/plasma. Our results suggest developed readers not only improved the detection limit by more than an order of magnitude, but also enables reliable quantification of target analytes.

Colorimetric detection using microfluidic paper-based analytical devices (µPADs) and smartphones enable lowcost mobile chemical analysis solutions. However, variable illumination conditions and phone characteristics (i.e. camera hardware and software capabilities) limit the accurate interpretation and reproducibility of quantitative results. In this paper, we describe a method to automatically compensate an image captured by a smartphone camera under variable illumination conditions. By incorporating a two-step algorithm, we approximate the mobile camera picture color distribution to resemble a laboratory-grade measurement under reference illumination conditions. For every test image, the algorithm first applies a color mapping step that performs histogram matching of a set of color reference spots printed on the device to a laboratory reference measurement. After this initial correction step, a transformation matrix is computed via a least-square fit to minimize the differences between the device and the laboratory references. This matrix is then applied to the RGB channel values obtained from a µPAD to correct for illumination variations. The methodology was tested by correcting a test dataset captured using a smartphone to approximate to a calibration dataset acquired using a lab-grade camera. After correction, the relative error between the datasets fell to 10-20%, leading to an increase in classification accuracy between 12-33%. This approach enables colorimetric chemical analysis with smartphones outside the lab, removing the need to control external lighting conditions.

Gestational diabetes mellitus (GDM) affects between 2-14% of pregnant women in the United States every year. The glycated version of serum albumin, the most abundant protein in blood, owing to its half-life of ~21 days can effectively be used as an intermediate biomarker for monitoring GDM. Normal level of glycation of albumin is between 10-16% whereas in patients with diabetes it is much higher, between 16-40%. Thus, a point-of-care (POC) monitoring system to detect glycated albumin (GA) as a % of total serum albumin has been developed here. Specifically, a paper fluidic test to measure glycated and unglycated serum albumin has been developed that uses an aptamer-based assay with gold nanoparticles to produce colorimetric measurements. The assays were constructed using a sandwich aptamer format and colorimetric intensity was measured by scanning the capture layer of the paper fluidic device using a standard flatbed scanner followed by RGB analysis. The assays are able to determine the concentration of glycated and serum albumin in their physiologically relevant ranges of 50-300μM and 500-750μM. The paper fluidic system enabled the placement of gold nanoparticle probes in the device thereby automating the system and minimizing user intervention. Using aptamers as recognition elements and colorimetric transduction with gold nanoparticles, the system was shown, to possess the required sensitivity, selectivity, and dynamic range for physiologic monitoring.

Precise monitoring of specific biomarkers in biological fluids with accurate biodiagnostic sensors is critical for early diagnosis of diseases and subsequent treatment planning. In this work, we demonstrated an innovative biodiagnostic sensor, PRADA: portable reusable accurate diagnostics with nanostar antennas, for multiplexed biomarker detection in small volumes enabled in a microfluidic platform. Here, PRADA simultaneously detected two biomarkers of myocardial infarction, cardiac troponin I, which is well accepted for cardiac disorders, and neuropeptide Y, which controls cardiac sympathetic drive. We envision low-cost PRADA will have tremendous translational impact and amenable to resource-limited settings for accurate treatment planning in patients.

Current diagnosis of pediatric eosinophilic esophagitis relies heavily on anesthesia and random biopsies during initial diagnosis and treatment monitoring. Investigation of patient’s saliva biochemical and biomolecular composition, and the potential biomarkers within, via surface enhanced Raman spectroscopy can provide key markers for distinguishing the EoE disease from non-EoE, including acid reflux disease. This optical modality coupled with paper-fluidic platform has the potential to provide a rapid diagnostic tool for non-invasive detection of EoE.

Human immunodeficiency virus (HIV) weakens a person’s immune system by destroying cells which are important to fighting the disease and infection. HIV is a major global public health issue with an estimated 38 million people living with HIV at the end of 2019. There is no cure for HIV. However, increased access to effective prevention, diagnosis and treatment has enabled people living with HIV to lead healthy lives. Rapid diagnosis forms an important part of the WHO’s strategy for ensuring those who are HIV positive have immediate access to care. Perhaps more critical however is that effective diagnostic testing informs individuals of their HIV status, reducing the risk of transmission. HIV prevalence within the US is disproportionately high amongst Black/African American and Hispanic/Latino American populations who often have limited access to advanced medical clinics. In this paper, we present a lateral flow device designed to detect miR-150-5p; an emerging biomarker of HIV. Based on our preliminary results shown here, we are capable of detecting the miRNA sequence at sub-ng uL^-1 using colorimetric analysis, without prior amplification of the target material. We have also detailed our initial results obtained from surface-enhanced Raman scattering measurements made at the device capture line, whilst the standard deviations are large, the technique shows lots of promise for lowering the detection limit in the future.

Blood pressure (BP) is one of the most important indicators of physical and mental health. BP monitoring helps with controlling ailments such as heart disease and may help with stress assessment. Currently, BP measuring technologies use inflatable cuffs, which are inconvenient to use, being undesirable for continuous BP monitoring. Here we use photoplethysmographic (PPG) pulse wave contour to estimate BP using pulse decomposition analysis. As blood is ejected from the heart, the pulse moves both distally to the arms and down the aorta, partially reflecting at the renal and iliac arteries branches. These reflections move up the aorta and distally to the extremities, such that finger PPG signals are composed of three waves: the primary pulse and two delayed reflected waves. This model has been used by others, fitting Gaussian waves to the PPG signal. However, fitting stability and correlation with BP could be improved. In our proposed method, each PPG pulse is the sum of three hyperbolic secants (sech) waves, whose features are determined by PPG curve fitting. An increase in blood pressure makes pulse wave velocity increase, decreasing the intervals between waves. To verify the method, we have collected PPG signals and continuously measured BP from a volunteer. Multiple regression analysis between the PPG extracted features and continuous BP readings shows a very high correlation and high statistical significance. The decomposition in sech showed both higher stability and better correlation with BP than the Gaussian wave decompositions reported in the literature.

In this paper, we propose a measurement method using an RGB camera to non-invasively capture the pulse wave in rats. Most attempts to capture biological information from an animal, such as pulse wave, requires contact that is invasive and influence the animal. In this study, we attempt to apply remote photoplethysmography (rPPG) to rats. Our rPPG method uses an RGB camera to detect the change of hemoglobin amount in the skin and derives pulse waves. First, we removed body hair and captured an image of the skin in the hair removed area. The rat's pulse rate is approximately 300 beats per minute, which is much faster than the pulse rate of a human; then we captured video of the skin at a frame rate of 250 frames per second (fps). As a result, pulse waves were obtained from the image signals of the skin with signal processing. Next, we focused on the sole of rats whose skin is directly visible, and we tried to detect the pulse wave from the sole. We made a novel rat observation apparatus, where the cage floor is made of a transparent acrylic plate, and images of rate roles were captured through the acrylic plate by setting the RGB camera under the cage. As a result, we were able to measure pulse waves in rats by a non-contact, non-invasive, unrestrained, and no anesthesia approach. We also demonstrated the effectiveness of the proposed method we could successfully detecting arrhythmia caused by fear (fox smell).

We present a camera-based approach for remote acquisition of vital signs. Remote photoplethysmography (PPG) and 3-D depth analysis are used to detect heart rate and respiratory rate robustly and independently. By comparing the intensity/PPG and depth channels, a correlation can be observed between face PPG signal and physiological body movement. Pulsatile activity results in periodic head motion, which is correlated with fluctuations in face PPG intensity. Respiration data can be obtained from face PPG intensity as well as face and chest motion. This system is illumination and motion tolerant and has the benefit of redundancy with two independent image channels.

We propose a new image sensor based on multi-aperture optics and multi-tap charge modulators for simultaneous multi-band spatial frequency domain imaging (SFDI) and blood flow mapping by multi-exposure laser speckle contrast imaging (ME-LSCI). Wavelength-multiplexed imaging implemented by attaching different bandpass filters to each lens enables to perform multi-band SFDI and ME-LSCI simultaneously. A prototype camera for 4-band SFDI (568, 668, 734, 846nm) and single-band LSCI (780nm) was built based on a commercial CMOS camera with enhanced NIR sensitivity to demonstrate the concept and tested using a rat model of graded burns.

Nailfold capillaroscopy is a technique for imaging the capillary bed in the finger nailfold, that is used in the diagnosis of scleroderma. Knowledge of the capillary oxygenation profile would be a substantial advantage in disease evaluation. A compact, low-cost LED-illuminated capillaroscopy system was conceived based on inexpensive parts and optical hardware. The system uses a compact Raspberry Pi to control a custom-designed LED ring light, with white-light LEDs interleaved with three narrowband LEDs, and a Raspberry Pi camera. Capillary visualisation and distinction of haemoglobin contrast is demonstrated, suggesting future promise for application of multispectral nailfold capillaroscopy in low-resource settings.

Although diffuse reflectance measurement has convenience in obtaining spectra from skin, it has extremely low light efficiency compared with other configurations as the skin has forward scattering characteristics. To increase the amount of photon illumination and enhance SNR, we suggest a honeycombed optical skin interface with multi-fibers based probe for the diffuse reflectance measurement of skin. Experimental results with human and swine skin measurements show the spectral noise of the skin spectra in the range of 13~16 µAU and the effective water path length in the range of 1.8~2.2 mm. With this honeycombed skin interface, 5~6 times enhanced spectral SNR can be obtained.

Background: A customized sensor, based on near-infrared spectroscopy (NIRS), was developed to non-invasively monitor spinal cord hemodynamics after acute spinal cord injury (SCI). However, the effect of direct contact and emission of the NIRS signals on the spinal cord tissue structure was not clear. This information is essential because even minimal heating or contact pressure from the NIRS sensor placed over the injured spinal cord may lead to further damage to the spinal cord tissue. Here, we evaluate the safety of the custom-made NIRS sensor as it is essential prior to its clinical translation. Methods: A custom-made multi-wavelength miniaturized NIRS sensor was placed extradurally on the spinal cord of six Yucatan mini-pigs who received a T10 SCI. After seven days of continuous data collection at 100 Hz, the sensor was removed and the spinal cord tissue was examined. Histological assessment of the spinal cord revealed evidence of cellular damage at the NIRS sensor placement in two animals. An in-vitro experiment was performed to evaluate the possibility of heat damage caused by the NIRS sensor. Using a digital thermometer with two probes, one directly touching the NIRS emitter and the other one at a control site one centimeter away from the emitter. The amount of heat generation of the NIRS emitter after seven days of continuous operation at 100 Hz was measured and compared with the control site. Results: In-vitro heat tests showed no heat generation by the NIRS sensor. The temperature measured from the emitter site of the NIRS sensor and control temperature probe was identical during the seven days. Conclusion: The custom-made NIRS sensor does not generate heat at the emitter site and physical damage observed with regards to histology is due to the compression applied from the sensor. By refining the sensor to be smaller and more flexible with an even surface, we will improve the safety of the NIRS sensor before translating this technology to human patients. The new sensor will be further examined.

We propose a new non-invasive approach to transabdominally measure fetal oxygen saturation based on time-domain interferometric near-infrared spectroscopy. We use the frequency-modulated continuous-wave technique to measure the time resolved reflectance of near-infrared light shining on the maternal abdomen. By modeling the maternal abdomen as two-layered media (i.e. maternal and fetal tissue) through diffusion equations, the optical properties of both the maternal and fetal tissue can be deduced. Using two optical wavelengths, oxygen saturation can be measured for both the mother and fetus. This technique could provide an important assessment of intrapartum fetal health during labor in the delivery room.

Accurate and reliable non-invasive monitoring of early systemic disease—such as ongoing hemorrhage, sepsis, and acute respiratory disease like COVID-19—is one of the largest unmet needs in biomedicine. An early alert to progression with high sensitivity and an acceptable false-positive rate would allow medical staff to risk-stratify patients, saving resources, lives, and in the context of pandemic disease, minimize staff exposure. Noninvasive technologies have thus far failed to produce a reliable early detection system, reflecting the limitation of uniplex approaches to describe complex pathophysiology. Our team, in collaboration with an STTR start-up, have developed an optico-impedance system combining near-infrared spectroscopy and electrical impedance tomography measured at three locations (thorax, abdomen, limb) together with machine learning methods to provide exceptional diagnostic performance in systemic disease. The optical portion consists of 6 pairs of time-multiplexed red and IR LEDs embedded in custom 3D-printed probes, which are each connected to the leg of a trifurcated fiber bundle, allowing measurement of three-location, two-distance broadband 550-950 nm spectra using a single commercial spectrometer. Data is demultiplexed and analyzed using derivative spectroscopy to quantify oxy/deoxyhemoglobin. Additional diagnostic signal was obtained from: impedance tomography and spectroscopy, ECG and plethysmography. In one of the largest porcine hemorrhage studies to date (n = 60), we demonstrate an 85% accuracy to detect a 2-3% blood volume loss. Preliminary results from 11 healthy human subjects undergoing lower body negative pressure (LBNP) challenge show a 95% accuracy in detecting 15-mmHg changes in pressure—an excellent surrogate for occult hemorrhage. Our system fills a critical need, including in the current pandemic, where clinicians struggle to predict which patients will deteriorate.

Neutropenia is a condition where the hematopoietic system has a suppressed production of neutrophils, a type of white blood cell that is critical for fighting infections. This condition affects half to nearly eighty percent of cancer patients receiving chemotherapy, depending on the type of malignancy. Neutropenia can also be congenital or acquired from autoimmune disorders or nutritional deficits, in addition to cancer. Neutropenia, formally defined as <1500 neutrophils/µL in peripheral blood, puts patients at an increased risk of life-threatening infections. Thus, it is critical to constantly monitor neutrophil counts for many patients. Hematological analysis of neutropenia is performed by highly trained personnel at certified laboratories via complete blood count (CBC) and visual inspection which require complex, time-consuming, and expensive sample preparation and instrumentation. Thus, an easy-to-use, label- and reagent-free, and inexpensive hematology analysis device is highly desirable to circumvent these limitations and allow point-of-care disease monitoring and diagnosis. In this work, we demonstrate the application of deep-ultraviolet (UV) microscopy as label-free method for rapid and facile neutropenia detection. Our approach provides key hematological information and enables quantitative assessment of live blood cells based on their molecular and structural signatures in minutes. Here we show the ability of deep-UV microscopy to clearly identify patients with moderate and severe neutropenia based on an automated blood smear analysis. We also demonstrate a pseudo-colorization scheme which recapitulates the gold-standard Giemsa stains and allows visual inspection and enumeration of various blood cells types. This work has significant implications for developing a simple and low-cost point-of-care device that can ultimately improve the care and quality of life of many neutropenia and cancer patients.

In this work we present a new microscope based on Nano-illumination microscopy (NIM), i.e., an innovative technique based on a 2D array of nano-Light-Emitting Diodes (LEDs) used to illuminate a sample. The key point of this method is that the pitch of the LED array fixes the spatial resolution. So, potentially, with LED pitches lower than the diffraction limit, super resolution could be achieved. While nanometer sized LEDs are not available yet, we present a prototype based on optical downscaling of a single 5µm lateral size LED. Extended Field-of-View (FOV) is obtained by mechanical movement with nanopositioners. Aspects of NIM microscopy such as its size, its flexibility in the sensing hardware or its potential for fluorescence, make it a perfect candidate to enhance emerging sensing applications in different fields, but especially life science (medical imaging, genomics, ...). We demonstrate the possibilities of the NIM technique with patterns as well as with biological samples.

Lens-free holographic microscopy (LFHM) is cost-effective and field-portable, making it a promising diagnostic approach for point-of-care applications. However, LFHM has not yet been applied to protein molecule sensing in solution . Here we develop a quantitative large-area binding sensor by combining a high-speed LFHM with a one-step bead-based agglutination assay, where agglutination of >10^4 2-μm beads in solution undergoing Brownian motion are imaged and quantified. We sense NeutrAvidin molecules and interferon-gamma (an immune system biomarker) in solution, achieving a limit of detection of <27 ng/mL for NeutrAvidin and <3 ng/mL for mouse interferon-gamma.

Dynamic thermal imaging has improved bulk tissue characterization, but fails to capture subtle thermal property differences in heterogeneous systems. We present focal dynamic thermal imaging (FDTI), a simple, label-free, and high-resolution technology for delineating tissue heterogeneity. Stimulation of focal regions of absorptive materials with a narrow beam, low power, and low cost 405 nm laser locally perturbs the thermal equilibrium. Measurement of phantoms, ex vivo tissue, and in vivo animal models of cancer reveals finite structures of materials and delineates diseased from healthy tissue. Portable FDTI holds promise to capture the heterogeneous nature of malignant tissue.

Diabetic foot is a serious chronic complication of diabetes mellitus affecting 15 % diabetic patients during their lifetime. Approximately 85 % lower-limb amputations are preceded by an untreated diabetic foot. Several techniques are available to diagnose foot ulceration by monitoring average blood oxygenation state of the diabetic foot. However, these techniques couldn’t resolve relative local blood volume fraction of reduced/-oxyhemoglobin within the bulk of highly scattering tissue media. Therefore, the aim of this study is to extract localized blood volume fraction of reduced/- oxyhemoglobin from vascular beds of human foot. In this study, we investigated the ability of diffuse reflectance spectroscopy to quantitatively measure localized blood volume fraction of reduced hemoglobin (RHb), oxyhemoglobin (HbO₂), and oxygen saturation (SO₂) from various sites of the human foot sole. The preliminary investigation shows that the proposed approach can reliably determine the local volume fractions of RHb, HbO₂ and SO₂ in four different sites namely great toe, ball of great joint, 5th metatarsal, and calcaneum of the human foot sole. In addition, it also concludes that each part of the foot has different levels of blood volume fraction. Thus, the preliminary results suggest that this method may be used as a diagnostic tool for monitoring blood oxygenation parameters of ulcerated diabetic foot. It may help in to reduce the health-care cost and improve the quality of life of diabetic patient.

Remote and continuous blood glucose monitoring is a highly researched topic due to the prevalence of diabetes. In addition to being the 7th leading cause of death, diabetes features high comorbidity rates involving chronic diseases such as cardiovascular disease and kidney disease. This is in part due to poor monitoring of blood glucose levels, especially amongst the medically underserved who lack regular physician access. Optical signal transduction via a fully implantable biosensor is a promising way to provide necessary disease monitoring due to potential for low cost, longer lifetime and lack of transcutaneous components. Such a sensor would enable administration through a syringe and thus allow other healthcare workers to administer the biosensor- expanding access. However, light transport through turbid media such as skin features many absorptive and scattering events that lower assay efficacy. One such way to increase signal is the inclusion of multiple sensing modalities and rational design selection. Here, we present design selection for a multimodal and fully implantable glucose biosensor. First, three designs are postulated, then their fluorescence is simulated via Monte Carlo Modeling. The best performing design is then further improved upon by determining the number of needed repeating units as well as length. Overall, it was determined that a stacked cylinder design, 0.43cm in length with 0.036cm thick repeating units provides the best fluorescent signal. Future work should involve the experimental validation of this model, as well as the inclusion of the sensing modalities so that an exact response can be estimated.

The possibility to monitor blood-pH has long been acknowledged to provide significant information for the diagnosis, management and treatment of a variety of diseases and it would be of considerable support for the administration of several treatments such as, for example, extracorporeal (blood) circulation (ECC). During ECC, the patient’s blood flows outside the body in disposable bloodlines and devices for treatments such as blood purification or circulation/ventilation/oxygenation support. Although blood-pH can be measured since the early twentieth century by using ion-selective electrodes (ISEs) and, more recently, also by using point-of-care testing (POCT) instruments, nowadays no measurement method has fully succeeded in providing a cost-effective, reliable and accurate estimate of the blood-pH to be routinely used for its real-time monitoring. In a recent paper, we have proposed and demonstrated a measuring instrument for the in-line and real-time monitoring of blood-pH during ECC. Such a measuring system consists of a low-cost fluorescent disposable sensor that can be integrated into the bloodline and, of a non-disposable reading system that interrogates the sensor without contacting the patient’s blood. In this paper, we investigated the robustness of such a measuring system to variations of blood parameters such as blood flow and hematocrit. The obtained results demonstrate that, although during the tests the pH, flow, and hematocrit values were significantly varied — pH from ≈ 6.8 pH, to ≈ 7.4 pH; hematocrit from 32%, to 40%; flow from 250 ml/min, to 400 ml/min, — the measuring system continued to guarantee a measurement error inferior to ±0.04 pH, thus complying with the metrological requirements for in-line and real-time monitoring of blood-pH during ECC

In recent years, conjugated nanoparticles have gained significant applications in diagnostics, particularly gold nanoparticles (AuNPs). When functionalized with antibodies, AuNPs can selectively interact with cells and biomolecules. The conjugation of biomolecules to AuNPs has been achieved using a variety of techniques, one such approach is the covalent coupling method used in the current study. Generally, in diagnostics, the conjugation of different moieties such as antibodies to the AuNPs widens their applications and provides them with new or enhanced properties. Due to their high specificity and diversity, antibodies are widely used to provide specificity and bioactivity to AuNPs, particularly for biosensor applications. Localized surface plasmon resonance (LSPR) has emerged as a leader among label-free biosensing techniques because it offers sensitive, robust, and rapid detection of biological analytes. Biomolecular adsorptions on AuNPs surface increases the dielectric constant and change the intensities and the wavelengths of the LSPR band associated with AuNPs. As a result, the adsorptions of biomolecules onto surfaces of this AuNPs can be monitored by measuring the absorption spectra of the AuNPs. In this study, TB antibodies were covalently conjugated to AuNPs and used to detect mycolic acid TB antigens at various concentrations. Characterization of the AuNPs was done using transmission electron microscopy (TEM) while the biomolecular interaction between TB antibodies and the antigen was measured using LSPR. From our findings, it was realised that the use of antibodyconjugated AuNPs enhanced the detection of the analyte even at low concentrations of the analyte.

Measuring body temperature in cats is an essential part of every clinical examination. Typically, rectal temperature measurement is conducted, but the procedure is poorly tolerated, and it often triggers stress-related changes in physiological parameters like pulse rate and blood pressure. Therefore, non-contact infrared thermometers have been studied on a few body surface measurement sites. However, existing studies included only commercial thermometers, which do not guarantee the correct temperature readings. In this study, we applied a custom-made and calibrated infrared thermometer for measuring feline body surface temperature on easily-accessible measurement sites of the eye, gum, and inguinal region. Results showed that body surface temperature was correlated poorly with rectal temperature, achieving the Spearman correlation coefficient of up to 0.25. Furthermore, the differences between body surface and rectal temperate were high (± 4°C). However, the infrared thermometer-based measurements provoked significantly lower stress response, achieving an average stress score of 2.8 (5 being maximum). On the other hand, rectal measurements resulted in a mean stress score of 3.7. Although the non-contact body surface temperature measurements with an infrared thermometer were tolerated significantly better, the poor agreement with rectal temperature prevents the approach to be endorsed for clinical body temperature measurements in cats.