In this work, two types of nanocomposites, silica-coated nano-sea-urchins and silica-coated gold nanostars, were
fabricated. CTAB-coated nano-sea-urchins with an average size of about 100 nm demonstrate an absorption peak near
600-700 nm and stability in aqueous suspension. CTAB was exchanged with m-PEG-SH by an intermediate PEG layer.
A layer of silica was synthesized on the nano-sea-urchins surface with thickness of about 20 nm. Nanostars with an
average size of about 60 nm with a number of thin sharp branches were fabricated and functionalized by PVP to improve
their stability. PVP-coated nanostars were used in optical coherence tomography experiments to show their contrasting
properties. After silica-coating, stable and monodispersed nanoparticles with silica shell thickness about 60 nm were
obtained. Nontoxicity of the silica-coated nanostars at least until the concentration of nanoparticles about 400 μg/mL was
showed by fluorescent cell viability assay using propidium iodide. Extinction coefficient of the gold nanostars and
nanocomposites was estimated by a spectrophotometer system in collimated transmission regime.
In this study, we propose an all optical sensor based on nonlinearity in a multimode
interference coupler. The sensor can be tuned to highest sensitivity in the refractive index ranges
sufficient to detect protein- based molecules or other water- soluble chemical or biological
materials. The nonlinear regimes show the capability to operate on any choice of materials for slab
waveguide even conventional glass. The Kerr nonlinear effect is considered as the nonlinear effect
for third order nonlinearity materials; this effect is studied in the multimode waveguide with MPA
method that promises to investigate the coupler in small lengths. The visible changes of field
profile at output facet in various surrounding layer refractive index show the high sensitivity to the
refractive index of surrounding layer that is foundation of introducing a sensor. Also, the result
show the high distinguished changes on output intensity in various refractive index of surrounding
layer even in conventional glass as a chosen material for coupler. To the best of our knowledge
this is the first time that a nonlinear MMI in a few micrometers is proposed as a robustness sensor.
In fact, this paper brings a useful and powerful way to progress the all optical sensors based on
An analytical model of mass diffusion and biochemical transformation kinetics in bruise development and healing
process was recently developed in order to simulate bruised skin color at various time points and enable objective
determination of the time of injury. However, parameters of the model were not determined directly. Instead,
biologically plausable values were applied in prior analyses. Pulsed photothermal radiometry (PPTR) allows noninvasive
determination of the laser-induced temperature depth profile in human skin. We have applied this technique to
characterize dynamics of extravasated hemoglobin concentration profile evolution. By applying Monte Carlo simulation
of laser energy deposition and simulation of PPTR signal, a more exact comparison with measured temperature profiles
is possible. We show that PPTR depth profiling can be used to derive rather accurate estimates of the hemoglobin mass
diffusivity, hemoglobin degradation time, as well as approximate skin geometry. This enables assessment of the bruise
healing dynamics and could offer a valuable addition to existing bruise age determination techniques.
Mechanical property of a cell is investigated from reaction force generated on a particle fixed on a cell by moving with
optical tweezers. This system is called as cell palpation system. By using of this system we can measure mechanical
property at a desired location on a cell surface just by locating the probe particle with optical tweezers. We have
investigated focal adhesion formation through mechanical property measurement after initiation of touching by the probe
Multi-spectral photoplethysmograph biosensor intended for analysis of peripheral blood volume pulsations at different
vascular depths has been experimentally tested. Light emitting diodes with four different wavelengths were used as the
light emitters. A single photodiode with multi-channel signal output processing was used as the light detector. This study
analyzed rising time difference between wavelengths at systole maximum, wavelengths relations between systole and
diastole peak difference. The proposed methodology is discussed.
Pterins are a group of biological compounds which have potential for use as a possible cancer diagnostic. This
paper considers reproducibility issues using Surface Enhanced Raman Scattering (SERS) for application in pterin
Experimental data on optical resonance spectra of whispering gallery modes of dielectric microspheres in antibiotic
solutions under varied in wide range concentration are represented. Optical resonance was demonstrated could be
detected at a laser power of less than 1 microwatt. Several antibiotics of different generations: Amoxicillin,
Azithromycin, Cephazolin, Chloramphenicol, Levofloxacin, Lincomicin Benzylpenicillin, Riphampicon both in deionized
water and physiological solution had been used for measurements. Both spectral shift and the structure of
resonance spectra were of specific interest in this investigation. Drag identification has been performed by developed
multilayer perceptron network. The network topology was designed included: a number of the hidden layers of
multilayered perceptron, a number of neurons in each of layers, a method of training of a neural network, activation
functions of layers, type and size of a deviation of the received values from required values. For a network training the
method of the back propagation error in various modifications has been used. Input vectors correspond to 6 classes of
biological substances under investigation. The result of classification was considered as positive when each of the region,
representing a certain substance in a space: relative spectral shift of an optical resonance maxima - relative efficiency of
excitation of WGM, was singly connected.
It was demonstrated that the approach described in the paper can be a promising platform for the development of
sensitive, lab-on-chip type sensors that can be used as an express diagnostic tools for different drugs and instrumentation
for proteomics, genomics, drug discovery, and membrane studies.
The surface plasmon resonance (SPR) is one of the most attractive and precise enabling mechanism for sensors in
biomedical applications. Conventional biological experiments are performed manually, time consuming intervention and
expensive interconnection techniques. This paper simulates three dimensional behavior of magnetic and electric fields of
light coupled into a SPR mode propagating along a thin gold layer surrounded by symmetric dielectric layers. This study
successfully illustrates the three-dimensional simulation of surface plasmon wave using finite element method in
COMSOL Multiphysics suit.
One of the challenges in anti-cancer drug delivery systems is to quantitatively discriminate non-specific receptorindependent
tumor accumulation from receptor-mediated uptake into the tumor cells. To overcome this challenge, we
develop a new near infrared fluorescence resonance energy transfer fluorescence lifetime imaging (NIR FRET FLIM)
technique with wide-field illumination strategies to validate and characterize cellular uptake in both cancer cells and
normal cells with different donor-acceptor ratios in vitro and in vivo. Our results demonstrate that NIR FRET FLIM can
quantitatively distinguish receptor-bound from unbound donor in live animals with high sensitivity and high accuracy.
Thus, it has a great potential for the quantitative detection of targeted delivery systems for diagnostic and therapeutic
We demonstrate an efficient algorithm for the temporal and spatial based calculation of the laser speckle contrast analysis
(LASCA) for the imaging of blood flow that reduces the numerical complexity of necessary calculations, facilitates a multicore
implementation of the speckle analysis and enables an independence of temporal or spatial resolution and SNR. The
new algorithm was evaluated for both spatial and temporal based analysis of speckle patterns with different image sizes and
incorporated pixels as sequential and multi-core code. The improvement is about a factor of 5 and can be increased to about a
factor of 15 for multi-core computers. This allows an online-analysis of larger speckle images or at a higher frame rate.
We report on the high-resolution deep-tissue imaging using novel water-dispersible upconversion nanoparticles (UCNPs)
β-NaYF4:Yb3+:Tm3+. Luminescence from the UCNP embedded into tissue-mimicking phantoms at the depth of 4 mm epi-illuminated with 975-nm laser radiation was detected. Fiber-optic detection shows 2-times better resolution compared with that obtained using CCD-based imaging modality. The conversion efficiency of upconversion particles and their cytotoxicity to HeLa cells were also investigated and reported.
The large dynamic range of fluorescence emission collected is one of the major challenges in wide-field fluorescence
lifetime imaging. To overcome this challenge, we developed an active illumination strategy to acquire optimal
fluorescence signals over the sample imaged even in the presence of large fluorophore concentration distributions. We
validated the stability of our approach in a multi-well plate setting with fluorophore concentrations ranging <2 orders of
magnitude. We report the ability of our method to retrieve accurately the lifetime over this concentration range based on
optimized wide-field data. Our results demonstrate that active wide-field illumination can improve the signal-to-noise
ratio and weak-signal sensitivity for enhanced accuracy of fluorescence decay curve fitting and lifetime estimation at
high acquisition speed.