Journal of Innovative Optical Health Sciences

The current pandemic SARS-CoV-2 (also known as 2019-nCoV and COVID-19) viral infection is growing globally and has created a disastrous situation all over the world. One of the biggest challenges is that no drugs are available to treat this life-threatening disease. As no drugs are available for definitive treatment of this disease and the mortality rate is very high, there is an utmost need to cure the infection using novel technologies. This study will point out some new antimicrobial technologies that have great potentials for eradicating and preventing emerging infections. They can be considered as treatments of choice for viral infections in the future.

Determination of the precise location and the degree of the Choroidal neovascularization (CNV) lesion is essential for diagnosation Neovascular age-related macular degeneration (AMD) and evaluation the efficacy of treatment. Noninvasive imaging techniques with specific contrast for CNV evaluation are demanded. In this paper, two noninvasive imaging techniques, namely Optical coherence tomography (OCT) and Photoacoustic microscopy (PAM), are combined to provide specific detection of CNV for their complimentary contrast mechanisms. In vivo time-serial evaluation of Laser-induced CNV in rats is present at days 1, 3, 5, 7, 14, 21 after laser photocoagulation is applied to the rat fundus. Both OCT and PAM show that the CNV increases to its maximum at day 7 and decreases at day 14. Quantification of CNV area and CNV thickness is given. The dual-modal information of CNV is consistent with the histologic evaluation by hematoxylin and eosin (H&E) staining.

This study was conducted to understand the cellular proliferative effect of Photobiomodulation Therapy (PBMT) on thawed dental pulp stem cells (DPSCs) stored for 2 years. For this purpose, cells were exposed to PBMT for short period of time to evaluate the most appropriate PBMT parameter for stimulating cellular proliferation that can be used for future tissue engineering therapies. Fully characterized DPSCs were seperated into three groups according to the laser energy densities (5J/cm² or 7J/cm²) applied and a group was served as control in which cells did not receive any laser irradiation. The cells in laser-irradiated groups were further divided into two subgroups according to the period of application (24h and 0h) and exposed to Gallium–Aluminum–Arsenide diode laser irradiation. Cell viability and the proliferation rate of the cells were analyzed with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, any PBMT related cellular cytotoxicity were determined by performing a lactate dehydrogenase assay (LDH) and statistical analysis of data were performed. The percentage of proliferation seemed to increase upon laser therapy in both different doses of irradiation (5J/cm² and 7J/cm²). DPSCs showed significantly higher proliferation rate upon 7J/cm² irradiation in both 0h and 24h when compared to control groups. However, DPSCs irradiated with 5J/cm² dose induced relatively lower proliferation rate when compared to 7J/cm² dose of irradiation. According to the LDH data, PBMT exposure did not show any significant cytotoxicity at both energy densities in all different time periods. PBMT at 7J/cm² should be an effective parameter to stimulate proliferation of long-term cryopreserved DPSCs in a short term time period. Photobiomodulation therapy may be an upcoming tool for future tissue enngineering and regenerative dentistry applications.

Precipitation is a key manufacturing unit during the immunoglobulin G (IgG) production, which guarantees the quality of the final product. Ethanol is usually used to purify IgG during the precipitation process, so it is important to monitor the ethanol concentration online. Near-infrared (NIR) spectroscopy is a powerful process analytical technology (PAT) which has been proved to be feasible to determine the ethanol concentration during the precipitation process. However, the NIR model is usually established based on the specific process, so a universal model is needed. And the clarity degree of solution will affect the quality of the spectra. Therefore, in this study an integrated NIR system was introduced to establish a universal NIR model which could predict the ethanol concentration online and determine the end-point of the whole process. First, a spectra acquisition device was designed and established in order to get high-quality NIR spectra. Then, a simple prepared ethanol NIR model was constructed to predict the actual manufacturing process. Finally, the end-point was determined to stop the peristaltic pump when the ethanol concentration reached 20%. The results showed that the spectra quality was good, model prediction was accurate, and process monitoring was accurate. In conclusion, all results indicated that the integrated NIR system could be used to monitor the biopharmaceutical process to help us understand the pharmaceutical process.

Stimulated Raman scattering (SRS) microscopy has the ability of noninvasive imaging of specific chemical bonds and been increasingly used in biomedicine in recent years. Two pulsed Gaussian beams are used in traditional SRS microscopes, providing with high lateral and axial spatial resolution. Because of the tight focus of the Gaussian beam, such an SRS microscopy is difficult to be used for imaging deep targets in scattering tissues. The SRS microscopy based on Bessel beams can solve the imaging problem to a certain extent. Here, we establish a theoretical model to calculate the SRS signal excited by two Bessel beams by integrating the SRS signal generation theory with the fractal propagation method. The fractal model of refractive index turbulence is employed to generate the scattering tissues where the light transport is modeled by the beam propagation method. We model the scattering tissues containing chemicals, calculate the SRS signals stimulated by two Bessel beams, discuss the influence of the fractal model parameters on signal generation, and compare them with those generated by the Gaussian beams. The results show that, even though the modeling parameters have great influence on SRS signal generation, the Bessel beams-based SRS can generate signals in deeper scattering tissues.

Photodynamic therapy (PDT) takes advantage of photosensitizers (PSs) to generate reactive oxygen species (ROS) for cell killing when excited by light. It has been widely used in clinic for therapy of multiple cancers. Currently, all the FDA-approved PSs, including porphyrin, are all small organic molecules, suffering from aggregation-caused quenching (ACQ) issues in biological environment and lacking tumor targeting capability. Nanoparticles (NPs) with size between 20nm and 200nm possess tumor targeting capability due to the enhanced permeability and retention (EPR) effect. It is urgent to develop a new strategy to form clinical-approved-PSs-based NPs with improved ROS generation capability. In this study, we report a strategy to overwhelm the ACQ of porphyrin by doping it with a type of aggregation-induced emission (AIE) luminogen to produce a binary NPs with high biocompatibility, and enhanced fluorescence and ROS generation capability. Such NPs can be readily synthesized by mixing a porphyrin derivative, Ce6 with a typical AIE luminogen, TPE-Br. Here, our experimental results have demonstrated the feasibility and effectiveness of this strategy, endowing it a great potential in clinical applications.

Optical coherence tomography (OCT) has been extensively used as noninvasive tool for biological tissues owing to its three-dimensional imaging ability and high axial resolution. OCT quality assurance is vital in these occasions to keep the reliability and accuracy in medical diagnosis. It is necessary to develop a calibration tool for OCT product manufacture, calibration, and quality control. A practical tool is demanded in the OCT quality control and calibration of OCT. So far, there is no such a practical tool that can test all the key parameters of OCT. We design and fabricate a model eye tool, which has this function. The model eye comprises a doublet lens, a single filament, a piece of glass plate and the microsphere-embedded phantom. The doublets lens is bonded by two pieces of planoconvex lenses in the plane position. The first lens focuses parallel light onto the rear surface of the second lens. The rear surface marked with concentric circles serves as retina to measure the angular field of view (FOV). The small flat surface on the peak of the second lens is used to test signal to noise ratio (SNR). The single filament with 125$\mu$m diameter is used to check the co-alignment of preview and OCT scan. The empty chamber between the small plane of the second lens and the first surface of glass plate is used to measure the depth scaling of the OCT. The microspheres of 1$\mu$m diameter distributed uniformly in the phantom, which can test the lateral and the axial resolution of OCT equipment. Experimental results are presented to show the validity of the proposed tool. It is shown that the tool is able to be used in the calibration and quality control of retinal OCT.

Typical fundus photography produces a two-dimensional image. This makes it difficult to observe the microvascular and neural abnormalities, because the depth of the image is missing. To provide depth appreciation, we develop a single-channel stereoscopic fundus video imaging system based on a rotating refractor. With respect to the pupil center, the rotating refractor laterally displaces the optical path and the illumination. This allows standard monocular fundus cameras to generate stereo-parallax and image disparity through sequential image acquisition. We optimize our imaging system, characterize the stereo-base, and image an eyeball model and a rabbit eye. When virtual realities are considered, our imaging system can be a simple yet efficient technique to provide depth perception in a virtual space that allows users to perceive abnormalities in the eye fundus.

Surgical tumor resection is a common approach to cancer treatment. India Ink tattoos are widely used to aid tumor resection by localizing and mapping the tumor edge at the surface. However, India Ink tattoos are easily obscured during electrosurgical resection, and fade in intensity over time. In this work, a novel near-infrared (NIR) fluorescent marker is introduced as an alternative. The NIR marker was made by mixing indocyanine green (ICG), biocompatible cyanoacrylate, and acetone. The marking strategy was evaluated in a chronic ex vivo feasibility study using porcine tissues, followed by a chronic in vivo mouse study while compared with India Ink. In both studies, signal-to-noise (SNR) ratios and dimensions of the NIR markers and/or India Ink over the study period were calculated and reported. Electrocautery was performed on the last day of the mouse study after mice were euthanized, and SNR ratios and dimensions were quantified and compared. Biopsy was performed at all injection sites and slides were examined by a pathologist. The proposed NIR marker achieved (i) consistent visibility in the 26-day feasibility study and (ii) improved durability, visibility, and biocompatibility when compared to traditional India Ink over the six-week period in an in vivo mouse model. These effects persist after electrocautery whereas the India Ink markers were obscured. The use of a NIR fluorescent presurgical marking strategy has the potential for intraoperative tracking during long-term treatment protocols.

An implantable optrode with micro-thermal detectors was designed to investigate the availability and safety of INS using high repetition rates. Optical auditory brainstem responses (oABRs) were recorded in normal-hearing guinea pigs, and the energy thresholds, pulse durations, and amplitudes evoked by the varied stimulus repetitions were analyzed. Stable oABRs could be evoked through INS even as the repetition rate of stimulation reached 19kHz. The energy threshold of oABRs was elevated, the amplitudes decreased as pulse durations increased and repetition rates were higher, and the latencies were delayed as the pulse durations increased. The temperature variation curves on the site of stimulation significantly increased as the pulse duration increased to 400 $\mu$s. INS elevated the temperature around the stimulus site area via thermal accumulation during radiation, especially when higher repetition stimuli were used. Our results demonstrate that high repetition infrared stimulations can safely evoke stable and available oABRs in normal-hearing guinea pigs.