SARS-CoV-2 is a pandemic that claimed millions of lives, and to date, there has been no identifiable cure for SARS-CoV- 2. LLLT is a thriving technology used to treat different kinds of conditions that require stimulation of healing, relief of pain and inflammation, and repair of function. LLLT has been used to treat wounds, sports injuries, chronic pain, dermatitis, and hair loss. Although LLLT can treat some medical conditions, it has been observed that it can cause an increase in blood antioxidants and heat shock protein expression. There are many kinds of stress caused by laser irradiation, and how a cell reacts to them depends on the kind and severity of the insult. The aim of this study is to investigate the effect of LLLT on SARS-CoV-2-infected HEK293/ACE2 cells. In this study, biological assays, including MTT assay, cell viability live/dead, green/deep red assay, and reactive oxygen species (ROS) detection assay, were used to determine the effects of laser irradiation on SARS-CoV-2 infected and uninfected HEK293/ACE2. HEK29/ACE2 cells were infected with SARS-CoV-2 and 48 hours post-infection they were subject to laser irradiation. After 24 hours post-irradiation, biological assays were performed. Both infected non-irradiated and irradiated cells displayed signs of cell stress and produced ROS. There were more dead cells observed in infected HEK293/ACE2 cells, while more viable cells were seen in the uninfected irradiated HEK293/ACE2 cells. LLLT can be used to explore the therapeutic qualities of laser light in SARS-CoV-2 research. LLLT can be used to explore the therapeutic effects of laser light in SARS-CoV-2 research.
Low-level laser therapy (LLLT) is a method of exposing cells or tissue to low levels of red and near-infrared light that has a high success rate for the treatment of various ailments. LLLT has been used to treat various diseases, including wounds, spinal cord injuries, and symptoms of viral conditions like blisters caused by the Herpes Simplex Virus. The aims of the study are to investigate the effect of laser irradiation on SARS-CoV-2 infected cells and on uninfected cells using a scanning electron microscope (SEM) and transmission electron microscopy (TEM) as analysis tools. SEM was used to determine the morphological differences caused by laser irradiation on SARS-CoV-2 infected HEK293/ACE2 cells as well as non-irradiated SARS-CoV-2 infected ones. In addition, the results obtained were compared to irradiated and non-irradiated uninfected cells. To further evaluate the effect of irradiation and SARS-CoV-2, the transmission electron microscope (TEM) was used to investigate the changes in the interior of the aforementioned cells. In preparation for SEM and TEM, HEK293/ACE2 cells were infected with SARS-CoV-2 and irradiated with a 640nm laser at different fluences. Following irradiation, the cells were then fixed and mounted. The data obtained using different magnifications in SEM, revealed differences in the occurrence of surface projections and shape of SARS-CoV-2 infected and uninfected cells, and in TEM they display clear difference in the interior structure of both SARS-CoV-2 infected and uninfected HEK29/ACE2 cells irradiated.
Tuberculosis (TB) is one of the world’s largest infectious diseases. It causes high mortality in humans and leads to about three million deaths worldwide annually, hence early detection is crucial, especially in a point-of-care (POC) setting to prevent the spreading of the pathogen by undiagnosed individuals. In the current work, a photonic crystal (PhC)-based optical biosensor chip was developed for diagnosing TB using mycolic acid TB antigen as a biorecognition element to capture anti-mycobacterium tuberculosis antibodies. Mycolic acid was successfully immobilized on the PhC biosensor chip to react with anti- mycobacterium tuberculosis antibody, and the white light-based transmission setup was used for optical biosensing to monitor biomolecular interactions between the antigen and antibody. Gold nanoparticles (AuNPs) before and after bioconjugation with goat anti-rabbit IgG H&L secondary antibody were characterised using ultravioletvisible (UV-vis) spectroscopy. Bioconjugated AuNPs were subsequently bound to the biosensing surface to enhance the detection signal of biomolecular binding events. The biosensing surface was further characterised using atomic force microscopy (AFM). Analysis of biomolecular binding events on the biosensing surface was achieved using a custom-built PhC optical biosensing setup which successfully distinguished between experiment and control samples. From our findings, it was realised for the first time that mycolic acid antigen could be immobilised on a biosensing surface to capture anti-mycobacterium tuberculosis antibodies. From this result, it was concluded that the PhC optical biosensing technique was successful in detecting small refractive index changes on the biosensing surface for the diagnosis of TB. These results pave the way for the development of a photonics-based POC diagnostic device for TB.
When it comes to diagnostics for various microorganisms, 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. In this study, for the first time, an optical biosensor chip was developed and analysed using a localised surface plasmon resonance (LSPR) optical biosensing technique to monitor biomolecular interactions between mycolic acid TB antigen and anti-mycobacterium tuberculosis antibody. Mycolic acid was successfully immobilised on a gold-coated biosensor chip and allowed to react with an anti-mycobacterium tuberculosis antibody. To enhance the detection signal from biomolecular binding events, AuNPs were used and successfully bioconjugated with goat anti-rabbit IgG H&L secondary antibody and characterised using ultraviolet-visible (UV-vis) spectroscopy and subsequently introduced on the biosensing layer. Scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) spectroscopy were used to characterise the biosensing surface. The optimised biosensor chip was analysed using a custom-built biosensing transmission spectroscopy setup to perform LSPR biosensing. From our findings, it was realised that mycolic acid was successfully immobilised on the biosensing surface and made it possible to capture anti-mycobacterium tuberculosis antibodies. The LSPR optical biosensing technique was indeed successful in the detection of anti-mycobacterium tuberculosis antibodies.
This work presents some results of pulse and spectral responses, performed for laser-excited pilot sample of earlier on designed and fabricated chiral silica few-mode optical fiber (FMF) with induced twisting 66 revolutions per meter (rpm), typical (for telecommunication optical fibers) cladding diameter 125 μm, weakly increased core diameter up to 11 μm and numerical aperture NA=0.22, corresponding to improved height of quasi-step refractive index profile. Described FMF 11/125 provides propagation of 4 and 6 guided modes over “C” and “O”-bands, respectively. We present results of tests, focused on researches of few-mode effects, occurring under laser-excited optical signal propagation over pilot sample optical fiber, and their influence on pulse and spectral responses, including some measurements, performed for fiber Bragg grating, recorded in tested FMF 11/125.
Two photon fields to date, are generated by a fully coherent pump beam. We have experimentally studied the generation of polarisation entangled single photon pairs using a partially coherent pump beam. The spatial coherence effects of the pump beam on the coincidence detection of an entangled single photon source was investigated. The fully coherent coincidence detection was compared to the partial coherence detection. The results show that the partial coherence of the pump beam leads to an increase in coincidence detection. The coherence properties of a beam is significant for freespace optical transmission specifically for free-space quantum communication over long distances.
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