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Browsing Journal Articles by browse.metadata.impactarea "Biophotonics"
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Item The effect of low-level laser therapy on severe acute respiratory syndrome coronavirus-2 infected cells(2024-03) Mngwengwe, Luleka; Lugongolo, Masixole Y; Ombinda-Lemboumba, Saturnin; Ismail, Y; Mthunzi-Kufa, PatienceSARS-CoV-2 is a threat to public health due to its ability to undergo crucial mutations, increasing its infectivity and decreasing the vaccine's effectiveness. There is a need to find and introduce alternative and effective methods of controlling SARS-CoV-2. LLLT treats diseases by exposing cells or tissues to low levels of red and near-infrared light. The study aims to investigate for the first time the impact of LLLT on SARS-CoV-2 infected HEK293/ACE2 cells and compare them to uninfected ones. Cells were irradiated at 640 nm, at different fluences. Subsequently, the effects of laser irradiation on the virus and cells were assessed using biological assays. Irradiated uninfected cells showed no changes in cell viability and cytotoxicity, while there were changes in irradiated infected cells. Furthermore, uninfected irradiated cells showed no luciferase activity while laser irradiation reduced luciferase activity in infected cells. Under SEM, there was a clear difference between the infected and uninfected cells.Item HEK293/ACE2 cells' response to severe acute respiratory syndrome coronavirus-2 infection and low-level-laser therapy under microscopy(2024-01) Mngwengwe, Luleka; Lugongolo, Masixole Y; Ombinda-Lemboumba, Saturnin; Ismail, Y; Mthunzi-Kufa, PatienceLow-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.Item A molecular study of aspirin and tenofovir using gold/dextran nanocomposites and surface-enhanced raman spectroscopy(2022-04) Thobakgale, Setumo L; Ombinda-Lemboumba, Saturnin; Mthunzi-Kufa, PatienceIn this study, we show how surface enhanced Raman spectroscopy (SERS) can be used to monitor the molecular behaviour of aspirin and tenofovir as a means of screening medication for quality control purposes. Gold-coated slides combined with gold/dextran nanoaggregates were used to provide signal enhancement of the drugs using SERS. Aspirin (10% w/v) and tenofovir (20% v/v) were analysed in the presence of the nanomaterials to determine trends in molecular response to changes in gold/dextran concentrations. Qualitative analysis of the functional groups showed specific trends where the peak area increased with polarizability, electron density and decreased atomic radii. Steric hinderance effects also affected the trends in peak area due to the amount of gold/dextran nanoparticles in solution. Statistical analysis provided accurate and precise linear relationships (R2 = 0.99) for the ester and adenine functional groups of aspirin and tenofovir, respectively. From the above findings, the combined use of gold nano-scaffolds and gold/dextran nanomaterials amplified the Raman signal from the drugs to allow for systematic evaluation of their molecular properties. Although more experiments to correlate the findings are still needed, this SERS approach shows great potential as a screening method in the quality control of medications.Item On the remarkable nonlinear optical properties of natural tomato lycopene(2022-05) Numan, N; Jeyaram, S; Kaviyarasu, K; Neethling, P; Sackey, J; Kotsedi, CL; Akbari, M; Morad, R; Mthunzi-Kufa, Patience; Sahraoui, B; Maaza, MIn line with the renewed interest in developing novel Non Linear Optical (NLO) materials, natural Lycopene’s NLO Properties are reported for the first time within the scientific literature. Correlated to its 1-D conjugated p-electrons linear conformation, it is shown that natural Lycopene exhibits a significantly elevated 3rd order nonlinearity (3) as high as 2.65 10-6 esu, the largest value of any investigated natural phyto-compound so far, including ß-carotene. In addition to a saturable absorption, the corresponding observed self-defocusing effect in Lycopene seems to be the result of a thermal nonlinearity. The nonlinear response coupled to the observed fluorescence in the Visible spectral range points to a potential photodynamic therapy application as well as the possibility of engineering of novel hybrid Lycopene based NLO nano-materials.