Background In this study, the ability of antimicrobial photodynamic therapy (aPDT) as a treatment approach and adjuvant therapy using curcumin-poly (lactic-co-glycolic acid) nanoparticles (Cur@PLGA-NPs) to inactivate Coronavirus disease 2019 (COVID-19) in plasma was investigated. Furthermore, to verify whether the quality requirement of aPDT-treated plasma is acceptable, the differences of the levels of clotting factors, total plasma proteins, and anti-A and/or anti-B antibodies titrations in plasma of patient before and after aPDT treatment were investigated. Materials and Methods Cur@PLGA-NPs was synthesized using Electrospinning process and characterized by different analysis including Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Fourier Transform Infrared (FTIR) spectroscopy assays. The presence of the SARS-CoV-2 in the plasma samples of patients suspected of having COVID-19 was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. Then, the treated plasma samples with Cur@PLGA-NPs plus blue laser were exposed to Vero cells. Eventually, cell cytotoxicity and apoptotic effects of treated Vero cells were evaluated. Levels of clotting factors including prothrombin time (PT) and activated partial thromboplastin time (APTT), total plasma proteins, and anti-A and/or anti-B antibodies measurements were performed using the coagulometer, method of Bradford, and titration procedure, respectively. Results The presence of SARS-CoV-2 was positive in 84.3 % of samples. Different concentrations of Cur@PLGA-NPs (3, 5, 7, and 10 % wt.), the irradiation times of blue laser (1, 3, and 5 min), and aPDT with the maximum dosed of blue laser light (522.8 J/cm 2 ) plus 10 % wt. Cur@PLGA-NPs had no cytotoxicity. Although there were significant cell degradation and apoptotic effects in treated Vero cells with treated plasma using 10 % wt. Cur@PLGA-NPs, and a blue laser at an energy density of 522.8 J/cm 2 , no visible changes in cells and apoptosis were observed following aPDT. Total plasma protein content, PT, APTT, and anti-A and/or anti-B antibodies titers showed no significant changes (P > 0.05 for all comparisons) in treated plasma as compared to untreated plasma. Conclusion aPDT exhibited in vitro anti-COVID-19 activities in the treated plasma containing SARS-COV-2 without Vero cell apoptosis and any adverse effects on plasma quality in aPDT-exposed plasma.

The study evaluated the thermal-stability of Listeria phages P100 and A511 at temperatures simulating the preparation of ready-to-eat meats. The phage infectivity after heating to 71°C and holding for a minimum of 30 s, before eventually cooling to 4°C were examined. Higher temperatures of 75, 80, and 85°C were also tested to evaluate their effect on phages thermal-stability. This study found that despite minor differences in the amino acid sequences of their structural proteins, the two phages responded differently to high temperatures. P100 activity declined at least 10 log (PFU mL-1) with exposure to 71°C (30 s) and falling below the limit of detection (1 log PFU mL-1) while, A511 dropped from 108 to 105 PFU mL-1. Cooling resulted in partial reconstitution of P100 phage particles to 103 PFU mL-1. Exposure to 75°C (30 s) abolished A511 activity (8 log PFU mL-1) and both phages showed reconstitution during cooling phase after exposure to 75°C. P100 exhibited reconstitution after treatment at 80°C (30 s), conversely A511 showed no reconstitution activity. Heating P100 to 85°C abolished the reconstitution potential. Substantial differences were found in thermal-stability and reconstitution of the examined phages showing A511 to be more thermo-stable than P100, while P100 exhibited reconstitution during cooling after treatment at 80°C which was absent in A511. The differences in predicted melting temperatures of structural proteins of P100 and A511 were consistent with the observed differences in thermal stability and morphological changes observed with transmission electron microscopy.

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