Photodynamic Inactivation of SARS-CoV-2 Infectivity and Antiviral Treatment Effects In Vitro

Abstract

Despite available vaccines, antibodies and antiviral agents, the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic still continues to cause severe disease and death. Current treatment options are limited, and emerging new mutations are a challenge. Thus, novel treatments and measures for prevention of viral infections are urgently required. Photodynamic inactivation (PDI) is a potential treatment for infections by a broad variety of critical pathogens, including viruses. We explored the infectiousness of clinical SARS-CoV-2 isolates in Vero cell cultures after PDI-treatment, using the photosensitizer Tetrahydroporphyrin-tetratosylate (THPTS) and near-infrared light. Replication of viral RNA (qPCR), viral cytopathic effects (microscopy) and mitochondrial activity were assessed. PDI of virus suspension with 1 µM THPTS before infection resulted in a reduction of detectable viral RNA by 3 log levels at day 3 and 6 after infection to similar levels as in previously heat-inactivated virions (<99.9%; p < 0.05). Mitochondrial activity, which was significantly reduced by viral infection, was markedly increased by PDI to levels similar to uninfected cell cultures. When applying THPTS-based PDI after infection, a single treatment had a virus load-reducing effect only at a higher concentration (3 µM) and reduced cell viability in terms of PDI-induced toxicity. Repeated PDI with 0.3 µM THPTS every 4 h for 3 d after infection reduced the viral load by more than 99.9% (p < 0.05), while cell viability was maintained. Our data demonstrate that THPTS-based antiviral PDI might constitute a promising approach for inactivation of SARS-CoV-2. Further testing will demonstrate if THPTS is also suitable to reduce the viral load in vivo.

Neuropeptides, New Ligands of SARS-CoV-2 Nucleoprotein, a Potential Link between Replication, Inflammation and Neurotransmission

“…ZnTPPS is one of the sensitizers that can release singlet oxygen and ROS upon light/ultrasound activation. Such compounds have been useful in the treatment of some cancers and proposed as antiviral treatment to inactivate SARS-CoV-2 [56].…”

Photodynamic nasal SARS-CoV-2 decolonization shortens infectivity and influences specific T-Cell responses

“…When applied in early stages of SARS-CoV-2 infection, local decolonization of nasal passages could be clinically relevant for the inhibition of viral spread both from person to person and from upper to lower respiratory tract, in clinical and non-clinical settings. PDT has been proposed as a valid approach to inactivate SARS-CoV-2 ( Almeida et al., 2020 ; Dias et al., 2020 ; Sabino et al., 2020 ; Ziganshyna et al., 2022 ), and the ex-vivo efficacy of PDT against SARS-CoV-2 virion has been demonstrated ( Arentz and von der Heide, 2022 ). This study is the first prospective randomized trial exploring the safety and efficacy of PDT nasal decolonization in SARS-CoV-2 infected individuals.…”

Anti-Viral Surfaces in the Fight against the Spread of Coronaviruses

“…Some materials, such as graphene and its derivatives, disrupt membranes through the puncture [ 74 ], while others disarrange virus membranes by dehydration. On the other hand, photosensitizing surfaces induces the generation of reactive oxygen species (ROS), thereby damaging virus proteins [ 75 , 76 ]. Biopolymers, in turn, inactivate viruses by binding to the capsid proteins or membrane [ 77 , 78 ].…”