Ultrashort pulsed laser treatment inactivates viruses by inhibiting viral replication and transcription in the host nucleus

Abstract

Ultrashort pulsed laser irradiation is a new method for virus reduction in pharmaceuticals and blood products. Current evidence suggests that ultrashort pulsed laser irradiation inactivates viruses through an impulsive stimulated Raman scattering process, resulting in aggregation of viral capsid proteins. However, the specific functional defect(s) in viruses inactivated in this manner have not been demonstrated. This information is critical for the optimization and the extension of this treatment platform to other applications. Toward this goal, we investigated whether viral internalization, replication, or gene expression in cells were altered by ultrashort pulsed laser irradiation. Murine Cytomegalovirus (MCMV), an enveloped DNA virus, was used as a model virus. Using electron and fluorescence microscopy, we found that laser-treated MCMV virions successfully internalized in cells, as evidenced by the detection of intracellular virions, which was confirmed by the detection of intracellular viral DNA via PCR. Although the viral DNA itself remained polymerase-amplifiable after laser treatment, no viral replication or gene expression was observed in cells infected with laser-treated virus. These results, along with evidence from previous studies, support a model whereby the laser treatment stabilizes the capsid, which inhibits capsid uncoating within cells. By targeting the mechanical properties of viral capsids, ultrashort pulsed laser treatment represents a unique potential strategy to overcome viral mutational escape, with implications for combatting emerging or drug-resistant pathogens.

The application of Raman spectroscopy for the detection and identification of microorganisms

“…Based on the Raman spectral fingerprint, the discrimination of various pathogens and even between closely related strains was achieved, including S. aureus , S. epidermidis ,pathogenic and non‐pathogenic E. coli , Salmonella , Pseudomonas , Chlamydia , Enterococcus strains, mycobacteria, L. monocytogenes , and many more. Also, viral pathogens were objects of investigation in a clinical context, as it was reported for rotavirus, cytomegalovirus, influenza strains, human papillomavirus (HPV), Varicella zoster virus, and Porcine teschovirus , as well as echovirus 1 . Additionally, by means of Raman spectroscopy, clinically relevant eukaryotic microorganisms were studied such as several pathogenic fungi, Candida , Candida and Aspergillus , dermatophytes of the genus Trichophyton , and the protozoa Toxoplasma gondii .…”

Selective Photonic Disinfection of Cell Culture Using a Visible Ultrashort Pulsed Laser

“…For instance, irradiation of a visible USP laser can (1) significantly reduce pathogen infectivity, while retaining ≥ 70% of most of the coagulation factors in human plasma [22]; (2) inactivate enveloped viruses through laser-driven aggregation of viral capsid proteins without altering the structure of surface proteins -- hemagglutinin, leading to the very efficient generation of USP laser-inactivated whole influenza virus vaccines [23,24]. In this report, we show that, in addition to bacteria and viruses, visible USP laser treatment can efficiently inactivate mycoplasma and yeast, which are major cell culture contaminants, with good preservation of the viability of mammalian cell lines.…”

Phototherapy as a Rational Antioxidant Treatment Modality in COVID-19 Management; New Concept and Strategic Approach: Critical Review

“…During the last decade, the use of USP laser irradiation for preparation of WIV vaccines has been tried and tested to combat the influenza A virus subtype H1N1 [148,154,156]. Unlike its counterparts, USP irradiation utilises laser pulses with a pulse duration of several femtoseconds, which helps in the physical inactivation of the virus [154,156].…”