Photodynamic therapy: a new treatment against COVID-19

In 2019, a new coronavirus (COVID-19) was discovered in Wuhan, China, which soon spread all over the world. The main hallmark of the disease includes fever, diarrhea, vomiting, and dry cough with dyspnea in half of the patients and acute respiratory distress syndrome (ARDS). Currently, no definitive treatment or prevention therapy exists for COVID-19 but scientists and researchers all over the world are relentlessly working to understand COVID-19 to discover novel therapeutic tools and vaccines. Today, photodynamic therapy (PDT) has been investigated as a noninvasive therapy for the treatment of this pandemic and was able to increase the healing process with the help of appropriate photosensitizers by targeting the pathogen inside the patient's body.

Synthesis Strategy of Tetrapyrrolic Photosensitizers for Their Practical Application in Photodynamic Therapy

This review presents a wide range of tetrapyrrole photosensitizers used for photodynamic therapy (PDT), antimicrobial photodynamic therapy, photoinactivation of pathogens. Methods of synthesis and design of new photosensitizers with greater selectivity of accumulation in tumor tissue and increased photoinduced antitumor activity are considered. The issues of studying the properties of new photosensitizers, their photoactivity, the ability to generate singlet oxygen, and the possibility of using targeted photodynamic therapy in clinical practice are discussed. The review examines the work on PDT by national and foreign researchers.

Photodynamic inactivation of Rhizopus oryzae - in vitro study

During the COVID-19 pandemic, several complications arose in infected patients, one of them being mucormycosis, which is an extremely aggressive fungal disease with a high mortality rate, especially in patients with compromised immune systems. Most cases of mucormycosis are caused by the fungus Rhizopus oryzae, also known as black fungus, with 90% of cases affecting the rhinocerebral site. The treatment tools used are based on high doses of amphotericin B and posaconazole, associated with surgical resections when possible. However, even with aggressive antifungal treatment, the estimated attributable mortality rate is high [1]. In the absence of surgical debridement of the infected tissue, antifungal treatment alone is not curative. So there is a need for development of adjuvant treatments. Antimicrobial Photodynamic Therapy (aPDT) may constitute an auxiliary therapeutic option for mucormycosis [2]. Due to the lack of reports on the photodynamic inactivation of R. oryzae, we investigated different protocols Photodithazine (PDZ) as a photosensitizer. The response on the fungus growing rate under distinct treatment parameters as photosensitizer concentration, incubation time, and association with surfactant, will be presented for both white and black hyphal phases, and infective spore phase. Preliminary results show the potential use of photodynamic therapy for the inactivation and growth control of the R. oryzae.Copyright © 2023

Nasal photodisinfection in an industrial workplace for COVID-19 suppression

Antimicrobial photodynamic therapy (aPDT) [1] has been deployed in tens of thousands of patients in Canada for preoperative intranasal bacterial suppression to reduce the prevalence rate of surgical site infections [2]. This treatment has proven safe and effective, with infection rate reductions of 40-80% in tertiary care systems despite only requiring 4 minutes of therapy [2]. We previously demonstrated that aPDT eliminates the RNA signature of wild-type SARS-CoV-2 in vitro, with reduction of RT-qPCR threshold counts (DELTACt = 22) in a light-dose dependent manner (C = 320 muM, lambda = 664 nm, F = 36 J/cm2) [3]. Photodynamic targets were found to include the receptor binding domain, spike protein and nucleocapsid domain, consistent with a broad spectrum peroxidative effect on anionic moieties throughout the virion [3]. This work describes the benefits of using regular aPDT treatments in the industrial workplace for the purpose of employee COVID-19 prevention. From July 2020 to August 2021, aPDT was deployed at a large Canadian food processing plant. Meat processing facilities face distinctive challenges in control of infectious diseases, including SARS-CoV-2. Factors that increase processing workers' risk for exposure to SARS-CoV-2 include close contact for 8-12 hour shifts, shared transportation, and congregate housing [4,5]. The presence of a slaughtering plant in a community is associated with a 51 to 75% increase in COVID-19 cases per thousand over the baseline community rate, and a 37 to 50% increase in death rate over the baseline community rate [5]. Methylene blue-mediated aPDT (SteriwaveTM Nasal Photodisinfection System, Ondine Biomedical Inc., Vancouver, BC) was added to the standard infection control bundle at the plant, along with employee education. Treatments were administered free of charge to approximately 1,500 employees on a voluntary basis during paid work hours. Compliance levels of employees requesting aPDT were 85%. To determine intervention efficacy, the rate of qPCR-positive COVID-19 tests over the treatment time period was compared to the same rate in the surrounding province. Results demonstrated a reduction of COVID-19 rate of over 3 times (p<.0001, Fisher's Exact Test) in the treated population compared to the untreated population, with the largest adverse event being mild (self-limiting) rhinorrhea in < 1% of cases. The plant continued production and distribution of products without disruption. Important outcomes from this quality improvement initiative included (a) aPDT proved to be a rapid, lightweight intervention that could be deployed at high compliance levels in a commercial high-throughput food processing operation, (b) significant impact (>3X reduction) on the COVID-19 rates was observed and (c) COVID-19-related comorbidities including acute and long-term illness, disability, and death were proportionately avoided.Copyright © 2023

Photoactive conjugated polymer-based strategy to effectively inactivate RNA viruses

To efficiently combat viral infectious diseases, it is important to develop broadly applicable countermeasures, and efficient antiviral systems can be developed by elaborating the relationship of antiviral efficiency with the interactions between antiviral agents and viruses. In the present study, conjugated polymer (CP)-based photodynamic therapy was used to inhibit RNA virus infections. A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudotyped virus composed of an SARS-CoV-2 envelope coated with the S protein and luciferase RNA genome was employed to assess antiviral efficiency. Three cationic CPs with different backbone structures, fluorene-co-phenylene (PFP), thiophene (PMNT), and phenylene vinylene (PPV), exhibit different photoinactivation effects. The highly efficient photoinactivation of PPV and PMNT is derived from the complete photodegradation of spike proteins, nucleocapsid proteins and nucleic acids of SARS-CoV-2 after binding to the viral spike proteins. Although PFP showed the highest efficiency in the photodegradation of spike proteins due to its strong binding affinity, ineffective viral inhibition was observed, which occurred because the viral gene was partially damaged under light irradiation and the process of delivering the viral gene to cells received assistance. This work preliminarily reveals the effect of CP-virus interactions on their photoinactivation activity and should be beneficial for further research on the development of highly efficient antiviral PDT agents.In this work, a photodynamic therapy system based on conjugated polymers (CPs) is developed to inhibit the infection of RNA viruses. Three cationic CPs with different backbone structures fluorene-co-phenylene (PFP), thiophene (PMNT), and phenylene vinylene (PPV) exhibit different photoinactivation effects. PPV and PMNT cause effective inactivation of viruses under light irradiation, while SARS-CoV-2 pseudotyped viruses keep infectious after treated by PFP, which is determined by the interactions between CPs with the proteins and gene of viruses. This work preliminarily reveals the effect of CP-virus interactions on their photoinactivation activity and would be beneficial to develop high-efficient antiviral PDT agents.

Covalent organic frameworks and metal-organic frameworks against pathogenic viruses and antibiotic-resistant bacteria: Diagnostic and therapeutic applications

Antimicrobial resistance and antiviral infections statistics show that the number of global cases has been exponentially increasing;thus there is an unmet need for developing alternatives rather than to continue conventional strategies such as antibiotic administration, since they failed to show promise especially during the past few decades. Among different porous materials, metal-organic frameworks (MOFs) are a class of porous coordination polymers broadly explored in nano- and biomedicine due to their desirable properties, including excellent surface area, structural variability, the richness of their crystal structures/architectures, allowing for engineering synergies between metal nodes, functional linkers, encapsulated substrates or nanoparticles, heterogeneous catalysis, ion exchange, controlled and targeted drug delivery, energetics, etc. MOF-based sensing platforms have shown suitable potentials for specific viral detection. Covalent organic frameworks (COFs) are porous crystalline organic materials with two- or three-dimensional structures, which can be employed for reducing the interaction between the spike protein of SARS-CoV-2 and angiotensin-converting enzyme 2 (ACE2) in addition to other inhibitory effects. These frameworks can be applied for encapsulating antibiotics or antiviral agents against pathogens;they have been also studied for photodynamic inactivation of pathogenic bacteria. Herein, the most recent advancements pertaining to the applications of these frameworks for specific detection and inhibition of pathogenic viruses and antibiotic-resistant bacteria are cogitated, focusing on important challenges and perspectives. This review also provides expert recommendations on the future development and utility of these frameworks to manage antimicrobial resistance and infectious diseases more efficiently. © 2023 Elsevier Ltd

Daylight photodynamic therapy at home

Daylight photodynamic therapy (DPDT) is an established treatment for field-change actinic keratoses (AK) with high rates of satisfaction and success. In recent times there has been a push within the healthcare industry to reduce avoidable clinic time and complement it with community-based healthcare, including self-administration therapies. The importance of 'decentralized' healthcare and at-home therapies has been emphasized by the recent COVID-19 pandemic - access to treatments is restricted and many patients are not receiving the appropriate care in an attempt to minimize hospital-based treatments. In this project, we deconstructed DPDT and by utilizing principles of design and the concept of realistic medicine, transformed it into a user-friendly, environmentally conscious and engaging at-home therapeutic option. Information on protocols and best practice was obtained from clinical colleagues and a map of the patient pathway was outlined. The treatment was broken down and re-formed into simple steps, taking care with the number of instructions to prevent confusion. The physical form of the at-home kit was designed to facilitate the required materials for DPDT, while being simple and methodical to follow. Steps were separated into individual numbered sections, with only the materials needed at each step visible. Simple graphics are displayed alongside relevant instructions, with colouring to highlight importance. The at-home kit was iteratively improved with input from end users. As part of this initiative the DPDT athome kit is designed and prototyped in order to be posted directly to the user. In trialling this kit preclinically, the theoretical patient journey could be visualized, starting with the unboxing of the kit, then followed by the guides and directed procedure. Through feedback, iterations to the design have subsequently been made that efficiently translate the clinical procedure into a successful at-home design. One of the key principles of realistic medicine to consider is the reduction of waste. In this kit we have, where possible, used recycled and recyclable materials, and are in the process of incorporating medically approved biodegradable gloves, which will instantly reduce a high fraction of the nonrecyclable excess. Implementation of the kit in routine clinical practice will provide important feedback allowing further iterations to the design of the kit. Involving patients directly with the development work and continuously responding to the patient experience will significantly improve the final design of the at-home kit. Helping to implement an option to take this important treatment away from a hospitalized environment represents a paradigm shift in the possible delivery of DPDT and can be useful to optimize treatment delivery on a per-patient basis.

Nanozyme: a New Approach for Anti-microbial Infections

Bacteria and viruses always posed a threat to human health. Most impressively, SARS-CoV-2 has raged around the world for almost three years, causing huge loss to human health. Facing increasing challenges of drug-resistance and poor treatment efficacy, new solutions are urgently needed to combat pathogenic microorganisms. Recently, nanozymes with intrinsic enzyme-like activities emerged as a promising new type of "antibiotics”. Nanozymes exhibit superior antibacterial and antiviral activities under physiological conditions by efficiently catalyzing generation of a large number of reactive oxygen species. Moreover, enhanced therapeutic effects are achieved in nanozyme-based therapy aided by the unique physicochemical properties of nanomaterials such as photothermal and photodynamic effects. This paper reviews the latest research progress in the field of anti-microbial nanozymes, systematically summarizes and analyzes the principles of nanozymes in the treatment of bacteria and viruses from a mechanistic point of view. An outlook on the future direction and the challenges of new anti-microbial infection nanomaterials are proposed to provide inspiration for developing next generation anti-microbial nanozymes. © 2023 Science Press. All rights reserved.

Cationic Conjugated Microporous Polymers Coating for Dual-Modal Antimicrobial Inactivation with Self-Sterilization and Reusability Functions

COVID-19 pandemic outbreak poses a great threat to human health. Face masks have been considered as important personal protective equipment to prevent the COVID-19 transmission. However, pathogens can survive up to several days on the fabrics of commercial masks, which increases the risk of direct/indirect microbial transmission. Herein, new cationic conjugated microporous polymers (CCMPs)-based coating is developed, which possesses extended π-conjugated skeletons and massive quaternary ammonium salt (QAS) groups, exhibiting dual-modal antimicrobial inactivation, including sunlight-driven photodynamic sterilization through the generation of reactive oxygen species and contact sterilization through QAS groups. As a result, the CCMPs coatings can rapidly and efficiently eradicate 99% of model microbes, such as Escherichia coli and Staphylococcus aureus under solar illumination, and also ensure the great antimicrobial effect in the absence of light. More importantly, the CCMPs coatings exhibit excellent durability, reusability as well as antimicrobial stability in humid environment. Contributing to the outstanding processability and formability, CCMPs can be in situ synthesized and coated over fibers through a simple spray procedure. Taken together, the design provides a promising strategy for developing reusable and self-sterilizing antimicrobial fabrics, particularly for the application of face masks to tackle infectious pathogen and viruses in daily protection and medical applications. © 2023 Wiley-VCH GmbH.

Photoantibacterial Poly(vinyl)chloride Films Applying Curcumin Derivatives as Bio-Based Plasticizers and Photosensitizers.

Herein we describe the design of natural curcumin ester and ether derivatives and their application as potential bioplasticizers, to prepare photosensitive phthalate-free PVC-based materials. The preparation of PVC-based films incorporating several loadings of newly synthesized curcumin derivatives along with their standard solid-state characterization is also described. Remarkably, the plasticizing effect of the curcumin derivatives in the PVC material was found to be similar to that observed in previous PVC-phthalate materials. Finally, studies applying these new materials in the photoinactivation of S. aureus planktonic cultures revealed a strong structure/activity correlation, with the photosensitive materials reaching up to 6 log CFU reduction at low irradiation intensities.

Recent Advances in Green Metallic Nanoparticles for Enhanced Drug Delivery in Photodynamic Therapy: A Therapeutic Approach.

Globally, cancer is one of the leading causes of death among men and women, it is characterized by the unregulated proliferation of tumor cells. Some of the common risk factors associated with cancer development include the consistent exposure of body cells to carcinogenic agents such as alcohol, tobacco, toxins, gamma rays and alpha particles. Besides the above-mentioned risk factors, conventional therapies such as radiotherapy, and chemotherapy have also been linked to the development of cancer. Over the past decade, tremendous efforts have been invested in the synthesis of eco-friendly green metallic nanoparticles (NPs), and their medical application. Comparatively, metallic NPs have greater advantages over conventional therapies. Additionally, metallic NPs can be functionalized with different targeting moieties e.g., liposomes, antibodies, folic acid, transferrin, and carbohydrates. Herein, we review and discuss the synthesis, and therapeutic potential of green synthesized metallic NPs for enhanced cancer photodynamic therapy (PDT). Finally, the advantages of green hybridized activatable NPs over conventional photosensitizers (PSs) and the future perspectives of nanotechnology in cancer research are discussed in the review. Furthermore, we anticipate that the insights offered in this review will inspire the design and development of green nano-formulations for enhanced image-guided PDT in cancer treatment.

Color-variable dual-dyed photodynamic antimicrobial polyethylene terephthalate (PET)/cotton blended fabrics.

The urgent demand for scalable, potent, color variable, and comfortable antimicrobial textiles as personal protection equipment (PPE) to help reduce infection transmission in hospitals and healthcare facilities has significantly increased since the start of the COVID-19 pandemic. Here, we explored photodynamic antimicrobial polyethylene terephthalate/cotton (TC) blended fabrics comprised of photosensitizer-conjugated cotton fibers and polyethylene terephthalate (PET) fibers dyed with disperse dyes. A small library of TC blended fabrics was constructed wherein the PET fibers were embedded with traditional disperse dyes dominating the fabric color, thereby enabling variable color expression, while the cotton fibers were covalently coupled with the photosensitizer thionine acetate as the microbicidal agent. Physical (SEM, CLSM, TGA, XPS and mechanical strength) and colorimetric (K/S and CIELab values) characterization methods were employed to investigate the resultant fabrics, and photooxidation studies with DPBF demonstrated the ability of these materials to generate reactive oxygen species (i.e., singlet oxygen) upon visible light illumination. The best results demonstrated a photodynamic inactivation of 99.985% (~ 3.82 log unit reduction, P = 0.0021) against Gram-positive S. aureus, and detection limit inactivation (99.99%, 4 log unit reduction, P ≤ 0.0001) against Gram-negative E. coli upon illumination with visible light (60 min; ~ 300 mW/cm2; λ ≥ 420 nm). Enveloped human coronavirus 229E showed a photodynamic susceptibility of ~ 99.99% inactivation after 60 min illumination (400-700 nm, 65 ± 5 mW/cm2). The presence of the disperse dyes on the fabrics showed no significant effects on the aPDI results, and furthermore, appeared to provide the photosensitizer with some measure of protection from photobleaching, thus improving the photostability of the dual-dyed fabrics. Taken together, these results suggest the feasibility of low cost, scalable and color variable thionine-conjugated TC blended fabrics as potent self-disinfecting textiles.

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

Background: The main objective was to evaluate the efficacy of intranasal photodynamic therapy (PDT) in SARS-CoV-2 mildly symptomatic carriers on decreasing the infectivity period. SARS-CoV-2-specific immune-stimulating effects and safety were also analysed. Methods: We performed a randomized, placebo-controlled, clinical trial in a tertiary hospital (NCT05184205). Patients with a positive SARS-CoV-2 PCR in the last 48 hours were recruited and aleatorily assigned to PDT or placebo. Patients with pneumonia were excluded. Participants and investigators were masked to group assignment. The primary outcome was the reduction in in vitro infectivity of nasopharyngeal samples at days 3 and 7. Additional outcomes included safety assessment and quantification of humoral and T-cell immune-responses. Findings: Patients were recruited between December 2021 and February 2022. Most were previously healthy adults vaccinated against COVID-19 and most carried Omicron variant. 38 patients were assigned to placebo and 37 to PDT. Intranasal PDT reduced infectivity at day 3 post-treatment when compared to placebo with a ß-coefficient of -812.2 (CI95%= -478660 - -1.3, p<0.05) infectivity arbitrary units. The probability of becoming PCR negative (ct>34) at day 7 was higher on the PDT-group, with an OR of 0.15 (CI95%=0.04-0.58). There was a decay in anti-Spike titre and specific SARS-CoV-2 T cell immunity in the placebo group 10 and 20 weeks after infection, but not in the PDT-group. No serious adverse events were reported. Interpretation: Intranasal-PDT is safe in pauci-symptomatic COVID-19 patients, it reduces SARS-CoV-2 infectivity and decelerates the decline SARS-CoV-2 specific immune-responses.

Molecular docking study of potential antimicrobial photodynamic therapy as a potent inhibitor of SARS-CoV-2 main protease: An in silico insight.

BACKGROUND: Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) is rapidly spreading. Recently, antimicrobial photodynamic therapy (aPDT) using safe and cost-effective photosensitizers is introduced as a valuable therapy for the eradication of microbial infections. OBJECTIVE: This in silico study aimed to investigate the potential of aPDT against of SARS-CoV-2 main protease (MPro). METHODS: In this study to evaluate possible inhibitors of SARS-CoV-2 during aPDT, a computational model of the SARS-CoV-2 MPro was constructed in complex with emodin, resveratrol, pterin, and hypericin as the natural photosensitizers. RESULTS: According to the molecular docking analysis of protein-ligand complexes, emodin and resveratrol with a high affinity for SARS-CoV-2 MPro showed binding affinity -7.65 and -6.81 kcal/mol, respectively. All natural photosensitizers with ligand efficiency less than 0.3 fulfilled all the criteria of Lipinski's, Veber's, and Pfizer's rules, except hypericin. Also, the results of molecular dynamic simulation confirmed the stability of the SARS-CoV-2 MPro and inhibitor complexes. CONCLUSION: As the results showed, emodin, resveratrol, and pterin could efficiently interact with MPro of SARS CoV-2. It can be concluded that aPDT using these natural photosensitizers may be considered as a potential SARS-CoV-2 MPro inhibitor to control COVID-19.

Clinical effectiveness and prospects of methylene blue A systematic review

Methylene blue (MB) is a well-known pharmaceutical ingredient that is thought to have a multi-targeted therapeutic effect as an anti-malarial and neuroprotective agent and has recently been identified as a treatment for coronavirus disease 2019 (COVID-19). In this review, we present an overview of relevant clinical trials, including ongoing trials, on the therapeutic uses of MB. A search for clinical trials on clinicaltrials.gov was performed using the terms "methylene blue" and "methylthionine chloride." This review focuses on clinical trials of MB-based therapies applied to brain diseases, cancer imaging and diagnosis, infectious diseases such as malaria or COVID-19, and cardiovascular diseases. Nanoparticle-based delivery techniques have also been briefly discussed in addition to common delivery methods.

Photodynamic therapy: A new treatment against Covid-19

In 2019, a new coronavirus (COVID-19) was discovered in Wuhan, China, which soon spread all over the world. The main hallmark of the disease includes fever, diarrhea, vomiting, and dry cough with dyspnea in half of the patients and acute respiratory distress syndrome (ARDS). Currently, no definitive treatment or prevention therapy exists for COVID-19 but scientists and researchers all over the world are relentlessly working to understand COVID-19 to discover novel therapeutic tools and vaccines. Today, photodynamic therapy (PDT) has been investigated as a noninvasive therapy for the treatment of this pandemic and was able to increase the healing process with the help of appropriate photosensitizers by targeting the pathogen inside the patient's body. Copyright © 2022, Semnan University of Medical Sciences. All rights reserved.

A Novel Approach of Combining Methylene Blue Photodynamic Inactivation, Photobiomodulation and Oral Ingested Methylene Blue in COVID-19 Management: A Pilot Clinical Study with 12-Month Follow-Up.

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 virus was first recognized in late 2019 and remains a significant threat. We therefore assessed the use of local methylene blue photodynamic viral inactivation (MB-PDI) in the oral and nasal cavities, in combination with the systemic anti-viral, anti-inflammatory and antioxidant actions of orally ingested methylene blue (MB) and photobiomodulation (PBM) for COVID-19 disease. The proposed protocol leverages the separate and combined effects of MB and 660nm red light emitted diode (LED) to comprehensively address the pathophysiological sequelae of COVID-19. A total of eight pilot subjects with COVID-19 disease were treated in the Bahamas over the period June 2021-August 2021, using a remote care program that was developed for this purpose. Although not a pre-requisite for inclusion, none of the subjects had received any COVID-19 vaccination prior to commencing the study. Clinical outcome assessment tools included serial cycle threshold measurements as a surrogate estimate of viral load; serial online questionnaires to document symptom response and adverse effects; and a one-year follow-up survey to assess long-term outcomes. All subjects received MB-PDI to target the main sites of viral entry in the nose and mouth. This was the central component of the treatment protocol with the addition of orally ingested MB and/or PBM based on clinical requirements. The mucosal surfaces were irradiated with 660 nm LED in a continuous emission mode at energy density of 49 J/cm2 for PDI and 4.9 J/cm2 for PBM. Although our pilot subjects had significant co-morbidities, extremely high viral loads and moderately severe symptoms during the Delta phase of the pandemic, the response to treatment was highly encouraging. Rapid reductions in viral loads were observed and negative PCR tests were documented within a median of 4 days. These laboratory findings occurred in parallel with significant clinical improvement, mostly within 12-24 h of commencing the treatment protocol. There were no significant adverse effects and none of the subjects who completed the protocol required in-patient hospitalization. The outcomes were similarly encouraging at one-year follow-up with virtual absence of "long COVID" symptoms or of COVID-19 re-infection. Our results indicate that the protocols may be a safe and promising approach to challenging COVID-19 disease. Moreover, due its broad spectrum of activity, this approach has the potential to address the prevailing and future COVID-19 variants and other infections transmitted via the upper respiratory tract. Extensive studies with a large cohort are warranted to validate our results.

Photodynamic viral inactivation assisted by photosensitizers

The deadly viruses, which are spreading worldwide at an alarming rate, are a major challenge for the life sci-ences. More efficient and cost-effective methods with fewer side effects can provide a good alternative to traditional drug-based methods. Currently, physical phenomena such as light in the form of photodynamic action are increasingly being used to inactivate viruses. Photodynamic inactivation (PDI) uses a photosensitizer (PS), light, and oxygen to generate reactive oxygen species (ROS) to inactivate microorganisms. This article reviews the use of existing PSs, as one of the essential anti-viral agents, and introduces new materials and strategies combined with PDI. Physiochemical properties of PSs and their role in interaction with virus components are discussed. Furthermore, the effectiveness of optical sensitizers with radiation methods to inactivate viruses is highlighted.