Rapid inactivation of SARS-CoV-2 with LED irradiation of visible spectrum wavelengths.

Difficulty in controlling SARS-CoV-2 transmission made the ability to inactivate viruses in aerosols and fomites to be an important and attractive risk reduction measure. Evidence that light frequencies have the ability to inhibit microorganisms has already been reported by many studies which, however, focused on ultraviolet (UV) wavelengths, which are known to induce potential injury in humans. In the present study, the effect on suspensions of SARS-CoV-2 of a Light Emitting Diode (LED) device capable of radiating frequencies in the non-hazardous visible light spectrum (VIS) was investigated. In order to evaluate the efficiency of viral inactivation, plaque assay and western blot of viral proteins were performed. The observed results showed a significant reduction in infectious particles that had been exposed to the LED irradiation of visible light. Furthermore, the analysis of the intracellular expression of viral proteins confirmed the inactivating effect of this irradiation technology. This in vitro study revealed for the first time the inactivation of SARS-CoV-2 through LED irradiation with multiple wavelengths of the visible spectrum. However additional and more in-depth studies can aim to demonstrate the data obtained during these experiments in different matrices, in mutable environmental conditions and on other respiratory viruses such as the influenza virus. The type of LED technology can decisively contribute on reducing virus transmission through the continuous sanitation of common environments without risks for humans and animals.

Magnetic beads combined with carbon black-based screen-printed electrodes for COVID-19: A reliable and miniaturized electrochemical immunosensor for SARS-CoV-2 detection in saliva.

The diffusion of novel SARS-CoV-2 coronavirus over the world generated COVID-19 pandemic event as reported by World Health Organization on March 2020. The huge issue is the high infectivity and the absence of vaccine and customised drugs allowing for hard management of this outbreak, thus a rapid and on site analysis is a need to contain the spread of COVID-19. Herein, we developed an electrochemical immunoassay for rapid and smart detection of SARS-CoV-2 coronavirus in saliva. The electrochemical assay was conceived for Spike (S) protein or Nucleocapsid (N) protein detection using magnetic beads as support of immunological chain and secondary antibody with alkaline phosphatase as immunological label. The enzymatic by-product 1-naphtol was detected using screen-printed electrodes modified with carbon black nanomaterial. The analytical features of the electrochemical immunoassay were evaluated using the standard solution of S and N protein in buffer solution and untreated saliva with a detection limit equal to 19 ng/mL and 8 ng/mL in untreated saliva, respectively for S and N protein. Its effectiveness was assessed using cultured virus in biosafety level 3 and in saliva clinical samples comparing the data using the nasopharyngeal swab specimens tested with Real-Time PCR. The agreement of the data, the low detection limit achieved, the rapid analysis (30 min), the miniaturization, and portability of the instrument combined with the easiness to use and no-invasive sampling, confer to this analytical tool high potentiality for market entry as the first highly sensitive electrochemical immunoassay for SARS-CoV-2 detection in untreated saliva.

Human Fibroblasts In Vitro Exposed to 2.45 GHz Continuous and Pulsed Wave Signals: Evaluation of Biological Effects with a Multimethodological Approach.

The increasing exposure to radiofrequency electromagnetic fields (RF-EMF), especially from wireless communication devices, raises questions about their possible adverse health effects. So far, several in vitro studies evaluating RF-EMF genotoxic and cytotoxic non-thermal effects have reported contradictory results that could be mainly due to inadequate experimental design and lack of well-characterized exposure systems and conditions. Moreover, a topic poorly investigated is related to signal modulation induced by electromagnetic fields. The aim of this study was to perform an analysis of the potential non-thermal biological effects induced by 2.45 GHz exposures through a characterized exposure system and a multimethodological approach. Human fibroblasts were exposed to continuous (CW) and pulsed (PW) signals for 2 h in a wire patch cell-based exposure system at the specific absorption rate (SAR) of 0.7 W/kg. The evaluation of the potential biological effects was carried out through a multimethodological approach, including classical biological markers (genotoxic, cell cycle, and ultrastructural) and the evaluation of gene expression profile through the powerful high-throughput next generation sequencing (NGS) RNA sequencing (RNA-seq) approach. Our results suggest that 2.45 GHz radiofrequency fields did not induce significant biological effects at a cellular or molecular level for the evaluated exposure parameters and conditions.

Genotoxic Effects in Human Fibroblasts Exposed to Microwave Radiation.

In the last decades, technological development has led to an increasing use of devices and systems based on microwave radiation. The increased employment of these devices has elicited questions about the potential long-term health consequences associated with microwave radiation exposure. From this perspective, biological effects of microwave radiation have been the focus of many studies, but the reported scientific data are unclear and contradictory. The aim of this study is to evaluate the potential genotoxic and cellular effects associated with in vitro exposure of human fetal and adult fibroblasts to microwave radiation at the frequency of 25 GHz. For this purpose, several genetic and biological end points were evaluated. Results obtained from comet assay, phosphorylation of H2AX histone, and antikinetochore antibody (CREST)-negative micronuclei frequency excluded direct DNA damage to human fetal and adult fibroblasts exposed to microwaves. No induction of apoptosis or changes in prosurvival signalling proteins were detected. Moreover, CREST analysis showed for both the cell lines an increase in the total number of micronuclei and centromere positive micronuclei in exposed samples, indicating aneuploidy induction due to chromosome loss.

Study of the effects of 0.15 terahertz radiation on genome integrity of adult fibroblasts.

The applications of Terahertz (THz) technologies have significantly developed in recent years, and the complete understanding of the biological effects of exposure to THz radiation is becoming increasingly important. In a previous study, we found that THz radiation induced genomic damage in fetal fibroblasts. Although these cells demonstrated to be a useful model, exposure of human foetuses to THz radiation is highly improbable. Conversely, THz irradiation of adult dermal tissues is cause of possible concern for some professional and nonprofessional categories. Therefore, we extended our study to the investigation of the effects of THz radiation on adult fibroblasts (HDF). In this work, the effects of THz exposure on HDF cells genome integrity, cell cycle, cytological ultrastructure and proteins expression were assessed. Results of centromere-negative micronuclei frequencies, phosphorylation of H2AX histone, and telomere length modulation indicated no induction of DNA damage. Concordantly, no changes in the expression of proteins associated with DNA damage sensing and repair were detected. Conversely, our results showed an increase of centromere-positive micronuclei frequencies and chromosomal nondisjunction events, indicating induction of aneuploidy. Therefore, our results indicate that THz radiation exposure may affect genome integrity through aneugenic effects, and not by DNA breakage. Our findings are compared to published studies, and possible biophysical mechanisms are discussed. Environ. Mol. Mutagen. 59:476-487, 2018. © 2018 Wiley Periodicals, Inc.

RENEB intercomparison exercises analyzing micronuclei (Cytokinesis-block Micronucleus Assay).

PURPOSE: In the framework of the 'Realizing the European Network of Biodosimetry' (RENEB) project, two intercomparison exercises were conducted to assess the suitability of an optimized version of the cytokinesis-block micronucleus assay, and to evaluate the capacity of a large laboratory network performing biodosimetry for radiation emergency triages. Twelve European institutions participated in the first exercise, and four non-RENEB labs were added in the second one. MATERIALS AND METHODS: Irradiated blood samples were shipped to participating labs, whose task was to culture these samples and provide a blind dose estimate. Micronucleus analysis was performed by automated, semi-automated and manual procedures. RESULTS: The dose estimates provided by network laboratories were in good agreement with true administered doses. The most accurate estimates were reported for low dose points (≤ 0.94 Gy). For higher dose points (≥ 2.7 Gy) a larger variation in estimates was observed, though in the second exercise the number of acceptable estimates increased satisfactorily. Higher accuracy was achieved with the semi-automated method. CONCLUSION: The results of the two exercises performed by our network demonstrate that the micronucleus assay is a useful tool for large-scale radiation emergencies, and can be successfully implemented within a large network of laboratories.

Biological effects of in vitro THz radiation exposure in human foetal fibroblasts.

In recent years, terahertz (THz) radiation has been widely used in a variety of applications: medical, security, telecommunications and military areas. However, few data are available on the biological effects of this type of electromagnetic radiation and the reported results, using different genetic or cellular assays, are quite discordant. This multidisciplinary study focuses on potential genotoxic and cytotoxic effects, evaluated by several end-points, associated with THz radiation. For this purpose, in vitro exposure of human foetal fibroblasts to low frequency THz radiation (0.1-0.15THz) was performed using a Compact Free Electron Laser. We did not observe an induction of DNA damage evaluated by Comet assay, phosphorylation of H2AX histone or telomere length modulation. In addiction, no induction of apoptosis or changes in pro-survival signalling proteins were detected. Moreover, our results indicated an increase in the total number of micronuclei and centromere positive micronuclei induction evaluated by CREST analysis, indicating that THz radiation could induce aneugenic rather than clastogenic effects, probably leading to chromosome loss. Furthermore, an increase of actin polymerization observed by ultrastructural analysis after THz irradiation, supports the hypothesis that an abnormal assembly of spindle proteins could lead to the observed chromosomal malsegregation.

Dose estimation using dicentric chromosome assay and cytokinesis block micronucleus assay: comparison between manual and automated scoring in triage mode.

In cases of an accidental overexposure to ionizing radiation, it is essential to estimate the individual absorbed dose of a potentially radiation-exposed person. For this purpose, biological dosimetry can be performed to confirm, complement or even replace physical dosimetry when this proves to be unavailable. The most validated biodosimetry techniques for dose estimation are the dicentric chromosome assay, the "gold standard" for individual dose assessment, and cytokinesis-block micronucleus assay. However, both assays are time consuming and require skilled scorers. In case of large-scale accidents, different strategies have been developed to increase the throughput of cytogenetic service laboratories. These are the decrease of cell numbers to be scored for triage dosimetry; the automation of procedures including the scoring of, for example, aberrant chromosomes and micronuclei; and the establishment of laboratory networks in order to enable mutual assistance if necessary. In this study, the authors compared the accuracy of triage mode biodosimetry by dicentric chromosome analysis and the cytokinesis block micronucleus assay performing both the manual and the automated scoring mode. For dose estimation using dicentric chromosome assay of 10 blind samples irradiated up to 6.4 Gy of x-rays, a number of metaphase spreads were analyzed ranging from 20 up to 50 cells for the manual and from 20 up to 500 cells for the automatic scoring mode. For dose estimation based on the cytokinesis block micronucleus assay, the micronucleus frequency in both 100 and 200 binucleated cells was determined by manual and automatic scoring. The results of both assays and scoring modes were compared and analyzed considering the sensitivity, specificity, and accuracy of dose estimation with regard to the discrimination power of clinically relevant binary categories of exposure doses.

Pattern of HPV infection in basal cell carcinoma and in perilesional skin biopsies from immunocompetent patients.

BACKGROUND: The association between human papillomavirus (HPV) infection and non-melanoma skin cancers (NMSCs) such as squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) is not yet fully understood. We analysed the prevalence and spectrum of cutaneous beta-HPV types and mucosal/genital HPV types in paired biopsies (tumour and corresponding perilesional skin) obtained from 50 BCC immunocompetent patients. A small group of SCC patients (n=9) was also included. We also evaluated some previously postulated risk factors for HPV infection in NMSC patients. RESULTS: All biopsies were negative for mucosal/genital HPV types. Overall, beta-HPV DNA was detected more often in SCC compared to BCC patients (78% vs 55% of total samples). The frequency of infection increased with the patient's age [OR=4.88 (95% CI 1.29-18.39)]. There was no significant correlation between beta-HPV positivity and sex, skin type and UV exposure. The prevalence of beta-HPV species 1 types was significantly higher than those belonging to other beta-HPV species in biopsies from BCC (p=0.022) but not from SCC subjects (p=0.091). There was no significant difference in the overall prevalence of beta-HPV infection and the number of viral types between tumour lesions and perilesional skin. BCC samples were significantly more likely to be infected with beta-HPV species 1 types compared to perilesional skin (p=0.036) and showed a higher frequency of mixed infections (p=0.028). CONCLUSIONS: These findings demonstrate that beta-HPV types belonging to species 1 are the most common HPV types detected in the skin of BCC patients. Moreover beta-1-HPV types and mixed infections are significantly more frequent in tumour samples than in healthy perilesional skin. Our results suggest that beta-1-HPVs as well as co-infection with more than one viral type could be important in NMSC and in particular in BCC.Further studies aimed to compare the biological activity of viral types in tumours and in healthy skin (viral replication and expression, interference of infection with cellular functions) are necessary to understand the role of HPV infection in skin cancer.