Banca de QUALIFICAÇÃO: JAMES HENRIQUE ALMEIDA

VALIDATION OF A LOW-COST PORTABLE LIGHT ON HUMAN KERATINOCYTES AND PROTECTIVE EFFECT OF PERSONAL PROTECTIVE EQUIPMENT (PPE)

Ultraviolet Radiation; Accidental exposure; Prototype Validation

Admissions and preventable deaths occur annually in healthcare facilities due to infections acquired in these environments. Surface contamination by pathogenic microorganisms exacerbates this scenario, necessitating disinfection measures. Ultraviolet (UV) radiation is a well-established method in the literature, inactivating microorganisms by damaging their nucleic acids. Exposure to radiation can affect not only the intracellular material of the microorganism but also a set of cells in exposed individuals. In response to COVID-19 in 2020, researchers from the Federal Institute of Alagoas developed a low-cost UV-C radiation luminaire for comprehensive disinfection, especially in healthcare units. The efficacy of this device requires validation of its proposed effects to validate its subsequent use. Therefore, the present study aimed to contribute to the validation of the efficacy of a low-cost UV-C radiation luminaire, investigating potential cellular damage caused by exposure in a lineage of non-tumoral human keratinocytes (HaCaT) at different exposure times. For this purpose, keratinocytes were exposed for different periods (10, 60, or 300s) to UVC radiation (±16 mW/cm², 254 nm) and evaluated at 1, 6, 24, or 72 hours after exposure, with or without the presence of personal protective equipment (PPE). The parameters evaluated included cell viability, morphological analysis by optical microscopy on violet-stained cells, fluorescent dye staining to assess cell death by apoptosis or necrosis (acridine orange and propidium iodide - AO/PI staining), and clonogenic assay. Exposure to radiation for 10 seconds resulted in a significant reduction in cell viability, with a noticeable percentage decrease in viable cells over the assessed time intervals. Cell density and morphological characteristics were altered after exposure, revealing atypical features compared to unexposed cells. The fluorescence assay with AO/PI revealed an increase in dead cell quantification, reflecting a lower density of cells adhered to the plate. The clonogenic assay demonstrated complete elimination of cells after 10 seconds of exposure during the 14-day trial period.Tests conducted using Personal Protective Equipment (PPE) revealed a level of protection to cells that varied depending on the material used. Notably, latex and nitrile gloves yielded the best results, maintaining cell viability, morphology, and the quantity of dead cells similar to the unexposed group, indicating positive outcomes.The results of this study demonstrate, as expected, that the luminaire induces toxic effects on cells by promoting DNA damage. The presence of specific PPEs provides considerable protection in cases of accidental exposure by luminaire users. These findings contribute to the validation process for the use of the fabricated device.