Ion Munteanu

A new UV-C decontamination device has been tested at laboratory scale for its potential to inactivate microorganisms in commercial baker’s yeast solu

This study explores the potential of pulsed UV-C radiation within the 220 - 280 nm spectral range for microbiological decontamination, achieved through coupling evanescent waves generated at metamaterial surfaces with incident UV-C radiation. The main objective is to assess the decontamination efficiency as a function of varying temporal intervals between UV-C pulses, while maintaining a constant pulse energy. Experiments were conducted on yeast solutions (Saccharomyces cerevisiae) used as a biological model, subjected to irradiation over different exposure durations. Optical absorption spectra revealed significant alterations in the biochemical and structural properties of the cells, correlated with the irradiation timing parameters. The findings confirm the enhanced efficiency of combining pulsed UV-C radiation with metamaterial structures for pathogen inactivation, providing a robust foundation for the development of advanced decontamination technologies in medical and industrial environments

This chapter introduces an optical framework for the generation of molecular superstructures from tertiary components through Raman-induced interactions with a bimodal cavity field. A nonlinear model is developed based on cooperative processes analogous to multiple Raman scattering and their integration with biomolecular assemblies. Particular attention is given to phase transitions leading to the formation of supramolecular structures, where induced Raman excitation enables the stabilization of multimeric states such as dimers, trimers, tetramers, and pentamers. The proposed master equation describes the synthesis and stabilization of such structures under Raman excitation. Importantly, the model can also be applied inversely, where large molecular aggregates are dissociated into smaller components via induced multiple Raman scattering. This dual mechanism provides a theoretical basis for designing highly efficient optical metamaterials with potential applications in advanced decontamination technologies. To illustrate the applicability, experimental investigations were performed using yeast fungi as a surrogate for more sensitive pathogens (viruses and bacteria). The results revealed two distinct decontamination regimes under nanosecond-pulsed ultraviolet C radiation, consistent with the predictions of the multiple Raman dimerization model. These findings highlight the potential of Raman-driven cooperative processes in both molecular synthesis and selective pathogen inactivation.

The COVID-19 pandemic has intensified the need for advanced pathogen inactivation strategies, with ultraviolet-C (UV-C) radiation emerging as a potent disinfection method. This study investigates the efficacy of short-pulse UV-C irradiation (220–280 nm) compared to continuous-wave exposure for decontaminating pathogens, using Baker’s yeast as a safe biological model. Our primary objective is to evaluate the decontamination efficacy of pulsed UV-C radiation by varying pulse intervals while maintaining constant pulse energy. We observed a progressive increase in yeast inactivation with higher pulse counts, evidenced by reduced transparency at 230 nm and 267 nm and increased solution absorbance, indicative of DNA chain disruption. The research addresses two main components: (1) a theoretical model examining the effects of short UV-C pulses on biomolecules during radiation propagation, and (2) practical applications for pathogen diagnosis, treatment, and inactivation, with significant implications for ontogenetic and public health outcomes.

A semi-classical model (classical by the field and quantum by describing biomolecules) is proposed, which establishes the dependence of the DNA/RNA dimerization rate on ultraviolet C (UVC) radiation intensity. In particular, a nonlinear model based on cooperative processes similar to the Ramanlike in quantum optics is developed. The main result of the theory demonstrates that the dimerization process in DNA/RNA strongly depends on the UVC light intensity, thus proving a possible quantum microscopic mechanism of UVC light interactions with DNA. A notion of a photonic molecule consisting of the normal state and the dimer state under the action of the bimodal Raman field is given. This type of molecule exists only in the presence of the excited field, and after it is turned off, the biomolecule remains part of the time in the entangled state after which DNA dimerization is probabilistically established. A nonlinear dependence on the intensity of the applied radiation was established, which was confirmed in a series of experiments on the inactivation of pathogens (or yeast colonies) reproduction under the action of ultraviolet radiation. The main objective of this study was to establish a link between the intensity of UV C radiation and the efficiency of decontamination using metamaterials with an increased contact surface with contaminated fluid by pathogens, that cause nosocomial infections, namely Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Candida glabrata. These microorganisms were put through different forms of packing, both thick fibers repacked with thin fibers and millimeter balls repacked with sub-millimeter quartz balls. The results demonstrate that bacterial pathogens respond differently to exposure to UV-C radiation, depending on the contact surface created between the elements of the quasi-periodic metamaterials.

The inactivation of pathogens using ultraviolet (UV) radiation has become a critical research focus following the COVID-19 pandemic, underscoring the need for advanced decontamination strategies against viruses, bacteria, and other pathogens. This study proposes the use of short pulses of UV-C radiation (220–280 nm) as an effective method for pathogen inactivation. Our primary objective is to evaluate the decontamination efficacy of pulsed UV-C radiation by varying the time intervals between pulses while maintaining constant pulse energy, and to analyze the resulting absorption spectra of a yeast solution across different irradiation durations. The research addresses two main components: (1) a theoretical model examining the effects of short UV-C pulses on biomolecules during radiation propagation, and (2) practical applications for pathogen diagnosis, treatment, and inactivation, with significant implications for ontogenetic and public health outcomes.

At the present time, a special attention is given to the large-scale using of implant treatments. Modern implants have a good rate of success, reliability and longevity, they are minimally invasive, delicate and resistant. Due to the development of some forms of pathogens at the implant-tissue contact, there are situations of poor adhesion of the implant surface to the organic tissue. The application of chemical or surgical methods in such situations are difficult. But in order to solve these phenomena, new techniques are needed to be implemented. That why it is proposed to apply ultraviolet radiation on the optical system (photonic crystals and photonic fiber crystals) of modern implants to treat the infection that can appear on the surface between the implant and the cellular tissue in the process of poor adhesion. These combinations of periodic quartz optical structures are deposited and regularly arranged (set of fibers or spheres) on the implant surface, which can be used as a large volume dispersion of ultraviolet C radiation to treat the infection at the surface between the implant and adhesion tissue. The proposed periodic optical structure contributes considerably to increasing the adhesion of the implant to the cellular tissue, thus stimulating cellular growth between the elements and the implant.

A new method for repackaging optical metamaterials formed from quartz spheres (fibers) of various diameters is proposed for ultraviolet C disinfection of infected liquids by pathogens (viruses and bacteria). The main idea of the new equipment is connected with the rotation of a contaminated fluid by screw channels within a metamaterial matrix prepared from UVC fibers/spherical optics, to improve the decontamination efficiency. In demonstration of the viability of this approach, dynamic and static inactivation of Baker's yeast via Ultraviolet C radiation regimes are used in this paper to show the efficacy of decontamination within the screw channels.

În ultima perioadă, utilizarea tratamentelor cu implant se bucură de notorietate. Datorită dezvoltări unor forme de patogeni la contactul implant-țesu,t există situații de slabă aderență a suprafeței implantului la țesutul organic. Odată ce metodele chimice sau chirurgicale sunt anevoioase în astfel de situații, sunt necesare tehnici noi pentru a putea soluționa aceste fenomene. Propunem aplicarea radiațiilor ultraviolete asupra sistemului optic (cristale fotonice și fibră de cristal fotonic) din implanturile moderne pentru a trata infecția dintre implant și țesutul celular în procesul de slabă aderență. Aceste seturi de structuri optice periodice din cuarț, aranjate în mod regulat (setul de fibre sau sfere), sunt depuse pe suprafața implantului și pot fi utilizate ca un volum mare de dispersie a radiației UV-C pentru tratarea infecției dintre implant și țesutul de adeziune. Această structura optică periodică favorizează aderența implantului la țesutul uman, astfel stimulând creșterea celulară între elemente și implant.