Pterins are an inseparable part of living organisms. Pterins participate in metabolic reactions mostly as tetrahydropterins. Dihydropterins are usually intermediates of these reactions, whereas oxidized pterins can be biomarkers of diseases. In this review, we analyze the available data on the quantum chemistry of unconjugated pterins as well as their photonics. This gives a comprehensive overview about the electronic structure of pterins and offers some benefits for biomedicine applications: (1) one can affect the enzymatic reactions of aromatic amino acid hydroxylases, NO synthases, and alkylglycerol monooxygenase through UV irradiation of H₄pterins since UV provokes electron donor reactions of H₄pterins; (2) the emission properties of H₂pterins and oxidized pterins can be used in fluorescence diagnostics; (3) two-photon absorption (TPA) should be used in such pterin-related infrared therapy because single-photon absorption in the UV range is inefficient and scatters in vivo; (4) one can affect pathogen organisms through TPA excitation of H₄pterin cofactors, such as the molybdenum cofactor, leading to its detachment from proteins and subsequent oxidation; (5) metal nanostructures can be used for the UV-vis, fluorescence, and Raman spectroscopy detection of pterin biomarkers. Therefore, we investigated both the biochemistry and physical chemistry of pterins and suggested some potential prospects for pterin-related biomedicine.

A discharge operating in a 80-cm-long discharge tube with an inner diameter of 15 mm, filled with a 3 : 1 neon–argon mixture at a pressure of 1 Torr, was investigated experimentally. Square voltage...

Enteric viruses are a major cause of waterborne infections due to their high environmental stability and extremely low infectious dose. Current molecular diagnostic methods, while accurate, often depend on thermal cycling and centralized laboratory facilities, limiting their applicability in decentralized or resource-limited settings. In this study, we developed an isothermal biosensor based on a split deoxyribozyme that reconstitutes its catalytic core upon hybridization with a conserved sequence of enteroviral RNA. This activation leads to site-specific cleavage of a fluorogenic substrate, producing a quantifiable fluorescent signal. The system was experimentally validated using both synthetic enteroviral RNA and RNA extracted from environmental water samples. To enhance detection sensitivity, the DNAzyme-based assay was coupled with isothermal RNA amplification. The results demonstrate high selectivity and compatibility with real-world samples, supporting the sensor’s utility for field-deployable viral RNA detection. Overall, this study highlights the potential of the DNAzyme-based platform as a portable, sequence-specific, and amplification-assisted diagnostic tool for environmental surveillance of enteric viruses.

Bolivian hemorrhagic fever (BHF) is a zoonotic disease caused by Mammarenavirus machupoense (MACV) featuring severe neurological and hemorrhagic symptoms and a high mortality rate. BHF is usually diagnosed by serological tests or real-time polymerase chain reaction (RT-PCR); these methods are often inaccessible in endemic regions due to a lack of laboratory infrastructure, creating a demand for sensitive and rapid equipment-free alternatives. Here, we present an isothermal method for MACV nucleic acid detection based on the Cas12a-based DETECTR system combined with recombinase polymerase amplification (RPA) in a single tube: the RT-RPA/DETECTR assay. We demonstrate the possibility of using more than one primer set for the simultaneous detection of MACV genetic variants containing multiple point mutations. The method was optimized and tested using specially developed virus-like armored particles containing the target sequence. The multiplex RT-RPA/DETECTR method achieved a limit of detection of approximately 5 × 10⁴ copies/ mL (80 aM) of armored particles. The method was validated using clinical samples spiked with virus-like particles. The assay proved to be selective and reliable in detecting certain nucleotide substitutions simultaneously.

Identification of Salmonella Enterica Serovar Typhi DNA by loop-mediated isothermal amplification with fluorescent detection Идентификация ДНК Salmonella Enterica Serovar Typhi методом петлевой изотермической амплификации с флюоресцентной детекцией