A gliding arc discharge (GAD) plasma device has been developed and tested. Possible applications areas for GAD plasma could be microalgae suspension treatments and the creation of plasma-activated water. To understand its behavior, the influence of the input power on the electrical characteristics of the generated GAD plasma was investigated using an oscilloscope. The waveforms of the voltage and current of GAD plasma are presented. The duration of the discharge time and the evolution of the arc during discharge were determined and investigated. It was revealed that the increase in the output voltage prolonged the duration of the arc discharge. The composition of the air plasma was investigated using a flame-emission spectrometer and acousto-optic emission spectrometer. It was revealed that the main species in the emission spectra of the GAD air plasma were N₂, N₂⁺, N⁺, NO, and O species. Furthermore, the increase in the input power enhanced the ionization degree of the air plasma and increased the intensities of the emission lines associated with N₂⁺, NO, and O species. An increase in the conductivity of the BG-11 medium was observed. Physicochemical analyses of the plasma-activated BG-11 medium indicated an increase in the concentration of nitrite and nitrate ions and hydrogen peroxide with an enhancement of the voltage.

Photoactive hydrogels facilitate light-triggered photochemical processes, positioning them as innovative solutions in biomedical applications, especially in antimicrobial photodynamic therapy. This study presents a novel methylene blue-based photoactive hydrogel designed as a topical gel solution to overcome the limitations of traditional pad-based systems by offering enhanced adaptability to irregular wound surfaces, uniform photosensitizer distribution, and deeper therapeutic light penetration. This study investigated the development of hydrogels by cross-linking gelatin with glutaraldehyde (GA) and incorporating methylene blue (MB) to investigate the effects of cross-linking density, network structure, and small molecule inclusion on hydrogel properties. The results showed that while glutaraldehyde concentration influenced swelling behavior and network structure, the inclusion of MB altered these properties, particularly reducing swelling and MB retention at higher GA concentrations. Rheological and thermal analyses confirmed that higher GA concentrations made the hydrogels more rigid, with MB influencing both mechanical and thermal properties. Additionally, the hydrogels exhibited enhanced antimicrobial properties through increased reactive oxygen species production, particularly in light-activated conditions, demonstrating the potential of MB-based photoactive hydrogels for improving antimicrobial efficacy, especially against S. aureus, E. coli, and C. albicans, offering as a possible alternative to traditional antimicrobial treatments.

This study presents a novel approach for treating chronic biofilm-associated infections by utilizing a gel-like hydrogel (HG1MB1) incorporating methylene blue (MB), a photosensitizer, to enhance photoinactivation of microbial biofilms. The key novelty of this work lies in the gel-like structure of HG1MB1, which significantly improves the penetration of MB into the deeper layers of the biofilm, promoting more effective disruption of the biofilm matrix. This improved uptake and interaction with the extracellular polymeric substances (EPS) of the biofilm leads to a reduction in EPS and breakdown of the biofilm structure. Additionally, the hydrogel’s ability to generate reactive oxygen species (ROS) upon light activation enhances its antimicrobial efficacy. HG1MB1 also demonstrated broad-spectrum activity against both bacterial and fungal biofilms, suggesting its potential as an effective treatment for chronic infections.