María Cebriá-Mendoza

Airborne fungi and bacteria pose a severe challenge for conservators, as they can settle on artistic surfaces, leading to chemical, physical and aesthetic degradation of artworks. A new air-cleaning system has been developed to reduce indoor airborne microorganisms by leveraging the antimicrobial potential of Tea Tree (Melaleuca alternifolia) Essential Oil (TTEO) encapsulated within the pores of MCM-41 mesoporous silica microparticles (MCM-TTEO), thereby extending its antimicrobial activity and enhancing its efficacy. Experimental data showed a progressive release of TTEO from the MCM-TTEO system during the 5 weeks monitoring. The release rate was quite linear in the first week, reaching about 16.2%, before plateauing at approximately 30% in the next weeks. A comparison of the performances of the MCM-TTEO system with those of the non-encapsulated (‘free’) TTEO was performed using a comprehensive air quality monitoring approach, which tracked temperature, relative humidity, microbial loads and particulate matter. Results demonstrate that the MCM-TTEO system maintained higher biocidal activity over the 5-week study period than the free EO. Furthermore, the biocidal efficacy increased when the MCM-TTEO system was used in direct contact with microorganisms. These promising findings highlight the potential for exploring different combinations of the two components in both passive and active configurations, including the development of air filtration systems.

Background/Objectives: Orthopaedic infections associated with implant surgery remain a major public health concern, often caused by bacterial colonization of implant surfaces. Staphylococcus epidermidis is among the most common pathogens involved. Developing antimicrobial bone implants that prevent infection without compromising bone regeneration is therefore essential. This study investigates the antimicrobial and osteointegrative performance of calcium phosphate (CaP) materials functionalized with vanillin, an essential oil component with known antimicrobial properties. Methods: Commercial CaP regenerative materials were covalently coated with vanillin. Antibacterial activity was evaluated against Staphylococcus epidermidis RP62A using viability assays. In vivo osseointegration was assessed in New Zealand female rabbits implanted with vanillin-coated and uncoated CaP scaffolds. Results: Vanillin-functionalized CaP scaffolds exhibited strong bactericidal activity at 24 h and bacteriostatic effects at 48 h at a concentration of 10 mg/mL. In vivo analyses showed no significant differences in osseointegration between vanillin-coated implants and control CaP materials. Conclusions: Vanillin-functionalized CaP materials maintain a high safety profile without impairing bone integration, supporting their potential use in clinical applications.

Anelloviruses are the most common human infectious viruses and are considered essentially harmless. Compared to other human viruses, they are characterized by enormous diversity, and recombination is suggested to play an important role in their diversification and evolution.

Bacteriophages represent an alternative strategy to combat pathogenic bacteria. Currently, Mycobacterium tuberculosis infections constitute a major public health problem due to extensive antibiotic resistance in some strains. Using a non-pathogenic species of the same genus as an experimental model, Mycobacterium smegmatis, here we have set up a basic methodology for mycobacteriophage growth and we have explored directed evolution as a tool for increasing phage infectivity and lytic activity. We demonstrate mycobacteriophage adaptation to its host under different conditions. Directed evolution could be used for the development of future phage therapy applications against mycobacteria.