Plants have evolved an enormous arsenal of phytochemicals as the defence against microbial infections. Many plant extracts display excellent bactericidal and fungicidal activities, while remaining innocuous. A number of papers have been demonstrated that thyme oil and corresponding phytochemical, thymol, possess an outstanding antimicrobial ability against bacteria and fungi. This work delves into their formulation into coating materials for sustained surface disinfection via microencapsulation and controlled-release mechanism. The thyme oil based antimicrobial coating has been formulated and optimized by the standard bactericidal assessment which is flourished for the antimicrobial surface to probe the biocidal activity of the coating. A long-term bactericidal test shows the optimized...[ Read more ]

Plants have evolved an enormous arsenal of phytochemicals as the defence against microbial infections. Many plant extracts display excellent bactericidal and fungicidal activities, while remaining innocuous. A number of papers have been demonstrated that thyme oil and corresponding phytochemical, thymol, possess an outstanding antimicrobial ability against bacteria and fungi. This work delves into their formulation into coating materials for sustained surface disinfection via microencapsulation and controlled-release mechanism. The thyme oil based antimicrobial coating has been formulated and optimized by the standard bactericidal assessment which is flourished for the antimicrobial surface to probe the biocidal activity of the coating. A long-term bactericidal test shows the optimized formulation is able to maintain an outstanding bactericidal performance. The release profile of the antimicrobial coating is examined by the use of Gas Chromatography-Mass Spectrometry (GC-MS) to investigate controlled release characteristics at different storage temperatures. Polymer related factors are scrutinized for an understanding of the controlled release mechanism, ensuing in the formulation of the coating for both sustained release and continuous surface disinfection. TOF-SIMS result indicates that the establish coating could stably attach while retaining the thymol content on the glass surface. 28-day sporicidal test illustrates that the coating can achieve >90% reduction in a contact time of 10 minutes throughout the experimental period. In addition to applying to a surface, the antimicrobial coating is employed to a porous medium, high-efficiency particulate air (HEPA) filter. The antimicrobial filter is able to maintain approximate 90% reduction against S. aureus with 10-minute contact time during 28-day experimental period. A field study for the antimicrobial filter was conducted in office and hospital areas to ascertain the significance level of the antimicrobial efficacy. The statistical data conclude that the antimicrobial filter is able to achieve significant and marginal bacterial reduction in office and hospital areas (p=0.000 and p=0.084), and significant fungal reduction in the hospital area (p=0.009).