Contribution to the development of materials for the prevention of infectious diseases is expected
For the prevention of infectious diseases such as COVID-19, the use of antibacterial and antiviral coatings on frequently touched surfaces is effective. Traditionally, the standard method proposed by the International Organization for Standardization (ISO) has been used to evaluate the performance of such antibacterial coatings; however, this method does not allow the spatial and/or real-time distribution of bacterial cells to be obtained because the bacterial cells grown on the coatings are washed out and then re-cultured on agar. It has also been shown that several factors, such as the density of bacteria inoculated on the coatings, affect the evaluation results, but optimization of these parameters has been insufficient. For these reasons, a novel evaluation system was needed to more accurately assess the performance of antibacterial coatings.
In this research, we succeeded in visualizing the spatial distribution of bacterial cells simultaneously grown on the antibacterial coating substrate by acquiring images of green fluorescent protein-expressing E. coli using a fluorescence observation setup consisting of an LED light source, optical filter, and digital camera. It was possible to analyze the temporal changes in the spatial distribution of bacterial cells on the substrate, which could not be assessed by the conventional ISO method. The acquired fluorescence images were converted into several quantitative indicator values, and the effects of the size of the coating substrates and the amount of inoculated bacterial broth on the evaluation results were systematically investigated and optimized. Under the optimized observation conditions, the antibacterial activity of the coating material developed for the prevention of infectious diseases was successfully demonstrated. In the future, more accurate evaluation of the antibacterial activities of various coating materials and promotion of their widespread use are expected to contribute to the prevention of infectious diseases.
Papers
Journal: Scientific Reports
Title: Systematic study on the evaluation method of surface antibacterial activity based on the fluorescent observation of bacterial growth
Authors: Noriko Nakamura, Tatsuki Yamagishi, Wataru Nagata, Yuki Akahane, Hyemin Seo, Ayaka Otsuka, Daiki Hishikawa, Risa Yoshimoto, Nobuhiro Miyamae, Seiichi Ohta*
Super-multiplex imaging of cellular dynamics and heterogeneity by integrated stimulated Raman and fluorescence microscopy
Super-resolution vibrational imaging based on photoswitchable Raman probe
