Fluorescence imaging studies of the processes leading to photodynamic inactivation of bacteria have been limited due to the small size of microorganisms as well as by the faint fluorescence of most photosensitizers. A versatile method based on highly-sensitive fluorescence microscopy is presented which allows to study, in real time, the incorporation of photosensitizers inside S. aureus upon photodynamic action. The method takes advantage of the fluorescence enhancement of phenothiazine and porphyrin photosensitizers upon entering the bacterial cytosol after the cell wall has been compromised. In combination with typical assays, such as the addition of specific enhancers of reactive oxygen species, it is possible to extract mechanistic information about the pathway of photodynamic damage at the single-cell level. Imaging experiments in deuterated buffer strongly support a Type-I mechanism for methylene blue and a very minor role of singlet oxygen.

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201500259DOI Listing

Publication Analysis

Top Keywords

photodynamic action
8
real-time imaging
4
photodynamic
4
imaging photodynamic
4
action bacteria
4
fluorescence
4
bacteria fluorescence
4
fluorescence imaging
4
imaging studies
4
studies processes
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!