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Induction of lethal photosensitization in biofilms using a confocal scanning laser as the excitation source
1School of Dental Sciences, The University of Liverpool, Daulby Street, Liverpool L69 3GN, UK. c.hope@liv.ac.uk
Objectives:
To induce lethal photosensitization in biofilms of Streptococcus pyogenes using the scanning laser in a confocal microscope to photoactivate Sn (IV) chlorin e6 (SnCe6) while simultaneously measuring changes in cell vitality using fluorescent indicators of membrane integrity.
Methods:
Biofilms of S. pyogenes were immersed in a solution of 50 mg/L (70.28 microM) SnCe6 and scanned with the 488 nm argon and 543 nm HeNe lasers in a confocal microscope. Changes in membrane permeability were quantified using image analysis tools.
Results:
Cell permeability increased in biofilms of S. pyogenes after successive scanning/exposure cycles in the presence of SnCe6.
Conclusions:
Cell death was induced in biofilms of S. pyogenes by the photosensitizer SnCe6 on exposure to the scanning laser emissions of a confocal microscope. The simultaneous recording of cell death demonstrates the real-time evaluation of a light-activated antimicrobial compound against a biofilm.
