Induction of lethal photosensitization in biofilms using a confocal scanning laser as the excitation source.
OBJECTIVE
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.
Hope
C K
CK
School of Dental Sciences, The University of Liverpool, Daulby Street, Liverpool L69 3GN, UK. c.hope@liv.ac.uk
Wilson
M
M
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002462:Cell Membrane / Q000473:pathology; D002463:Cell Membrane Permeability / Q000502:physiology; D005456:Fluorescent Dyes / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D008665:Metalloporphyrins / Q000494:pharmacology*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013297:Streptococcus pyogenes / Q000187:drug effects* / Q000254:growth & development
D000900:Anti-Bacterial Agents; D005456:Fluorescent Dyes; D008665:Metalloporphyrins; D017319:Photosensitizing Agents; C069117:tin(IV) chlorin e6