The Effects of Photodynamic Therapy in Oral Biofilms - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 446

Fig. 3 Scanning electron microscope of different biofilms. Image ( a ) refers to control biofilms of
Staphylococcus aureus not sensitised with methylene blue (MB) and not exposed to laser light and
( b ) shows biofilms sensitised with MB for 5 min and exposed to laser for 98 s. Image ( c ) refers to
control biofilms of Candida albicans , Staphylococcus aureus and Streptococcus mutans not
sensitised with MB and not exposed to laser light and ( d ) shows sensitised biofilms with MB for
5 min and exposed to laser for 98 s. Magnification ¼ 10,000. Partially reproduced from Pereira
et al. ( 2011 ). Lasers in medical science by European Laser Association, Reproduced with
permission of Springer-Verlag, London Ltd
presented by C. albicans can be explained by the structural differences between
biofilm bacteria and yeast or failure of light to penetrate thick biofilms formed by
Candida (Lee et al. 2004 ).
There are differences in physiological and environmental bacteria growing in
biofilms compared to planktonic counterparts. In biofilms, bacteria respond best to
the antimicrobial methods of nutrient deprivation, pH changes, oxygen radicals,
and antibiotics compared to bacteria in the planktonic form (Wei et al. 2006 ).
Some phenotypic changes may render the bacteria more resistant to environ-
mental changes as they move from the planktonic to the sessile state of biofilm,