To determine the potential for visible light (405 or 624 nm) to produce an inhibitory effect on Candida albicans. In addition, the study sought to evaluate a series of doses in terms of their respective inhibiting capabilities.
The authors have studied the effect of blue light on Staphylococcus aureus and found that a bactericidal outcome can be obtained with low doses of blue light.
Candida albicans was tested because of its common appearance in human skin and mucous membrane infections. The organism was treated in vitro with 405-nm (blue) and with 624-nm (red) light emitted from a supraluminous diode array. Doses of 3, 9, 15, 30, and 60 J/cm2 were used. Colony counts were performed and compared with untreated controls using Student t tests and 1-way analysis of variance with Tukey post hoc analysis.
The results revealed no inhibition produced by 405 nm on C albicans (F 4,20 = 0.901; P = .482). However, 624 nm did inhibit growth of C albicans at 3, 9, and 30 J/cm2 (F 4,20 = 6.064; P = .002).
Appropriate doses of 624-nm light from a supraluminous diode array can inhibit the growth of C albicans in vitro. Three, 9, and 30 J/cm2 are all effective dose levels.
J. Stephen Guffey, PT, EdD, is an Associate Professor of Physical Therapy; William Payne, MS, ASCP(MT), is an Assistant Professor of Clinical Laboratory Science; Leslie James, BS, is a Doctor of Physical Therapy Student; Zhuoyuan Qian, BS, is a Doctor of Physical Therapy Student; and Carly Dodson is a Clinical Laboratory Science Student; all at Arkansas State University, Jonesboro, Arkansas. Dr Guffey has disclosed that he is a consultant for Dynatronics Corporation. The coauthors have disclosed that they have no financial relationships related to this article.
Submitted April 8, 2013; accepted in revised form August 16, 2013.