OBJECTIVE: 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.
BACKGROUND DATA: 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.
METHODS: 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.
RESULTS: The results revealed no inhibition produced by 405 nm on C albicans (F4,20 = 0.901; P = .482). However, 624 nm did inhibit growth of C albicans at 3, 9, and 30 J/cm2 (F4,20 = 6.064; P = .002).
CONCLUSIONS: 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.