This study describes the association of curcumin with light emitting diode (LED) for the inactivation of Candida albicans. Suspensions of Candida were treated with nine curcumin concentrations and exposed to LED at different fluences. The protocol that showed the best outcomes for Candida inactivation was selected to evaluate the effect of the preirradiation time (PIT) on photodynamic therapy (PDT) effectiveness, the uptake of curcumin by C. albicans cells and the possible involvement of singlet oxygen in the photodynamic action. Curcumin-mediated PDT was also assessed against biofilms. In addition to the microbiological experiments, similar protocols were tested on a macrophage cell line and the effect was evaluated by Methyltetrazolium assay (MTT) and SEM analysis. The optical properties of curcumin were investigated as a function of illumination fluence. When compared with the control group, a statistically significant reduction in C. albicans viability was observed after PDT (P < 0.05), for both planktonic and biofilm cultures. Photodynamic effect was greatly increased with the presence of curcumin in the surrounding media and the PIT of 20 min improved PDT effectiveness against biofilms. Although PDT was phototoxic to macrophages, the therapy was more effective in inactivating the yeast cell than the defense cell. The spectral changes showed a high photobleaching rate of curcumin.

Objective. In vivo studies of antimicrobial PDT in animal models of oral candidosis are scarce and the association of porphyrin and LED light has not been evaluated for in vivo photoinactivation of Candida. In this study the effectiveness of photodynamic therapy (PDT) on the inactivation of Candida albicans in vivo was evaluated. Study design. Seventy-one 6-week-old female Swiss mice were immunosuppressed, provided tetracycline to their drinking water, then orally swabbed with a suspension of C. albicans (10 7 CFU/mL). Four days after oral inoculation, PDT was performed on the dorsum of the tongue after topical administration of Photogem at 400, 500, or 1000 mg/L and followed 30 minutes later by illumination with LED light (305 J/cm 2 ) at 455 or 630 nm (n ϭ 5 each). After swabbing to recover yeast from the tongue, the number of surviving yeast cells was determined (CFU/mL) and analyzed by ANOVA and Holm-Sidak tests (P Ͻ .05). Animals were humanely killed, and the tongues surgically removed and processed for histological evaluation of presence of yeast and inflammatory reaction. Results. PDT resulted in a significant reduction in C. albicans recovered from the tongue (P Ͻ .001) when compared with mice from the positive control group. There was no difference between the concentrations of Photogem and LED light wavelengths used. Histological evaluation of the tongue revealed that PDT causes no significant adverse effects to the local mucosa. Conclusion. PDT promoted significant reduction in the viability of C. albicans biofilm without harming the tongue tissue.

Although the oral cavity is easily accessible to inspection, patients with oral cancer most often present at a late stage, leading to high morbidity and mortality. Autofluorescence imaging has emerged as a promising technology to aid clinicians in screening for oral neoplasia and as an aid to resection, but current approaches rely on subjective interpretation. We present a new method to objectively delineate neoplastic oral mucosa using autofluorescence imaging.Autofluorescence images were obtained from 56 patients with oral lesions and 11 normal volunteers. From these images, 276 measurements from 159 unique regions of interest (ROI) sites corresponding to normal and confirmed neoplastic areas were identified. Data from ROIs in the first 46 subjects were used to develop a simple classification algorithm based on the ratio of red-to-green fluorescence; performance of this algorithm was then validated using data from the ROIs in the last 21 subjects. This algorithm was applied to patient images to create visual disease probability maps across the field of view. Histologic sections of resected tissue were used to validate the disease probability maps.The best discrimination between neoplastic and nonneoplastic areas was obtained at 405 nm excitation; normal tissue could be discriminated from dysplasia and invasive cancer with a 95.9% sensitivity and 96.2% specificity in the training set, and with a 100% sensitivity and 91.4% specificity in the validation set. Disease probability maps qualitatively agreed with both clinical impression and histology. Autofluorescence imaging coupled with objective image analysis provided a sensitive and noninvasive tool for the detection of oral neoplasia.