Effective photosensitizing ability of three dyes at varying concentrations using culturing techniques – an in-vitro study

Introduction: Although different photosensitization agents/dyes have been extensively used in literature, but little is correlated to their actual absorption spectrum or concentrations when analyzing the results obtained from those studies. Also whether the bactericidal effect is due to the agent itself or effect of photo activation is not clear.
Aims and Objectives:
1. To evaluate the absorption and spectrum of range of 3-dyes using
Spectrophotometer.
2. To evaluate the bactericidal efficacy of 3-dyes at varying concentrations
using culture technique.
3. To evaluate the difference in bactericidal efficiency of each dye on
photoactivation.
Methodology: The absorption and the spectrum of range for 3-dyes at varying
Concentrations (Methylene blue 1%, 2% ; Erythrosine 2%, 3%; Eosine 1%, 3%) was evaluated using a Spectrophotometer. To determine the photosensitizing effect of the dyes at varying concentrations, two different experiments were performed for each concentration on blood-agar plates. Zone of bacterial inhibition was evaluated on parallel set of dyes with/ without photoactivation using 980nm diode laser.
Results: Photo-activation of the dyes at suitable concentration leads to a decrease in the microbial count.
Conclusion: Greater microbicidal benefits can be achieved if the absorption range and concentration of a dye are correlated to the energy delivered for photo-activation.