Rose Bengal incorporated to α-cyclodextrin microparticles for photodynamic therapy against the cariogenic microorganism Streptococcus mutans

α-Cyclodextrin Microparticles with Rose Bengal significantly improve photodynamic therapy against the cariogenic microorganism Streptococcus mutans. [Display omitted] •Rose Bengal@α-cyclodextrin (RB@α-CD) microparticles (μPs) were prepared.•RB inclusion in α-CD was experimentally demonstrated.•Classical molecular mechanics calculations assessed the inclusion geometries.•The microparticles were tested against cariogenic Streptoccocus mutans.•RB@α-CD μPs is 10 times more efficient than pure RB against these bacteria. Rose Bengal@α-cyclodextrin (RB@α-CD) microparticles (μPs) were prepared and the RB inclusion in α-CD was experimentally demonstrated through infrared, UV–VIS absorption spectroscopy and cyclic voltammetry. The RB inclusion in α-CD was theoretically investigated using classical molecular mechanics calculations, the simulation results showing that RB can be included in both the narrow and wide apertures of the α-cyclodextrin ring with configurations exhibiting average binding energies of about 27 kcal mol−1. The prepared RB@α-CD microparticles were characterized through Scanning Electron Microscopy (SEM) and it was demonstrated that they are highly efficient in the photodynamic therapy against a Streptococcus mutans (the main bacteria of cariogenic dental plaque) suspension, as a concentration of RB@α-CD μPs 10 times smaller than the usual concentration of pure RB is still capable to produce significant antibacterial activity.