Phosphorylated pullulan as a local drug delivery matrix for cationic antibacterial chemicals to prevent oral biofilm

Preventing oral infections, such as oral caries and periodontal disease, helps reduce the risks of various systemic diseases. In this study, the polysaccharide pullulan produced by the black yeast Aureobasidium pullulans was modified in combination with the cationic surfactant cetylpyridinium chloride (CPC) to create a local drug delivery system, and its antibacterial potential on oral bacteria was examined in vitro.

Pullulan was phosphorylated at the CH₂OH residue of α6 in the maltotriose structure and mixed with CPC. Bacterial attachment of cariogenic Streptococcus mutans on hydroxyapatite plates (HAPs) treated with the phosphorylated pullulan (PP) and CPC compound (0.01% PP and 0.001- 0.03% CPC, and vice versa) was assessed by observing bacteria using a field emission scanning electron microscope (FE-SEM) and quantified through 16 S rRNA amplification via real-time polymerase chain reaction (PCR). Additionally, the quartz crystal microbalance (QCM) method was employed to evaluate the sustained release of CPC.

PP-CPC compound maintained significant bactericidal activity even at 0.01%, which is one-fifth of the conventional applicable concentration of CPC. Additionally, a residual mixture was detected by the hydroxyapatite sensor of the crystal oscillator microbalance detector, suggesting an unknown molecular interaction that enables the sustained release of CPC after attachment to hydroxyapatite.

The combination of PP and CPC may contribute to the low concentration and effective prevention of oral infections, such as dental caries.