Smart Stimuli-Responsive Piezoelectric Antibacterial Adhesives For Caries Prevention

Piezoelectric materials, exhibiting stimuli-responsive characteristics, possess controllable and reusable antimicrobial properties. This study fabricated a piezoelectric adhesive, which can be activated by oral movements and ultrasonic toothbrushes to sustain antimicrobial activity, offering a novel strategy for caries prevention. A piezoelectric adhesive containing silver-loaded barium titanate was synthesized and characterized, followed by safety assessment. An oscillatory device simulating oral movements and an ultrasonic generator mimicking ultrasonic toothbrushes were used to activate the piezoelectric properties of the modified adhesive, and its antimicrobial effects were assessed by evaluating biofilm formation/removal, metabolic activity, and structural integrity of Streptococcus mutans (S. mutans). Furthermore, the antimicrobial mechanism was elucidated by quantifying intracellular reactive oxygen species (ROS) levels, while ROS production was evaluated following simulated aging processes. The modified adhesive retained good adhesive properties and cellular safety. It significantly inhibited biofilm formation and metabolic activity under motion stimulation (P < 0.05). Upon ultrasound activation, it further removed residual biofilm and reduced metabolic vitality (P < 0.05), with the antimicrobial efficacy exhibiting a dose-dependent enhancement. The antimicrobial mechanism was associated with increased ROS production, which exhibited long-term efficacy. In this study, a smart piezoelectric adhesive with antimicrobial properties was successfully developed, which could effectively combat the S. mutans biofilm under motion stimulation and ultrasound activation. It demonstrated dynamic antimicrobial activity, opening up a novel stimuli-responsive approach for caries prevention.