Saliva-permeable and antimicrobial potentiometric pH sensor for oral health monitoring

Oral health hinges on tightly regulated acid-base chemistry that fluctuates within minutes after eating or hygiene, yet existing assessments are episodic and miss these transient events. We demonstrate a liquid-permeable potentiometric pH sensor designed for non-invasive intraoral monitoring that integrates a saliva-through fibrous layer for fast convective-capillary transport, a percolated silver-nanowire network for low-impedance readout and antibacterial activity, and a pH-responsive sensing layer paired with an on-board Ag/AgCl reference. The integration sensor delivers near-Nernstian sensitivity, rapid and reversible responses, and low drift during extended operation under simulated oral conditions. Microbiological assays show the inhibition of Streptococcus mutans and Candida albicans, supporting resistance to biofilm fouling. Moreover, in human-use demonstrations, the sensor captures real-time salivary pH excursions during sugar intake, mixed meals, and tooth brushing. This platform establishes a practical route toward patient-centric oral electronics that shift diagnosis and prevention from the clinic into everyday life.