Development and preliminary evaluation of tongue cleaner-based pH and glucose biosensors for salivary assessment

Saliva reflects both oral and systemic health. Monitoring salivary pH and glucose using tongue cleaner-based biosensors may provide a simple non-invasive method for routine salivary assessment.

To develop and preliminarily evaluate separate tongue cleaner-based biosensors for salivary pH and glucose detection in healthy individuals and those with oral disease.

Separate pH and glucose biosensors were fabricated on tongue cleaner platforms. The pH biosensor used an anthocyanin-chitosan-pullulan membrane, while the glucose biosensor incorporated glucose oxidase-functionalized carbon graphite and silver/silver chloride electrodes. Eighty participants aged 18-65 years were included: 40 with dental caries or periodontitis and 40 healthy controls. The glucose sensor was calibrated using glucose standards and validated against the GOD-POD assay.

Salivary pH was significantly lower in the study group than controls (6.71 ± 0.41 vs 7.44 ± 0.22; p < 0.001). Glucose resistance values were significantly higher in the study group (39.03 ± 15.54 kΩ vs 10.24 ± 1.13 kΩ; p < 0.001), indicating elevated salivary glucose levels. Very large effect sizes were observed for pH, glucose resistance, and glucose levels. Potentiometric measurements strongly correlated with the GOD-POD assay (r = 0.96; p < 0.001).

The developed tongue cleaner-based biosensors demonstrated measurable differences in salivary pH and glucose between healthy individuals and those with oral disease. These low-cost, non-invasive biosensors show potential for salivary assessment, although further large-scale validation is required.