An electrochemical sensing platform for early prediction of dental caries.

Dental caries, with a global prevalence of 29 %, represents a major public health challenge. Traditional diagnostic methods often delay intervention, leading to irreversible tooth damage. In this study, we present a saliva-based electrochemical sensing platform for the early prediction of dental caries through the simultaneous detection of three key biomarkers: Streptococcus mutans, Ca2+, and pH. A nanocomposite electrode, constructed from Prussian blue, metal-organic framework, polypyrrole, and carboxylated multi-walled carbon nanotubes, provided a highly active electrochemical surface with reduced interfacial resistance and an enhanced electron transfer rate. For S. mutans detection, dual-recognition elements comprising a competence-stimulating peptide and an S. mutans-imprinted polymer were used to ensure selective binding. Ca2+ and pH were detected using a Ca2+ ion-selective membrane and a doped polyaniline film, respectively. The platform demonstrated detection ranges of 101-108 CFU mL-1 for S. mutans, 0.01-100 mM for Ca2+, and pH 4.0-8.0, with excellent resistance to salivary interference, high reproducibility, and long-term stability. Testing on clinical samples confirmed the platform's ability to accurately distinguish caries status, highlighting its potential as a non-invasive and portable diagnostic tool for early dental caries prediction.