Advances in saliva-based glucose sensors

Diabetes mellitus is a chronic disease that affects millions of people around the world, with estimations resulting in currently over 400 million patients and projections foreshadowing further increasing case numbers in the years to come. This chronic disease impacts the patients’ quality of life and places a major burden on healthcare systems worldwide. An effective diabetes management critically needs adequate glucose monitoring to maintain optimal blood glucose levels and to prevent complications. The conventional blood glucose monitoring practices are inconvenient and invasive, posing challenges for various patient populations especially infants, the elderly and those with limited mobility. These methods could further increase the risk of infection and discomfort. Saliva is an easily accessible and non-invasive fluid that offers a promising alternative to conventional glucose tests. This review provides an overview of recent important developments in saliva-based glucose sensing and discusses the progress made in sensing methods, nanomaterials and various approaches. In addition, the review examines the progress for the development of nanomaterial-based glucose sensors from 2022 to 2025 including electrochemical, field-effect transistor (FET) and optical sensors. These sensor types are evaluated based on their analytical performance which includes sensitivity, detection range, limit of detection, selectivity, stability and accuracy in measuring glucose levels in real/artificial saliva. This review addresses some of the challenges facing the measurement of glucose levels in saliva such as low concentrations of glucose and interference from interfering substances. In addition, future perspectives are presented for the development of efficient and robust saliva-based glucose sensors to enhance diabetes care and patient management.