Unveiling role of carbon dots for non-invasive and ultra-sensitive glucose detection in biofluids for personal preventive care testing

• Noninvasive glucose detection is a promising means for the prevention of non-communicable diseases (NCDs). • Carbon dot synthesis and the effects of size, dopants, and surface modification on their properties are discussed. • Tunable fluorescence and simple functionalization are promising features of CDs for artificial enzyme reactions. • Peroxidase-like activity of various nanozymes for glucose detection was discussed. • Non-invasive, low-cost, accurate, and ultrasensitive assays for ultralow glucose level sensing in tears, sweat, and saliva were presented. Non-communicable diseases (NCDs) have become significant risks for humans due to sedentary lifestyles and inaccurate diagnoses. Early detection of NCDs using simple technologies greatly reduces the burden and is set to revolutionize clinical intervention and healthcare delivery. Diabetes is one of the metabolic disorders that is indicated by increasing blood glucose levels that cause an increased risk of other vascular diseases and NCDs. Carbon dots (CDs), zero-dimensional nanomaterial, is one of the carbonaceous nanomaterials including 1-D carbon nanotubes, 2-D graphene and graphene oxide (GO), and 3-D carbon-based core-shell or spatial carbon nanostructures, which has been rapidly developed as substrate materials for biosensors. This review critically examines recent advancements in ultrasensitive and noninvasive glucose detection focusing on biofluids based on carbon nanomaterials along with the current stage and future development. The main focus is on the principles behind the design, fabrication, and functioning of these carbon-based materials emphasizing carbon dots for effective electrochemical, and optical glucose biosensing such as colorimetry, fluorimetry, and fluorescence imaging. Additionally, insights into the swiftly expanding potential of a variety of glucose sensors in biomedical and biological engineering were revealed. This review serves as a roadmap to guide researchers in creating next-generation surface-enhanced and functionalized biosensors while emphasizing the latest advancements in the field. The review thoroughly examined the balance between sustainability and effectiveness in glucose sensing techniques, emphasizing low reagent toxicity, minimal waste, and high sensitivity. This analysis underlines the importance of ongoing innovation to enhance both the performance and sustainability of glucose detection technologies.