Abstract

Obesity-associated type 2 diabetes is characterized by chronic hyperglycemia, insulin resistance, dyslipidemia 
and low-grade inflammation, all of which fluctuate markedly in response to meals, physical activity, stress and 
medication use. Conventional monitoring based on fasting glucose, HbA1c and occasional finger-stick tests 
provides only sparse snapshots of this dynamic state and is particularly inadequate in individuals with obesity, 
who often exhibit greater glycemic variability, complex polypharmacy and multiple comorbidities. Nano
biosensors, which integrate biorecognition elements with nanostructured transducers, offer a route to minimally 
invasive, continuous and potentially multiplex monitoring of key metabolic biomarkers in real time. By 
exploiting the high surface area, excellent electrical and optical properties and tunable surface chemistry of 
nanomaterials such as graphene, carbon nanotubes, metal nanoparticles and nanozymes, these systems can reach 
physiologically relevant detection limits in tiny volumes of interstitial fluid, sweat, saliva or tears. When 
embedded in skin-interfaced patches, microneedle arrays, textiles or wearable devices, nano-biosensors can track 
glucose and complementary markers such as lactate, ketones and stress indicators continuously, with the 
potential to inform precision treatment, improve adherence and enable earlier detection of metabolic 
decompensation. This review discusses the rationale for continuous metabolic monitoring in obese diabetic 
individuals, the relevant biomarker landscape, key design principles of nano-biosensors, emerging fluid-specific 
and wearable platforms, current evidence and translational challenges, and future directions including multiplex 
devices and AI-assisted analytics.