Graphene-based nanomaterials in biosensing: current advances, challenges, and future directions for precision diagnostics.

BACKGROUND

Graphene-based nanomaterials (GBNs), including graphene oxide, reduced graphene oxide, graphene quantum dots, and their composites, combine ultra-high surface area, superior conductivity, and tunable optical properties, making them powerful materials for ultra-sensitive biosensing.

AIM AND SCOPE: Unlike earlier descriptive, platform-specific surveys, this review is organised around structure-property-performance relationships and applies a uniform critical lens to the primary literature.

METHODS

We examine optical (fluorescence, surface plasmon resonance, colorimetric, SERS), electrochemical, and field-effect transistor (FET) biosensors. We compare them head-to-head on sensitivity, reproducibility, scalability, and clinical readiness.

KEY FINDINGS: GBN platforms detect pathogens such as SARS-CoV-2, cancer biomarkers, metabolites, and environmental toxins with high sensitivity and selectivity. However, many reported ultra-low detection limits are extrapolated from buffer calibrations rather than measured, and they are rarely validated in blinded clinical cohorts. Some are also physically implausible given the number of target molecules in the assay volume.

CHALLENGES: Key barriers are cytotoxicity, non-specific binding, irreproducible synthesis, and regulatory validation. For FETs specifically, the main obstacles are Debye screening, baseline drift, and poor wafer-scale yield.

CONCLUSIONS

AI-assisted signal processing, wearable and implantable devices, and 3D-printed multi-analyte lab-on-a-chip systems are critical future directions. Addressing these challenges through interdisciplinary effort could make GBN biosensors a foundation for personalized, point-of-care healthcare.