The human body is an intelligent system, continuously generating signals that correlate with specific vital activities and indicate the state of our health and fitness. Therefore, accurate and real-time tracking of these signals is important for monitoring our health and timely medical interventions. The quantification of these signals in real-time is made possible by using skin wearable devices that detect disease-related biomarkers in bodily fluids, such as sweat and interstitial fluid. Integrating nanomaterials, particularly graphene, into wearable devices has dramatically enhanced the performance of wearable biosensors. The exemplary electrical properties, mechanical flexibility, and biocompatibility of graphene have made it a revolutionary material to shape the future of wearable devices. Graphene is versatile because its surface chemistry can be easily tuned to accommodate different biorecognition elements. This review provides an overview of flexible wearable biosensing devices, their sampling methods, and how microfluidic approaches enhance their performance. The paper also discusses the different strategies for the synthesis of graphene nanostructures, their integration into wearable systems, and their ability to improve sensing performance. Various surface chemistry modification techniques are also explored for enhancement of immobilisation of biomolecules. Finally, the paper discusses the challenges of graphene-based wearable technologies and their roles in continuous health monitoring and personalised medicine.
