B. Fenech-Salerno, M. Holicky, C. Yao, F. Torrisi
Imperial College London,
Keywords: graphene, biosensors, chemosensors, sensors, diagnostics, point-of-care, affordable
Summary:Diagnostic tests and devices are increasingly becoming integral to the diagnosis, treatment and even prevention of disease. For maximum impact, tests should demonstrate Real-time connectivity, Ease of sample collection, whilst also being Affordable, Sensitive, Specific, User friendly, Rapid and robust, Equipment-free and Deliverable to end-user or REASSURED. Consequently, diagnostic tests empower clinicians to provide patients with tailored and timely treatment. However, expensive equipment and a constrain on trained staff, have highlighted the need for simple, rapid tests that can be administer at the point-of-care (PoC). In this work, our team presents the development of a novel, low-cost biosensing platform in line with the REASSURED criteria for implementation at the point of care. Our device leverages the superb sensing properties of printable graphene inks. We synthesise simple graphene inks, with tailored concentrations, long shelf lives, and flake sizes with high aspect ratio (mean > 65). The high-quality inks were sprayed on custom-designed electrodes using high-throughput fabrication methods, to produce electrolyte-gate field effect transistors (EG-GFETs) with reliable and replicable manufacturing production techniques. The EG-GFETs were subsequently optimised to detect for pH through pH 3 – 11, with a resolution of 0.04 pH units and a sensitivity of 26 mV/pH. We further demonstrate the utility of the platform, by combining with selective protein recognition elements and macromolecules to detect for drugs and ions (such as Na+ and K+).