A multiplexed laser-scribed graphene immunosensor for simultaneous detection of adiponectin and leptin: a point-of-care solution for early insulin resistance diagnosis

The increasing prevalence of insulin resistance (IR) highlights the importance of early diagnosis and timely medical intervention. The ratio of adiponectin to leptin proteins (A/L) is believed to be a key indicator of IR, but the lack of adequate ways of tracking it prevents its clinical utilization. To that end, we have developed a laser-scribed graphene (LSG) based immunosensor capable of detecting adiponectin and leptin simultaneously. The sensors are decorated with gold nanostructure (AuNS) that are bio-functionalized with adiponectin and leptin antibodies via EDC/NHS covalent chemistry. We demonstrate that the immunosensor is suitable for clinical utilization, with a detection limit of 0.59 μg/mL for adiponectin and 0.18 ng/mL for leptin. Furthermore, the multiplexed nature of the assay allows for IR assessments at reduced sample volume whilst not compromising accuracy. Lastly, we validate the applicability of the immunosensor for point-of-care (PoC) settings by integrating with a customized miniaturized potentiostat connected to a smartphone application. The resulting device can be used for the facile quantification of A/L at clinically relevant accuracy, facilitating faster IR assessment relative to conventional methods that rely on independent measurements of the two biomarkers.