Low-Cost Point of Care Detection of the Stress Hormone Cortisol (Hydrocortisone) Using Molecular Imprinted Polymer Technology on a Laser Induced Graphene Electrode

Abstract

The rapid detection of hormone biomarkers is a necessity for many applications within medical screening and diagnostics. The measurement and monitoring of the stress hormone Cortisol levels is essential for the development of a personalised medicine approach, as excess or insufficient levels can cause various diseases and health issues. Here we present a low-cost point of care sensor for the potential monitoring of Cortisol levels. Using an imprinting approach, electropolymerized molecularly imprinted polymer (eMIPs) nanoparticles of approximately 65 nm, were produced onto a laser induced graphene electrode, to offer a highly selective and robust alternative recognition material to the more traditionally used antibodies. A combination of acrylamide and acylate-based monomers were used to incorporate a range of functionality into the polymers, while different crosslinkers were explored to provide the recognition materials the best opportunity for selective binding. The eMIPs in this study produced excellent affinity for their target, with KD­ values in the sub-nanomolar range (0.75-0.79 nM), as well as LODs and LOQs in the 0.21-1.97 ng mL-1 and 0.65-5.98 ng mL-1ranges, respectively, from human serum. The introduction of the eMIP nanoparticles to the highly porous LIG electrode offers a new and promising strategy for the rapid production of low-cost biosensors, that can easily be adapted for a range of biomarkers. Potentially revolutionising the development of low-cost point of care diagnostics and biosensing.

Keywords: Molecularly imprinted polymer, Laser Induced Graphene, Point of Care, Cortisol Detection, biosensor, Low-Cost