Polyaniline-graphene based α-amylase biosensor with a linear dynamic range in excess of 6 orders of magnitude

Abstract

α-amylase is an established marker for diagnosis of pancreatic and salivary disease, and recent research has seen a substantial expansion of its use in therapeutic and diagnostic applications for infection, cancer and wound healing. The lack of bedside monitoring devices for α-amylase detection has hitherto re- stricted the clinical progress of such applications. We have developed a highly sensitive α-amylase immunosensor platform, produced via in situ electropolymerization of aniline onto a screen-printed graphene support (SPE). Covalently binding an α- amylase specific antibody to a polyaniline (PANI) layer and controlling device assembly using electro- chemical impedance spectroscopy (EIS), we have achieved a highly linear response against α-amylase concentration. Each stage of the assembly was characterized using a suite of high-resolution topo- graphical, chemical and mechanical techniques. Quantitative, highly sensitive detection was demon- strated using an artificially spiked human blood plasma samples. The device has a remarkably wide limit of quantification (0.025–1000 IU/L) compared to α-amylase assays in current clinical use. With potential for simple scale up to volume manufacturing though standard semiconductor production techniques and subsequently clinical application, this biosensor will enable clinical benefit through early disease de- tection, and better informed administration of correct therapeutic dose of drugs used to treat α-amylase related diseases.