Multiplex Surface Plasmon Resonance Imaging-Based Biosensor for Human Pancreatic Islets Hormones Quantification

Diabetes arises from secretory defects in vascularized micro-organs known as the islets of Langerhans. Recent studies indicated that furthering our understanding of the paracrine effect of somatostatin on glucose-induced insulin secretion could represent a novel therapeutic avenue for diabetes. While many research groups are interested in insulin and glucagon secretion, few are particularly focused on studying the paracrine interaction in islets' cells, and none on monitoring a secretory fingerprint that contemplates more than two hormones. Surface plasmon resonance imaging can achieve high-throughput and multiplexed biomolecule quantification, making it an ideal candidate for detection of multiple islet's secretion products if arrays of hormones can be properly implemented on the sensing surface. In this study, we introduced a multiplex surface plasmon resonance imaging-based biosensor for simultaneous quantification of insulin, glucagon, and somatostatin. Performing this multiplex biosensing of hormones was mainly the result of the design of an antifouling sensing surface comprised by a mixed self-assembly monolayer of CH3O-PEG-SH and 16-mercaptohexadecanoic acid, which allowed it to operate in a complex matrix such as an islet secretome. The limit of detection in multiplex mode was 1 nM for insulin, 4 nM for glucagon, and 246 nM for somatostatin with a total analysis time of 21 min per point, making our approach the first reporting a label-free and multiplex measurement of such a combination of human hormones. This biosensor holds the promise of providing us with a mean for the further understanding of the paracrine effect of somatostatin on glucose-induced insulin secretion and consequently help develop novel therapeutic agents for diabetes.