Electrochemical Aptamer-Based Sensor for Real-Time Monitoring of\nInsulin

Abstract

In\nthis paper, we developed an electrochemical, aptamer-based (E-AB)\nfor the real-time monitoring of insulin. The sensor utilizes a redox\nlabel-modified guanine-rich aptamer which folds into a G-quadruplex\nfor specific recognition of insulin. To develop a reproducible E-AB\nsensor employing insulin aptamer probes for the detection of insulin,\n10% sodium dodecyl sulfate (SDS) pretreatment is crucial as it disrupts\ninterstrand G-quartets. After sensor pretreatment with 10% SDS, a\nmore uniform sensor response is obtained. Upon introduction of the\ninsulin target, binding-induced steric hindrance quantitatively reduces\nthe efficiency of electron transfer of a distal-end redox label leading\nto the rapid signal change within ∼60 s. Testing demonstrates\nthat the E-AB insulin exhibits a limit of detection of 20 nM and can\nbe used to discriminate against both glucagon and somatostatin in\nKrebs–Ringer bicarbonate buffer, typically used in perfusion\nexperiments. These results demonstrate that this assay has potential\nfor rapid, specific, and quantitative analysis of insulin.