Development of an electrochemical insulin sensor based on the insulin-linked polymorphic region

作者：Gerasimov Jennifer Y; Schaefer Cody S; Yang Weiwei; Grout Rebecca L; Lai Rebecca Y^*

来源：Biosensors and Bioelectronics, 2013, 42: 62-68.

DOI：10.1016/j.bios.2012.10.046

• Insulin
• Insulin-linked polymorphic region
• Electrochemical
• Methylene blue
• Circular dichroism

Here we report the design and fabrication of an electrochemical aptamer-based (E-AB) sensor for detection of insulin. The aptamer used in this study is the insulin-linked polymorphic region (ILPR) sequence, a G-rich sequence that presumably undergoes ligand-induced folding to form a G-quadruplex in presence of insulin. Our circular dichroism data, however, suggests that the ILPR sequence, even in absence of the target, is predominantly in a G-quadruplex-like form. Insulin binding, however, has shown to further induce the formation of the G-quadruplex. To evaluate the potential of the ILPR sequence as a biosensing element, we constructed two E-AB insulin sensors that are identical in all aspects but the location of the methylene blue (MB) redox label. We find that the sensor fabricated with internal MB-modified probes (In-IT) shows enhanced sensing behavior when compared to one fabricated using terminal-MB modified probes (In1). The improvements observed with the In-IT sensor could be attributed to the more effective obstruction of electron transfer upon insulin binding. Overall, both sensors perform well, affording a detection limit of 10 nM and 50 nM for the In-IT and In1 sensors, respectively.

• 出版日期2013-4-15