Detection of protein kinase using an aptamer on a microchip integrated electrolyte-insulator-semiconductor sensor

Abstract

Herein, we developed a microchip electrolyte-insulator-semiconductor (EIS) sensor for the capacitive detection of protein kinase A (PKA). EIS sensing is customarily performed in a Teflon cell to define the sensing area. However, in this work, a rapid prototyping technique was followed to integrate polymeric microchip, a reference electrode, and the EIS sensor. The aptameric peptide was used for one-step and label-free detection of PKA enzyme. The thiolated PKA-specific aptamer was immobilized on the gold nanoparticles decorated EIS sensor surface. The detection of PKA in microchip was based on the change in surface charge of EIS sensor. We also analyzed the ability of microchip-EIS sensor to distinguish between buffers at different pH. An average sensitivity of 96mV/pH for a pH range of 5–9 was obtained. The quantitative detection of PKA was performed by analyzing the capacitance-voltage curve after the aptamer-PKA interaction. The EIS sensor showed a detection limit of 2U/mL with a relative linearity from 10U/mL to 80U/mL for the detection of PKA. This study proposes an integrated and point-of-care applicable biosensor for the rapid diagnosis.