Development of a Soluble KIT (sKIT) Electrochemical Aptasensor For Cancer Theranostics

Abstract

AbstractA conformational changing aptamer based electrochemical sensor was developed for the detection of soluble KIT, a cancer biomarker, in human serum. The sensor was fabricated with a ferrocene labeled aptamer (Kd < 5 nM) conjugated to a gold electrode. Quantitative KIT detection was performed using electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV). The experimental parameters such as the ratio of aptamer to spacer, aptamer immobilization time, pH, and KIT incubation time were optimized by EIS, and the sensing surface was characterized with voltammetry. The assay specificity was investigated using interfering species showing high specificity towards the target protein. The aptasensor exhibited a wide dynamic range from 10 pg/mL to 100 ng/mL in buffer with a detection limit of 1.15 pg/mL. The sensor also exhibited a linear response with increased KIT concentrations spiked in human serum. The applicability of the sensor was successfully demonstrated using cancer cell conditioned media. The proposed aptasensor can be used in continuous or intermittent approach for cancer therapy monitoring and diagnostics (theranostics).