Gold-enhanced current-volt dielectrode junction for biosensing with an aptamer-insulin-like growth factor-1-antibody sandwich pattern

Abstract

Insulin-like growth factor-1 (IGF-1) is a hormone comprising seventy amino acids that is a key regulator of muscle and bone health and is highly related to the development of cancer. An aptamer-antibody sandwich assay was performed to determine the presence of IGF1 on a gold nanoparticle-enhanced dielectrode junctional sensing surface by using this surface as a transducer. High-resolution microscopy observations showed the characteristics of the sensing surface and gold nanoparticles. The gold nanoparticle-enhanced surface induces high immobilization of the anti-IGF1 aptamer and enhances the interactions of IGF1. With this probe surface, the aptamer-IGF1-antibody sandwich assay resulted in an increased current for each different solution concentration of IGF1, and the detection limit was 0.5 pg/mL with an R2 value of 0.9631 on a linear calibration curve with IGF1 solution concentrations of 1–16 pg/mL. In addition, IGF1-spiked serum reached a similar limit of detection of 0.5 pg/mL, confirming that selective IGF1 detection occurred for the biological sample.