A signal-amplification electrochemical aptasensor based on porous Pt nanotubes and tetrahedral DNA nanostructures for ultrasensitive detection of citrinin

Abstract

A highly sensitive and accurate electrochemical aptasensor integrated tetrahedral DNA nanostructures (TDN) and porous platinum nanotubes (p-PtNTs) for citrinin (CIT) detection was constructed in this study. The TDN, the probe support material, was hybridized with an aptamer (Apt) to create a TDN-Apt anchored to the electrode surface. This effectively controls the distance between probes and reduces entanglement of Apt on the electrode. Furthermore, p-PtNTs are used to achieve the signal amplification. With their substantial surface area, p-PtNTs can load more methylene blue (MB) and offer more DNA strand binding sites. When CIT was added, it preferred to bind with Apt to form the CIT-Apt complex and detach from the electrode surface. Afterwards, p-PtNTs loaded with MB and complementary-strand DNA1 can bind with TDN to generate a strong signal. The proposed electrochemical aptasensor showed superior performance in CIT detection within 0.1 ng·mL−1 to 1×104 ng·mL−1, with a detection limit of 1.95×10−2 ng·mL−1 (S/N=3). The proposed electrochemical aptasensor based on a signal amplification strategy provided an effective detection strategy for CIT with excellent selectivity and exceptional stability, which has promising prospects for future detection.