Solvent dispersible nanocomposite based on rgo surface decorated with au nanoparticles for electrochemical genosensors

Abstract

A novel hybrid nanocomposite, formed of Reduced Graphene Oxide (RGO) flakes surface functionalized with 1-pyrene carboxylic acid (PCA) and decorated by Au nanoparticles (NPs), has been synthesized for the electrochemical detection of the miRNA-221 cancer biomarker. The hybrid material has been prepared by a facile approach, relaying on the in situ synthesis of the Au NPs onto the PCA carboxylic groups in presence of 3,4-dimethylbenzenethiol (DMBT) and NaBH4. The short aromatic thiol DMBT acts as reducing and coordinating agent, and hence, enables the dispersion of the nanocomposite in organic solvents. Concomitantly, DMBT favors the non-covalent anchoring of the Au NPs onto RGO, potentially allowing an efficient particle/RGO and interparticle π-π mediated electron coupling, which enhances the electron conductivity and charge transfer. PCA-RGO flakes, densely and uniformly decorated with a multilayer network of DMBT-coated Au NPs, 2.8 ± 0.6 nm in size, have been obtained, overcoming limitations previously reported for similar hybrid materials in terms of coating density and NP size distribution. Screen-Printed Carbon Electrodes (SPCEs), modified by the hybrid material and then functionalized with a thiolated DNA capture probe, have been tested for the determination of miRNA-221 in spiked human serum samples.