A stable Au–N bond controlled probe immobilization approach for the sensitive detection of kirsten rat sarcoma viral oncogene DNA using NH2-HMS@Au

Designing and developing electrochemical DNA biosensors based on nanotechnology to solve the low hybridization efficiency of DNA has gained wide attention in recent years because nanomaterials can enhance surface area of electrode and increase amount of probe DNA immobilization. Herein, a new label-free electrochemical DNA biosensor was constructed for sensitive detection of kirsten rat sarcoma viral oncogene (KRAS) DNA. During this process, based on the large specific surface of hollow mesoporous silica (HMS), amino-functionalized hollow mesoporous silica (NH2-HMS) nanocomposite was synthesized, and then highly dispersed gold nanoparticles (Au NPs) were uniformly and stably anchored onto its surface to form Au NPs combined with amino-functionalized hollow mesoporous silica (NH2-HMS@Au), which was utilized as supporting material for decorating the electrode surface. The amino-terminated probe DNA was subsequently immobilized onto the modified electrode surface via Au–N bond and employed as probes to determine the target DNA (t-DNA). The synergetic effects of NH2-HMS with Au NPs achieved enhance of the analytical performance of biosensor. Under the optimized conditions, the prepared DNA biosensor possessed a wide linear range from 1 × 10−12 to 1 × 10−7 M with a low detection limit of 0.366 pM. Moreover, the DNA biosensor displayed satisfying selectivity, remarkable stability, which provided a promising application for clinical diagnosis and analysis.