Synthesis, Characterization Of Gold Nanorods And Their Applications In Biosensing

Gold nanorods (AuNRs) possess unique photophysical and photochemical properties. The attractive features of Gold nanorods include good biocompatibility, stability, and conductivity and low toxicity, making it a good candidate in optics and biosensing applications. Pb2+is an environmental pollutant, causing serious problems to human health and ecosystems. A rapid method for the detection of Pb2+with good selectivity and sensitivity is much preferred.In this work, gold nanorods modified with DNA molecular device induced by Pb2+were constructed and used for the detection of Pb2+. In the presence of gold nanorods modified with DNA (T30695), the fluorescence intensity of zinc protoporphyrin (ZnPPIX) was significantly enhanced by Pb2+. The mechanism of the fluorescence enhancement involves the formation of a stable quadrupole (G-quadruplex) facilitated by Pb2+, which enhanced the fluorescence of zinc protoporphyrin. The dynamic range of the method was5.0×10-9～1×10-6mol·L-1and the detection limit was estimated to be10-9mol·L-1. The feasibility of the method for the determination of Pb+in water and human sera samples has been demonstrated. The sensing protocol serves as a good alternative for detection of Pb2+Taking advantage of the electrostatic interaction between the graphene (GN) and the AuNRs, a new hydrogen peroxide (H2O2) sensor has been developed. The AuNRs were directly assembled onto the graphene-modified glassy carbon electrode (GCE), and the detection of H2O2was carried out by cyclic voltammetry and chronoamperometry. T The linear range for H2O2assay was25～712μmol·L-1and the detection limit (S/N=3) was estimated to be7.5μmol·L-1. The proposed sensor is stable, sensitive, and suitable for monitoring H2O2.