Viologen-terminated polyamidoamine (PAMAM) dendrimer encapsulated with gold nanoparticles for nonenzymatic determination of hydrogen peroxide

The development of an accurate and low-cost monitoring technique for hydrogen peroxide (H2O2) is a crucial demand in environment, food industry, medicine and biology. Herein, we report the design and synthesis of viologen terminated second (G2.0) and third generation (G3.0) poly(amidoamine) PAMAM dendrimers, followed by encapsulation with gold nanoparticles to form G2.0 and G3.0 Vio-PAMAM-AuNPs. The G2.0 and G3.0 Vio-PAMAM-AuNPs were deposited over glassy carbon electrode (GCE) to form G2.0 and G3.0 Vio-PAMAM-AuNPs/GCE modified electrodes, respectively. The electrochemical behavior of G2.0 and G3.0 Vio-PAMAM-AuNPs/GCEs were investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Both the G2.0 and G3.0 Vio-PAMAM-AuNPs/GCEs showed a pair of well-defined redox peaks in 0.1 M phosphate buffer corresponding to the redox behavior of viologen V2+↔V•+ radical. G3.0 Vio-PAMAM-AuNPs/GCE has shown a higher current response than that of the G2.0 Vio-PAMAM-AuNPs/GCE and further the G3.0 Vio-PAMAM-AuNPs/GCE demonstrated impressive electrocatalytic activity towards reduction of H2O2, based on which a nonenzymatic sensor for the detection of H2O2 has been developed. The developed nonenzymatic sensor has displayed excellent performance towards H2O2 detection in the broad linear range of 0.1 mM – 6.2 mM with a low detection limit of 27 μM and high sensitivity of 202.7 μA mM−1 cm−2. The G3.0 Vio-PAMAM-AuNPs/GCE modified electrode with its extensive dendritic structure creating tailored sanctuary to accommodate a large number of viologen mediator and AuNPs exhibited good operational and long term stability and further the quantification of H2O2 in real samples has been verified by standard addition method. [Display omitted] •Second and third generation viologen terminated PAMAM dendrimers were synthesized.•Gold nanoparticles were encapsulated into the viologen terminated dendrimers.•Modified electrodes fabricated using these dendrimer encapsulated AuNPs were used for H2O2 detection.•Developed nonenzymatic sensor offered very good selectivity, sensitivity and stability.