Zwitterionic daptomycin stabilized palladium nanoparticles with enhanced peroxidase-like properties for glucose detection

Abstract

Mimic enzymes, especially noble metal nanomaterials, replace natural horseradish peroxidase due to the artificial regulation of catalytic activity by adjusting particle size and morphology. However, the existing mimic enzymes still have disadvantages such as large particle size, easy clustering and poor biocompatibility. Herein, well-dispersed daptomycin stabilized palladium nanoparticles (Dap-Pdn NPs) were synthesized by using daptomycin as a biological template. The average particle size of palladium nanoparticles of Dap-Pd0.25 NPs was 1.73 nm, the hydrodynamic size of Dap-Pd0.25 NPs detected by DLS method was 49.97 nm, Dap-Pd0.25 NPs were stable in fibrinogen solution. In addition, Dap-Pd0.25 NPs had excellent peroxidase-like activity, which effectively catalyzed the colorimetric oxidation reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2. Dap-Pd0.25 NPs were used to detect glucose concentration based on the colorimetric reaction of TMB, which had a wide detection range (0.02–1 mM) and low detection limit (5.6 μM) for glucose. Besides, fluorescence experiments proved that Dap-Pdn NPs catalyzed H2O2 to generate·OH. Taken together, a simple, green and inexpensive synthesis method of palladium nanoparticles with enhanced peroxidase-like activity was proved in this research. Dap-Pdn NPs will have great application prospects in biological detection in the future.