Magnetic nanoparticles composed of Fe3(PO4) 2 ·8H2O by Burkholderia cepacia CG-1：A study of peroxidase-like activity and its application in H2O2 and glucose detection

Abstract

Abstract In this study, magnetic nanoparticles were successfully separated from the strain Burkholderia cepacia CG-1. The composition, structure and morphology of the magnetic nanoparticles were characterized. The results indicated that the magnetic nanoparticles were indicated as Fe3(PO4)2·8H2O clusters with an average size of 69 nm. The values of magnetic parameters such as coercivity, saturation remanence and saturation magnetization were 150.93 Oe, 1.9333 emu/g and 15.844 emu/g, respectively. We have confirmed that the Fe3(PO4)2·8H2O magnetic nanoparticles exhibitted an intrinsic peroxidase-like activity which could catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H2O2. Comparing with HRP, the peroxidase mimic was more stable under different physiochemical conditions. The mechanisms of the peroxidase-like catalysis with Fe3(PO4)2·8H2O were investigated by the fluorescence spectroscopy and Electron spin resonance (ESR) analysis. The results showed that the peroxidase-like activity of Fe3(PO4)2·8H2O originated from the generation of hydroxyl radical (•OH). In addition, we have established a platform for colorimetic detection H2O2 and glucose. As low as 1.0×10− 3 mmol L− 1 H2O2 and 5.0×10− 3 mmol L− 1 glucose could be dectected via our method. Moreover, this sensitive method was successfully applied for the determination of glucose in human serum.