Facile preparation of Fe 3 O 4 @Pt nanoparticles as peroxidase mimics for sensitive glucose detection by a paper-based colorimetric assay

A simple strategy to rapidly detect glucose was developed by utilizing core (Fe3O4)-shell (Pt) magnetic nanoparticles (Fe3O4@Pt NPs) as a nanoenzyme and a paper-based colorimetric sensor. In the presence of H2O2, Fe3O4@Pt NPs catalyze the redox reaction of 3,3',5,5'-tetramethylbenzidine (TMB) and generate a colour change from colourless to blue. On this basis, a colorimetric glucose sensing method assisted by glucose oxidase (GOx) was developed. Under the optimal conditions, the detection limits of the proposed assay for H2O2 and glucose were 0.36 µM and 1.27 µM, respectively. Furthermore, the fabricated colorimetric method was successfully applied to analyze glucose concentrations by using a paper device as a measuring platform without a spectrometer. In addition, this method exhibited satisfactory recovery for glucose detection in human serum samples and urine samples, which satisfied the requirements for normal detection of real samples. This study provides a good candidate for health monitoring of glucose and also expands the applications of nanoenzymes and paper-based colorimetric assays in point-of-care testing.