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 (Fe 3 O 4 )-shell (Pt) magnetic nanoparticles (Fe 3 O 4 @Pt NPs) as a nanoenzyme and a paper-based colorimetric sensor. In the presence of H 2 O 2 , Fe 3 O 4 @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 H 2 O 2 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.