Molecular Self‐Assembly of Au Nanoparticles on a Porous Cellulose Membrane Template for Highly Sensitive Colorimetric Detection of Glucose

Abstract

AbstractA sensitive glucose colorimetric detection system (Au@QCM) based on quaternized cellulose membrane (QCM) and enzyme‐mimicking Au nanoparticles (AuNPs) was successfully developed via a simple molecular self‐assembly strategy. The positively charged QCM functioned as a template to guide the negatively charged citric acid‐reduced AuNPs uniformly distributed on the surfaces along the pore walls of its porous structure, and thus gave AuNPs an ordered interconnected three‐dimensional network. This electrostatic interaction could effectively prevent the aggregation of the AuNPs and greatly increase their exposed surface area, thus endow the Au@QCM with highly active catalytic properties towards glucose oxidation with glucose oxidase (GOx). The experimental studies showed that the color change of redox indicator 3,3′,5,5′‐tetramethylbenzidine (TMB) can be clearly observed with naked eyes and the absorbance of the oxidized TMB (at 653 nm) was directly proportional to the concentration of glucose. Au@QCM could achieve a sensitive glucose detection with a limit of detection of 0.55 μM and linear response in the range of 0.01–0.5 mM. Besides, it also had good applicability in real samples detection and excellent selectivity to glucose. This novel detection system significantly improved detection performance compared to previous work based on cellulose‐based strips loaded with GOx and horseradish peroxides.