Smartphone and paper-based device for glucose monitoring using acetylene black-hemin nanozyme as catalyst

Glucose management is an important part of disease control for diabetes patients, thus the development of a rapid and real-time point of care testing (POCT) device for monitoring blood glucose is of great significance. In this work, a paper-based analytical device (PAD) is constructed by combining acetylene black (AB)-hemin complex modified filter paper as sensing platform with a smartphone as signal detector. Large specific surface area of AB decreases the self-associate and aggregate of hemin in aqueous solution, resulting in improved peroxidase-like activity of hemin. Compared with graphene oxide supported hemin, AB-hemin exhibits superior signal response on paper. Glucose oxidase (GOx) catalyzes the conversion of blood glucose to hydrogen peroxide, and then AB-hemin complex catalyzes the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue TMB oxidized products (TMB⁺) in the presence of hydrogen peroxide, thus achieving the visual detection of blood glucose. In optimal conditions, PAD provides an applicable linear range from 0.2 mM to 30 mM and a low limit of detection (LOD) (0.06 mM). Notably, the detection accuracy of the developed paper-based sensor is in good agreement with that of the commercially available blood glucose meter (p > 0.05). Moreover, the proposed PAD presents high recoveries from 95.4% to 112% (RSD ≤ 3.2%), and therefore holds great potential for glucose monitoring and diabetes diagnosis.