A simple colorimetric and paper-based-smartphone sensing platform based on the enhanced peroxidase-like activity of Al doping Prussian blue for point-of-care detection of GSH

Glutathione (GSH) is a very important antioxidant and also participates in many important physiological processes, accurate determination of GSH in food and blood fluid is crucial for human health. Herein, we introduce a simple colorimetric and paper-based-smartphone dual signal output platform for point-of-care (POC) detection of GSH in garlic and human serum. The experiment revealed that the peroxidase-like activity of Aluminum-doped Prussian blue (AlPB) could be enhanced by the doping of Al element on Prussian blue. AlPB exhibited excellent peroxidase-like activity and efficiently catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 to generate blue oxidized TMB, resulting in an absorbance and color-based-smartphone dual signal readouts. Enzyme kinetic studies also indicated that the AlPB showed high affinity towards TMB. Hence, a reliable colorimetric and color-based-smartphone dual signal readouts assay was constructed based on AlPB-mediated the peroxidase-like activity, it was used for highly sensitive colorimetric and POC detection of GSH in food and human serum within 7 min with a wide range of linear response from 1 to 20 μM, a low detection limit of 0.1748 μM. This work demonstrates a novel and versatile strategy to develop superior peroxidase mimics and holds great potential for rapid and portable detection of GSH in food, healthcare and clinical diagnosis, and also open promising avenues for more powerful paper-based POC tests.