A multiplex paper-based nanobiocatalytic system for simultaneous determination of glucose and uric acid in whole blood.

In this work, a versatile point-of-care assay platform based on a microfluidic paper-based analytic device (µPAD) was developed for the simultaneous detection of multiple targets. The µPAD with a central zone and six test zones is fabricated by a simple and inexpensive wax printing method. A flower-like hybrid nanocomplex synthesized with specific dual enzymes and Cu3(PO4)2 inorganic nanocrystals is spotted in the test zones on the µPAD, followed by the introduction of assay targets. Using dual-enzyme inorganic hybrid nanoflowers in the µPAD as nanobiocatalysts, which preserve the activity and enhance the stability of the enzymes, based on the H2O2-mediated catalytic oxidizing chromogenic reaction produced by glucose/uric acid, the developed multiplex paper-based nanobiocatalytic system is demonstrated to enable simultaneous and sensitive detection of glucose and uric acid with a detection limit of 60 and 25 µM, respectively. More importantly, it has been successfully used for detecting glucose and uric acid levels in human whole blood samples. The developed multiplex paper-based nanobiocatalytic system features very easy fabrication and operation, low cost, and high sensitivity and has promising prospects for a clinical multianalyte point-of-care test.