GOx@ZIF-90@CuCo-MOF paper-based nanozyme sensor for rapid and noninvasive glucose detection in saliva

GOx@ZIF-90@CuCo-MOF composite was synthesized via synergistic self-assembly. • Bimetallic sites and ZIF-90 shell significantly enhanced nanozyme activity. • The GOx@ZIF-90@CuCo-MOF paper-based nanozyme sensor was fabricated for rapid and noninvasive glucose detection in saliva. • The sensor achieved a 13.5 μM detection limit within a 20-min reaction. Glucose biosensors are pivotal to diabetes management; however, traditional fingerstick blood collection methods are often challenging due to their invasiveness, pain, high cost, and inability to provide continuous monitoring. Here, we constructed a paper-based colorimetric sensing platform using a multifunctional metal–organic framework (MOF) composite system to enable rapid, noninvasive detection of glucose in saliva. This platform utilized a CuCo-MOF framework, loaded with glucose oxidase (GOx) and ZIF-90 via a synergistic self-assembly mechanism, to catalyze the colorimetric reaction of H 2 O 2 and tetramethylbenzidine (TMB). The synergistic effect of the composite significantly enhanced the overall catalytic efficiency, enabling a sensitive response to glucose levels in saliva. Using ImageJ, color images captured with a smartphone were analyzed using RGB color channels to quantitatively determine glucose levels in saliva. The detection time was 20 min, with a detection limit (LOD) of 13.5 μM and a linear range of 50–2000 μM. This platform offered advantages with the absence of blood sample collection, ease of operation, and visual response. It provided new material strategies and design ideas for developing portable, non-invasive blood glucose monitoring technology. Download: Download high-res image (367KB) Download: Download full-size image