Dual-Mode Spatial Confinement of GOx/HRP Tandem System in Orderly-Assembled Metal–Organic Framework@Smart Polymer Enzyme Reactors for Glucose Detection

The transition of metal-organic framework and polymer from random assembly to ordered spatial organization in enzymatic tandem systems is critical for enhancing cascade catalytic performance. Herein, thermo-responsive poly(styrene-co-maleic anhydride)-block-poly(N-isopropylacrylamide) (PSMN) was designed and employed to integrate UiO-66-NH2 (U) with glucose oxidase and horseradish peroxidase (GOx/HRP), constructing orderly-assembled U@PSMN@GOx/HRP, random assembled Up-PSMN@GOx/HRP and PSMN@GOx/HRP enzyme reactors with spatial confinement. The thermo-responsive conformational transition of flexible PSMN, together with the structural restriction imposed by covalently integrated rigid U, cooperatively established a more ordered spatial confinement space around GOx/HRP. At 37 °C, the Kcat value of U@PSMN@GOx/HRP was 83.2-fold higher than that at 15 °C, while, 155.5- and 130.1-fold higher than those values of PSMN@GOx/HRP and UP-PSMN@GOx/HRP, respectively. The enhanced cascade catalysis was further translated into sensitive glucose detection, affording a broad linear range of 2.0-1200.0 μM and a detection limit of 0.67 μM, together with reliable analytical performance in orange fruits. This study provides strategy for coupling stimuli-responsive polymer yielded confined space with orderly-assembled MOFs@polymer@enzyme induced confinement to enhance enzymatic cascade catalysis.