Magnetic PAES-COOH Nanofibers as Efficient and Reusable Carriers for Glucose Oxidase Immobilization

Free glucose oxidase (GOx) exhibits high specificity and catalytic efficiency under mild conditions; however, its practical application is limited by poor stability and reusability. In this study, a magnetic nanofiber carrier was fabricated from carboxyl-functionalized polyaryl ether sulfone (PAES-COOH) nanofibers via a facile acid precipitation method. The preparation parameters of the magnetic PAES-COOH nanofiber carrier (MNPAES) and the immobilization conditions for GOx were systematically optimized. The structural and surface properties of PAES-COOH nanofibers and MNPAES were characterized by SEM, FT-IR, XPS, 1 H NMR, GPC, and BET analyses. Compared with pristine nanofibers, MNPAES exhibited an increased specific surface area (from 9.5 to 21.1 m 2 /g) and an enlarged average pore size (from 2.3 to 123 nm), facilitating enzyme immobilization. GOx immobilized on MNPAES (GOx@MNPAES) showed a lower apparent K m value and a higher V max / K m ratio than free GOx, indicating enhanced apparent catalytic efficiency. In addition, GOx@MNPAES demonstrated good storage stability, rapid magnetic separation, and high reusability, retaining approximately 60% of its initial activity after 20 cycles. These results suggest that magnetic PAES-COOH nanofibers are effective carriers for GOx immobilization.