Simultaneously enhancing the selectivity and stability of enzymatic probes via bio-imprinting technology

Abstract

The application of enzymes in sensing has been severely limited due to their low stability. Moreover, some enzymes could catalyze diverse substrates, meaning their out-standing selectivity is still facing challenges in sensing systems containing multiple substrates. Therefore, their catalytic selectivity and stability enhancement is still of great significance for fabrication of biosensors with excellent sensing performance. However, few works for simultaneously enhancing the selectivity and stability of enzymes have been reported yet. Herein, an exquisite molecular coat prepared by molecular imprinting polymers, which could simultaneously enhance the selectivity and conformational stability of enzymes is directly weaved on the surface of glucose oxidase (GOx) immobilized on Ti-NiCo2O4 @Fe3O4-Au nanoarrays. Accordingly, the relative selectivity coefficients K(β-D-glucose/mannose), K(β-D-glucose/xylose) of molecularly imprinted GOx are 803% and 874% higher than that of pristine GOx, respectively. Moreover, the as-prepared biosensors show improved stability and sensitivity (LOD = 20 μM) with a wide detection range of 0.2–8 mM in practical β-D-glucose detection. Impressively, after consecutive glucose detection for five times, only a slight decrease (3.46%) of signal could be observed, indicating that the as-prepared biosensor with superior stability is reusable in practical sensing applications.