Dopamine-Modulated Highly Oxygen-Vacancy Ce Metal–Organic Frameworks Boost Phosphatase-Catalyzed Chemiluminescence

Le résumé fourni par la source

Owing to target recognition hindrance, common metal–organic frameworks (MOFs) as nanocarriers lead to the dramatically decreased catalytic activity (by 90%) of immobilized enzymes. Herein, a dopamine-modulated enclosure strategy was proposed to successfully immobilize alkaline phosphatase (ALP) on phosphatase-like Ce-2-methylimidazole (2-MIm) MOFs for the formation of a Ce-2-MIm@ALP@polydopamine (PDA) biocomposite. Although the activity proportion (1.22%) of Ce-2-MIm to Ce-2-MIm@ALP@PDA was negligible, Ce-2-MIm MOFs facilitated 2.5-fold higher catalytic activity of immobilized ALP than free ALP. Note that shortened Ce–Ce bonds and increased Ce–OH groups were verified by X-ray absorption spectroscopy for the increased active Ce sites on the Ce-2-MIm support. Thereby, the phosphatase-like Ce-2-MIm possessed enhanced substrate affinity ( K m = 86.79 μM) 16.5 times superior to ordinary Ce-based nanozymes ( K m = 1428.57 μM). The experimental data and density functional theory calculations demonstrated that the flexible scaffold coating of PDA endowed Ce-2-MIm with improved oxygen vacancies for the preferable binding affinity and hydrolysis activity. The marked affinity effect of the Ce-2-MIm-based support imparted the dominant improvement of catalytic activity to fixed enzymes in the enzyme immobilization. For the proof-of-concept application on chemiluminescence (CL) catalysis, the prepared Ce-2-MIm@ALP@PDA is successfully employed for the detection of carbendazol (CAB), with a low detection limit of 56 pg/mL. This work highlights the merits of nanozymes as an efficient affinity-type support for enzyme assemblies, which exhibits great potential for considerable activity exaltation of enzymes even in an immobilization manner.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.