Construction of Photo- and Thermo-Responsive Polymer-MOF@Enzyme Composites for Enhancing Its Biocatalytic Performance

Recently, metal-organic framework (MOF)@enzyme composites have attracted increasing research interest. However, the fabrication of polymers-modified MOF@enzyme composites with high bio-catalytic performance remains challenging. Herein, a stimulus-responsive polymer, poly(acrylate-3′,3′-dimethyl-6-nitro-spiro-2H-1-benzopyran-2,2′ indoline-1′-ester-co-N-isopropyl acrylamide) (PSPN), was in-situ polymerized in UiO-66-NH₂ (UN). The dual-responsive PSPN-UN@L-ASNase composites were constructed following L-asparaginase (L-ASNase) covalently attached to the UN surface. Interestingly, under 365 nm UV irradiation at 45 °C, the PSP moiety in PSPN underwent a trans-to-cis conformational change and the PN moiety in PSPN transferred from a stretched- to a coiled-state, generating a confinement effect that significantly enhanced the bio-catalytic performance of the composites. Compared with free L-ASNase, the composites showed a 42.0-folds increase in maximum catalytic reaction velocity. Furthermore, the PSPN-UN@L-ASNase composites demonstrated high toxicity for Jurkat leukaemia cells. The stimulus-responsive polymer-MOF@enzyme composites provide a novel avenue for controlled bio-catalysis with great potential for targeted leukaemia therapy.