Three-dimensional ordered macroporous MOF-based smart gating membrane with size screening effect and aptamer specificity for highly efficient thrombin isolation

Membrane separation is an efficient technique for the separation and extraction of biomolecules from complex matrices. Herein, a thrombin aptamer-functionalized temperature-responsive smart gating metal-organic framework (MOF) membrane was fabricated by three-dimensional ordered macroporous ZIF-8 (3DOM ZIF-8) and copolymer of sodium alginate grafted with poly(N-isopropylacrylamide) (SA-PNIPAM) for thrombin (TB) isolation. The SA-PNIPAM on the exterior surface of 3DOM MOFs endows the membrane with favorable protein penetration selectivity via temperature-controlled size-screening effect, and the aptamer functionalized on the interior macropore provides excellent thrombin capturing specificity. The separation factor of the smart gating membrane ranges from 13.88 to 49.22 for mixtures of TB with other protein species, and TB enrichment factor is high up to 95.97 under a TB/HSA mass ratio of 1:1000. The aptamer functionalized smart gating membrane is applied to the selective isolation of TB from the human serum. Fibrin production tests demonstrate that the biological activity of the isolated TB is well maintained and suitable for ensuing applications. Moreover, this 3DOM MOF-based smarting gating membrane exhibits high fouling-resistance performance.