Zeolitic Imidazolate Framework-8 Grown on Nanoporous SiO2 with Aptamer Functionalization for Selective Isolation of Thrombin

A three-dimensional ordered macroporous composite (3DOM SiO2@ZIF-8-TBA) was fabricated via the in situ growth of metal-organic framework ZIF-8 (similar to 50 nm) on the surface of macroporous SiO2 (pore size of similar to 250 nm) and the subsequent functionalization with a thrombin aptamer. The obtained 3DOM SiO2@ZIF-8-TBA composite has been proven to be a potential protein-enriching adsorbent, which exhibits high selectivity toward the adsorption of thrombin due to the specific conformation between the aptamer and thrombin. The adsorption behavior of thrombin onto the 3DOM SiO2@ZIF-8-TBA composite conforms to the Langmuir adsorption model, resulting in a superior adsorption capacity of 40.9 U mg(-1), contributed by the ordered macroporous structure. The retained thrombin could be readily recovered by 1.0% NH3 center dot H2O (m/v) with a recovery of 92.3%. Circular dichroism spectra illustrate that the 3DOM SiO2@ZIF-8-TBA composite-based adsorption/desorption processes have no influence on thrombin conformation. The application of the 3DOM SiO2@ZIF-8-TBA composite in separating thrombin from human serum has been verified; fibrin production tests prove that the activity of recovered thrombin is well retained.

Automated summary

The 3DOM SiO2@ZIF-8-TBA composite, with its ordered macroporous structure, demonstrates high selectivity and superior adsorption capacity towards thrombin. Recovering the retained thrombin with 1.0% NH3·H2O shows a recovery efficiency of 92.3%. The composite-based adsorption/desorption processes have no impact on the conformation of thrombin, as confirmed by circular dichroism spectra.