PEGylation of metal-organic framework for selective isolation of glycoprotein immunoglobulin G

Metal-organic frameworks (MOFs) have been gaining extensive popularity in the field of sample pretreatment due to their designable structures and easy-modifiable surfaces. Herein, zirconium-based MOFs UiO-66-NH 2 is first coated with graphene oxide (GO) layer to enhance the stability, and then grafted with hydrophilic polyethylene glycol (PEG) via amidation reaction to give a product of hydrophilic MOF-based nanomaterial UiO@GO@PEG. The obtained nanoparticles exhibit typical hydrophilic interaction liquid chromatography (HILIC) behavior towards glycoproteins , making itself powerful adsorbent for the extraction of glycoproteins from complex matrices. Under pH 9.0, an adsorption capacity of 139.6 mg g −1 for glycoprotein immunoglobulin G (IgG) is achieved, and the retained IgG could be recovered by 0.5% (m/v) ammonium hydroxide (NH 4 OH) as stripping reagent with a recovery rate of 82.6%. Moreover, the UiO@GO@PEG shows excellent reusability in IgG isolation. The practicability of UiO@GO@PEG is verified by the selective isolation of IgG from human serum, demonstrating the purity of isolated IgG with SDS-PAGE assay.