A Facile Hydrophilic Coating to Construct Immobilized Metal Affinity Chromatography for Protein Adsorption

Immobilized metal affinity chromatography is a green method applied to the separation and purification of proteins and biomolecules in downstream processing. With its unique internal pores, the membrane carriers have more active sites than typical magnetic nanoparticles and beads. It also greatly overcomes the mass-transfer resistance brought by traditional column chromatography. In this study, polysulfone was selected as the pristine membrane. Tannic acid and 3-aminopropyltriethoxysilane coatings were employed to construct the secondary reaction platform, which was then covalently coupled with polyethyleneimine and grafted with iminodiacetic acid groups to chelate Cu²⁺. Bovine serum albumin was utilized as the adsorption protein to adjust and optimize the modification parameters. The results demonstrated that the adsorption amount per unit membrane area reached 0.19 mg/cm² under the solution condition of pH 8.5. The adsorption thermodynamics followed the Langmuir model, and the corresponding model parameters were obtained.