New affinity nylon membrane used for adsorption of γ-globulin

Microporous polyamide membranes were first modified by acid hydrolysis and subsequently bound with hydroxyethylcellulose to amplify reactive groups and reduce nonspecific interactions with proteins. Then 1,6-diaminohexane as space arm and phenylalanine as ligand were immobilized onto the nylon membranes by s-triazine trichloride activation. Affinity membranes thus obtained were set in a stack and used to adsorb γ-globulin. The adsorption capacity (qm) of the affinity membrane is 53 μg γ-globulin per m2 membrane and the desorption constant (Kd) is 2.35·10−6 mol/l. The effects of feed, washing and elution rates on adsorption and desorption behavior were investigated. The results showed that affinity purification through these membranes could not be operated at very high flow-rates. A stack of 20 membranes with 47 mm diameter can adsorb 7.8 mg γ-globulin with a purity of 91.6% from 4 ml of human plasma in a single-pass mode.