Collagen and fibronectin carrying PHEMA microbeads as cell affinity sorbents

PHEMA microbeads, produced by suspension polymerization, were modified by the immobilization of a spacer (hexamethylene diamine, HMDA), and two proteins, collagen or fibronectin. Adsorption of collagen and fibronectin onto the plain and periodate oxidized PHEMA microbeads were similar; 0.05-0.1 mg of collagen and 0.04-0.05 mg of fibronectin per g of polymer, respectively. Collagen and fibronectin immobilization on PHEMA microbeads were studied at different temperatures, time and pH. The optimal values for immobilization were 0.1 mg/mL for fibronectin; and 0.25 mg/mL for collagen at 25 degrees C for fibronectin and 4 degrees C for collagen; pH 7 in 120 min. Both fibroblastic 3T3 and epithelial MDBK cells were attached to unmodified and modified microbeads. The attachments of both 3T3 and MDBK cells, to the fibronectin and collagen immobilized microbeads were more than 2000 cells per mg of polymer.