Coating of polyurethane scaffolds with collagen: comparison of coating and cross-linking techniques

Collagen has been coated successfully onto numerous hydrophilic polymer scaffolds to improve cell adhesion. Due to the hydrophobic nature of thermoplastic polyurethane (TPU), coating with aqueous collagen solution is problematic for such scaffolds. This study facilitated the coating of TPU with collagen and compared cross-linking and coating techniques. Three different cross-linking methods were compared. Both thermal and glutaraldehyde methods showed proof of cross-linking; however glutaraldehyde seemed to be superior to the other methods. The use of human urine as a wetting agent and the chemical glutaraldehyde had no effect on a cytotoxicity test performed by means of a WST-1 assay with a fibroblastic cell line. Three different coating techniques for porous TPU scaffolds were also investigated: ultrasound, pressurized air and injection. Of these, injection performed best. This method facilitated a coating of 100% of the porous scaffolds examined, which was verified by staining, FTIR and SEM.