Co-immobilization of active antibiotics and cell adhesion peptides on calcium based biomaterials

• Active vancomycin and KRSR were covalently adhered to a calcium based biomaterial.
• Three different reaction sequences resulted in successful double modification.
• Bacterial tests showed that modified substrates had a similar effect as a 30 μg dose.
• Osteoblast adhesion was significantly increased using modified calcium aluminate.

Two bioactive molecules with unrelated functions, vancomycin and a cell adhesion peptide, were immobilized on the surface of a potential bone scaffold material, calcium aluminum oxide. In order to accomplish immobilization and retain bioactivity three sequential surface functionalization strategies were compared: 1.) vancomycin was chemically immobilized before a cell adhesion peptide (KRSR), 2.) vancomycin was chemically immobilized after KRSR and 3.) vancomycin was adsorbed after binding the cell adhesion peptide. Both molecules remained on the surface and active using all three reaction sequences and after autoclave sterilization based on osteoblast attachment, bacterial turbidity and bacterial zone inhibition test results. However, the second strategy was superior at enhancing osteoblast attachment and significantly decreasing bacterial growth when compared to the other sequences.