Terminal group modification of carbon nanotubes determines covalently bound osteogenic peptide performance

Osteogenic peptides are often introduced to improve biological activities and the osteogenic ability of artificial bone materials as an effective approach. Covalent bindings between the peptide and the host material can increase the molecular interactions and make the functionalized surface more stable. However, covalent bindings through different functional groups can bring different effects on the overall bioactivities. In this study, carboxyl and amino groups were respectively introduced onto carbon nanotubes, a nano-reinforcement for synthetic scaffold materials, which were subsequently covalently attached by RGD / BMP-2 osteogenic peptide. MC3T3-E1 cells were cultured on scaffolds containing peptide-modified carbon nanotubes. The results showed that the peptide through amino group binding could promote cell functions more effectively than those through carboxyl groups. The mechanism may be that the amino group could bring more positive charges to carbon nanotube surfaces which further led to differen...