Optimizing non-crosslinked type I collagen barrier membranes for guided bone regeneration: a comparative study of a BMP-2 derived peptide adsorption and covalent grafting

Oral diseases like periodontitis and tooth loss affect billions worldwide, causing alveolar bone resorption and complicating implant placement and bone regeneration. Guided bone regeneration addresses these defects using barrier membranes that block soft tissue infiltration and promote bone growth. CollaTape®, a type I bovine collagen membrane, is widely used for its biocompatibility and resorbability, though its bioactivity and antibacterial properties could be improved. This study compares two functionalization methods for enhancing CollaTape® membranes: adsorption of GBMP1α peptide (a BMP-2 biomimetic) and covalent anchoring of its analogue Aoa-GBMP1<i>α</i>. Both functionalizations were performed at concentrations of 0.25, 0.5, 1, and 1.5 mg ml^-1. Optimal conditions were selected basing on osteoblast mineralization assays and resulted to be 0.25 mg ml^-1for adsorption and 1.5 mg ml^-1for covalent binding. Peptide surface density analysis revealed values of 0.040 μmol cm^-2for adsorption and 0.278 μmol cm^-2for covalent anchoring. Biological assays assessed mineralization, proliferation, and gene expression (<i>SPP1, RUNX2</i>) in human osteoblasts, and antibacterial activity against<i>Staphylococcus aureus</i>and<i>Escherichia coli</i>. All functionalized membranes improved osteoblast activity, with adsorption showing superior results. Antibacterial tests showed slight but significant reductions in bacterial colonies, especially for adsorption. Additional mechanical tests via unconfined compression were performed to evaluate the effect of functionalization on the membranes' mechanical properties. These tests confirmed that neither functionalization method compromised the stiffness of the membrane, a critical parameter in clinical applications. Overall, peptide adsorption is a simple and clinically adaptable strategy to enhance CollaTape®'s bioactivity and antibacterial properties while maintaining their original mechanical properties.