Bioactive and Elastic Nanocomposites with Antimicrobial Properties for Bone Tissue Regeneration

Bone injuries represent a major challenge in the medical field. The commonly used treatments for bone regeneration rely on the use of bone grafts that are usually associated with complications such as donor site morbidity, disease transmission, high cost, and lack of availability. Bone tissue engineering has become a golden solution for the repair of bone injuries by regenerating the damaged biological tissues using biocompatible scaffolds. However, most of the tissue engineered scaffolds do not possess the combined properties of high elasticity, appropriate stiffness, biocompatibility, osteoinductivity, and antimicrobial properties. In this study, we engineered bioactive and antimicrobial nanocomposites that can promote bone formation while simultaneously provide a barrier against bacterial infections commonly associated with bone implants. We used PEGylated polyglycerol sebacate as nanocomposites base, which was functionalized with Laponite nanosilicates, a synthetic nanoclay, and an antimicrobial peptide (AMP). The successful synthesis of the PEGylated polyglycerol sebacate and Laponite incorporation within the nanocomposites were confirmed through nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The scaffolds had an elastic modulus and ultimate tensile strength within a range of 3.8-4.7 MPa and 1.5-3 MPa, respectively. Furthermore, the scaffolds loaded with antimicrobial peptide exhibited a significant antimicrobial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. The in vitro cytocompatibility tests showed >90% viability of preosteoblast (W-20-17) cells. Moreover, in vitro differentiation assays demonstrated the scaffolds' ability to promote osteogenic differentiation of W-20-17. Collectively, the nanocomposites containing Laponite and antimicrobial peptide were proven to have osteoinductive and antimicrobial activity, making them desirable for bone tissue engineering applications.