Nanoparticle-polymer composite scaffolds for bone tissue engineering. A review

Bone tissue engineering is a promising field for developing new treatments for bone defects and diseases. Polymer scaffolds are one of the most widely used approaches for bone tissue engineering because they provide a three-dimensional structure that can support the growth and differentiation of bone cells. However, polymer scaffolds alone have limitations such as poor bioactivity and biocompatibility. Nanoparticles can be incorporated into polymer scaffolds to improve their properties. The synthesis of composite scaffolds combining nanoparticles and polymers has opened a new frontier in tissue engineering. These composite materials synergistically harness the properties of polymers and bioactive attributes of nanoparticles, resulting in scaffolds that offer an optimal microenvironment for cellular adhesion, proliferation, and differentiation. Metallic, metal oxide, organic, and inorganic nanoparticles, such as Ag, Au, ZnO, hydroxyapatite, and bioceramics, when integrated into polymeric matrices, mimic the natural extracellular matrix, amplifying osteoconductive and osteoinductive properties imperative for bone regeneration. They can also help reduce the inflammatory response and scar tissue formation, thereby increasing the mechanical strength of the scaffold, which can help support loads and prevent deformation. In addition, encapsulating drugs or therapeutic molecules into nanoparticles can be used to deliver these agents to the site of injury in a controlled manner. Furthermore, the fine-tuned biodegradability of these composite scaffolds ensured their gradual replacement with native tissues over time. This review aims to present the prevalent nanoparticles, polymers, techniques employed in synthesizing composite scaffolds, and their biological assessments. This review provides an overview of the various options available for creating these scaffolds, guided by their potential applications in tissue regeneration.