Active Biomaterials for Bone Tissue Regeneration

Bone tissue is critical for structural support and mobility. It is capable of self-repairing through processes such as growth and remodeling, but often this ability is not enough to allow a complete bone healing. To date, autologous bone graft transplant remains the most used solution in clinics despite its notable limitations, such as donor site morbidity and unpredictable graft resorption. Tissue engineering aims to develop strategies to regenerate bone tissue, avoiding autograft implants, by using stem cells and biomaterials. To achieve functional skeletal regeneration, biomaterials play a crucial role in supporting cellular viability and functionality upon implantation, promoting tissue regeneration. Smart bioactive materials come to the fore as an original solution for tissue engineering, tuning their physicochemical properties in response to external stimuli, managing to replicate bone stimuli, and actively guiding the differentiation of stem cells. These smart materials are also useful as therapeutic tools for targeted sites during delivery by improving the efficacy of therapies. A number of stimulation techniques are available, and among these approaches, acoustic and magnetic fields arise as original solutions for the treatment of bone diseases. Furthermore, the piezoelectric properties of natural bone tissue serve as the basis for active biomaterial scaffolds that mimic the physiological functions of bone, including restoring bioelectrical activity. Recent studies highlight the potential of these bioactive materials to respond to stimuli, providing active signals to stem cells able to improve osteogenic differentiation. Thus, stimuli-responsive materials are a new class of active compounds capable of addressing clinical challenges in skeletal repair, promising strategies to optimize bone regeneration.