Unveiling the biomaterial facet of polarized piezoelectric sodium potassium niobate: A comprehensive study

The fabrication of electro-active bone substitute materials has sparked a significant attention due to the intrinsic electrical characteristics of bone. Recent studies have focused on improving the interaction between biomaterials and bone, recognizing its critical role in implant functionality. Early-stage implantation significantly influences the long-term success of an implant, with post-operative infections posing a major clinical challenge. This underscores the urgent need for advanced biocompatible materials that not only enhance tissue regeneration but also provide effective antibacterial defense. The exploration of bioelectricity in facilitating tissue repair has gained momentum, driven by the growing understanding of piezoelectric properties in natural bone. Harnessing the intrinsic electrical activity of biomaterials presents a promising approach, as bioelectricity is an inherent feature of bone cells, directly regulating their metabolic processes and contributing to tissue regeneration. Having a perovskite structure, lead-free piezo-ceramic sodium potassium niobate (NKN) possesses remarkable electroactive characteristics such as significantly high dielectric constant, superior piezoelectric characteristics, and strong electromechanical coupling coefficient, making it a potential electroactive candidate for tissue engineering. Due to the evidence of enhanced cytocompatibility, osteogenesis, antibacterial activities, along with electrical characteristics, it has been recognized as a potential electro-active bone substitute. This review provides a comprehensive analysis of bone and its intrinsic electrical properties, along with an in-depth examination of NKN—including its doping strategies, electroactive response mechanisms, and structural characteristics. Additionally, the role of poling in enhancing NKN’s electroactivity is explored, reinforcing its potential for biomedical applications. The review highlights NKN’s implications in bone tissue regeneration, soft tissue repair (nerve and vascular regeneration), and cancer therapy, underscoring its relevance across various fields of biomedical engineering. Finally, the summary outlines future research directions, emphasizing opportunities for further exploration and optimization of NKN-based biomaterials.