Tissues like bone and cartilage are remodeled dynamically for their functional requirements by signaling pathways. The signals are controlled by the cells and extracellular matrix and transmitted through an electrical and chemical synapse. Scaffold-based tissue engineering therapies largely disturb the natural signaling pathways, due to their rigidity towards signal conduction, despite their therapeutic advantages. Thus, there is a high need of smart biomaterials, which can conveniently generate and transfer the bioelectric signals analogous to native tissues for appropriate physiological functions. Piezoelectric materials can generate electrical signals in response to the applied stress. Furthermore, they can stimulate the signaling pathways and thereby enhance the tissue regeneration at the impaired site. The piezoelectric scaffolds can act as sensitive mechanoelectrical transduction systems. Hence, it is applicable to the regions, where mechanical loads are predominant. The present review is mainly concentrated on the mechanism related to the electrical stimulation in a biological system and the different piezoelectric materials suitable for bone and cartilage tissue engineering.

Piezoelectric materials strive to articulate smart materials and transduce electric fields by applying mechanical pressure and vice versa. This study demarcates augmented cartilage regeneration from the praxis of the smart material intervention that denotes the method of the utilized piezoelectric mechanism. The smart piezoelectric nanohybrid is developed from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and barium titanate (BaTiO 3 ). Further, the electrospinning technique is adopted for the scaffolding to mimic the structure of natural cartilage. The scaffold with 20% BaTiO 3 shows enhanced mechanical properties and a piezoelectric coefficient (1.4 pC/ N) similar to native tissue. Interestingly, the corona poled (electrically polarized) scaffolds demonstrated better cellular activity than unpoled. Human mesenchymal stem-cell-derived chondrocytes are utilized for in vitro studies. The polarized scaffolds highly promote the cell attachment, proliferation, and collagen II gene expression against control (pure PHBV) and unpolarised scaffolds; the effect was quite dominant even in high-piezoelectric-coefficient scaffolds. Therefore, the electric-field-originated scaffolds show the potential effect on cartilage regeneration without the addition of any stimulating molecules.