Piezoelectric energy harvesting systems for biomedical applications

In the present era, self-powered technology and smart materials have paved the way for the design of numerous implantable energy harvesting and biomedical applications. Piezoelectric is a class of materials that could generate an electrical output on the application of strain or stress. Piezoelectric energy harvesters (PEHs) are capable of harvesting various types of ubiquitous mechanical energy into electricity, unlike several other technologies such as triboelectric and electromagnetic. The piezoelectric effect is an important component for the PEH to deliver the maximum electrical output, considering its superior properties such as high electromechanical coefficient, wide environment, and thermal stability. The wide variety of piezoelectric biomaterials and numerous device designs could directly boost performance and make them compatible with various operational environments. Motions from human movements and vital organs could be an effective medium for transforming mechanical vibrations into electrical energy through PEH. This review sheds light upon the use of PEH in biomedical and implantable energy harvesting devices. A detailed summary of various piezoelectric biomaterials, device designs, and possible applications such as health monitoring, cell stimulation, stimulation of the brain, and tissue engineering. The future challenges and the roadmap for sustainable development of PEH are also outlined. Overcoming the existing problems in PEHs can lead to their acting as an alternative power source for biomedical applications and future healthcare sensors. Further, this review highlights the recent developments in piezoelectric biomaterials and their potential in various biomedical applications.