Environmental bacteria engineered piezoelectric bio-organic energy harvester towards clinical applications

Abstract

State-of-the-art biomedical applications including healthcare monitoring, in vivo real-time sensing and disease treatment largely relies on bio-piezoelectric platforms consisting of biocompatibility and piezoelectricity. However, the inability to design a high performance piezoelectric material with biocompatibility is the major challenges towards practical implementation. Here we present the concept and design principles of an biocompatible piezoelectric material with the assistance of environmental (hot spring) bacterial strain. The biological bacterial protein engineered the microstructure of organic polymer poly(vinylidene fluoride) (PVDF) in order to design the porous bio-organic films with increased biocompatibility, piezoelectric phase content and crystallinity. The porous microstructure significantly enhances the piezoelectric coefficient (d33~ −43 pC/N) and piezoelectric figure of merit (FoMp~ 18.8 ×10−12 Pa−1) of the bio-organic film compared with non-porous pure PVDF (d33~ −0.85 pC/N, FoMp~ 8.5 ×10−15 Pa−1). The proof-of-concept of device designing is also studied, that is nanogenerator composed of bio-organic film is capable to generate maximum output power of as high as 640 mW/m2, possesses energy conversion efficiency of 62.5% which is further used for driving several commercial light emitting diodes (LEDs) and charge capacitors. The enhanced piezoelectric performance is attributed via porosity formation and validated through finite element method (FEM) based theoretical simulation. With the good biocompatibility and piezoelectric pressure sensitivity (1.26 VkPa−1 and 0.86 VkPa−1 in the pressure range of 0.01 −1 kPa and 2 −15 kPa respectively), the device was implemented towards clinical applications of real-time healthcare monitoring from subtle pulse pressure waveform detection to vibrotactile information collection. With its natural biocompatibility, easy to prepare formulation and superior energy harvesting performance, the bio-organic film offers attractive prospects towards the development of effective, sustainable and autonomous electromechanical device for next generation self-powered biomedical devices.