Energy Harvester and Cell Proliferation from Biocompatible PMLG Nanofibers Prepared Using Near-Field Electrospinning and Electrospray Technology

This paper describes the application of piezoelectric fibers and films formed using near-field electrospinning (NFES) and electrospray (ESP) technology. Poly(γ-methyl L-glutamate) (PMLG), a biocompatible material, was mixed with poly(ethylene oxide) (PEO) and surfactant to obtain a solution of appropriate viscosity and conductance. Because the orientation of the dipoles in PMLG was enhanced upon applying an electric field, we could use the NFES and ESP processes to align dipoles and enhance the piezoelectric properties of the resulting fibrous materials. The maximum peak voltage of a fiber-based harvester prepared using this approach was 0.056 V. Because the fibers and films were non-toxic biological materials displaying excellent piezoelectric characteristics, we deposited them on glass substrates coated with indium tin oxide to observe their effects on the proliferation of cells. The negative charge of PMLG decreased the proliferation of mouse fibroblast cells (NIH3T3); indeed, decreasing the interspacing between the fibers slightly decreased the proliferation of these cells. Moreover, the migration of the cells was inhibited significantly, or even halted, when the coverage of the ESP films increased, implying a growth inhibition effect.