Noninvasive methods for in situ electrical stimulation of human cells open new frontiers to future bioelectronic therapies, where controlled electrical impulses could replace the use of chemical drugs for disease treatment. Here, this study demonstrates that the interaction of living cells with piezoelectric nanogenerators (NGs) induces a local electric field that self-stimulates and modulates their cell activity, without applying an additional chemical or physical external stimulation. When cells are cultured on top of the NGs, based on 2D ZnO nanosheets, the electromechanical NG-cell interactions stimulate the motility of macrophages and trigger the opening of ion channels present in the plasma membrane of osteoblast-like cells (Saos-2) inducing intracellular calcium transients. In addition, excellent cell viability, proliferation, and differentiation are validated. This in situ cell-scale electrical stimulation of osteoblast-like cells can be extrapolated to other excitable cells such as neurons or muscle cells, paving the way for future bioelectronic medicines based on cell-targeted electrical impulses.

Electrospinning and plasma post-modification lead to PVDF scaffolds with favorable electromechanical properties and enhanced wettability.

The hybridization of different nanomaterials has been studied widely for the versatile use of nanogenerators in a range of environments. This paper reports an analysis of the power enhancements in a hybrid piezoelectric structure comprised of zinc oxide (ZnO) nanowires and poly(vinylidene fluoride) (PVDF) polymer. The mechanical properties were examined by atomic force microscopy and simulated by the finite element method. The electrical properties of the hybrid nanogenerators were observed by electrostatic force microscopy and direct I-V measurements. Based on this analysis, the ZnO nanowires delivered internal strain to the PVDF in the hybrid structure, which enhanced the electrical power output of a hybrid nanogenerator. These results may open up new ways to optimize a hybrid piezoelectric structure in terms of its design and the spatial arrangement of each nanostructure.

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This letter presents the design, fabrication, and demonstration of a CMOS-MEMS filter based on two high-Q submicrometer-scale clamped-clamped beam resonators with resonance frequency around 22 MHz. The MEMS resonators are fabricated with a 0.35-μm CMOS process and monolithically integrated with an on-chip differential amplifier. The CMOS-MEMS resonator shows high-quality factors of 227 in air conditions and 4400 in a vacuum for a bias voltage of 5 V. In air conditions, the CMOS-MEMS parallel filter presents a programmable bandwidth from 100 to 200 kHz with a < 1-dB ripple. In a vacuum, the filter presents a stop-band attenuation of 37 dB and a shape factor as low as 2.5 for a CMOS-compatible bias voltage of 5 V, demonstrating competitive performance compared with the state of the art of not fully integrated MEMS filters. Index Terms-Bandpass filter, CMOS-MEMS, micromechanical filter, system-on-chip.