Ultra-Sharp Nanowire Arrays Natively Permeate, Record, and Stimulate Intracellular Activity in Neuronal and Cardiac Networks

Intracellular access with high spatiotemporal resolution can enhance our understanding of how neurons or cardiomyocytes regulate and orchestrate network activity, and how this activity can be affected with pharmacology or other interventional modalities. Nanoscale devices often employ electroporation to transiently permeate the cell membrane and record intracellular potentials, which tend to decrease rapidly to extracellular potential amplitudes with time. Here, we report innovative scalable, vertical, ultra-sharp nanowire arrays that are individually addressable to enable long-term, native recordings of intracellular potentials. We report large action potential amplitudes that are indicative of intracellular access from 3D tissue-like networks of neurons and cardiomyocytes across recording days and that do not decrease to extracellular amplitudes for the duration of the recording of several minutes. Our findings are validated with cross-sectional microscopy, pharmacology, and electrical interventions. Our experiments and simulations demonstrate that individual electrical addressability of nanowires is necessary for high-fidelity intracellular electrophysiological recordings. This study advances our understanding of and control over high-quality multi-channel intracellular recordings, and paves the way toward predictive, high-throughput, and low-cost electrophysiological drug screening platforms.Comment: Main manuscript: 33 pages, 4 figures, Supporting information: 43 pages, 27 figures, Submitted to Advanced Material

Effects of high frequency vibration on the expression of osteogenic genes in SAOS-2 and BMSCs.

Introduction Mechanical stresses are important to the development of musculoskeletal system (1), but biological mechanisms that are involved by these stimuli remain largely unknown. On the other hand, muscle vibration is used in clinical therapy and sports training to enhance strength and improve motor control (2), (3). Positive therapeutic effects of muscle vibration have been reported in different experimental conditions, for example in the treatment of sportsmen after an accident (3). So, the aim of this work is to understand this phenomena at cellular level and, for this reason, we have designed and realized a system to produce vibration with all the adaptations for “in vivo” studies. Materials and Methods The device to produce vibrating stimuli is composed by an eccentric motor controlled with voltage working with frequency of 30 Hz and imposing a displacement with 3 m/s2 of acceleration and by a 3D accelerometer to record this amplitude (Fig.1). We have taken 30 newborn mice CD1 wild type, divided in two groups, one as control and one treated group. Fifteen mice of treated group were stimulated with a vibration of 30 Hz for 5 weeks 5 days/week for 1h/day. Every week we collected for controls and treated mice tibials and quadriceps anterior muscles and we analyzed on criosections perimeter and surface of muscle fibers with a morfometric analysis software (Image J system). Moreover with molecular biology analysis we investigated genes involved in terminal differentiation, such as MyOD (myogenic differentiation) and MCK (myosin creatin-kinase). Results and Discussion Results of morphometric analysis of muscle fibers (Fig.2) demonstrate that whole-body vibration increases the rate of proliferation of muscle fibers in the first weeks of treatment (increase of fibers number and reduction of surface), while at the end of the experiment (at five weeks of treatment) treated and control fibers tend to balance and probably, tend to fuse to form mature muscle. Molecular biology analysis (Real-Time PCR) was performed only at the second and at the third week on treated and control muscles. Results seem to reveal that high frequency vibrations promote better differentiation of treated muscle tissue with respect to the control ones. This experiment represent a preliminary investigation of the effect of high frequency vibrations at cellular level and at tissue level. Moreover it can establish the starting point for further studies on muscle development and muscle regeneration after injury and treatment with a vibrating system

Characterization and molecular profiling of PSEN1 familial Alzheimer's disease iPSC-derived neural progenitors.

Presenilin 1 (PSEN1) encodes the catalytic subunit of γ-secretase, and PSEN1 mutations are the most common cause of early onset familial Alzheimer's disease (FAD). In order to elucidate pathways downstream of PSEN1, we characterized neural progenitor cells (NPCs) derived from FAD mutant PSEN1 subjects. Thus, we generated induced pluripotent stem cells (iPSCs) from affected and unaffected individuals from two families carrying PSEN1 mutations. PSEN1 mutant fibroblasts, and NPCs produced greater ratios of Aβ42 to Aβ40 relative to their control counterparts, with the elevated ratio even more apparent in PSEN1 NPCs than in fibroblasts. Molecular profiling identified 14 genes differentially-regulated in PSEN1 NPCs relative to control NPCs. Five of these targets showed differential expression in late onset AD/Intermediate AD pathology brains. Therefore, in our PSEN1 iPSC model, we have reconstituted an essential feature in the molecular pathogenesis of FAD, increased generation of Aβ42/40, and have characterized novel expression changes

Ultra‐Sharp Nanowire Arrays Natively Permeate, Record, and Stimulate Intracellular Activity in Neuronal and Cardiac Networks

We report innovative scalable, vertical, ultra-sharp nanowire arrays that are individually addressable to enable long-term, native recordings of intracellular potentials. Stable amplitudes of intracellular potentials from 3D tissue-like networks of neurons and cardiomyocytes are obtained. Individual electrical addressability is necessary for high-fidelity intracellular electrophysiological recordings. This study paves the way toward predictive, high-throughput, and low-cost electrophysiological drug screening platforms

High Density Individually Addressable Nanowire Arrays Record Intracellular Activity from Primary Rodent and Human Stem Cell Derived Neurons

We report a new hybrid integration scheme that offers for the first time a nanowire-on-lead approach, which enables independent electrical addressability, is scalable, and has superior spatial resolution in vertical nanowire arrays. The fabrication of these nanowire arrays is demonstrated to be scalable down to submicrometer site-to-site spacing and can be combined with standard integrated circuit fabrication technologies. We utilize these arrays to perform electrophysiological recordings from mouse and rat primary neurons and human induced pluripotent stem cell (hiPSC)-derived neurons, which revealed high signal-to-noise ratios and sensitivity to subthreshold postsynaptic potentials (PSPs). We measured electrical activity from rodent neurons from 8 days in vitro (DIV) to 14 DIV and from hiPSC-derived neurons at 6 weeks in vitro post culture with signal amplitudes up to 99 mV. Overall, our platform paves the way for longitudinal electrophysiological experiments on synaptic activity in human iPSC based disease models of neuronal networks, critical for understanding the mechanisms of neurological diseases and for developing drugs to treat them