Beck Connor L, Kirby Andrew M, Roberts Samuel, Kunze Anja
Department of Electrical and Computer Engineering, Montana State University, Bozeman, Montana 59717, United States.
Department of Chemical Engineering, Montana State University, Bozeman, Montana 59717, United States.
ACS Nano. 2024 Dec 24;18(51):34630-34645. doi: 10.1021/acsnano.4c09542. Epub 2024 Dec 9.
Nanomagnetic forces deliver precise mechanical cues to biological systems through the remote pulling of magnetic nanoparticles under a permanent magnetic field. Cortical neurons respond to nanomagnetic forces with cytosolic calcium influx and event rate shifts. However, the underlying consequences of nanomagnetic force modulation on cortical neurons remain to be elucidated. Here, we integrate electrophysiological and optical recording modalities with nanomagnetic forces to characterize the functional response to mechanical cues. Neurons exposed to chitosan functionalized magnetic nanoparticles for 24 h and then exposed to magnetic fields capable of generating forces of 2-160 pN present elevated cytosolic calcium in neurons and a time-dynamic electrophysiological spike rate and magnitude response. Extracellular recordings with microelectrode arrays revealed a 2-8 pN force-specific increase in electrophysiological spiking with a trend in reduced activity following 2 min of continuous force exposure. Nanomagnetic forces in the 16-160 pN range produced increased electrophysiological activity and remained excited for up to 4 h under continuous stimulation before silencing. Furthermore, the neuronal response to nanomagnetic forces at 16-160 pN can be electrophysiologically mediated without calcium influx by altering the magnetic nanoparticle-neuron interactions. These results demonstrate that low pN nanomagnetic forces mediate neuronal function and suggest that magnetic nanoparticle interactions and force magnitudes can be harnessed to provoke different responses in cortical neurons.
纳米磁力通过在永久磁场下远程拉动磁性纳米颗粒，向生物系统传递精确的机械信号。皮层神经元会以胞质钙内流和事件发生率变化来响应纳米磁力。然而，纳米磁力调制对皮层神经元的潜在影响仍有待阐明。在此，我们将电生理和光学记录方式与纳米磁力相结合，以表征对机械信号的功能反应。暴露于壳聚糖功能化磁性纳米颗粒24小时的神经元，随后暴露于能够产生2-160皮牛力的磁场中，会使神经元胞质钙升高，并呈现出时间动态的电生理尖峰频率和幅度反应。用微电极阵列进行的细胞外记录显示，电生理尖峰有2-8皮牛力特异性增加，在持续施加力2分钟后活动有降低趋势。16-160皮牛范围内的纳米磁力会使电生理活动增加，在持续刺激下直至沉默前可兴奋长达4小时。此外，通过改变磁性纳米颗粒与神经元的相互作用，在16-160皮牛时神经元对纳米磁力的反应可在无钙内流的情况下通过电生理介导。这些结果表明，低皮牛的纳米磁力介导神经元功能，并表明可以利用磁性纳米颗粒相互作用和力的大小在皮层神经元中引发不同反应。
