Damnjanovic Ratka, Bazard Parveen, Frisina Robert D, Bhethanabotla Venkat R
ACS Nano. 2020 Sep 22;14(9):10917-10928. doi: 10.1021/acsnano.0c00722. Epub 2020 Jul 6.
Biomedical prosthetics utilizing electrical stimulation have limited, effective spatial resolution due to spread of electrical currents to surrounding tissue, causing nonselective stimulation. So, precise spatial resolution is not possible for traditional neural prosthetic devices, such as cochlear implants. More recently, alternative methods utilize optical stimulation, mainly infrared, sometimes paired with nanotechnology for stimulating action potentials. Infrared stimulation has its own drawbacks, as it may cause collateral heating of surrounding tissue. In previous work, we employed a plasmonic method for stimulation of an electrically excitable neuroblastoma cell line, which had limited success. Here, we report the development of a hybrid electro-plasmonic stimulation platform for spatially and temporally precise neural excitation to address the above deficiencies. Primary trigeminal neurons were costimulated in a whole-cell patch-clamp configuration with subthreshold-level short-duration (1-5 ms) electrical and visible light pulses (1-5 ms). The visible light pulses were aimed at a gold-nanoparticle-coated nanoelectrode placed alongside the neuron, within 2 μm distance. Membrane action potentials were recorded with a 3-fold higher success rate and 5-fold better poststimulation cell recovery rate than with pure optical stimulation alone. Also, electrical stimulus current input was being reduced by up to 40%. The subthreshold levels of electrical stimuli in conjunction with visible light (532 nm) reliably triggered trains of action potentials. This single-cell hybrid activation was reliable and repeatable, without any damage as observed with pure optical stimulation. This work represents an empirical cellular study of the membrane action potential response produced by the cultured primary sensory trigeminal neurons when costimulated with plasmonic and electrical (hybrid) stimulation. Our hybrid neurostimulation method can be used toward development of high-acuity neural modulation prosthetic devices, tunable for individual needs, which would qualify as a preferred alternative over traditional electrical stimulation technologies.
利用电刺激的生物医学假肢由于电流扩散到周围组织而导致非选择性刺激，其有效的空间分辨率有限。因此，对于传统的神经假肢设备，如人工耳蜗，精确的空间分辨率是不可能实现的。最近，替代方法利用光刺激，主要是红外线，有时与纳米技术结合来刺激动作电位。红外线刺激有其自身的缺点，因为它可能会导致周围组织的附带加热。在之前的工作中，我们采用了一种等离子体方法来刺激电可兴奋的神经母细胞瘤细胞系，但效果有限。在这里，我们报告了一种用于空间和时间上精确神经激发的混合电 - 等离子体刺激平台的开发，以解决上述不足。在全细胞膜片钳配置中，用亚阈值水平的短持续时间（1 - 5毫秒）电脉冲和可见光脉冲（1 - 5毫秒）共同刺激初级三叉神经元。可见光脉冲瞄准放置在距离神经元2微米范围内的涂有金纳米颗粒的纳米电极。与单独的纯光刺激相比，记录膜动作电位的成功率提高了3倍，刺激后细胞恢复率提高了5倍。此外，电刺激电流输入减少了高达40%。亚阈值水平的电刺激与可见光（532纳米）相结合可靠地触发了动作电位序列。这种单细胞混合激活是可靠且可重复的，没有观察到纯光刺激所造成的任何损伤。这项工作代表了一项关于培养的初级感觉三叉神经元在等离子体和电（混合）刺激共同作用下产生的膜动作电位反应的实证细胞研究。我们的混合神经刺激方法可用于开发高灵敏度神经调制假肢设备，可根据个体需求进行调整，这将成为优于传统电刺激技术的首选替代方案。
