StiMote: An Ultrasmall, Modular Neurophotonic Stimulator

视力丧失仍然是一个重大的社会问题，降低了全世界数百万人的独立性和生活质量。 虽然视觉通路神经元的电刺激在严重失明的人中产生了光的感觉，但脑机接口（BMI）技术不足是这种潜在影响力技术临床实施的障碍。 目前的系统使用大束电线将视觉皮层（大脑处理视觉信息的部分）连接到头骨，这导致移动，疤痕和最终的设备故障。该研究项目将创建和测试StiMote，这是一种模块化脑刺激器，使用光（而不是电线）为各个模块供电和编程，并通过电刺激激活大脑中的神经，以重建感官知觉或调节大脑活动。 StiMote的边长仅为0.3毫米，旨在帮助视力严重受损的人更充分地参与社会。StiMote架构还可用于治疗其他疾病，包括影响大脑或神经系统的疾病。为了促进研究和社会的多样性、公平性和包容性（DEI），调查人员将接触校园团体，包括女工程师协会、全国黑人工程师协会、和西班牙裔专业工程师协会，让他们了解该项目，并通过实习让他们参与研究。该项目的重点是解决重大的技术挑战，通过StiMote的开发实现了平行的大脑接口。StiMote旨在克服当前视皮层假体（VCP）方法的三个局限性：（1）低分辨率的表面刺激，（2）可以满足密度和通道数要求的穿透电极阵列，但会引起明显的异物反应，需要将刚性多线系绳连接到大型经皮连接器上，以及（3）具有感应功率的模块化刺激器/由于感应线圈尺寸要求，数据方案不满足恢复高敏锐度视力所需的密度。初步估计表明，与目前临床试验中的VCP相比，StiMote可以将刺激的空间分辨率提高60倍以上。八微米碳纤维电极将与电沉积铂铱结合，以创建一个高效的神经接口。碳纤维在长期植入物中的疤痕最小，导致电极20微米内的大量健康神经元。这种紧密的接近提高了刺激的效率。电沉积铂铱通过有效的电荷转移最大限度地减少刺激期间的电极极化。研究人员将开发新的光伏和超低功耗电路芯片，以形成迄今为止功耗最低的无线刺激微尘。该项目将整合技术进步到StiMote中，并在失明动物模型中证明StiMote用于视力恢复的安全性和有效性。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Vision loss remains a significant societal problem, decreasing independence and quality of life for millions world-wide. Though electrical stimulation of visual pathway neurons creates the sensation of light in people with severe blindness, inadequate brain machine interface (BMI) technology represents a barrier to clinical implementation of this potentially impactful technology. Current systems use large bundles of wires connecting the visual cortex (the part of the brain that processes visual information) to the skull, which leads to movement, scarring, and eventual device failure. This research project will create and test StiMote, a modular brain stimulator that uses light (rather than wires) to power and program individual modules and electrical stimulation to activate nerves in the brain to recreate sensory perception or modulate brain activity. StiMote is only 0.3 mm on a side and is being designed for sight restoration to help people with severe visual impairment participate more fully in society. The StiMote architecture can also be used to treat other medical conditions, including diseases affecting the brain or nervous system. To promote diversity, equity, and inclusion (DEI) in research and society, the investigators will reach but to campus groups including the local chapters of Society of Women Engineers, the National Society of Black Engineers, and the Society of Hispanic Professional Engineers to make them aware of the project and involve them in research through internships.This project is focused on solving significant technical challenges that will enable impactful parallel brain interfaces through the development of StiMote. StiMote is designed to overcome three limitations in current approaches for Visual Cortex Prostheses (VCPs): (1) Surface stimulation that is low resolution, (2) Penetrating electrode arrays that can meet requirements for density and channel count, but will evoke significant foreign body reaction and require stiff multi-wire tethers to large percutaneous connectors and (3) Modular stimulators with inductive power/data schemes that do not meet the density needed to restore high acuity vision due to inductive coil size requirements. The initial estimates suggest that StiMote can improve the spatial resolution of stimulation by more than 60X compared to VCPs currently in clinical trials. Eight micron carbon fiber electrodes will be combined with electrodeposited platinum iridium to create a highly efficient neural interface. Carbon fibers are minimally scarring in long term implants, resulting in a large number of healthy neurons within 20 microns of the electrode. This close proximity improves the efficiency of stimulation. Electrodeposited platinum iridium minimizes electrode polarization during stimulation, through efficient charge transfer. The investigators will develop new photovoltaic and ultra-low power circuit chips to form a wireless stimulation mote with the lowest power consumption to date. The project will integrate technical advances into StiMote and demonstrate the safety and efficacy of StiMote for vision restoration in an animal model of blindness.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.