Optical modulation of nervous system becomes increasingly popular as the wide adoption of optogenetics. For these applications, upconversion materials hold great promise as novel photonic elements. This study describes an upconversion based strategy for combinatorial neural stimulation both in vitro and in vivo by using spectrum‐selective upconversion nanoparticles (UCNPs). NaYF₄ based UCNPs are used to absorb near‐infrared (NIR) energy and to emit visible light for stimulating neurons expressing different channelrhodopsin (ChR) proteins. The emission spectrum of the UCNPs is selectively tuned by different doping strategy (Tm³⁺ or Er³⁺) to match the responsive wavelength of ChR2 or C1V1. When the UCNPs are packaged into a glass microoptrode, and placed close to or in direct contact with neurons expressing ChR2 or C1V1, the cells can be reliably activated by NIR illumination at single cell level as well as network level, which is characterized by patch‐clamping and multielectrode‐array recording in culture primary neurons. Furthermore, the UCNP‐based optrode is implanted into the brain of live rodents to achieve all‐optical remote activation of brain tissues in mammalian animals. It is believed that this proof‐of‐concept study opens up completely new applications of upconversion materials for regulating physiological functions, especially in neuroscience research.

中文翻译：

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光谱选择性上转换纳米粒子对神经元的多重光遗传学刺激。

随着光遗传学的广泛采用，神经系统的光调制变得越来越流行。对于这些应用，上转换材料作为新型光子元件具有广阔的前景。这项研究描述了通过使用光谱选择性上转换纳米粒子（UCNPs）在体内和体外进行组合神经刺激的基于上转换的策略。基于NaYF ₄的UCNP用于吸收近红外（NIR）能量并发射可见光，以刺激表达不同通道视紫红质（ChR）蛋白的神经元。UCNP的发射光谱通过不同的掺杂策略（Tm ³⁺或Er ³⁺）以匹配ChR2或C1V1的响应波长。当将UCNP包装到玻璃微光极中并放置在与表达ChR2或C1V1的神经元接近或直接接触时，可以通过单细胞水平和网络水平的NIR照明可靠地激活细胞，其特征在于贴片-培养原代神经元的钳位和多电极阵列记录。此外，将基于UCNP的光极植入活的啮齿动物的大脑中，以实现哺乳动物脑组织的全光学远程激活。可以相信，这一概念验证研究为调节生理功能，特别是在神经科学研究中的上转换材料开辟了全新的应用领域。