New class of DNA-templated near-infrared voltage-reporter for deep-brain imaging

电压尖峰的传输在大脑中的细胞与细胞通信中起着重要作用。这些通信决定了行为、记忆、感觉输入和运动功能的神经基础，并在阿尔茨海默氏症和帕金森氏症等神经退行性疾病中发挥作用。 虽然在啮齿动物的电压活动的光学成像方面取得了巨大的进展，以更好地了解大脑中的细胞信号，但这些技术仅限于微观视野，并且通常需要侵入性方法才能进入大脑深处的感兴趣区域。由于近红外（NIR）光比可见光更深地穿透到生物组织中，因此使用NIR光的成像方法提供了对大脑中更深结构进行非侵入性成像的机会。该项目将开发新型的基于DNA的纳米颗粒，这些纳米颗粒可以与染料精确结合，这些染料可以在近红外范围内改变其色谱，以响应神经细胞膜电压的变化。 这些纳米粒子探针将用于在活体脑芯片模型中成像电压尖峰。 开发的工具可以促进未来的临床相关研究，这些研究使用小动物模型来研究功能连接和神经血管耦合在神经退行性疾病中的作用。 这项研究将通过神经技术和计算神经科学集中的课程设置以及支持参加CASBBI NSF研究培训计划的研究生的培训，与乔治梅森大学生物工程系和脑-体相互作用自适应系统中心（CASBBI）的教育使命相结合。通过报告分子对光的特异性吸收以及随后的热弹性产生的超声脉冲，其不像光那样容易在组织中散射。尽管派是一种用于成像啮齿动物脑中的血流动力学的成熟技术，但NIR光声电压报告物的缺乏阻碍了其用于直接映射神经元信号的实用性。拟议的工作使用DNA纳米技术来生产探针，该探针由具有拴系的ICG染料的靶向DNA NP组成，ICG染料是FDA批准的电压传感染料。这些DNA集成的电压指示纳米颗粒（DIVIN）探针提供了几个优点：1）NIR激发：NIR光比可见光穿透大脑更深; 2）精密纳米工程：染料分子的预定组织，用于高局部浓度和光稳定性;以及3）细胞特异性标记：DNA NP可以与靶向部分缀合以实现DIVIN探针的细胞特异性靶向，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进行评估，被认为值得支持的搜索.

Transmission of voltage spikes plays a major role in cell-to-cell communication in the brain. These communications determine the neural underpinnings of behavior, memory, sensory input, and motor function as well as play a role in neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. While tremendous progress has been made in optical imaging of voltage activity in rodents to better understand cellular signaling in the brain, these techniques are limited to microscopic fields of view, and often necessitate invasive methods to gain access to the region of interest deep in the brain. Since near-infrared (NIR) light penetrates much deeper into biological tissue than visible light, imaging methods that use NIR light offer opportunities to noninvasively image deeper structures in the brain. This project will develop novel DNA-based nanoparticles that can be precisely combined with dyes that change their color spectrum in the NIR range in response to changes in the voltage of neuronal cell membranes. These nanoparticle probes will be used to image voltage spikes in a living brain-on-chip model. The tools developed can facilitate future clinically relevant studies that use small-animal models to examine the role of functional connectivity and neurovascular coupling in neurogenerative diseases. The research will be integrated with the educational mission of the Bioengineering department and the Center for Adaptive Systems of Brain-body Interactions (CASBBI) at George Mason University through curriculum offerings in the Neurotechnology and Computational Neuroscience concentration and by supporting training of graduate students participating in the CASBBI NSF Research Traineeship program.Photoacoustic imaging (PAI) relies on wavelength-specific absorption of light by reporter molecules and subsequent thermoelastic generation of ultrasound pulses that are not as susceptible to scattering in tissue as light. Although PAI is a well-established technique for imaging hemodynamics in rodent brains, a lack of NIR photoacoustic voltage reporters hinders its utility for directly mapping neuronal signaling. The proposed work uses DNA nanotechnology to produce probes that comprise of targeted DNA NPs with tethered ICG dye, which is an FDA-approved voltage-sensing dye. These DNA-integrated voltage indicating nanoparticle (DIVIN) probes offer several advantages: 1) NIR excitation: NIR light penetrates deeper in the brain than visible light; 2) Precision nano-engineering: pre-determined organization of dye molecules for high local concentration and photostability; and 3) Cell-specific labeling: DNA NPs can be conjugated with targeting moieties to enable cell-specific targeting of DIVIN-probes, which are small enough.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.