Multispectral near Infrared Imaging of Catecholamine Neurotransmitters with Fluorescent Nanosensors

利用荧光纳米传感器对儿茶酚胺神经递质进行多光谱近红外成像

• 批准号: 426834208
• 负责人: Professor Dr. Sebastian Kruss
• 金额: --
• 依托单位: Lehrstuhl für Physikalische Chemie II: Laserspektroskopie und Biophotonik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426834208?language=en
• 关键词: Multispectral; near; Infrared; Imaging; Catecholamine

The aim of this project is to create near infrared (nIR) fluorescent nanosensors for neurotransmitters, measure and understand their kinetics/selectivity and use them for multispectral imaging of chemical communication between cells. This project is motivated by the importance of chemical communication in multicellular organisms. Neuronal networks such as those in the human brain are the most intriguing example for the complexity of this process. So far, there are not many analytical tools available to image small molecules such as neurotransmitters on small length scales and fast time scales in complex biological environments. For that reason, fast chemical communication between cells and most notably neurotransmitter release and diffusion in neural networks remains largely unexplored. We have recently introduced semiconducting single-walled carbon nanotubes (SWCNTs) as versatile building blocks for (molecular) sensors or probes. SWCNTs are hollow cylinders of one-atom-thick sheets of carbon. They possess an intrinsic size-dependent bandgap, which results in non-bleaching near infrared (nIR) fluorescence (900 nm - 1700 nm), a very beneficial spectral region for optical imaging because of reduced scattering and background. Our previous results indicate that SWCNTs functionalized non-covalently with certain single stranded DNA sequences are able to detect important catecholamine neurotransmitters including dopamine. The organic DNA phase (corona) around the SWCNTs interacts with dopamine, which affects and changes their fluorescence. The goal of this project is to create different sensors for catecholamines by changing the immobilized DNA sequence around SWCNTs. Most importantly, we will measure sensor kinetics in single-molecule experiments (on- and off-rates). For that purpose, we will make use of a nIR microscope that can image single nanosensors of different emission wavelength ("color"). Our theoretical simulations imply that only sensors with certain kinetic properties are useful for imaging of fast processes such as neurotransmitter release. The planned experiments will provide fundamental insights into SWCNT photophysics and how the corona (DNA sequence) affects rate constants and selectivity to structurally very similar catecholamine neurotransmitters (dopamine, epinephrine, norepinephrine). Furthermore, these experiments will reveal candidates with suitable properties for different envisioned sensing applications and kinetic simulations are used to predict their spatiotemporal resolution. The major idea of this project is that combining multiple sensors enhances sensitivity or selectivity. To this end SWCNTs of different color (emission wavelength) and different kinetics/selectivity will be imaged at the same time in a multiplexing approach (multispectral imaging). Finally, we want to demonstrate the versatility of this approach by resolving catecholamine release from cells.

该项目的目的是为神经递质创建近红外（nIR）荧光纳米传感器，测量和了解它们的动力学/选择性，并将其用于细胞之间化学通讯的多光谱成像。该项目的动机是多细胞生物中化学通讯的重要性。像人脑中的神经元网络是这个过程复杂性的最有趣的例子。到目前为止，还没有太多的分析工具可以在复杂的生物环境中对小分子（如神经递质）进行小长度尺度和快速时间尺度的成像。由于这个原因，细胞之间的快速化学通讯，尤其是神经网络中神经递质的释放和扩散，在很大程度上仍未得到探索。我们最近推出了半导体单壁碳纳米管（SWCNT）作为（分子）传感器或探针的通用构建块。单壁碳纳米管是一个原子厚的碳片的中空圆柱体。它们具有固有的尺寸依赖性带隙，这导致非漂白近红外（nIR）荧光（900 nm - 1700 nm），这是一个非常有益的光谱区域，因为减少了散射和背景。我们以前的研究结果表明，与某些单链DNA序列非共价官能化的单壁碳纳米管能够检测重要的儿茶酚胺神经递质，包括多巴胺。单壁碳纳米管周围的有机DNA相（电晕）与多巴胺相互作用，从而影响和改变它们的荧光。该项目的目标是通过改变单壁碳纳米管周围的固定化DNA序列来创建不同的儿茶酚胺传感器。最重要的是，我们将在单分子实验中测量传感器动力学（开和关速率）。为此，我们将利用一个nIR显微镜，可以成像不同发射波长（“颜色”）的单个纳米传感器。我们的理论模拟意味着，只有具有某些动力学特性的传感器是有用的快速过程，如神经递质释放成像。计划中的实验将提供对SWCNT生物物理学的基本见解，以及电晕（DNA序列）如何影响结构非常相似的儿茶酚胺神经递质（多巴胺，肾上腺素，去甲肾上腺素）的速率常数和选择性。此外，这些实验将揭示候选人与不同的设想传感应用和动力学模拟的合适属性被用来预测他们的时空分辨率。该项目的主要思想是将多个传感器结合起来，提高灵敏度或选择性。为此，不同颜色（发射波长）和不同动力学/选择性的SWCNT将在多路复用方法（多光谱成像）中同时成像。最后，我们希望通过解析细胞释放的儿茶酚胺来证明这种方法的多功能性。