Hybrid nanomaterials for dynamic, intracellular radioisotope detection

描述(由申请人提供)：分析细胞信号转导通路的能力，具有越来越高的灵敏度和时间分辨率，在理解涉及人类疾病和紊乱的潜在分子通路方面发挥着关键作用。最具挑战性的分析物是那些浓度非常低、时间变异性很高的分析物，以及缺乏可用于光学和/或电化学检测的部分的小分子。在这两项研究中，放射性同位素标记在生物系统的研究中发挥着关键作用 和临床环境，特别是碳水化合物衍生的小分子信号。与荧光标记等相比，放射性同位素促进了对分析物的最小干扰的高灵敏检测。由于生物分子中普遍存在β粒子发射体，包括32P、35S、14C和3H，这些原子通常被用作生物示踪剂。由于氢在分子体系中的普遍存在，最通用的放射性同位素标记是~3H。~3H具有许多固有的优点，包括标记和未标记化合物之间的低质量差、合理的存储半衰期以及低能量和短渗透深度，使其成为生物分析中最安全的b发射同位素。不幸的是，与其他放射性同位素相比，低能量和短穿透深度也使~3H的检测变得复杂，使分析单个细胞或小细胞组中的动态信号过程的能力降至最低。我们建议开发和表征一种新型的核壳纳米材料，称为纳米SPA，用闪烁染料功能化，用于灵敏地检测细胞内环境中的低能放射性同位素。这种纳米材料是通过在掺有放射性同位素响应性闪烁剂的聚合物核心上沉积一层薄薄的二氧化硅外壳来制备的。聚合物基质促进了能量从放射性同位素到闪烁染料的吸收和转移，而二氧化硅壳层的加入增加了在水样中的溶解度，并提供了易于修饰的表面。与现有技术相比，纳米SPA具有许多优点，包括：a)与水样的兼容性增强；b)高比表面积/体积比(SA/V)，用于改进SPA；c)易于修饰的表面，用于生物分子和其他化学物种的附着；以及d)适用于细胞内放射性同位素成像。这里提出的纳米SPA平台将在与人类健康相关的广泛应用中提供关键的使能技术。虽然我们将把最初的概念验证工作重点放在与葡萄糖调节的胰岛素分泌相关的分析上，但这项技术的应用范围非常广泛。

DESCRIPTION (provided by applicant): The capability to analyze cellular signal transduction pathways with increasing sensitivity and temporal resolution plays a key role in understanding the underlying molecular pathways involved in human diseases and disorders. Among the most challenging analytes are those present at very low concentrations with high temporal variability and small molecules lacking moieties amenable for optical and/or electrochemical detection. Radioisotopic labels play key roles in the investigation of biological systems in both the research and clinical environments, particularly for small molecule signals derived from carbohydrates. Radioisotopes facilitate highly sensitive detection with minimal perturbation of the analyte, compared to fluorescent labels, etc. Beta-particle emitters, including 32P, 35S, 14C and 3H are commonly used as biological tracers due to the prevalence of these atoms in biological molecules. The most universal radioisotopic label is 3H, due to the ubiquitous presence of H in molecular systems. 3H possesses a number of inherent advantages, including low mass differences between labeled and unlabeled compounds, a reasonable half-life for storage and low energy and short penetration depth that make 3H the safest b-emitting isotope commonly used for biological analysis. Unfortunately, the low energy and short penetration depth also complicate detection of 3H compared to other radioisotopes, minimizing the ability to analyze dynamic signaling processes in single cells or small groups of cells. We propose to develop and characterize a novel core-shell nanomaterial, termed nanoSPA, functionalized with scintillating dyes for sensitive detection of low energy radioisotopes in intracellular environments. This nanomaterial is prepared by depositing a thin silica shell onto a polymer core that is doped with radioisotope- responsive scintillants. The polymer matrix facilitates energy absorption and transfer from the radioisotope to the scintillant dye, whereas addition of the silica shell increass solubility in aqueous samples, and provides an easily modified surface. nanoSPA presents a number of advantages compared to existing technologies, including: a) enhanced compatibility with aqueous samples; b) a high-surface area to volume (SA/V) ratio for improved SPA; c) an easily modified surface for attachment of biomolecules and other chemical species; and d) applicability for intracellular radioisotope imaging. The nanoSPA platform that is proposed herein will provide a key enabling technology in a wide range of applications relevant to human health. Though we will focus our initial, proof-of-concept efforts on assays relevant to glucose-regulated insulin secretion, the range of applications for this technology is extremely broad.