Multiplexed Imaging in the Near Infrared with Indium Phosphide Quantum Shells

项目总结/摘要 由于荧光的成本相对较低，因此荧光在生物医学成像应用中具有巨大的潜力 成像设备，非电离辐射的标称毒性（即，光），分子成像的潜力 使用靶特异性造影剂，以及使用离散彩色成像的多路成像的前景 荧光团。生物组织中常见的分子，包括脂质、水和血红蛋白， 光，使组织对可见波长不透明，但更长的近红外（NIR）波长穿透 更深，给我们一个观察身体的光学窗口。要看到组织内部，我们需要明亮，耐光，高度 吸收的近红外荧光团。尽管在体外获得了优异的结果，但我们可以改善 有机染料、荧光蛋白和传统的半导体量子点（QD），它们通常是暗淡的， 有毒，不够红，或者以上都有。我们创造了一种材料，它可以将量子点从里到外翻转， 以制造由无毒元素（In、P、Se、Zn、S）组成的量子壳（QS），其可从500 - 900 nm.由于InP比CdSe更有效地吸收，因此这些材料比先前的材料更亮， 更小的尺寸，同时在近红外发射并降低毒性。我们提出了一项技术发展计划， 将使我们能够细化这些粒子的结构和光学特性， 调色板的荧光团，使多路复用在深层组织。我们将在宽视场成像中部署这些粒子 和多光子显微镜（MPM）实验，首先客观地量化，然后证明光学 这些探测器的优势。在评估了各种制剂的体外和体内生物相容性后， 水溶性量子点，我们将使用靶向和非靶向量子点一起用于细胞表面的双探针成像 生物标志物以选择性地突出异种移植肿瘤。除了宽视野成像，我们将客观地评估 QSs的MPM对比度。颗粒的极高吸收率确保了高的二次和三次- 光子作用截面我们将定量比较的亮度和组织穿透深度的 InP QSs对其他红色和NIR荧光团。粒子的合成迭代将使用唯一粒子 几何形状以生成具有不同发射颜色但具有相同亮度的QS。我们将比较两性离子 涂层与我们的基准脂质-PEG涂层相比，试图通过更长的循环时间来增强成像对比度 更有效的瞄准。该项目的成功将产生一种无毒的近红外荧光团， 可以共同使用，可以改变临床前分子成像。

Project Summary/Abstract Fluorescence has significant potential for biomedical imaging applications because of the relatively low cost of imaging equipment, the nominal toxicity of non-ionizing radiation (i.e., light), the potential for molecular imaging using target-specific contrast agents, and the prospect of multiplexed imaging using discretely colored fluorophores. Molecules common in biological tissues including lipids, water, and hemoglobin scatter and absorb light, rendering tissue opaque to visible wavelengths, but longer, near infrared (NIR) wavelengths penetrate deeper, giving us an optical window into the body. To see inside a tissue, we require bright, photostable, highly absorbing, NIR fluorophores. Despite exceptional results in vitro, we can improve on the in vivo performance of organic dyes, fluorescent proteins, and traditional semiconductor quantum dots (QDs), which are typically dim, toxic, not red enough, or all of the above. We have created a material that literally flips a quantum dot inside out to make a quantum shell (QS) comprised of non-toxic elements (In, P, Se, Zn, S) that is tunable from 500 – 900 nm. Because InP absorbs more efficiently than CdSe, these materials are brighter than previous materials with a smaller size, while emitting in the NIR and reducing toxicity. We propose a technology development plan that would enable us to refine the structural and optical properties of these particles to generate a brightness-matched palette of fluorophores to enable multiplexing in deep tissue. We will deploy these particles in widefield imaging and multiphoton microscopy (MPM) experiments to first objectively quantify and then demonstrate the optical superiority of these probes. After evaluating the in vitro and in vivo biocompatibility of various formulations of water-soluble QSs, we will use targeted and untargeted QSs together for dual probe imaging of cell surface biomarkers to selectively highlight a xenograft tumor. In addition to widefield imaging, we will objectively evaluate the MPM contrast of the QSs. The exceptionally high absorptivity of the particles ensures high two- and three- photon action cross-sections. We will quantitatively compare the brightness and tissue penetration depth of the InP QSs against other red and NIR fluorophores. Synthetic iterations to the particles will use the unique particle geometry to generate QSs with varying emission colors, but the same brightness. We will compare zwitterionic coatings to our benchmark lipid-PEG coating to try to enhance imaging contrast through longer circulation time and more efficient targeting. The success of this project will yield a rainbow of non-toxic, NIR fluorophores that can be used collectively could transform preclinical molecular imaging.