Next-Generation Quantum Dots for Molecular and Cellular Imaging of Cancer

描述（由申请人提供）：本研究提案的目的是开发一类新的荧光纳米颗粒，用于体内肿瘤微环境的高灵敏度和可重复成像，以了解和改善纳米颗粒药物递送。我们将专注于半导体量子点（QD），这是纳米晶体，表现出明亮的荧光和独特的光学和电子特性。我们最近设计了一种新的量子点，称为“合金量子威尔斯”，它可以在很宽的光谱范围内均衡荧光亮度。这种新的特性是有机染料，荧光蛋白或传统量子点所无法获得的，并且将使纳米颗粒药物递送到实体肿瘤的定量研究成为可能。其基本思想是，我们可以修改尺寸，表面化学，或靶向配体对这些纳米粒子探针模型的药物制剂，然后可以定量比较吸收和渗透在实体肿瘤。由于这些颗粒在单分子水平上非常明亮，因此实体瘤的活体显微镜将允许对药物递送的限速步骤进行单分子机械理解。这种同时检测的方法对于异质性肿瘤微环境中的比较至关重要，并且不可能使用传统的光学探针。在这项提案中，我们将对这些纳米粒子进行光学工程设计，开发出尺寸紧凑、血液循环时间长的惰性表面涂层，并开发出基于自组装原理的新型高精度生物结合策略。我们将使用这些新的探针来成像靶向递送到肿瘤的微观过程，集中在小窝介导的转胞吞作用上，这是一种主动转运过程，最近已被证明可以有效地将纳米颗粒从肿瘤血管泵入间质组织。这些研究将实施高度相关的人类乳腺癌原位模型，以确保研究结果的临床意义。在该奖项的指导阶段，候选人将由埃默里大学的Shuming Nie博士和系统医学蛋白基因组研究所的Jan Schnitzer博士共同指导，并将接受人类癌症原位模型，活体显微镜技术和基于抗体的肿瘤靶向策略的使用培训。这两位导师都是纳米技术和癌症生物学各自领域的领导者，这将使专业知识的融合能够指导这个跨学科的研究项目，并促进候选人从受指导的博士后研究员过渡到学术环境中的独立研究员。 公共卫生相关性：基于纳米颗粒的药物是一种很有前途的癌症治疗方法，但我们合理和最佳设计这些颗粒的能力目前受到对其在肿瘤中行为的理解不足的限制。在这项提案中，我们将开发一类新的荧光纳米粒子探针，这将使癌症组织中的纳米粒子的高灵敏度，定量，单分子成像和跟踪成为可能。我们将使用这些探针来了解靶向纳米颗粒递送到肿瘤的机制，以告知将增强肿瘤摄取和治疗功效的设计参数。

DESCRIPTION (provided by applicant): The aim of this research proposal is to develop a new class of fluorescent nanoparticles for highly sensitive and multicolor imaging of the tumor microenvironment in vivo toward understanding and improving nanoparticle drug delivery. We will focus on semiconductor quantum dots (QDs), which are nanocrystals that exhibit bright fluorescence and unique optical and electronic properties. We have recently designed a new class of quantum dots called 'alloyed quantum wells,' which have equalized fluorescence brightness across a broad spectrum of colors. This novel property is not available from organic dyes, fluorescent proteins, or conventional quantum dots, and will enable quantitative studies of nanoparticle drug delivery to solid tumors. The basic idea is that we can modify the size, surface chemistry, or targeting ligands on these multicolor probes to model nanoparticle drug formulations, which can then be quantitatively compared for uptake and penetration in solid tumors. Because these particles are immensely bright on the single molecule level, intravital microscopy of solid tumors will allow a single-molecule, mechanistic understanding of the rate-limiting steps of drug delivery in a multicolor fashion. This simultaneous multicolor approach is critical for comparisons in the heterogeneous tumor microenvironment, and is not possible with conventional optical probes. In this proposal, we will optically engineer these nanoparticles, develop inert surface coatings for compact sizes and long circulation times in blood, and develop new high-precision bioconjugation strategies based on self-assembly principles. We will use these new probes to image the microscopic processes of targeted-delivery to tumors, concentrating on caveolae-mediated transcytosis, an active transport process that has recently been shown to efficiently pump nanoparticles from the tumor blood vessels into the interstitial tissue. These studies will implement highly relevant orthotopic models of human breast cancer that will ensure clinical significance of the findings. During the mentored phase of this award, the candidate will be co-mentored by Dr. Shuming Nie of Emory University and Dr. Jan Schnitzer of the Proteogenomic Research Institute for Systems Medicine, and will be trained in the use of orthotopic models of human cancer, intravital microscopy techniques, and antibody-based tumor targeting strategies. Both of these mentors are leaders in their respective fields of nanotechnology and cancer biology, which will enable a convergence of expertise to guide this interdisciplinary research project and to facility the transition of the candidate from a mentored postdoctoral fellow to an independent investigator in an academic setting. PUBLIC HEALTH RELEVANCE: Nanoparticle-based drugs are a promising therapeutic approach for cancer, however our ability to rationally and optimally design these particles is currently limited by a poor understanding of their behavior in tumors. In this proposal, we will develop a new class of fluorescent nanoparticle probes that will enable highly sensitive, quantitative, single-molecule imaging and tracking of nanoparticles in cancer tissue. We will use these probes to understand the mechanisms of targeted nanoparticle delivery to tumors to inform design parameters that will enhance tumor uptake and therapeutic efficacy.