Monovalent Nanocrystals for Biomedical Imaging

描述(申请人提供)：为了加强和改进生物医学成像技术，提出了一种方法来开发高效和通用的程序来合成无毒的量子点，并将这些点连接到蛋白质上。人们普遍认为，在蛋白质标记和其他成像技术的应用中，量子点(QD)比有机染料或金纳米晶具有许多优点。通过成像技术检测疾病的方法需要将量子点连接到生物分子上的新方法。拟议的项目涉及具有以下专业知识的首席研究人员之间的合作：有机合成(制备用于钝化和稳定纳米晶体的定制树枝状结构)、纳米晶体合成(设计和合成具有可调节的电子和光谱特性的无毒纳米晶体)、物理生物化学(证明设计的纳米晶体附着在参与细胞信号的代表性蛋白质上的可行性)和单分子光谱学(证明所设计的系统有助于蛋白质折叠研究的能力)。该团队将开发技术，在体外和随后的体内表征以前未实现的纳米晶体生物结合物的结构和/或生物学特性。该项目目标的实现有望证明生物纳米技术作为一种新的诊断和治疗方法的优势。本探索性项目有三个具体目标：1.合成、表征和优化合适的官能化树枝，用于连接无毒的掺锰锌硒(Mn：ZnSe d点)和InAs/InP/ZnS核/壳/壳近红外(NIR)量子点。2.探索固相合成方法制备共价键合在聚合物树脂上的Mn：ZnSe d-Dot。用甲氧乙胺封端的树枝状大分子衍生量子点的水溶性。3.通过四个连接体将单价d-点功能化以用于蛋白质连接，这四个连接体将在广泛的蛋白质应用中提供最大潜力：氮三乙酸(NTA)、N-羟基琥珀酰亚胺(NHS)、马来酰亚胺和酰肼。将d-点与具有代表性的蛋白质偶联，纯化，并进行化学和光谱表征。 与公共健康相关：有机染料多年来一直被用于生物医学成像应用，但它们受到一些限制，其中许多限制可以通过使用纳米晶体(纳米晶体，也称为量子点)来克服。过去在这一领域的努力有几个缺点，包括商业上可获得的纳米晶体材料中重金属组分的毒性，无毒量子点的合成方法，以及将量子点与蛋白质等生物分子偶联的低效方法。指导这个项目的阿肯色大学团队旨在克服这些限制，并且是唯一有资格这样做的团队，因为它包括在蛋白质偶联无毒量子点的合成和评估的各个方面都有专业知识的主要研究人员。

DESCRIPTION (provided by applicant): Methodology is proposed to develop efficient and general procedures for the synthesis of nontoxic quantum dots, and for conjugating, or 'tagging' these dots to proteins, for the purpose of enhancing and improving biomedical imaging techniques. It is generally agreed that quantum dots (QDs) offer many advantages over organic dyes or gold nanocrystals in applications of protein tagging and other imaging technologies. Approaches to disease detection via imaging techniques require novel methods of QD conjugation to biomolecules. The proposed project involves a collaboration between Principal Investigators with expertise in organic synthesis (to prepare tailored dendrons for use in passivating and stabilizing nanocrystals), nanocrystal synthesis (to design and synthesize nontoxic nanocrystals with tunable electronic and spectroscopic properties), physical biochemistry (to demonstrate the feasibility of attachment of the designed nanocrystals to a representative protein that is involved in cell signaling), and single molecule spectroscopy (to demonstrate the ability of the designed systems to aid in the study of protein folding). The team will develop techniques to characterize previously unrealized structural and/or biological properties of nanocrystal bioconjugates in-vitro, and subsequently in-vivo. Accomplishment of the aims of this project is expected to demonstrate the advantages of bionanotechnology as a new avenue of diagnostic and therapeutic treatment. This exploratory project has 3 specific aims: 1. Synthesize, characterize, and optimize appropriately functionalized dendrons for ligation to nontoxic Mn-doped ZnSe (Mn:ZnSe d-dots) and InAs/InP/ZnS core/shell/shell near infrared (NIR) QDs. 2. Explore solid-phase synthesis strategies to prepare Mn:ZnSe d-dots that are covalently attached to polymer resins. Derivatize the quantum dots for water solubility using methoxyethylamine-capped dendrimers. 3. Functionalize the monovalent d-dots for protein conjugation via four linkers that will provide maximum potential in a wide variety of protein applications: nitrilotriacetic acid (NTA), N-hydroxysuccinimide (NHS), maleimide, and acyl hydrazide. Conjugate the d-dots with representative proteins, purify, and characterize chemically and spectroscopically. PUBLIC HEALTH RELEVANCE: Organic dyes have been used for years in biomedical imaging applications, but they suffer from a number of limitations, many of which can be overcome by using nanometer-sized crystals (nanocrystals, also known as quantum dots). Past efforts in this area have several drawbacks, including toxicity from the heavy metal components of commercially available nanocrystalline materials, methods for the synthesis of nontoxic quantum dots, and inefficient methods for coupling quantum dots to biomolecules such as proteins. The University of Arkansas team directing this project aims to overcome these limitations, and is uniquely qualified to do so, since it comprises Principle Investigators with expertise in every aspect of the synthesis and evaluation of protein-coupled nontoxic quantum dots.