Magnetic quantum dots for active sensing of the nuclear envelope

描述（由申请人提供）：发光半导体纳米晶体（量子点，QDs）是一种无机荧光团纳米粒子，具有优异的材料和光学性能，包括高量子产率，窄发射和宽激发光谱，极高的光漂白阈值，以及对光和化学降解的高抗性。尽管人们对量子点在生物学上的应用有着广泛的兴趣，但量子点在很大程度上局限于体外传感器的应用，固定组织和细胞的染色，以及体内的简单标记。量子点领域面临的主要挑战包括主动操作、活体组织和细胞的高时空分辨率成像、量子点在生物膜上的可控易位以及对细胞器的特异性靶向。我们提出的研究的总体目标是通过开发一类新的磁性量子点（mqd）和新型mqd蛋白偶联物来直接解决这些挑战。mqd结合了半导体纳米晶体的独特特性和磁性粒子的主动操纵能力。我们建议利用所得到的mqd和开发mqd蛋白偶联物来获得生物膜科学和核膜微力学的新的重要见解。该提案的具体目标是：开发和测试mqd。我们将开发和制造用于活细胞应用的表面工程多功能mqd。2.具体目标；用已知生化成分和物理性质的模型膜系统测试mqd。利用NE脂质和NE蛋白（如核层蛋白）重建核膜模型。使用mqd探测这些模拟系统的渗透率。具体目标3。驱动mqd进入细胞核，探测活细胞内NE的微观力学。3 a。我们将开发一种新型的纳米颗粒弹道轰击系统，以确保mqd同时高速率转移到培养的许多细胞中。我们将使用外部磁场来探测细胞质和核质中弹道注射的mqd的组分，以及作为施加在mqd上的力的函数的局部NE变形。3 c。我们将研究纤层蛋白A/C的消耗或纤层蛋白A/C的致病突变是否会影响NE的微观力学。3 d。我们将研究肌动蛋白和微管网络是否以及如何影响NE的机械性能。

DESCRIPTION (provided by applicant): Luminescent semiconductor nanocrystals (quantum dots, QDs) are inorganic fluorophore nanoparticles with superior materials and optical properties, including high quantum yield, narrow emission and broad excitation spectra, extremely high photobleaching thresholds, and high resistance to photo- and chemical degradation. Despite widespread interest in QDs for biological applications, QDs have been largely confined to sensor applications in vitro, staining of fixed tissues and cells, and as simple markers in vivo. The key challenges facing the QD field include active manipulation, high spatial and temporal resolution imaging in living tissues and cells, controlled translocation of QDs across biological membranes, and specific targeting to organelles. The overall goal of our proposed research is to address these challenges directly by developing a new class of magnetic quantum dots (MQDs) and novel MQD-protein conjugates. MQDs combine the unique properties of semiconductor nanocrystals with the active manipulation capabilities of magnetic particles. We propose to use the resulting MQDs and develop MQD-protein conjugates to gain new and important insight in biomembrane science and nuclear envelope micromechanics. The specific aims of the proposal are: Specific Aim 1. Develop and test MQDs. We will develop and fabricate surface-engineered multifunctional MQDs for live-cell applications. Specific Aim 2. . Test the MQDs with model membrane systems of known biochemical compositions and physical propertie.. Reconstitute the nuclear envelope (NE) model using NE lipids and NE proteins such as nuclear lamins. Probe the permeability of these mimetic systems using MQDs. Specific Aim 3. Drive MQDs into the nucleus to probe NE micromechanics in live cells. 3a.We will develop a novel nanoparticle ballistic bombardment system to ensure a high rate of transfer of MQDs to many cells in culture simultaneously. Sb.We will use external magnetic fields to probe the fractions of ballistically injected MQDs in the cytoplasm and nucleoplasm as well as local NE deformation as a function of the applied force on the MQDs. 3c.We will investigate whether the depletion of lamin A/C or disease-causing mutations in lamin A/C affects NE micromechanics. 3d. We will investigate whether and how the actin and microtubule networks affect the mechanical properties of the NE.