Diffusing Colloidal Probe Microscopy of Zwitterionic Nanoparticles

第一部分：非技术概述最近在合成底物上模拟哺乳动物细胞外膜的抗生物污染性能的尝试越来越依赖于两性离子材料的使用，即那些带有正负电荷基团的材料。在用于药物输送应用的生物材料方面，防止诊断或治疗纳米颗粒聚集、沉淀或清除的表面修饰方法对于延长其在体内的循环时间并使其通过主动靶向在特定部位蓄积尤为重要。尽管两性离子材料具有巨大的潜力，但由于现有技术的有限敏感性，人们对粒子和细胞之间的弱相互作用知之甚少。在这项工作中，PI将使用粒子轨迹的非侵入性显微镜测量和揭示弱相互作用的分析来测量细胞和两性离子修饰粒子之间的纳米级相互作用。PI将使用这种方法来评估具有明确分子结构的两性离子聚合物功能化的纳米颗粒与细胞表面之间的相互作用。推广工作将包括本科生参与研究，并通过巴尔的摩小学基于教育的拉丁裔推广计划和STEM成就参与社区参与。第二部分：技术概述拟议的研究将提供对产生具有特定和非特定KT尺度与各种生物材料所需组合的两性离子(ZI)粒子的分子和工艺参数的基本和技术见解。将通过控制分子结构和结构来了解、设计和优化两性离子物种和生物材料之间的非特定排斥，这些结构将与直接敏感的测量和模型定量地联系在一起。有待研究的具体相互作用包括Sigma受体-苯甲酰胺和CD44-透明质酸相互作用。拟开展的工作分为四个方面。第一部分是锌聚合物的设计、合成和表征。我们的目标是生成一个具有越来越多建筑复杂性的材质库，这些材质库应该转化为不同的表面属性。第二个任务是通过共聚物在二氧化硅颗粒上的吸附或高度支化的两亲性大分子的自组装来研究锌颗粒的形成，使用工艺条件来影响锌颗粒的表面性质。第三项任务是用模型合成底物对锌颗粒进行扩散探针测量，最终确定聚合物结构和吸附/自组装条件的组合，从而产生所需的非特定斥力。在建立了这一点之后，这项提议的最后一项任务是利用这一知识对带有特定部分的ZI颗粒与癌细胞之间的特定相互作用进行扩散探针测量。这种测量将在乳腺癌细胞中进行，以研究透明质酸和CD44受体以及苯甲酰胺和西格玛受体之间的相互作用。这四项任务中的每一项都是总体计划的一部分，该计划旨在测量和解释纳米生物技术应用中合成和细胞表面上的共价附着、取向和组织如何影响颗粒-细胞相互作用。

Part I: Non-technical summaryRecent attempts to mimic the anti-biofouling properties of the external membrane of mammalian cells on synthetic substrates are increasingly relying on the use of zwitterionic-based materials, i.e., those bearing positively and negatively charged groups. In the context of biomaterials intended for drug delivery applications, surface modification methods that preclude aggregation, precipitation or clearance of diagnostic or therapeutic nanoparticles are particularly important to extend their circulation time in the body, and allow them to accumulate at specific sites through active targeting. Despite the tremendous potential of zwitterionic-based materials, little is known regarding weak interactions between particles and cells due to the limited sensitivity of existing techniques. In this work, the PIs will measure nanometer scale interactions between cells and zwitterionic-decorated particles using non-intrusive microscopy measurements of particle trajectories and analyses that reveal weak interactions. The PIs will use this method to evaluate interactions between nanoparticles functionalized with zwitterionic polymers with well-defined molecular architectures and cell surfaces. Outreach efforts will involve participation of undergraduate students in research, and community involvement through an education-based Latino outreach program and STEM Achievement in Baltimore Elementary Schools.Part II: Technical summaryThe proposed research will provide fundamental and technological insights into the molecular and processing parameters that produce zwitterionic (ZI) particles having the desired combination of specific and non-specific kT-scale interactions with various biomaterials. Non-specific repulsion between zwitterionic species and biomaterials will be understood, designed, optimized by controlling molecular architecture and structure, which will be quantitatively connected to direct sensitive measurements and models. Specific interactions to be investigated include sigma receptor-anisamide and CD44-hyaluronic acid interactions. The work proposed is divided into four tasks. The first deals with ZI polymer design, synthesis and characterization. The goal is to produce a library of materials with increasing architectural complexity that should translate into distinct surface properties. The second task is to examine ZI particle formation through either copolymer adsorption onto silica particles or self-assembly of highly branched amphiphilic macromolecules using processing conditions to affect ZI particle surface properties. The third task is to carry out diffusing probe measurements of ZI particles with model synthetic substrates, to ultimately establish the combination of polymer architecture and adsorption/self-assembly conditions that will result in desired non-specific repulsion. Having established this, the last task of this proposal is to use this knowledge to carry out diffusing probe measurements of specific interactions between ZI particles decorated with specific moieties and cancer cells. Such measurements will be performed for breast cancer cells to study interactions between hyaluronic acid and CD44 receptors, as well as, anisamide and sigma receptors. Each of the four tasks is part of an overarching plan to measure and interpret how particle-cell interactions are influenced by covalent attachment, orientation, and organization on synthetic and cell surfaces in nanobiotechnological applications.