Mechanistic studies of blood-nanoparticle interactions

描述（由申请人提供）：静脉注射纳米粒子（NP）在临床诊断和治疗应用中具有巨大的前景。它们实施中的一个关键问题是它们的体内生物分布，这导致靶向方法效率低下，导致纳米颗粒在非靶向（健康）器官中积累。我们的长期目标是使用金纳米粒子（GNP）模型系统阐明纳米粒子体内生物分布的机制。具体的假设是，GNP 的体内生物分布是由它们与血液成分的相互作用（或缺乏相互作用）决定的。该假设基于以下观察：1）血液是静脉注射纳米颗粒在体内相互作用的第一个媒介； 2）体外研究表明，NPs与血清蛋白（包括补体因子）相互作用，引起血小板聚集和红细胞溶血； 3）我们的初步数据表明，纳米粒子表面生物分子的存在增加了它们的血液保留时间。基于这些观察，该项目的实验重点是 NP 与血液成分的相互作用。具体目标是： (1) 表征体外血液-GNP 相互作用。我们将研究 GNP 与血浆和细胞成分的相互作用。将通过评估血浆中补体系统的激活来间接测试免疫系统的作用。将使用组织学评估 GNP 与细胞成分（红细胞和白细胞 -WBC）的相互作用，并使用透射电子显微镜 (TEM) 鉴定 GNP 的亚细胞定位。 (2) 表征体内血液-GNP 相互作用及其对生物分布的影响。我们将通过在正常和补体缺陷小鼠中进行实验来验证补体系统在 GNP 生物分布中的作用。将在不同时间点评估血液-GNP 相互作用及其与组织分布的相关性。肿瘤存在对血液-GNP 相互作用的影响将通过在正常和人类前列腺癌肿瘤或荷瘤小鼠中进行比较来评估。 公共健康相关性：鉴于正在临床环境中评估几种纳米粒子治疗癌症的效果，拟议研究的结果将是及时且重要的。所提出的研究目标的实现将通过提供有关控制纳米颗粒生物分布的基本机制的新信息，显着推进纳米颗粒生物分布领域的发展。这项研究的结果将有助于未来旨在设计纳米颗粒的研究，这些纳米颗粒可以避免在健康器官中积累，从而提高递送效率并降低临床环境中的毒性。

DESCRIPTION (provided by applicant): Intravenously injected nanoparticles (NPs) hold great promise for clinical diagnostic and therapeutic applications. A critical issue in their implementation is in their in vivo biodistribution which leads to inefficiency in targeting approaches resulting in the accumulation of NPs in untargeted (healthy) organs. Our long-term goal is to elucidate the mechanisms of in vivo biodistribution for NPs using a gold NP (GNP) model system. The specific hypothesis is that the in vivo biodistribution of GNPs is dictated by their interactions (or lack thereof) with blood components. This hypothesis is based on the observations that: 1) blood is the first medium of interaction in the body for intravenously injected NPs; 2) in vitro studies show that NPs interact with serum proteins (including complement factors), cause platelet aggregation and red blood cell hemolysis; 3) our preliminary data shows that the presence of a biomolecule on the surface of the NPs increase their blood retention time. Based on these observations, the experimental focus of this project is on the NP interactions with the blood com ponents. The specific aims are to: (1) Characterize the blood-GNP interactions in vitro. We will study the interactions of GNPs with both the plasma and cellular components. The role of the immune system will be tested indirectly by evaluating the complement system activation in plasma. The interactions of GNPs with the cellular components (RBCs and white blood cells-WBCs) will be evaluated using histology, and the subcellular localization of GNPs will be identified using transmission electron microscopy (TEM). (2) Characterize the blood-GNP interactions in vivo and their impact on biodistribution. We will evpplication proposed by a aluate the role of the compi ement system in the biodistribution of GNPs by conducting experiments in both normal and complement deficient mice. The blood-GNP interactions and their correlation with tissue distribution will be evaluated at various ti me points. The effect of the presence of a tu mor on the blood-GNP interactions will be evaluated by com paring them in normal and human prostate cancer tum or bearing m ice. Public Health Relevance: Given that several nanoparticles are being evaluated in c linical settings for the treatment of cancer, the outcomes of the proposed research will be timely and important. The realization of the proposed research goals will significantly advance the field of nanoparticle biodistributi on by providing new information on the underlying mechanisms that govern their biodistribution. The results of this study will facilitate future research aimed at the design of nanoparticles that can avoid accumulation in healthy organs thereby increasing the delivery effi ciency and reducing the toxicity in clinical settings.