纳米材料进入生物体后将立即与各种蛋白质相互作用，并在纳米材料表面形成被称为蛋白冠的包裹层，由此产生的生物效应是纳米材料生物医学应用及其生物安全性评估的一个关键问题，因而纳米粒子与蛋白质相互作用研究近年来受到广泛关注。然而目前相关研究主要集中在热力学方面，动力学特别是快速动力学研究非常缺乏，而纳米粒子与蛋白质相互作用是一个动力学决定过程，动力学研究更为关键因而急待开展。本项目拟在前期工作基础上，开展蛋白质与纳米粒子相互作用的快速动力学研究：通过停流技术实现纳米粒子与蛋白质的毫秒级混合，通过精确控制包裹层厚度的荧光二氧化硅纳米粒子和与之结合的第一层蛋白质之间的荧光共振能量转移研究相互作用动力学规律，阐明对纳米粒子体内命运影响最大的硬蛋白冠的形成与解离机理，探索影响蛋白冠形成的因素及机制，并以此为指导初步探索纳米粒子表面与蛋白质特异性结合的功能设计，以期抑制硬蛋白冠的形成，提高纳米药物的靶向性。

Once nanoparticles enter bio-systems, they will immediately interact with various proteins, forming a protein coating shell called protein corona. Protein corona changes the identity of nanoparticles and even causes unexpected bio-effects, which is the major challenge for the bio-application and biosafety of nanomaterials. Therefore, the interaction between nanoparticles and proteins has been extensively studied in recent years. Yet, most studies focused on the thermodynamic aspects of the interaction. Since the interaction between nanoparticles and proteins is a kinetically controlled process, kinetic study is more critical and highly demanded. In this project, we are going to investigate the kinetics of the interaction between nanoparticles and proteins, focusing on the most important issue of the formation of the “hard” protein corona and the related direct interaction between nanoparticles and the first layer of proteins binding on their surface. To achieve this goal, we will synthesis core-shell nanoparticles with a fluorescent protein core and a well-controlled shell to keep the distance between the fluorescent core and the first layer of absorbed protein within 10 nm, while keep the distance between the fluorescent core and the second layer of absorbed protein larger than 10 nm, to specifically monitor the interaction between the nanoparticles with the first layer of proteins with fluorescence resonance energy transfer (FRET). The fast kinetics of the absorption/dissociation of the first layer of proteins will be illuminated by stop-flow FRET and other techniques. The mechanism of how the factors, such as particle size and functional groups, influence the formation/dissociation of the “hard” protein corona will also be investigated. And the results will be used to guide the functional design of nanoparticles with specific binding feature with targeted proteins to prevent the formation of “hard” protein corona and to improve the targeting effect for nanomedicines.