Two-Components Colloidal Solutions: Tuning the Interactions of Functionalized Nanoparticles with Proteins

通过自组装单分子膜（SAM）和蛋白质（称为生物缀合物）功能化的纳米颗粒（NP）被广泛用于许多生物相关领域，例如生物分子检测和诊断应用。从胶体物理学的角度来看，理解这些双组分（NP加蛋白质）系统的相行为是一个挑战，特别是考虑到非平凡的成对相互作用及其对环境参数的不同响应。在这个建议中，我们将解决的问题：什么是特定的SAM形成分子的构象/结构的纳米粒子，并在SAM溶剂界面吸附的蛋白质？这些是如何影响胶体蛋白质溶液的相互作用和相行为的？蛋白质如何与自身以及与溶液中的功能化NP相互作用？决定这种双组分体系相行为的关键参数是什么（盐的性质和浓度、pH、温度等）？为了研究蛋白质-胶体混合物的相互作用和相行为，将使用几种典型的蛋白质，特别是白蛋白、酶和抗体，因为这些蛋白质在生物传感器中被彻底使用。一组互补的实验技术，包括小角散射（SAXS，SANS），动态光散射（DLS），和光谱（FTIR，UV-vis和圆二色性）将用于解决这些复杂系统中的不同问题。

Nanoparticles (NPs) functionalized by self-assembled monolayers (SAMs) and proteins (known as bioconjugates) are widely used in many bio-related areas, such as biomolecular detection and diagnostic applications. From the point of view of colloidal physics, understanding the phase behavior of these two-component (NPs plus proteins) systems is a challenge, especially given the non-trivial pair-wise interactions and their different response to environmental parameters. In this proposal, we will address the questions: What is the conformation/structure of specific SAM-forming molecules on NPs, and of adsorbed proteins at SAM-solvent interfaces? How do these affect the interactions and phase behavior of colloidprotein solutions? How do proteins interact with themselves as well as with functionalized NPs in solution? What are the key parameters determining the phase behavior of this two-component system (nature and concentration of salt, pH, T, …)? In order to study the interactions and phase behavior of protein-colloid mixtures in general, several typical proteins, specifically albumin, enzymes and antibodies will be used as those proteins are used exhaustively in biosensors. A set of complementary experimental techniques including small-angle scattering (SAXS, SANS), dynamic light scattering (DLS), and spectroscopy (FTIR, UV-vis and circular dichroism) will be used to address the different issues in these complex systems.