Formation kinetics, stability, and field-mediated interaction with biological systems of a protein corona generated on magnetic nanoparticles

本项目主要研究磁性纳米粒子(MNP)上蛋白质电晕的可控形成，不同因素对这一过程的影响，以及形成的电晕对这些杂化粒子与生物系统相互作用的影响。因此，我们将合成核壳杂化粒子，由一个磁核和一个不同电荷的聚合物壳组成。然后，这些杂交颗粒在胎牛血清(FSC)中孵育，以形成蛋白质电晕。我们特别感兴趣的是阐明粒子与不同生物系统孵育后的相互作用。这是通过监测MNP@CORON杂化颗粒与血液、不同细胞系和动物之间的接触来进行研究的--在某些情况下，还受到外场或场梯度的影响。适用的方法是微流变学、已建立的细胞毒性分析以及细胞系和动物的2D和3D显微技术。此外，我们还对如何制备或储存这些颗粒以用于体内应用感兴趣。这个项目的另一个重要目标是深入了解蛋白质电晕形成的动力学。为此，关键技术是磁弛豫法、交流敏感法和小角X射线散射(SAXS)-所有这些技术都对流体动力学直径的微小变化高度敏感，从而导致蛋白质电晕的生长。在这个优先计划的第一阶段，我们建立了明确和可重复的电晕形成技术。我们现在感兴趣的是探索蛋白质电晕的机械性质以及(化学)稳定性。这是通过在聚合物外壳和蛋白质电晕中加入代表FRET对(Förster共振能量转移)的两种染料来实现的。只要日冕完好无损，两个对应物都在很近的地方，可以检测到FRET。一旦蛋白质电晕释放，这种能量转移就会消失，我们计划利用这一点来探测不同条件下的电晕稳定性，包括体内实验。在这个项目的另一部分中，我们研究了分隔的聚合物外壳对蛋白质电晕形成的影响，例如通过疏水和亲水斑块的存在。我们预计，使用具有这种补丁的核壳颗粒既影响蛋白质的吸附机制，也影响形成的电晕的数量和组成。

This project focuses on the controlled formation of a protein corona on magnetic nanoparticles (MNP), the influence of different factors onto this process, as well as the influence of the formed corona on interactions of these hybrid particles with a biological system. We will therefore synthesize core-shell hybrid particles, consisting of a magnetic core and a polymer shell of varying charge. These hybrid particles then are incubated in fetal calve serum (FSC) for the formation of a protein corona. We are particularly interested in elucidating the interaction of particles after incubation with different biological systems. This is investigated by monitoring the contact between MNP@corona hybrid particles with blood, different cell lines, and animals - in certain cases also under the influence of an external field or field gradient. Suitable methods are µ-rheology, established cell toxicity assays, as well as 2D and 3D microscopic techniques for cell lines and animals. Further, we are also interested in how such particles have to be prepared or stored for in-vivo applications. Another important goal of this project is to gain in-depth understanding about the kinetics of protein corona formation. For this, key technologies are magnetic relaxometry, AC-susceptometry, and small angle X-ray scattering (SAXS) - all of which are highly sensitive towards small changes in hydrodynamic diameter and, hence, the growth of the protein corona. During the first period of this priority program, we established techniques for a defined and reproducible corona formation. We are now interested in probing mechanical properties as well as the (chemical) stability of the protein corona. This is realized by incorporating two dyes representing a FRET pair (Förster resonance energy transfer) within polymer shell and protein corona. As long as the corona is intact, both counterparts are in close proximity and FRET can be detected. Upon release of the protein corona, this energy transfer disappears and we plan to use this for probing corona stability under different conditions, including in-vivo experiments. In another part of this project, we investigate the effect of a compartmentalized polymer shell, e.g. through the presence of hydrophobic and hydrophilic patches, onto the protein corona formation. We anticipate that using core-shell particles featuring such patches influences both the mechanism of protein adsorption as well as the amount and composition of the corona being formed.