Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, PL-30239 Krakow, Poland.
Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland.
Biomacromolecules. 2022 Aug 8;23(8):3308-3317. doi: 10.1021/acs.biomac.2c00415. Epub 2022 Jul 13.
Adsorption kinetics of human vimentin on negatively charged substrates (mica, silica, and polymer particles) was analyzed using atomic force microscopy (AFM), quartz microbalance (QCM), and the laser doppler velocimetry (LDV) method. AFM studies realized under diffusion conditions proved that the adsorbed protein layer mainly consisted of aggregates in the form of compact tetramers and hexamers of a size equal to 11-12 nm. These results were consistent with vimentin adsorption kinetics under flow conditions investigated by QCM. It was established that vimentin aggregates efficiently adsorbed on the negatively charged silica sensor at pH 3.5 and 7.4, forming compact layers with the coverage reaching 3.5 mg m. Additionally, the formation of the vimentin corona at polymer particles was examined using the LDV method and interpreted in terms of the electrokinetic model. This allowed us to determine the zeta potential of the corona as a function of pH and the electrokinetic charge of aggregates, which was equal to -0.7 e nm at pH 7.4 in a 10 mM NaCl solution. The anomalous adsorption of aggregates exhibiting an average negative charge on the negatively charged substrates was interpreted as a result of a heterogeneous charge distribution. These investigations confirmed that it is feasible to deposit stable vimentin layers both at planar substrates and at carrier particles with well-controlled coverage and zeta potential. They can be used for investigations of vimentin interactions with various ligands including receptors of the innate immune system, immunoglobulins, bacterial virulence factors, and spike proteins of viruses.
使用原子力显微镜（AFM）、石英晶体微天平（QCM）和激光多普勒速度计（LDV）方法分析了人波形蛋白在带负电荷的基质（云母、二氧化硅和聚合物颗粒）上的吸附动力学。在扩散条件下进行的 AFM 研究证明，吸附的蛋白质层主要由以大小等于 11-12nm 的紧密四聚体和六聚体形式存在的聚集体组成。这些结果与 QCM 研究的流动条件下的波形蛋白吸附动力学一致。结果表明，波形蛋白聚集体在 pH3.5 和 7.4 时能有效地吸附在带负电荷的二氧化硅传感器上，形成覆盖率达到 3.5mgm 的紧密层。此外，还使用 LDV 方法研究了聚合物颗粒上的波形蛋白冠的形成，并根据动电模型进行了解释。这使得我们能够确定冠层的 ζ 电位作为 pH 和聚集体动电电荷的函数，在 10mMNaCl 溶液中 pH7.4 时为 -0.7e nm。在带负电荷的基质上，具有平均负电荷的聚集体的异常吸附被解释为异质电荷分布的结果。这些研究证实，在平面基底和具有良好控制的覆盖率和 ζ 电位的载体颗粒上沉积稳定的波形蛋白层是可行的。它们可用于研究波形蛋白与各种配体（包括先天免疫系统受体、免疫球蛋白、细菌毒力因子和病毒的刺突蛋白）的相互作用。
