Universitat des Saarlandes, Experimental Physics and Center for Biophysics, 66123 Saarbruecken, Germany.
Departament Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel.lí Domingo s/n, 43007 Tarragona, Spain.
Nanoscale. 2022 Sep 22;14(36):13178-13186. doi: 10.1039/d2nr01339h.
Lateral diffusion of nano-objects on lipid membranes is a crucial process in cell biology. Recent studies indicate that nanoparticle lateral diffusion is affected by the presence of membrane proteins and deviates from Brownian motion. Gold nanoparticles (Au NPs) stabilized by short thiol ligands were dispersed near a free-standing bilayer formed in a 3D microfluidic chip. Using dark-field microscopy, the position of single NPs at the bilayer surface was tracked over time. Numerical analysis of the NP trajectories shows that NP diffusion on the bilayer surface corresponds to Brownian motion. The addition of bovine serum albumin (BSA) protein to the solution led to the formation of a protein corona on the NP surface. We found that protein-coated NPs show anomalous superdiffusion and that the distribution of their relative displacement obeys Lévy flight statistics. This superdiffusive motion is attributed to a drastic reduction in adhesive energies between the NPs and the bilayer in the presence of the protein corona. This hypothesis was confirmed by numerical simulations mimicking the random walk of a single particle near a weakly adhesive surface. These results may be generalized to other classes of nano-objects that experience adsorption-desorption behaviour with a weakly adhesive surface.
脂质膜上纳米物体的侧向扩散是细胞生物学中的一个关键过程。最近的研究表明，纳米颗粒的侧向扩散受到膜蛋白的存在的影响，并且偏离了布朗运动。由短硫醇配体稳定的金纳米颗粒（Au NPs）在 3D 微流控芯片中形成的自由站立双层膜附近分散。使用暗场显微镜，随时间跟踪单层 NP 在双层膜表面的位置。对 NP 轨迹的数值分析表明，NP 在双层膜表面的扩散对应于布朗运动。向溶液中添加牛血清白蛋白（BSA）蛋白会导致 NP 表面形成蛋白质冠。我们发现，涂有蛋白质的 NP 表现出异常的超扩散，并且它们的相对位移分布符合 Lévy 飞行统计。这种超扩散运动归因于在蛋白质冠的存在下，NP 与双层之间的粘附能急剧降低。通过模拟单个粒子在弱粘附表面附近的随机游动的数值模拟证实了这一假设。这些结果可能推广到经历与弱粘附表面的吸附-解吸行为的其他类别的纳米物体。
