Gascoigne Levena, Tas Roderick P, Moerman Pepijn G, Voets Ilja K
Laboratory of Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Soft Matter. 2025 Apr 16;21(16):3058-3066. doi: 10.1039/d4sm01299b.
In this work, we utilize single-particle tracking photoactivated localization microscopy (sptPALM) to explore lipid dynamics in colloid-supported lipid bilayers (CSLBs) with liquid-like (DOPC), gel-like (DPPC), and phase-separated (DOPC:DPPC:cholesterol) membranes. Using total internal reflection fluorescence illumination, we tracked photoactivatable fluorescent dyes conjugated to lipids within these membranes. Analysis of tracked lipids revealed that bilayers across all compositions have heterogeneous dynamics, with lipid mobility varying over three orders of magnitude. We leveraged the temperature-dependent phase behavior of DPPC to transform gel-like membranes at room temperature into liquid-like membranes above 41 °C, which resulted in increased diffusivity and a surprising decrease in heterogeneity. Finally, we perform single lipid tracking in fluid-rich phases within gel-phase regions to demonstrate their dynamics with reduced lipid mobility because of soft confinement within phase-separated microdomains. Our findings have implications for colloidal assembly strategies that exploit ligand mobility to create controlled and reproducible colloidal superstructures.
在这项工作中，我们利用单粒子追踪光激活定位显微镜（sptPALM）来探索具有类液体（二油酰磷脂酰胆碱，DOPC）、类凝胶（二棕榈酰磷脂酰胆碱，DPPC）和相分离（DOPC:DPPC:胆固醇）膜的胶体支撑脂质双层（CSLB）中的脂质动力学。使用全内反射荧光照明，我们追踪了与这些膜内脂质偶联的光激活荧光染料。对追踪脂质的分析表明，所有组成的双层都具有异质动力学，脂质流动性在三个数量级上变化。我们利用DPPC的温度依赖性相行为，将室温下的类凝胶膜转变为41℃以上的类液体膜，这导致扩散率增加，异质性令人惊讶地降低。最后，我们在凝胶相区域内富含流体的相中进行单脂质追踪，以证明由于相分离微域内的软限制，其脂质流动性降低的动力学。我们的发现对利用配体流动性来创建可控和可重复的胶体超结构的胶体组装策略具有启示意义。
