MEMBRANE BIOPHYSICS VIA ATOMIC FORCE MICROSCOPY

在这个项目中，与NIAID的合作者一起，用原子力显微镜(AFM)研究了对许多生物过程至关重要的脂膜的物理化学性质。利用环境控制室中的敲击模式AFM图像，在不同温度下解析了2-二肉豆蔻-sn-甘油-磷胆碱(DMPC)的主要相变的定量特征。这些AFM图像显示，在预期的DMPC链熔化温度附近有两个膜相。我们已经从精确的AFM厚度测量中量化了DMPC膜在链熔化时的显著减薄和机械软化。我们还构建了一个新的生物物理模型，该模型允许从AFM获得的温度依赖相中估计热力学转变热、熵和膜相区大小。 分配。NIAID开发的独特的AFM技术正在进一步推动，以阐明与膜相关的生物分子事件，这些事件对医学上的重要过程至关重要。

The physical-chemical properties of lipid membranes, which are crucially important to many biological processes, are been investigated by atomic force microscopy (AFM) in this project with NIAID collaborators. Quantitative features of the main phase transition in 2-dimyristoyl-sn-glycero-phosphocholine (DMPC) have been resolved by tapping-mode AFM images in an environmentally controlled chamber at various temperatures. These AFM images reveal two membrane phases near the expected DMPC chain-melting temperature. We have quantified the marked thinning and mechanical softening of the DMPC membrane upon chain melting from precise AFM thickness measurements. We have also constructed a novel biophysical model, which permits an estimate of the thermodynamic transition enthalpy, entropy, and the membrane phase domain size from our AFM-acquired temperature-dependent phase distributions. The unique AFM technology developed at NIAID is being pushed further to elucidate membrane-associated biomolecular events critical to medically important processes.