US-Bulgaria Research on Flexoelectricity in Bilayer Lipid Membranes

这个由雪城大学的Janos H. Fendler博士和索非亚Georgi Nadjakov大学液晶和分子电子学实验室的Alexander G. Petrov博士合作的美国-保加利亚研究项目将研究双层脂质膜中的柔性电。保加利亚研究人员发现，双层脂质膜（BLM）的周期性弯曲导致微伏范围的跨膜电位。保加利亚人对这一现象进行了理论解释，并通过电学测量进行了检验，其中包括直接测定Uf和间接测定c。美国人使用光学干涉测量法测定超细、液体静压诱导的blm运动。在本提案中，研究人员提出：(1)使用实时频闪干涉测量直接确定周期性弯曲blm中的c；(2)同时确定blm的电学和光挠电系数，以检验挠电理论；(3)研究各种结构不同的blm；(4)利用干涉全息法和光学干涉法研究反挠曲电效应（跨膜电压引起的膜曲率）；(5)在相同的BLM制备上建立了直接挠曲电效应（曲率产生的膜极化）与反向挠曲电效应的对应关系；(6)研究光敏BLM在光照下的挠性电响应变化，揭示一种新的现象——光电挠性；(7)尝试通过将重复激光脉冲应用于有色素的BLM来观察光电现象。该生物物理学项目通过使美国和东欧的领先专家在共同感兴趣和能力强的领域结合互补人才和汇集资源，实现了推进科学知识的计划目标。

This U.S.-Bulgaria research project between Dr. Janos H. Fendler of Syracuse University and Dr. Alexander G. Petrov of the Laboratory of Liquid Crystals and Molecular Electronics of Georgi Nadjakov University, Sofia, will examine flexoelectricity in bilayer lipid membranes. The Bulgarian researchers have found that periodic bending of a bilayer lipid membrane (BLM) results in microvolt-range transmembrane potential. The Bulgarians have a theoretical rationalization of the phenomenon and have examined it by electrical measurements which included the direct determination of Uf and indirect determination of c. The Americans have used optical interferometry to determine ultrasmall, hydrostatic-pressure-induced movements of BLMs. In this proposal, the researchers propose to: (1) use real-time stroboscopic interferometric measurements to determine directly c in the periodically bent BLMs; (2) determine simultaneously electrical and optical flexoelectric coefficients of BLMs, to test theories of flexoelectricity; (3) investigate a variety of structurally different BLMs; (4) study converse flexoelectric effect (transmembrane voltage-induced membrane curvature) with interferometric holography and optical interferometry; (5) establish a correspondence between the direct flexoelectric effect (curvature-generated membrane polarization) and the converse one on the same BLM preparation; (6) investigate changes of the flexoelectric response of a photosensitive BLM under illumination to reveal a new phenomenon, photoflexoelectricity; and (7) attempt to observe photoflexoelectric phenomena by applying repetitive laser pulses to a pigmented BLM. This project in biophysics fulfills the program objective of advancing scientific knowledge by enabling leading experts in the United States and Eastern Europe to combine complementary talents and pool resources in areas of strong mutual interest and competence.