Biophysical Society Thematic Meeting| Padova 2019

Quantitative Aspects of Membrane Fusion and Fission

Poster Abstracts

12-POS Board 12 LIPID NANOTUBES FROM FREESTANDING LIPID MEMBRANES: OPTICAL TWEEZERS MANIPULATION AND QUANTITATIVE DETERMINATION OF MEMBRANE TENSION Aurora Dols-Perez 1 ; Guillermo J Amador 2 ; Victor Marin 1 ; Roland Kieffer 1 ; Daniel Tam 2 ; Marie-Eve Aubin-Tam 1 ; 1 Delft University of Technology, Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, Zuid-Holland, The Netherlands 2 Delft University of Technology, Laboratory for Aero and Hydrodynamics, Delft, Zuid-Holland, The Netherlands Lipid tubes, tubules or nanotubes are highly curved lamellar structures in the nanometer- micrometer scale with great importance in many biological processes. They play a vital structural role in different cellular organelles such as the endoplasmic reticulum, mitochondria and Golgi apparatus, but also in communication processes such as inter and intracellular exchanges and cellular migration. Their biophysical study is often carried using vesicles, supported lipid bilayers or living cells. In these systems, it is challenging to achieve asymmetric lipid distribution, dynamic buffer control and zero curvature. Using a freestanding lipid bilayer in a microfluidic device, these challenges can be solved and present additional advantages such as easy access to both sides of the membrane, possibility to create several membranes in a same device, possibility to circulate different solutions, and full compatibility with optical techniques. In this work, we show the combination of these novel freestanding lipid membranes formed inside a microfluidic chip with optical tweezers for the study of lipid nanotubes. Nanotubes were formed by pushing and pulling beads through or from the membranes, reaching lengths above half a millimeter. The quantification of the forces implied in the process, the tension of the membrane and the bending rigidity was possible without the need of additional sensors apart from the optical tweezers. Our method provides a robust platform, not only for nanotubes studies, but also for further study of protein-membrane interactions under controlled conditions on each side of the membrane, and modulated membrane complexity.

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