Micropipet aspiration for measuring elastic properties of lipid bilayers

Abstract

Micropipet aspiration of giant unilamellar vesicles can be used to determine the mechanical properties of area compressibility modulus, bending modulus, and lysis tension of lipid bilayers. In this technique, giant (approximately 25-microm diameter) single bilayered vesicles are aspirated into a pipet of inner diameter approximately 8 microm. The changes in projection length of each vesicle inside of the pipet in response to changes in aspiration (suction) pressure are used to determine mechanical moduli. The suction pressure of vesicle rupture (lysis) is used to determine the membrane tension of lysis (lysis tension). Micropipet aspiration of giant unilamellar vesicles is highly specialized, requiring custom laboratory fabrication of most components (e.g., micropipets, chambers, and manometer). Herein, methods for fabrication of each of these components and instructions for measurements are described.