Studying Topographical and Mechanical Properties of Bovine Lens-Lipid Nuclear and Cortical Membrane Using Atomic Force Microscopy
Faculty Mentor Information
Dr. Laxman Mainali (Mentor), Boise State University; and Dr. Nawal Khadka (Mentor), Boise State University
Abstract
The Chol concertation in the eye lens plasma membrane of the nuclear and cortical regions varies significantly. In the bovine eye lens, the cholesterol to lipid (phospholipids plus sphingolipids) ratio for the nuclear membrane is ~2, and for the cortical membrane is ~1. The effect on the membrane elastic properties of the lens due to the difference in Chol content in the lens's plasma membrane is unclear. Using atomic force microscopy (AFM), we investigated the properties of the nuclear lens lipid membrane and cortical lens lipid membrane. Total lipids (lipids plus Chol) from a two-year-old bovine lens are extracted using the monophasic extraction method. Rapid solvent exchange (RSE) exchange method is used to prepare multilamellar vesicles (MLVs). MLVs are transitioned to small unilamellar vesicles (SUVs) using Probe-tip sonication. The SUV suspension solution is dispensed on a freshly cleaved mica surface, which forms a supported lipid membrane (SLM). After acquiring the topographical images, force curves were obtained to assess the mechanical properties of the membranes. The membrane thickness was measured on a partially prepared SLM. The compressibility modulus (KA) and Young’s Modulus (E) were estimated by fitting force curves in the elastic regime of a fully prepared SLM.
Studying Topographical and Mechanical Properties of Bovine Lens-Lipid Nuclear and Cortical Membrane Using Atomic Force Microscopy
The Chol concertation in the eye lens plasma membrane of the nuclear and cortical regions varies significantly. In the bovine eye lens, the cholesterol to lipid (phospholipids plus sphingolipids) ratio for the nuclear membrane is ~2, and for the cortical membrane is ~1. The effect on the membrane elastic properties of the lens due to the difference in Chol content in the lens's plasma membrane is unclear. Using atomic force microscopy (AFM), we investigated the properties of the nuclear lens lipid membrane and cortical lens lipid membrane. Total lipids (lipids plus Chol) from a two-year-old bovine lens are extracted using the monophasic extraction method. Rapid solvent exchange (RSE) exchange method is used to prepare multilamellar vesicles (MLVs). MLVs are transitioned to small unilamellar vesicles (SUVs) using Probe-tip sonication. The SUV suspension solution is dispensed on a freshly cleaved mica surface, which forms a supported lipid membrane (SLM). After acquiring the topographical images, force curves were obtained to assess the mechanical properties of the membranes. The membrane thickness was measured on a partially prepared SLM. The compressibility modulus (KA) and Young’s Modulus (E) were estimated by fitting force curves in the elastic regime of a fully prepared SLM.