Abstract
Drop-coating deposition Raman (DCDR) spectroscopy was employed to study liposome suspensions. The method is based on a specific drying process on the hydrophobic surface that efficiently accumulates the macromolecular sample in a ring of the edge of the dried drop. We studied liposome suspensions purchased from two sources (Avanti Polar Lipids, Inc. and Sigma-Aldrich, Co.) and prepared under different conditions. Structure of the dried drop substantially depends on the lipid concentration, lipid composition of the sample, and used solvent. Optimal lipid concentration is about 0.3 mg/ml in all cases, asolectin and DSPC suspensions form compact dried drops when dissolved in water and phosphate buffer, respectively. Drying process of the sample drop does not influence the initial phase state (gel or liquid-crystalline) of the studied liposomes excepting DSPC from Sigma-Aldrich, Co.
Highlights
Liposomes as spherical sacs formed by curved lipid bilayer are often used as a model system of biological membranes
We focused our attention to the influence of liposome preparation procedure, namely lipid concentration, used solvent and lipid sources (Avanti Polar Lipids, Inc. versus Sigma-Aldrich, Co.) on obtained drop-coating deposition Raman (DCDR) spectra
Samples appropriately prepared with optimal lipid concentration form round drop with a distinct ring after deposition on a DCDR plate
Summary
Liposomes as spherical sacs formed by curved lipid bilayer are often used as a model system of biological membranes. Suitable noninvasive technique for their studies, requires high concentration and often large volume of sample. Low sensitivity of classical Raman technique can be overcome by drop-coating deposition Raman (DCDR) spectroscopy based on deposition of a small volume of the sample solution (units of μL) on a special hydrophobic surface [1]. Deposited sample evaporates with the “coffee ring effect” leading to formation of a ring in edge part of the droplet containing majority of the sample [2] The sample in this ring is highly concentrated and gives reproducible Raman signal. Raman spectra of liposomes in the initial solution concentration about 0.3 mg/mL can be obtained, and drying process does not change their initial phase state [5]. We focused our attention to the influence of liposome preparation procedure, namely lipid concentration, used solvent (water versus buffer) and lipid sources (Avanti Polar Lipids, Inc. versus Sigma-Aldrich, Co.) on obtained DCDR spectra
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
