A Preliminary Study On Hydrolysis Behavior Of Artificial Lipid Droplets In Giant Unilamellar Vesicles

Living systems are sustained by a constant flow of metabolic energy,and lipids rich in reduced hydrocarbons provide the energy source for many organisms.Since new energy sources are not always readily available,the ability to store lipids in cells and tissues is often critical for survival.Lipid droplets are the "lipid pool".In this thesis,the artificial lipid droplet model was constructed in a bottom-up way to solve the difficulty in separation and purification of natural lipid droplet,and the hydrolysis behavior of artificial lipid droplet was observed in giant phospholipid vesicles.The artificial lipid droplets are made up of components contained in the natural lipid droplets,such as phospholipids and glycerides trioleate.The effects of different amounts of phospholipids and triglycerides on the particle size of the emulsion were investigated.The emulsion was prepared by mixing 1 mg DPPC with 10 μL triglyceride and adding water to a total volume of 110 μL.The particle size does not change significantly when stored at room temperature and 4℃ for 7 days,indicating that the emulsion has good stability.The lipase is added in emulsion,to destroy the stability of the emulsion due to lipase hydrolysis with three oleic acid glyceride on part of the phospholipid molecules.The obtained contact and hydrolysis reaction,oleic acid was found as the product of hydrolysis reaction by mass spectrometry.The hydrolysis reaction time was set as 2 h.To explore the hydrolysis of lipase with different concentrations in 2 h and to determine an optimal concentration,hydrolysis reaction would occur in 2 h without using up the reaction substrate,so the concentration of lipase was 100 μg/m L.In order to further improve the stability,phospholipid composition and the effect of electronegativity were investigated.In order to improve the encapsulation rate,the influence of the concentration of artificial lipid droplets in electroformation method was explored.The encapsulation rate of glycerol trioleate emulsion with a concentration of 30.90 mg/m L was determined to be 56.3%,which could ensure enough artificial lipid droplets in each sample group.The hydrolytic effect of lipase on DOPC was investigated.The composition of DOPC was optimized.