THE EFFECT OF METAL NANO COLLOIDS ON FLUIDITY OF DPPC BILAYER

Abstract

Liposome is a colloidal structure formed by dynamic self-assembling of phospholipids molecules in aqueous medium. They have long been used as a model for biological membranes because they have a structure and functions similar to those of biological membranes. Recently, silver has been proved excellent medical metal, which has potential extinction, and protect against constant attack of unknown disease. Many attempts have been made to prepare silver loaded goods, such as surgical thread and adhesive plaster. However, there is currently a lack experimental correlation between the properties of metal colloids and the fluidity of lipid bilayer. But if silver is utilized to biomedical sciences, it is indispensible to investigate the effect of metal on lipid membrane.

In this study, liposome is prepared by the Bangham method are a heterogeneous mixture of MLV. We investigated the interaction between silver colloids and dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayer was examined with differential scanning calorimetry (DSC). Under the influence of metal colloids, the calorimetric enthalpy of DPPC was changed and a new phase appeared. DSC is a standard tool for measuring key thermotropic parameters in the interactions of alien substances with the membrane. We also investigate the morphology and the size of liposome by Optical Microscopy (OM). And the morphology and the size of metal is studied by Transmission Electric Microscopy (TEM). The distribution of metal colloid on liposome is investigated by Negative-Stain TEM.