The Studies On Hyaluronic Acid Application Basic And The Feasibility Of Chitosan As Gene Carrier By AFM

Hyaluronic acid and chitosan are polysaccharides which have many characteristics such as biocompatibility and biodegradability. They are widely used in the bio-medicine field and have great potential value as biomaterials. The fractal structure of hyaluronic acid and the images of hyaluronic acid (HA) in different pH, the preparation and properties of hyaluronic acid and pectin(PT) complex, the feasibility of chitosan(CS) as gene carrier were studied by atomic force microscope(AFM), FTIR and fluorescence microscope (FM) etc. Some useful results were found.1,To understand the configuration of hyaluronic acid on different conditions, the fractal structure of hyaluronic acid formed on the mica and images of hyaluronic acid (concentration of 0.1mg/ml) in different pH were observed. The results showed that hyaluronic acid chains developed and assembled to form dendritic fractal on the concentration 0.1mg/ml, and the fractal accorded with diffusion- limited aggregation (DLA) model. On the condition of strong acid, hyaluronic acid was easy to form membrane. On the condition of weak acid, hyaluronic acid curled and agglomerated to colloidal grain spontaneously. Furthermore, the colloidal grain assembled and formed into dendritic fractal in the pH of 5. On the low basic condition, hyaluronic acid formed peal network and regular network structure. On the condition of strong alkali, hyaluronic acid congregated greatly to form different fractal shape. The results will offer valuable data for studying the relation between the configuration of hyaluronic acid and its bio-function.2,The results from studying HA/PT complex showed that hyaluronic acid and pectin were complex and consistent when the concentrations of hyaluronic acid and pectin were above1mg/ml and 5mg/ml respectively, and the mass ratio was 1:5. The complexes self-assembled to composite grain shaped film. Comparing with simple hyaluronic acid, the viscosity of HA/PT complex was stronger and water-solubility was lower. The complex has bio-function of both hylauronic acid and pectin and has widely application potential in biology and medicine engineering field.3,To explore the feasibility of chitosan as gene carrier, the author prepared CS/siRNA and CS/DNA complexes and used the complexes to transfect HeLa cells respectively. AFM and FM were used to study HeLa cells which had been transfected. The results indicated that chitosan has following characteristics. a,Chitosan has the ability to take DNA to penetrate the cell membrane and enter the cell. b, chitosan has a tendency to transport DNA...