Research On Surface Modification Of RGD Peptides Onto Decellarized Scaffolds To Promote Constuction Of Tissue Engineering Heart Valve

Nowdays, current options of surgical heat valve replacement comprising of mechanical or biological prostheses substantially are the preferred replacement device in our clinical. Unfortunately, there are limitations as to the long term benefits of clinically available valve prosthesis. Mechanical valves are associated with a significant risk of thromboembolism, and biological valves suffer from structural dysfunction because of calcification and progressive tissue deterioration. Homograft valves also have a limited resources and durability. To overcome these limitations, the focus of prosthetic valve research has shifted to the development of tissue engineered heart valves (TEHV).In this study, we observed by studying the effect of epoxy chloropropane (EC) treatment on decellularized valve scaffolds, to well study the mechanism of EC treatment in preventing the valvular calcification and the feasibility of EC treatment on decellularized scaffold materials in preventing the valvular calcification of engineered heart valve. And then, we use linear peptide YGRGDSP (tyrosine-glycine-arginine-glycine-aspartic acid-serine-proline) and EC modified decellularized scaffold, and research the influence of immobilized RGD peptides on cell attachment of decellularized valve scaffold.Part one:To remove cells and its'cellular components from porcine aortic valve and study on the physico-chemical properties of decellularized scaffold materials after epoxy chloropropane treatment. By using trypsin, hyperosmosis and hyposmosis TritonX-100, acellular porcine aorta valve (APAV) was prepared. Glutaraldehyde (GA) and EC were used to treat APAV respectively. Physico-chemical properties and histocompatibility of these three groups were compared respectively. Results 1. The cells were removed effectively from cusps and roots of porcine aortic valves by trypsin and TritonX-100. 2.The mechanics, shrinkage temperature and the antienzymolysis capability of GA,EC treated APAV were greatly improved than that of initial APAV. The best effect among the different treatment is GA+EC. 3. Compared with the initial APAV, the EC treated APAV did not change the tissue histocompatibility of decellularized scaffold. It was greatly improved than GA treated APAV. Conclusion In this study, the physico-chemical properties of GA,EC treated APAV were greatly improved than that of initial APAV,and the biotoxicity of GA were reduced greatly after EC treatment. Both the plasma protein adsorption and platelet adhesion statistics proved that EC treatment could enhance the blood compatibility of APAV.Part two: Impact of immobilized RGD peptides on eell attachment of decellularized valve scaffolds Objective To investigate immobilized RGD containing peptides on cell attachment of decellularized valve scaffolds. Methods With the help of EC, decelluarized valve scaffolds were irnmobilized with YGRGDSP peptide. MFBs were seeded onto four groups of coupled, coated and untreated decelluarized valve scaffolds. Ninhydrin reaction, cell count and fluorescent imaging test were used to examine the effieiency of cell attachment. Results The results of ninhydrin reaction, cell count and fluorescent imaging test showed that more cells were prone to attach the decellularized valve scaffolds coupled with RGD peptides comparing with the other groups, which were correlated with attaching time and peptide concentration. Conclusion With the help of EC, YGRGDSP peptides can be irnmobilized by covalent bonding. In comparison with control groups, it is effective for chemical coupling with the RGD peptides to improve cell adhesion of decellularized valve scaffold.