Synthesis and applications of tetra-functional branched poly(ethylene glycol) derivative for the decellularized valve leaflets cross-linking

Abstract

To investigate the effects of polyethylene glycol cross-linking on the mechanical properties, 80 porcine aortic valves were harvested, decellularized, and introduced with sulfhydryl. Then the valves were randomly assigned into 5 experimental groups and 1 control group (n=16). For the valves in those experimental groups, branched polyethylene glycol diacrylate (PEG) of 5 different molecular weights (3.4, 8, 12, 20, 40 kDa) were synthesized and cross-linked with them respectively. The efficiency of the cross-linking was determined by measuring the amount of residual thiol group and the mechanical properties of the cross-linked valve leaflets were assessed by uni-axial planar tensile testing. The efficiency of the PEG 20 kDa group was 70.72±2.33%, obviously superior to that of the other groups (p<0.05). Tensile test proved that branched PEG cross-linking can significantly enhance the mechanical behaviors of the decellularized valve leaflet and the Young’s modulus of each group was positively correlated with the molecular weight of PEG. It was concluded that branched PEG with the molecular weight of 20 kDa can effectively cross-link the decellularized porcine aortic valves and improve their mechanical properties, which makes it a promising cross-linker that can be used in the modification of decellularized tissue engineering valves.

Keywords

decellularized aortic valves / polyethylene glycol diacrylate / cross-link / mechanical properties

References

[1] Steinhoff G, Stock U, Karim N, . Tissue Engineering of Pulmonary Heart Valves on Allogenic Acellular Matrix Conduits: in Vivo Restoration of Valve Tissue[J]. Circulation, 2000, 102(19Suppl.3): III50-55.

[2] Booth C, Korossis S A, Wilcox H E, . Tissue Engineering of Cardiac Valve Prostheses I: Development and Histological Characterization of An Acellular Porcine Scaffold[J]. J. Heart Valve Dis., 2002, 11(4): 457-462.

[3] Korossis S A, Booth C, Wilcox H E, . Tissue Engineering of Cardiac Valve Prostheses II: Biomechanical Characterization of Decellularized Porcine Aortic Heart Valves[J]. J. Heart Valve Dis., 2002, 11(4): 463-471.

[4] Cebotari S, Mertsching H, Kallenbach K, . Construction of Autologous Human Heart Valves Based on An Acellular Allograft Matrix[J]. Circulation, 2002, 106(12Suppl.1): 163-168.

[5] Mendelson K, Schoen F J Heart Valve Tissue Engineering: Concepts, Approaches, Progress, and Challenges[J]. Ann. Biomed. Eng., 2006, 34(12): 1 799-1 819.

[6] Liao J, Joyce E M, Sacks M S Effects of Decellularization on the Mechanical and Structural Properties of the Porcine Aortic Valve Leaflet[J]. Biomater., 2008, 29(8): 1 065-1 074.

[7] Balguid A, Rubbens M P, Mol A, . The Role of Collagen Crosslinks in Biomechanical Behavior of Human Aortic Heart Valve Leaflets-Relevance for Tissue Engineering[J]. Tissue Eng., 2007, 13(7): 1 501-1 511.

[8] Park S N, Park J C, Kim H O, . Characterization of Porous Collagen/Hyaluronic Acid Scaffold Modified by 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide Cross-linking[J]. Biomater., 2002, 23(4): 1 205-1 212.

[9] Baranska A, Irzyk B, Ski J N, . Decellularized Porcine Valve Scaffolds Modified with Carbodiimide for Heart Valve Tissue Engineering[J]. Int. J. Artif. Organs, 2007, 30(8): 728

[10] Carpentier A, Lemaigre G, Robert L, . Biological Factors Affecting Long-term Results of Valvular Heterografts[J]. J. Thorac. Cardiovasc. Surg., 1969, 58(4): 467-483.

[11] Jevsevar S, Kunstelj M, Porekar V G PEGylation of Therapeutic Proteins[J]. Biotechnol. J., 2010, 5(1): 113-128.

[12] Joralemon M J, McRae S, Emrick T, . PEGylated Polymers for Medicine: from Conjugation to Self-assembled Systems[J]. Chem. Commun., 2010, 46(9): 1 377-1 393.

[13] Thamm D H, Kurzman I D, Clark M A, . Preclinical Investigation of PEGylated Tumor Necrosis Factor Alpha in Dogs with Spontaneous Tumors: Phase I Evaluation[J]. Clin. Cancer. Res., 2010, 15(6): 1 498-1 508.

[14] Zeugolis D I, Paul R G, Attenburrow G Extruded Collagenpolyethylene Glycol Fibers for Tissue Engineering Applications[J]. J. Biomed. Mater. Res. B Appl. Biomater., 2007, 85(2): 343-352.

[15] Guiotto A, Canevari M, Pozzobon M, . Anchimeric Assistance EEfect on Regioselective Hydrolysis of Branched PEGs: a Mechanistic Investigation[J]. Bioorg. Med. Chem., 2004, 12(19): 5 031-5 037.

[16] Chen J S, Noah E M, Steffens GCM, . The Use of Bifunctional Polyethylene Glycol Derivatives for Coupling of Proteins to and Crosslinking of Collagen Matrices[J]. J. Mater. Sci. Mater. in Med., 2002, 13(11): 1 029-1 035.

[17] Harris J M, Struck E C, Case M G, . Synthesis and Characterization of Poly(ethylene glycol) Decontent in Monomethoxypoly( ethylene glycol)-modified Pro-rivatives[J]. J. Polym. Sci., Polym. Chem. Ed., 1984, 22(2): 341-352.