At present, the growth factors or functional protein with adhensive cells are directly grafted to the surface of scaffold in the most of the researches, but always can result in protein decomposition because of instability in external environment.OBJECTIVE:
To prepare a proposed polyphosphazene scaffold with regulation of biocompatibility to load containing gene fragments.DESIGN, TIME AND SETTING:
An observation of single sample was performed at the State Key Laboratory of Chemical Resource Engineering from April to June 2007.MATERIALS:
Hexachlorocyclotriphosphazene was purchased from Ningbo Boyuan Limited Company of Chemical Materials, alanine ethyl ester hydrochloride was purchased from Tianren Limited Company of Biochemical Science, methylamine hydrochloride was purchased from Beijing Shiying Chemical Factory, and methyl acrylate was purchased from Tianjin Bodi Limited Company of Chemical Materials.METHODS:
Two-step molecular design was performed: ① Based on polyphosphazene chain, preparation of a long-chain prepolymer used for hyperbranched tissue engineering scaffolds; ② graft gene fragments with certain features to the long-chain prepolymer, through its in situ expression, and code required for protein and growth factor. Firstly, alanine ethyl ester with good biocompatibility, performance and easily controlled was prepared to replace polyphosphazens; subsequently, hyperbranched polymers were prepared by substitution with ethylenediamine and synthesis with methacrylate.MAIN OUTCOME MEASURES:
① 1H-NMR performance of alanine ethyl nitrile phosphine substituted poly (G0.5); ② 13C-NMR performance of nitrile phosphine end aminopolysiloxane (G1.0); ③ 13C-NMR performance of phosphonic ester side polyethylene nitrile (G1.5).RESULTS:
1H-NMR indicated that alanine ethyl ester was successfully grafted on polyphosphazenes, and the polymer was the G0.5 target products. 13C-NMR of nitrile phosphine end aminopolysiloxane indicated that the exchange of amino ester occurred and G1.0 structure was formed. 13C-NMR of phosphonic ester side polyethylene nitrile indicated that addition reaction occurred and G1.5 structure was formed.CONCLUSION:
Hyperbranched polyphosphazen scaffolds are successfully designed, and 0.5, 1.0, and 1.5 polyphosphazene grafted poly (amide amine) polymers are successfully synthesized. 1H-NMR and 13C-NMR performance indicates the feasibility of polyphosphazene grafted poly (amide amine).