Study On The Synthesis, Structure And Property Of The Multifunctional Multilayer Dendrimer As Cyclotriphosphazene Core

(1) Synthesis of cyclotriphosphazene-core PAMAM dendrimer interms of molecular design1．Molecular design of structure: comparing with other PAMAMdendrimer core, cyclotriphosphazene has more functional groups on itscoal surface. Dendrimer especially PAMAM don't have immunogenicity,its toxicity is lower。This dendrimer polymer size, internal cavity and thesuperficial functional group had decided it may take the protein, theenzyme and virus's ideal man-made carrier.2．Molecular size design: the PAMAM dendrimer macro-molecule isa molecular level of nanometer pellet. All the characteristics about theshape, the molecular size, the molecular weight and its monodispersionare suitable for the medicine and the gene carrier.3．Functionalization : the amine-terminated group may be furtherdesigned to varied functions. For example: they could havenucleophilicity, nucleophilicity, hydrophilic and hydrophobic; could use as the gene, the anti-body and the protein carrier; may also have byelectrical, optical and magnetics property.Therefore, our work makes the original design by synthesizing of theG5 cyclotriphosphazene-core PAMAM dendrimer of high superficialfunctional group density used as the medicine release carrier.(2) Synthesis and characterization of functional amine-terminatedcyclotriphosphazene-core PAMAM dendrimerHas carried on the whole characterization to each generation ofproduct on structure: IR, 1H NMR. The determination obtained theexpectation structure product. Has got the intrinsic viscosity data. Hasdetermined that the intrinsic viscosity rise with increasing of eachgeneration.(3) As one of three main systhesize methods of amine-terminatedcyclotriphosphazene derivative, "amino-ester exchange reaction" wasmore suitable. However, the "reduction reaction" and "protection-deprotection reaction" are very complicated, high requirement for thetechnology and hard to be industrialized. In this work, the glycine ethylester cyclotriphosphazene has been synthesized from the hexachloro-cyclotriphosphazene as initiator. Then it was reacted with the ethylene-diamine which has double amino groups by "amino-ester exchange reaction" to get the amine-terminated cyclotriphosphazene derivative.This method has the advantages of convenient manipulation, mildreaction conditions and high yield.