Polyamidoamine structure

Cross-linked resins of polyamidoamine structure can be prepared in the same way as the linear polymers by partly substituting a, m-diaminoalkanes for the same quantity of difunctional aminic monomers in the polymerization process. According to the general scheme of poly(amido-amine)synthesis, bis(primary amine)s, having four mobile hydrogens, act as tetrafunctional monomers 47). 

Smith, P. B., Martin, S. J., Hall, M. J. and Tomalia, D. A. A characterization of the structure and synthetic reactions of polyamidoamine STARBURST polymers in Mitchell, J. (ed.), Appl. Polym. Analysis. Characterization, Hanser Publishers, Munich, Vienna, New York, pp. 357-385 (1987). 

Malik, N., et al. 2000. Dendrimers Relationship between structure and biocompatibility in vitro, and preliminary studies on the biodistribution of 1251-labelled polyamidoamine dendrimers in vivo. 

For asymmetric monodendrons, an increase in compression resulted in collapse of the dendrimer and the formation of a bilayer structure with the macromolecules compressed laterally with respect to the surface normal, with an axial ratio of 2 1. This situation is illustrated in Fig. 4.13. These dendritic macromolecules are flexible enough to assume a prolate conformation under modest lateral compression in a Langmuir trough. Polyamidoamine (PAMAM) dendrimers [109] were also used by Tsukruk et al. [110] to fabricate self - assembled monolayers. The thickness of all the monolayers were much smaller than the diameter of dendritic macromolecules in solution. This behavior can indicate collapse of the dendritic macromolecules, which become highly compressed along the surface normal and flattened. (See Fig. 4.13b). 

The use of dendrimers as soluble supports in combinatorial chemistry was recently introduced by Kim et al. [204] for the synthesis of a 27-member pool library of indoles (three pools by nine individuals). The structure of the dendritic support, which was prepared condensing the commercially available starburst polyamidoamine (PAMAM) dendrimer with the 4-hydroxymethyl benzoic acid (HMB) linker, is given in Figure 7.24. 

Roberts, J.C. Bhalgat, M.K. Zera, R.T. Preliminary biological evaluation of polyamidoamine (PAMAM) star-burst dendrimers. J. Biomed. Mater. Res. 1996, 30, 53-65. Malik, N. Wiwattanapatapee, R. Klopsch, R. Lorenz, K. Frey, H. Weener, J.W. Meijer, E.W. Paulus, W. Duncan, R. Dendrimers relationship between structure and biocompatibility in vitro, and preliminary studies on the biodistribution of l-Labeled polyamidoamine dendrimers in vivo. J. Control. Release 2000, 65, 133-148. 

Figure 2. Structures of some commonly known dendrimers A. Polyamidoamine (G2) B. Poly(propylene imine) (G4) C. Benzyl ether monodendron (G3) and D. Poly(phenylene) dendrimer (G2). (G represents the generation number)...

Kihara F, Arima H, Tsutsumi T, Hirayama F, Uekama K (2002) Effects of structure of polyamidoamine dendrimer on gene transfer efficiency of the dendrimer conjugate with a -cyclodextrin. Bioconjugate Chem 13 1211-1219... 

Arima, H., Kihara, F., Hirayama, F. and Uekama, K. (2001) Enhancement of gene expression by polyamidoamine dendrimer conjugates with a-, P-, and y-cyclodextrin. Bioconjugate. Chem. 12 476-484 Kihara, F., Arima, H., Tsutsumi, T. et al. (2002) Effects of structure of polyamidoamine dendrimer of gene transfer efficiency of the dendrimer conjugate with a-cyclodextrin. ibid. 13 1211-1219. 

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