Dendrimers polyamidoamine dendrimer

The first true dendrimers were the polyamidoamines (PAMAMs). They are also known as starburst dendrimers, and the term starburst is a trademark of the Dow Chemical Company, who have commercialized these materials for a range of applications. These dendrimers use ammonia as the core molecule, and this is reacted with methyl acrylate in the presence of methanol, after which ethylenediamine is added. This is shown in Scheme 9.2. 

Keywords. Polyamidoamine dendrimers. Activation of PAMAM dendrimers. Transfection, Gene transfer, DNA-dendrimer complex... 

Recently, highly branched macromolecular polyamidoamine dendrimers have been prepared with Co11 bound where the metal ions have additional exchangeable coordination sites.450 These macromolecules show a capacity for catalyzing the hydrolysis of phosphate esters, presumably via intermediate bound phosphoester species. 

Polyamidoamine (PAMAM) dendrimers have drawn considerable interest in recent years due to their potential applications in medicine, nanotechnology, and catalysis (6,7). The ability to control dendrimer interior/exterior functionalities and the macromolecular architecture of PAMAM dendrimers... 

Kukowska-Latallo JF, Bielinska AU, Johnson J, Spindler R, Tomalia DA, Baker JR Jr (1996) Efficient transfer of genetic material into mammalian cells using Starburst polyamidoamine dendrimers. Proc Natl Acad Sci USA 93 4897 -902... 

Biocompatible nanosized polyamidoamine (PAMAM) dendrimer films provided a suitable microenvironment for heme proteins to transfer electron directly with underlying pyrolytic graphite electrodes. The Mb-PAMAM film can catalytically reduced oxygen, hydrogen peroxide, and nitrite, indicating that the potential applicability of the film can be used to fabricate a new type of biosensor or bioreactor based on the direct electron transfer of Mb [234],... 

L. Shen and N.F. Hu, Heme protein films with polyamidoamine dendrimer direct electrochemistry and electrocatalysis. BBA-Bioenergetics 1608, 23—33 (2004). 

The use of dendrimers as supports to anchor transition metal catalysts has attracted considerable attention over the past decades [48] (see also Chapter 4 of this book). Several groups studied the use of dendrimers immobilised on insoluble supports [49], and this type of material meet the requirements for catalysis in interphases. Alper reported the use of diphosphine functionalised polyamidoamine (PAMAM) dendrimers... 

Polyamidoamine (PAMAM) dendrimers (G3.5-G10) were used by Tsukruk et al. [25,26] to fabricate self-assembled monolayers by an electrostatic deposition techniques [27],... 

Two different dendrimer families are presently commercially available Starburst polyamidoamine (PAMAM) dendrimers from Dendritech Inc., Midland, Michigan, and ASTRAMOL polypropyleneimine (PPI) dendrimers from DSM, Geleen, the Netherlands. 

Tomalia, D. A. and Dvornic, P. R. Dendritic polymers, divergent synthesis (starburst polyamidoamine dendrimers) , in Salamone, J. C. (ed.), Polymeric Materials Encyclopedia, Vol. 3, CRC Press, Boca Raton, FL, 1996, pp. 1814-1830. 

Interest in dendritic polymers (dendrimers) has grown steadily over the past decade due to use of these molecules in numerous industrial and biomedical applications. One particular class of dendrimers, Starburst polyamidoamine (PAMAM) polymers, a new class of nanoscopic, spherical polymers that appears safe and nonimmunogenic for potential use in a variety of therapeutic applications for human diseases. This chapter will focus on investigations into PAMAM dendrimers for in vitro and in vivo nonviral gene delivery as these studies have progressed from initial discoveries to recent animal trials. In addition, we will review other applications of dendrimers where the polymers are surface modified. This allows the opportunity to target-deliver therapeutics or act as competitive inhibitors of viral or toxin attachment to cells. 

The Polyamidoamine (PAMAM) dendrimer generation 4 can be purchased from Aldrich Co. 

Arima, H., F. Kihara, F. Hirayama, and K. Uekama. 2001. Enhancement of gene expression by polyamidoamine dendrimer conjugates with alpha-, beta-, and gamma-cyclodextrins. Bioconjug Chem 12(4) 476-84. 

O. Ozturk, et ah, Thermal decomposition of generation-4 polyamidoamine dendrimer films decomposition catalyzed by dendrimer-encapsulated R particles, Langmuir 21, 3998-4006 (2005). 

Star-burst polyamidoamine (PAMAM) dendrimers with primary amine end groups in d-methanol [306] and with hydroxyl or glucopeptide end groups in D2O [307] have been investigated by NSE in order to identify internal segment... 

Physical or electrochemical adsorption uses non-covalent forces to affix the nucleic acid to the solid support and represents a relatively simple mechanism for attachment that is easy to automate. Adsorption was favoured and described in some chapters as suitable immobilization technique when multisite attachment of DNA is needed to exploit the intrinsic DNA oxidation signal in hybridization reactions. Dendrimers such as polyamidoamine with a high density of terminal amino groups have been reported to increase the surface coverage of physically adsorbed DNA to the surface. Furthermore, electrochemical adsorption is described as a useful immobihzation strategy for electrochemical genosensor fabrication. 

The divergent method is illustrated in Fig. 2-22 for the synthesis of polyamidoamine (PAMAM) dendrimers [Tomalia et al., 1990]. A repetitive sequence of two reactions are used—the Michael addition of an amine to an a,P-unsaturated ester followed by nucleophilic substitution of ester by amine. Ammonia is the starting core molecule. The first step involves reaction of ammonia with excess methyl acrylate (MA) to form LXIII followed by reaction with excess ethylenediamine (EDA) to yield LXIV. LXV is a schematic representation of the dendrimer formed after four more repetitive sequences of MA and EDA. 

I,ee 1, Athey BD, Wetzel AW, Meixner W, Baker JR Jr. Stmctural molecular dynamics studies on polyamidoamine dendrimers for a therapeutic application effects of pH and generation. Macromolecules 2002 35 4510-4520. 

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