PAMAM dendrimers commercially available dendrimer

The addition of ammonia to excess methyl acrylate (a linear monomer), followed by amidation with excess ethylenediamine afforded the resultant cascade molecule, and thus Tomalia [37] created the commercially available PAMAM starburst series of dendrimers (2, Fig. 2). Related core molecules such as ethylenediamine and aminoalcohols and other functionalizable groups such as thiol moieties were used to prepare similar dendrimers [38]. This methodology is applicable to most primary amines, resulting in a 1 —> 2 branching pattern. Recently, examples of related Si-, [39] P-, [40] and metallo systems [41], which follow this linear monomer protocol have been reported. 

Other than the epoxy groups available on one Priostar dendrimer type and a methyl ester available on a PAMAM dendrimer, the commercial suppliers generally don t offer a selection of spontaneously reactive dendrimers for bioconjugation purposes. For this reason, most of the applications published for coupling biomolecules to dendrimers have used various modification or activation steps to create the appropriate reactive groups for conjugation (e.g., Leon etal., 1996). 

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. 

This chapter describes composite materials composed of dendrimers and metals or semiconductors. Three types of dendrimer/metal-ion composites are discussed dendrimers containing structural metal ions, nonstructimal exterior metal ions, and nonstructiu al interior metal ions. Nonstructural interior metal ions can be reduced to yield dendrimer-encapsulated metal and semiconductor nanoparticles. These materials are the principal focus of this chapter. Poly(amidoamine) (PAMAM) and poly(propylene imine) dendrimers, which are the two commercially available families of dendrimers, are in many cases monodisperse in size. Accordingly, they have a generation-dependent munber of interior tertiary amines. These are able to complex a range of metal ions including Pd +, and Pt +. The maximmn munber... 

In 1996, Kim and coworkers reported for the first time on the use of a polyami-doamine (PAMAM) dendrimer [Gl] as a soluble support for organic synthesis (Fig. 7.5) [37]. Advantages of PAMAM are its commercial availability and its high symmetry, which provides uniform site accessibility (in lower generations) and facilitates NMR interpretation. By attaching 4-hydroxymethylbenzoic acid (HMB) to... 

We have synthesized and tested an example boron-chelating polymer based on a commercially available dendrimeric poly(amido amine) (PAMAM). Dendrimeric chelants offer several advantages over polymers typically used in PAUF. Foremost among these is the reduced viscosity of dendrimer solutions as compared to solutions of linear polymers[6]. This allows the use of higher polymer concentrations than previously feasible (though in the present study we worked at polymer concentrations of less than 5% due to the expense of the starting dendrimer). In this study, the dendrimeric chelant also serves as a convenient, monodisperse polymer with which to test the mathematical model for boron speciation which is derived from the work of Wise and Weber[l],... 

Poly(amido amine) (PAMAM) dendrimers are the most common class of dendritic macromolecules and, due to their ease of synthesis and commercial availability, they have been the most utilized dendrimer-based vectors for gene transfer [1, 37, 84]. PAMAM dendrimers consist of an alkyl-diamine core with tertiary amine... 

Besides generation number and degree of flexibility, hyperbranched PAMAM can be synthesized with different chemical properties [37,43, 56, 58, 80,114,116], The biotechnology company QIAGEN offers two commercially available hyperbranched PAMAM dendrimers Superfect and Polyfect as in vitro transfections agents, which have been successfully used in many laboratories. 

An advantage of the divergent method - which was the first to be developed [1] - is the attainable high-molecular (nano)scaffold architecture as well as the possibility of automation of the repetitive steps. The divergent method is therefore the method of choice for - commercially available - POP AM and PAMAM dendrimers (see Section 4.1). 

Commercially available POPAM and PAMAM dendrimers (see Chapter 4) bearing terminal primary amino groups are currently the most commonly used divergently grown dendrimer structures, followed by poly(benzyl ether) den-drons or poly(benzyl ether) dendrimers (Frechet type) as representatives of con-vergently synthesised dendritic molecules. 

In the dendritic [Co(salen)] complexes prepared by Breinbauer and Jacobsen the dendrimer again serves as - covalent - support material for the catalytic entities attached to the periphery [62]. These dendritic Jacobsen catalysts were obtained by reaction of the corresponding PAMAM dendrimers with active ester derivates of chiral ]Co(II)-(salen)] units according to standard peptide coupling methods. In hydrolytic kinetic resolution of vinylcyclohexane oxide the dendrimer 14 (Fig. 6.40) showed a dramatically increased reactivity compared to the commercially available monomeric Jacobsen catalyst [63-67]. Whereas the latter merely gave a conversion of less than 1% with an indeterminable ee, 14 afforded a conversion of 50% with an ee of 98 2. 

The principal focus of interest has hitherto been on the group of flexible dendrimers, which embraces the major part of the dendrimers reported in the literature, also including the commercially available POPAM and PAMAM dendrimers having an aliphatic scaffold. In recent years valuable knowledge about the density profile, the three-dimensional structure, and the interactions of dendrimers in solution has been obtained with the aid of small-angle scattering techniques, as is apparent from the following overview. 

Glyco-coated dendrimers possess a core structure of varied chemical nature, with a number of peripheral groups to which carbohydrate moieties are attached. The most common core structures are based on polyaminoamides (PAMAM) or poly(propyleneimine) (Astramol ) with a primary amine at the periphery, and these are commercially available. Polyamides based on N,N-bis(3-aminopropyl)glycine and A,Ar-bis(3-aminopropyl)succinic acid have also been prepared.78... 

Starburst PAMAM dendrimers (Fig. 1), a specific class of commercially available dendrimers that have repeating amine/amide branching units, have drawn considerable interest in recent years due to their potential applications in medicine, nanotechnology, and catalysis [3-7]. These dendrimers are readily functionalized to terminate in diverse moieties such as primary amines, carboxylates, hydroxyls, or hydrophobic alkyl chains. Because dendrimer size and end groups can be varied, they are typically named by their generation (Gl, G2, etc.) and exterior functionality (- NH2, - OH). 

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. 

Although the synthesis of dendrimer-like structures was initially described in 1978, it is only since the 1990s that there has been an intense interest in these polymers, partly attributable to the availability of a commercial source of PAMAM dendrimers. 

---