Dendrimer medical application

See also Luminescent dendrimers antibacterial, 26 799 biocompatibility studies of, 26 800-801 in catalysis, 26 805-806 in cell targeting, 26 797-798 as chelators, 26 806-807 core and interior shells of, 26 789 cytotoxicity of, 26 800-801 in drug delivery, 26 792-795 in gene transfection, 26 791-792 as imaging agents, 26 795-797 luminescent, 26 801-804 medical applications of, 26 791-801 micelle-mimetic behavior of, 26 789 multiphoton applications of, 26 803-804... 

The successful application development for hyperbranched polyesteramides is primarily based on the many research programs started several years ago for dendrimers. For most of the potential and existing applications the high number of end groups and the multifunctionality are the predominant advantages. These characteristics are shared by dendrimers and hyperbranched materials alike. Only in some special cases, such as medical applications [23], is monodis-persity the main issue and thus dendrimers are preferred in this particular case. 

A manifold of dendrimers have been presented in the literature ranging from polyamidoamine, polyfpropylene imine), aromatic polyether and polyester, aliphatic polyether and polyester, polyalkane,polyphenylene, polysilane, and phosphorus dendrimers. Combinations of different backbones as well as architectural modifications have also been presented. For example, the incorporation of chirality in dendrimers, copolymers of linear blocks with dendrimer segments (dendrons), and block copolymers of different dendrons has been described. Numerous applications have been proposed for dendrimers such as biotemplates, liquid membranes, catalysts, or in medical applications. ... 

Some researchers see a bright future for dendrimers in many different industrial, medical, research, and consumer applications. One company that produces dendrimers lists applications in drug delivery systems, gene transfection, biotechnology, sensors for diagnostics and detection systems, carbon fiber coatings, microcontact printing, adhesion, molecular batteries, catalysis, separation systems, lasers, composites, and ultrathin films used in optics. 

Dendrimers and star polymers for pharamceutical and medical applications. [N. A. Peppas, A. B. Argade, In Proc. Int. Symp. Controlled Release Bioact. Mater., (Eds. T. J. Roseman N. A. Peppas H. L. Gabelnick), Controlled Release Society Deerfield, III., 1993] [ 413]. 

In industry, several dendrimers are already being synthesized on a hundred kilogram scale. The hopes for effective solubilizing systems suitable for medical applications may, however, not be justified. Phenolic ether or polyamine compounds are both normally not biodegradable so that major problems are foreseeable. An alternative is the employment of hydrolysable polyesters. One such compound already reported, is the imperfectly hyperbranched dendrimer which is easily accessible via thermal self-condensation of 3,5-bis(trimethyl-siloxyjbenzoyl chloride. This one-step procedure leads to a dendritic polyester... 

Recent reports [14,72] describe the preparation of various calcium phosphate nanoparticles. It is believed that such products might prove to be of great value in biomedicine, for drug delivery, gene silencing, and so on. Phosphoras-based dendrimers have recently been investigated with a view to medical applications, or as potentially useful nanoparticle or nanotube materials [73,74,75],... 

In addition, the huge number of functionalities on the surface of a dendrimer can be exploited. For example, attaching multiple copies of a substrate for an enzyme, or a recognition molecule for an antibody or cell adhesion protein can lead to novel effects. MRI image-enhancement molecules (complexes of Gd ) can decorate the surface of a dendrimer, producing an especially effective contrast agent. Studies thus far suggest that dendrimers are often quite nontoxic, and we can anticipate that more medical applications will appear. 

Dendrimers have been targeted in medical applications such as drug delivery as a consequence of their advantageous solubility characteristics, coupled to their multifunctional architecture, which enables drugs to be bound on or within the dendrimer, either via covalent or non-covalent means. 

An interesting medical application of the nitronylnitroxide-labeled dendrimers is spin trapping of nitric oxide. Nitronyl nitroxides can spin trap NO, but are unstable... 

Today research does no longer focus on the dendrimer itself but on the multiplication of functional components attached to a dendritic skeleton and new materials with specific properties (redox, ligand, and liquid crystalline properties, biochemical activity. ..) are anticipated. [9] Industry has also shown increasing interest in functional cascade molecules for applications in diverse areas such as medical engineering, agrochemistry, and the development of photocopier toner additives. Concrete applications include nanoscale catalysts [2a],... 

Taking into account the fact that most of the hydrophilic dendrimers described up to now in the literature have been proposed as tools for various biological applications (e.g., transfection, medical imaging, inhibition of viruses, see below) it is important to have not only water-soluble, but also water-stable compounds. This is the case of most of the phosphorus-containing dendrimers reported in this review, some of them being stable for months and even years in water, demonstrating the very high stability toward hydrolysis of both the internal and external hydrazone units and the whole skeleton of the dendrimer. 

---