Dendrimers contrast agents

Perrier RJ (2001) Direct Conversion of 5,6-Unsaturated Hexopyranosyl Compounds to Functionalized Glycohexanones. 215 277-291 Frey H, Schlenk C (2000) Silicon-Based Dendrimers. 210 69-129 Forster S (2003) Amphiphilic Block Copolymers for Templating Applications. 226 1-28 Frullano L, Rohovec J, Peters JA, Geraldes CFGC (2002) Structures of MRI Contrast Agents in Solution. 221 25-60... 

Wiener and co-workers used folic acid-conjugated Gd(DTPA)-PAMAM dendrimers for visualizing the high-affinity folate receptor, overexpressed in many tumors.201 The contrast agent accumulated in the cells, resulting in a remarkable contrast enhancement on 7)-weighted images. 

Kobayashi, H., Kawamoto, S., Star, R.A., Waldmann, T.A., Tagaya, Y., and Brechbiel, M.W. (2003) Micro-magnetic resonance lymphangiography in mice using a novel dendrimer-based magnetic resonance imaging contrast agent. Can. Res. 63, 271-276. 

Scheme 9. (A) Different dendrimers as macromolecular scaffolds for MRI contrast agents ethylenediamine cored polyamido amine, generation 4 (PAMAM G4), top hyperbranched, ethylenediamine cored polyethylene imine (HB-PEI), bottom left hyperbranched, amino functionalized polyglycerol (HB-PG), bottom right. (B) Different moieties attached to the respective dendrimers via amide or thiourea bonds.

Gadolinium-dendrimer conjugates have been used as blood pool contrast agents in vivo for nuclear magnetic resonance imaging (MRI) of tumors [65]. The efficacy of the conjugates in such applications is dependent on their biodistribution properties, and these properties vary as a function of dendrimer molecular weight and chemical composition [50]. Dendrimer architecture and synthesis... 

Kozhushkov SI, see de Meijere A (2000) 207 149-227 Krause W (2002) Liver-Specific X-Ray Contrast Agents. 222 173-200 Krause W, Hackmann-Schlichter N, Maier FK, Mller R (2000) Dendrimers in Diagnostics. 210 261-308... 

An even more challenging approach covers polymeric X-ray contrast agents derived either from linear or from branched backbones, e.g. dendrimers. An overview on this field of research has been published recently [8]. Additionally, the reader is referred to the chapter in this book by Idee et al. covering novel dendrimers with triiodobenzenes as building blocks. 

Scheme 6. Folate-targeted dendrimeric contrast agent (a 2nd generation species is presented) on a 4th generation dendrimer, 3 to 5 peripheral amine groups are randomly substituted by folic acid, the rest being conjugated to Gd-DTPA chelates...

The third International Dendrimer Symposium took place at Berlin Technical University in 2003. Interdisciplinary lectures demonstrated the extent to which dendritic molecules branch ouf into other areas of science, such as physics, biology, medicine, and engineering. The possibilities of functionalisation and resulting applications in industry were at the focus of this symposium. For example, nano-dimensioned dendrimer-based contrast agents were presented as multilabels for visualisation of blood vessels (see Chapter 8). Potential applications of dendritic materials as luminescence markers in diagnostics attracted lively interest (see Chapter 8). Consideration of the differences between dendrimers and hyperbranched polymers from the viewpoint of their cost-favourable application was also a topic of discussion [18]. 

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