Drug delivery and in therapeutics table 3 early

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Unformatted text preview: ased vesicles) commonly used in topical lotions and titanium nanoparticles used in sunscreen produced by Procter & Gamble (Cincinnati, OH, USA) and L’Oréal (Westfield, NJ, USA). Liposomes have been under development as delivery vehicles since the early 1990s. They have low toxicity, are versatile in size, composition and bilayer fluidity, and are capable of displaying drugs on their surface or encapsulating them within. However, they also have suffered from low delivery efficiencies (particularly in gene therapy applications) and high drug leakage (although the latter problem may be remedied by the introduction of colloidally stabilized liposomes). As liposomes have been covered in detail elsewhere, I will not discuss them further here. Figure 3 Neurons (neurons) penetrating into a three-dimensional network of the self-assembling nanofibers. Source: NanoMateria The surface chemistry of nanoparticles can be modified to display high concentrations of a therapeutic drug and/or molecules for tissue-specific recognition. Dendrimers—polymeric macromolecules structured as concentric shells—are one type of nanoparticle that can be functionalized with chemical groups to allow attachment of drugs or molecules of interest (Fig. 2). Companies such as Dendritic Nanotechnologies (Mt. Pleasant, MI, USA) and Alnis Biosciences (Emeryville, CA, USA) are already marketing dendrimers for use in research. In July, a first dendrimer drug, developed by StarPharma (Melbourne, Australia) for use against HIV, received regulatory clearance for phase 1 clinical trials from the US Food and Drug Administration (FDA; Rockville, MD, USA). The drug is a topical gel containing an anionic polyamidoamine dendrimer that is postulated to interfere with the entry and fusion process of the HIV particle. Other types of nanoparticle are also being developed for use in drug delivery. For example, C Sixty (Houston, TX, USA) is investigating fullerenes (clusters of 60 carbon atoms) as a means of delivering therapeutics, and Nanospectra Biosciences (Houston, Texas, USA) is developing nanoshells comprising a silica core and an ultrathin gold coat that will allow localized payload delivery or tissue ablation triggered by a secondary mechanism, such as light activation. Clearly, such platforms are Box 1 Making things grow Taking a page from nature, researchers are using biological molecules and structures as scaffolds for building and growing materials at the nanoscale. Exploiting the molecular recognition properties of DNA, for example, Chad Mirkin (Northwestern University, Evanston, IL, USA) and others have organized inorganic nanoparticles (such as colloidal gold) into ordered macrostructures3. Another approach that has seen some success is the use of viruses as templates for nanostructures. For Angela Belcher, a biochemist turned electrical engineer turned molecular biologist at the Massachusetts Institute of Technology (MIT; Cambridge, MA, USA), the inspiration came from abalone shell...
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This document was uploaded on 09/24/2013.

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