Biomedical applications molecules

In numerous applications of polymeric materials multilayers of films are used. This practice is found in microelectronic, aeronautical, and biomedical applications to name a few. Developing good adhesion between these layers requires interdiffusion of the molecules at the interfaces between the layers over size scales comparable to the molecular diameter (tens of nm). In addition, these interfaces are buried within the specimen. Aside from this practical aspect, interdififlision over short distances holds the key for critically evaluating current theories of polymer difllision. Theories of polymer interdiffusion predict specific shapes for the concentration profile of segments across the interface as a function of time. Interdiffiision studies on bilayered specimen comprised of a layer of polystyrene (PS) on a layer of perdeuterated (PS) d-PS, can be used as a model system that will capture the fundamental physics of the problem. Initially, the bilayer will have a sharp interface, which upon annealing will broaden with time. 

S. K. Choi, Synthetic multivalent molecules concepts and biomedical applications, Wiley, New York, 2004. 

Nanoparticles such as those of the heavy metals, like cadmium selenide, cadmium sulfide, lead sulfide, and cadmium telluride are potentially toxic [14,15]. The possible mechanisms by which nanoparticles cause toxicity inside cells are schematically shown in Fig. 2. They need to be coated or capped with low toxicity or nontoxic organic molecules or polymers (e.g., PEG) or with inorganic layers (e.g., ZnS and silica) for most of the biomedical applications. In fact, many biomedical imaging and detection applications of QDs encapsulated by complex molecules do not exhibit noticeable toxic effects [16]. One report shows that the tumor cells labeled with QDs survived in circulation and extravasated into tissues... 

A third type of detector, required for some environmental and biomedical applications, is the electron capture detector (ECD). This detector is especially useful for large halogenated hydrocarbon molecules since it is the only one that has an acceptable sensitivity for such molecules. Thus, it finds special utility in the analysis of halogenated pesticide residues found in environmental and biomedical samples. 

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. 

In recent years, CNTs have been receiving considerable attention because of their potential use in biomedical applications. Solubility of CNTs in aqueous media is a fundamental prerequisite to increase their biocompatibility. For this purpose several methods of dispersion and solubilisation have been developed leading to chemically modified CNTs (see Paragraph 2). The modification of carbon nanotubes also provides multiple sites for the attachment of several kinds of molecules, making functionalised CNTs a promising alternative for the delivery of therapeutic compounds. 

Isotopic distribution within an element will vary between living organisms depending on the biosynthetic pathways that lead to its formation. Furthermore, the rate at which a molecule crosses cellular membranes will depend on the molecule s isotopic distribution. Hence, detectable differences in isotopic composition can be observed in the products formed. Detection of adulterated vegetable oils, flavourings and fruit juices, as well as the study of metabolism in plants and numerous biomedical applications, use isotopic abundance as a tool. For example, the... 

A series of advances over the past decade have made CRS microscopy a highly sensitive tool for label-free imaging and vibrational microspectroscopy that is capable of real-time, non-perturbative studies of complex biological samples based on molecular Raman spectroscopy. In particular, biomedical applications where fluorescent labeling of small molecules represents a severe pertur-... 

These features of these materials spurred the scientific community to utilize them in biomedical applications [49]. In particular, the synergy between their multivalency and size on the nanoscale enables a chemical smartness along their molecular scaffold that achieves environmentally sensitive modalities. These functional materials are expected to revolutionize the existing therapeutic practice. Dendritic molecules, such as polyamidoamine, polylysine, polyester, polyglycerol (PG), and triazine dendrimers, have been introduced for biomedical applications to amplify or multiply molecularly pathopharmacological effects [73]. 

Gasteier P, Reska A, Schulte P et al (2007) Surface grafting of PEO-based star-shaped molecules for bioanalytical and biomedical applications. Macromol Biosci 7 1010-1023... 

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