Nanoparticles and nanostructured carriers for drug delivery and contrast enhancement

Abstract

Currently, nanotechnologies are widely used in science and industry. It is known that the application of drug delivery nanostructured carriers for biomedicine is one of the promising areas of nanotechnology. Nanostructured carriers can be used in the diagnosis process for detecting a neoplastic tumor cells in peripheral blood, for contrast enhancement on magnetic resonance imaging (MRI), as well as for targeted drug delivery to tumor tissues. Agents for the targeted delivery (nanoparticles, liposomes, microcapsules, and etc) can affect the healthy tissues and organs, cause side effects and have a toxic effect. Therefore, it necessary to study the morphological changes that occur not only in the "target", such as a tumor, but also the internal organs, taking place under the influence of both the agents for targeted drug delivery and physical impact induced remote controlled drug release. Thus , the aim of our work is selection of the most promising agents for targeted drug delivery to tumor and contrast agents for in vivo visualization of tumor tissue boundaries , as well as their impact on the organs and tissues as results of nanostructured object biodistribution. OVERVIEWAt present time it is difficult to name the area of science, where nanotechnologies have not found their application. A lot of works demonstrate that the range of nanotechnology applications in biomedicine is quite wide, for example, magnetite nanoparticles can be used to enhance contrast and improve diagnostic sensitivity in (MRI) [1-6], targeted delivery [7-9], hyperthemia [10,11], tissue engineering [12]. The magnetite nanoparticles have a considerably lower toxicity as compared with the analogues based on nickel, cobalt and other substances and sufficient magnitude of effective magnetic characteristics [13][14][15]. Magnetite is quite a promising material for biomedical applications, because it does not affect the cardiovascular system [13], its intravenous administration is permitted by U.S. Federal agency of Food and Drug Administration [14]. Clinical trials have shown excellent biocompatibility of magnetite nanoparticles [16][17][18]. Low toxicity was also determined in vivo by morphological study of internal organs of laboratory animals after different methods of administration of magnetite nanoparticles [19][20][21].Stability of nanoparticles is the most important characteristic for the biomedical applications. Surface modification of nanoparticles enables them to ensure not only colloidal stability but also biocompatibility. The aggregation and oxidation were observed for inorganic nanoparticles. Coatings of organic and inorganic nature for surface modification of nanoparticles are used to prevent actions like aggregation, sedimentation and [22][23][24][25]. Gold modifies the surface in such a way that increases the stability of nanoparticles in aqueous solution [26,27]. Dextran and its derivatives have a high biocompatibility and are used for stabilization of nanoparticles [28][29][30]. Nanoparticles stabilized by alginate and chitosa...