Individual inorganic nanoparticles: preparation and in vitro biomedical diagnostic applications

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Individual inorganic nanoparticles are promising candidates for in vitro and in vivo biomedical applications. This can be attributed to their interesting features, which emanate from their nanosize, including physical properties such as optical, superparamagnetic, electronic, and catalytic properties, in addition to some specific biological activity (e.g. bactericidal activity of Ag and gold in the specific affinity toward proteins). Nowadays, the specific optical or magnetic features of the inorganic nanoparticles are exploited and integrated into microsystems and devices providing fast analysis with high sensitivity for low volume analyte. While the benefits of inorganic nanoparticles for in vitro applications are recognized, their use for the in vivo area is still very restricted. This may be attributed to the extensive toxicity studies which have to be done before using in vivo therapy or diagnostics or theranostics. Furthermore, in order to be conveniently used for in vitro or in vivo bio-related applications, the surface of the inorganic nanoparticles must be modified not only to increase their biocompatibility (low toxicity) but also to enhance their colloidal stability preventing theirs in vivo aggregation, chemical degradation or accumulation. This can be achieved by optimization of the synthesis process in order to prepare structured nanoparticles with well-defined properties in order to answer the drastic criteria of bionanotechnology.

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