Nanoparticles surface modification

Keywords Biocompatible Cancer diagnostics Functionalization Imaging Nanoparticles Surface modification Targeted drug delivery... 

Nanoparticle surface modification is of tremendous importance to prevent nanoparticle aggregation prior to injection, decrease the toxicity, and increase the solubility and the biocompatibility in a living system [20]. Imaging studies in mice clearly show that QD surface coatings alter the disposition and pharmacokinetic properties of the nanoparticles. The key factors in surface modifications include the use of proper solvents and chemicals or biomolecules used for the attachment of the drug, targeting ligands, proteins, peptides, nucleic acids etc. for their site-specific biomedical applications. The functionalized or capped nanoparticles should be preferably dispersible in aqueous media. 

In rubber-rubber blend nanocomposites, nanoparticles are incorporated into a blend which can significantly affect the properties of the matrix. The properties of these composites depend on the type of nanoparticles that are incorporated, their size and shape, their concentration and their interactions with the polymer matrix. It is difficult to produce monodispersed nanoparticles in a rubber blend because of the agglomeration of nanoparticles. This problem can be overcome by modification of the surface of the nanoparticles. Surface modification improves the interfacial interactions between the nanoparticles and the polymer matrix. Nanofillers when added to blend systems are known to cause a considerable change in dynamic properties. 

Zhao et al. [32] carried out a surface modification of Ti02 nanoparticles with the silane coupling agents 3-aminopropyl trimethoxysilane (APTMS) and 3-Isocyanato propyl trimethoxysilane (IPTMS). The process of nanoparticle surface modification by silane coupling agents is shown in Fig. 2. Various anionic surfactants have been used to disperse nano Ti02 [33],... 

V Labhasetwar, C Song, W Humphrey, R Shebuski, RJ Levy. Arterial uptake of biodegradable nanoparticles effect of surface modifications. J Pharm Sci 87(10) 1229-1234, 1998. 

Surface modification is necessary in nanoparticles for various reasons (1) to make them biocompatible and non-immunogenic for biomedical applications,... 

The Stober method can be used to form core-shell silica nanoparticles when a presynthesized core is suspended in a water-alcohol mixture. The core can be a silica nanoparticle or other types of nanomaterials [46, 47]. If the core is a silica nanoparticle, before adding silicon alkoxide precursors, the hydroxysilicates hydrolyzed from precursors condense by the hydroxide groups on the surface of the silica cores to form additional layers. If the core is a colloid, surface modification of the core might be necessary. For example, a gold colloid core was modified by poly (vinylpyrrolidone) prior to a silica layer coating [46]. 

Based on well established silica chemistry, the surface of silica nanomaterials can be modified to introduce a variety of functionalizations [3, 11, 118]. The toxicity of surface-modified nanomaterials is largely determined by their surface functional groups. As an example, Kreuter reported that an apolipoprotein coating on silica nanoparticles aided their endocytosis in brain capillaries through the LDL-receptor [122-124]. Overall, silica nanomaterials are low-toxicity materials, although their toxicity can be altered by surface modifications. 

Irantzu, L., et ah, Carbon nanotube surface modification with polyelectrolyte brushes endowed with quantum dots and metal oxide nanoparticles through in situ synthesis. Nanotechnology, 2010. 21(5) p. 055605. 

The 10% Ft ML core-shell catalysts were tested in an MEA and gave satisfactory performance with 10 ppm CO in H2 with an electrode loading of 0.018 mg Ft cm-. i A similar surface modification of a Ft core with Ru has been investigated by Crabb et al. They reported that, on reduction, a surface FtRu alloy formed and showed similar CO tolerance to a conventional nanoparticle FtRu alloy. 

Tsuruoka T, Akamatsu K, Nawafune H (2004) Synthesis, surface modification, and multilayer construction of mixed-monolayer-protected CdS nanoparticles. Langmuir 20 11169-11174... 

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