Nanoparticle aggregation

Pt/silica catalysts are shown in Figure 10. Severe nanoparticle aggregation or phase separation is eliminated under neutral pFI conditions. 

Murr, L.E., Garza, K.M., Soto, K.F., Carrasco, A., Powell, T.G., Ramirez, D.A., Guerrero, P.A., Lopez, D.A., and Venzorlll, J. (2005) Cytotoxicity assessment of some carbon nanotubes and related carbon nanoparticle aggregates and the implications for anthropogenic carbon nanotube aggregates in the environment. International Journal of Environmental Research and Public Health, 2 (1), 31-42. 

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. 

Klajn, R. Bishop, K. J. M. Fialkowski, M. Paszewski, M. Campbell, C. I Gray, T. E Grzybowski, B. A. 2007. Plastic and moldable metals by self-assembly of sticky nanoparticle aggregates. Science 316 261-264. 

Murr LE, Bang JJ, Esquivel EV, Guerrero PA, Lopez A (2004) Carbon nanotubes, nanocrystal forms, and complex nanoparticle aggregates in common fuel-gas combustion sources and the ambient air. J Nanopart Res 6 241-251. 

Na, G. C. and Rajagopalan, N. (1994) Use of non-ionic cloud point modi ers to minimize nanoparticle aggregation during sterilization, US Patent 5,346,702. 

Srinivasachari S, Liu Y, Zhang G et al (2006) Trehalose click polymers inhibit nanoparticle aggregation and promote pDNA delivery in serum. J Am Chem Soc 128(25) 8176—8184... 

Keywords Nanoparticle Aggregation Stabilization Precipitation Milling... 

Fig. 7 (PLL/HA)24/PLL film with embedded DNA before (a, c) and after (b, d) irradiation with IR light. PLL in the film is labeled with FITC (a, b), and DNA is labeled with EtBr (c, d). Scale bars 5 pm. (e) Suggested mechanism of DNA release induced by the distortion of the DNA-doping PLL interaction as a result of partial thermal film decomposition in vicinity of nanoparticle aggregates. Reproduced from [98]...

When the phase boundary of a liquid is given by a metal, other phenomena occur. We have so far examined the case of specimens with the metal in a nanoparticle aggregation, with the opportune morphology of the metal subsystem (noble metals are more appropriate) Surface enhancement effects on the spectroscopic property of a chromophore have been evidenced, in agreement with the available experimental findings (especially for SERS, but also for other spectroscopic signals) [9]. In some experiments of this type, the metal is covered by a substance with a dielectric response differing from that of the bulk liquid, Which has also been introduced in PCM [9],... 

The threading of the dibenzylammonium cation into dibenzo[24]crown[8] has been exploited to assemble pseudorotaxanes at the surface of a nanocrystal96 and to induce and control formation of nanoparticle aggregates.97 However, the possibility of pH-triggered aggregation, related to the acid-base controlled dethreading of hydrogen-bonded pseudorotaxanes, was not explored. 

Figure 19.18 Thennosensitive hybrid microgel containing gold nanoparticles. The color changes originate from nanoparticle aggregation induced by the swelling/deswelling of the thermosensitive microgel.

Aslan, K. and Geddes, C. D. (2007). Microwave-Accelerated Ultrafiist Nanoparticle Aggregation Assays Using Gold Colloids. Anal. Chem. 79 2131-2136. 

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