Single Nanoparticles

FIGURE 1.10 Constant-current topography images of (a) differentiated PC12 eeUs, (b) eardiac myocyte, and (c) hippocampus neurons obtained with the earbon-based nanotips held at —500 mV versus Ag/AgCl in PBS containing 10 mM Ru(NH3)6Cl3. (Reprinted with permission from Takahashi, Y. et al., Proc. Natl. Acad. Sci. USA, Vol. 109, 2012 pp. 11540-11545.) 

FIGURE 1.11 (a) Schematic representation of the feedback mode at a single nanoparticle 

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Nie S and Emory S R 1997 Probing single molecules and single nanoparticles by surface-enhanced Raman scattering Science 275 1102-6... 

F. and Buuren, T.v. (2005) Comment on Gold nanoshells improve single nanoparticle molecular sensors . Nano Letters, 5, 809-810. 

Spatially resolved measurements, based on the confocal laser microscope and related techniques, have recently enabled direct detection of individual molecules, single nanoparticles, and molecular assemblies, leading to elucidation of the heterogeneous nature of these systems and its dependence on the individual environments. 

Another technique, which allows the controlled deposition of a single nanoparticle between two metal nanoelect-odes, i.e. the technique of electrostatic trapping (ET) was reported by Schmid and Dekker [29]. A polarized metal nanoparticle is attracted to the strongest point of an electric field, which was applied to two Pt electrodes (Figure 12). 

Casanova D, Giaume D, Moreau M, Martin JL, Gacoin T, Boilot JP, Alexandrou A (2007) Counting the number of proteins coupled to single nanoparticles. J Am Chem Soc 129 12592-12593... 

Aslan K, Wu M, Lakowicz JR, Geddes CD (2007) Fluorescent core-shell Ag Si02 nanocomposites for metal-enhanced fluorescence and single nanoparticle sensing platforms. J Am Chem Soc 129 1524-1525... 

Wu C, Bull B, Christensen K, McNeill J (2009) Ratiometric single-nanoparticle oxygen sensors for biological imaging. Angew Chem Int Ed 48 2741-2745... 

The analysis of the current-time curves at electrodes or microelectrodes of different geometries has also a great interest in detecting the presence of small particles or nanoparticles at its surface or even single nanoparticles events through the current due to the electro-oxidation (or reduction) of the particles (see Fig. 2.18) or to a electrocatalytic reaction on the nanoparticle surface when this comes into contact with the electrode and transiently sticks to it [62-65]. 

Doering WE, Nie S. Single-molecule and single-nanoparticle SERS examining the roles of surface active sites and chemical enhancement. Journal of Physical Chemistry B 2001, 106, 311-317. 

Asahi, T. Masuhara, H. Microspectroscopy of single nanoparticles (ed. Masuhara, H. N., Hachiro Sasaki, Keiji) (Springer Berlin, 2003). 

As an inorganic mineral, most unmodified nanoadditives are strongly hydrophilic and are generally compatible and miscible only with a few hydrophilic polymers, for instance, clay can only be made into PNs with polyethylene oxide),27 poly(vinyl alcohol),28 and a few other water soluble polymers. Most polymers are hydrophobic and thus they are neither compatible nor miscible with the unmodified nanoadditives, leading to an inability to achieve a PN with a good nanodispersion in most cases. Therefore, for most nanoadditives that have been used to prepare the PNs, an important and necessary feature is their surface treatment that provides compatibility to the nanoadditives and enables them to be uniformly dispersed (and/or separated into single nanoparticles) in the polymer matrix. 

In the case of PNs containing nanoadditives other than nanolayers, such as CNTs and POSS, the terms above are not used. They also show similar observations as those seen for the clay in the polymer matrix Aggregated to a large extent (immiscible or partially immiscible) or a few nanoadditive nanoparticles or separated into single nanoparticle, and all of these may coexist in the same PN. 

A parallel development in sensor technology is the use of gold nanoparticles (AuNPs) and their localized surface plasmon resonances (LSPR) [41] for sensing purposes. Mirkin et al. [42] showed how single nanoparticles (NPs) in solution can... 

It works with very small volnmes, for example, a single nanoparticle or nanotnbe. 

Clear relationship - Low Mw chitosan 2D chains between - Medium molecular weight chitosan single nanoparticles morphology and - High molecular weight chitosan nanoplates molecular weight... 

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