Nanocrystal colloids

Littau KAefa/1993 A luminescent silicon nanocrystal colloid via a high temperature aerosol reaction J. Phys. Chem. 97 1224... 

Blanton S A ef a/1997 Dielectric dispersion measurements of CdSe nanocrystals colloids observations of a permanent dipole moment Phys. Rev. Lett. 79 865... 

This case study deals with the transfer of a complex, proprietary delivery system into a CMO. The delivery system was developed to better deliver poorly soluble compounds, using Alkermes proprietary Nanocrystal Colloidal Dispersion (NCD ) system. The major challenges associated with the transfer of this technology into an Alkermes production facility (Anon, 2012), included ... 

Many approaches have been taken to prepare colloidal doped semiconductor nanocrystals. For example, hot-injection methods have been used to synthesize colloidal Mn2+-doped CdSe (47, 48), ZnSe (49), and PbSe (50) colloidal nanocrystals. Colloidal ZnO DMS-QDs doped with Co2+, Ni2+, and Mn2+ have been prepared by low-temperature hydrolysis and condensation (51-54). Sol-gel methods have been used to prepare colloidal doped TiC>2 (55-57) and Sn02 (58-62) nanocrystals. Inverted micelle methods have been used for preparation of a range of doped II-VI sulfide DMS-QDs at low temperatures (63-68). A high-temperature lyothermal single-source method was used to synthesize Co2+- and Eu3+-doped CdSe nanocrystals (69, 70). Autoclaving has occasionally been used to induce crystallization at lower temperatures than reached under atmospheric pressures while retaining colloidal properties, for... 

NanoCrystal Colloidal Dispersion —B— NanoCrystal Solid Dosage Form Fig. 8 Pharmacokinetic profiles of three formulations of meloxicam... 

Lisiecki, 1. (2004) Size control of spherical metallic nanocrystals. Colloids and Surfaces A-Physicochemical and Engineering Aspects, 250,499-507. 

For tire purjDoses of tliis review, a nanocrystal is defined as a crystalline solid, witli feature sizes less tlian 50 nm, recovered as a purified powder from a chemical syntliesis and subsequently dissolved as isolated particles in an appropriate solvent. In many ways, tliis definition shares many features witli tliat of colloids , defined broadly as a particle tliat has some linear dimension between 1 and 1000 nm [1] tire study of nanocrystals may be drought of as a new kind of colloid science [2]. Much of die early work on colloidal metal and semiconductor particles stemmed from die photophysics and applications to electrochemistry. (See, for example, die excellent review by Henglein [3].) However, the definition of a colloid does not include any specification of die internal stmcture of die particle. Therein lies die cmcial distinction in nanocrystals, die interior crystalline stmcture is of overwhelming importance. Nanocrystals must tmly be little solids (figure C2.17.1), widi internal stmctures equivalent (or nearly equivalent) to drat of bulk materials. This is a necessary condition if size-dependent studies of nanometre-sized objects are to offer any insight into die behaviour of bulk solids. 

There are many ingenious and successful routes now developed for nanocry stalline syntliesis some rely on gas phase reactions followed by product dispersal into solvents [7, 9,13,14 and 15]. Otliers are adaptations of classic colloidal syntlieses [16,17,18 and 19]. Electrochemical and related template metliods can also be used to fomi nanostmctures, especially tliose witli anisotropic shapes [20, 21, 22 and 23]. Ratlier tlian outline all of tlie available metliods, this section will focus on two different techniques of nanocrystal syntliesis which together demonstrate tlie general strategies. 

Peng Z G, Wickham J and Alivisatos A P 1998 Kinetics of ll-VI and lll-V colloidal semiconductor nanocrystal growth focusing of size distributions J. Am. Chem. Soc. 120 5343... 

Guzellan A A et al 1997 Colloidal chemical synthesis and characterization of InAs nanocrystal quantum dots Appl. Phys. Lett. 69 1432... 

Hines, M. A. and Scholes, G. D. (2003). Colloidal PbS Nanocrystals with Size-Timable Near-Infrared Emission Observation of Post-Synthesis Self-Narrowing of the Particle Size Distribution. Adv. Mater. 15 1844-1849... 

Peng, X. G. (2003). Mechanisms for the Shape-control and Shape-Evolution of Colloidal Semiconductor Nanocrystals. Adv. Mater., 15,459-463. 

Peng X, Wickham J, Ahvisatos AP (1998) Kinetics of 11-VI and III-V colloidal semiconductor nanocrystal growth Focusing of size distributions. J Am Chem Soc 120 5343-5344... 

This protocol was extended to other inorganic colloids (e.g., ZnS, PbS), and it was pointed out that such extension paves the way to an electrochemical coding technology for the simultaneous detection of multiple DNA targets based on nanocrystal tags with diverse redox potentials [148]. 

Doose, S., Tsay, J. M., Pinaud, F. and Weiss, S. (2005) Comparison of photophysical and colloidal properties of biocompatible semiconductor nanocrystals using fluorescence correlation spectroscopy. Anal. Chem., 77, 2235-2242. 

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