PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 12618117

Surface-modified silica colloid for diagnostic imaging.

Hoon Choi·I-Wei Chen
View original source ↗Export metadata ↓

Abstract

A method of preparing nanometer-sized oxide colloids suitable as substance carriers for size-sensitive diagnostic imaging and other biomedical applications is described. The nanometer-sized silica particles prepared by the Stober process were reacted with silane to obtain amine-terminated colloidal surfaces under aqueous conditions. The surface-modified colloids can be further treated to combine or conjugate with imaging agents and other diagnostic or therapeutic substances. The water-stable colloidal carriers are spherical and have a narrow size distribution that can be controlled to range from 10 to 200 nm.

Explore related subjects

ColloidsDiagnostic ImagingDrug CarriersMicroscopy, Atomic ForceSilicon DioxideSurface PropertiesWaterLetterResearch Support, U.S. Gov't, Non-P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Hoon Choi, I-Wei Chen. 2003-02-15. Surface-modified silica colloid for diagnostic imaging.. https://doi.org/10.1016/s0021-9797(02)00130-3

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Mechanistic study of precursor evolution in colloidal group II-VI semiconductor nanocrystal synthesis.

The molecular mechanism of precursor evolution in the synthesis of colloidal group II-VI semiconductor nanocrystals was studied using 1H, 13C, and 31P NMR spectroscopy and mass spectrometry. Tri-n-butylphosphine chalcogenides (TBPE; E = S, Se, Te) react with an oleic acid complex of cadmium or zinc (M-OA; M = Zn, Cd) in a noncoordinating solvent (octadecene (ODE), n-nonane-d20, or n-decane-d22), affording ME nanocrystals, tri-n-butylphosphine oxide (TBPO), and oleic acid anhydride ((OA)2O). Likewise, the reaction between trialkylphosphine selenide and cadmium n-octadecylphosphonic acid complex (Cd-ODPA) in tri-n-octylphosphine oxide (TOPO) produces CdSe nanocrystals, trialkylphosphine oxide, and anhydrides of n-octadecylphosphonic acid. The disappearance of tri-n-octylphosphine selenide in the presence of Cd-OA and Cd-ODPA can be fit to a single-exponential decay (kobs = (1.30 +/- 0.08) x 10-3 s-1, Cd-ODPA, 260 degrees C, and kobs = (1.51 +/- 0.04) x 10-3 s-1, Cd-OA, 117 degrees C). The reaction approaches completion at 70-80% conversion of TOPSe under anhydrous conditions and 100% conversion in the presence of added water. Activation parameters for the reaction between TBPSe and Cd-OA in n-nonane-d20 were determined from the temperature dependence of the TBPSe decay over the range of 358-400 K (deltaH++ = 62.0 +/- 2.8 kJ.mol-1, deltaS++ = -145 +/- 8 J.mol-1.K-1). A reaction mechanism is proposed where trialkylphsophine chalcogenides deoxygenate the oleic acid or phosphonic acid surfactant to generate trialkylphosphine oxide and oleic or phosphonic acid anhydride products. Results from kinetics experiments suggest that cleavage of the phosphorus chalcogenide double bond (TOP=E) proceeds by the nucleophilic attack of phosphonate or oleate on a (TOP=E)-M complex, generating the initial M-E bond.

Colloids↗
PubMed2007

The renormalized jellium model for spherical and cylindrical colloids.

Starting from a mean-field description for a dispersion of highly charged spherical or (parallel) rodlike colloids, we introduce the simplification of a homogeneous background to include the contribution of other polyions to the static field created by a tagged polyion. The charge of this background is self-consistently renormalized to coincide with the polyion effective charge, the latter quantity thereby exhibiting a nontrivial density dependence, which directly enters into the equation of state through a simple analytical expression. The good agreement observed between the pressures calculated using the renormalized jellium and Monte Carlo simulations confirms the relevance of the renormalized jellium model for theoretical and experimental purposes and provides an alternative to the Poisson-Boltzmann cell model since it is free of some of the intrinsic limitations of this approach.

Colloids↗