Fabrication and dual imaging properties of quantum dot/silica core-shell particles immobilized with gold nanoparticles.

The present work proposes a preparation method for core-shell nanoparticles composed of quantum dots (QDs), SiO₂, large Au nanoparticles (Au^L), and small Au nanoparticles (Au^S). The QDs were silica-coated with a sol-gel method using tetraethyl orthosilicate (QD/SiO₂). Au^L and Au^S were fabricated by reducing Au3+ ions with sodium citrate and tetrakis(hydroxymethyl)phosphonium chloride in water, respectively. Amino groups were introduced onto QD/SiO₂ surface by using (3-aminopropyl)-triethoxysilane (QD/SiO₂/NH₂). Both Au^L and Au^S were immobilized on QD/SiO₂/NH₂ by successively reacting Au^L and Au^S with QD/SiO₂/NH₂ (QD/SiO₂/NH₂/Au^L/Au^S). Surface modification of QD/SiO₂/NH₂/Au^L/Au^S was performed by using polyethylene glycol (PEG) with a thiol group (QD/SiO₂/NH₂/Au^L/Au^S/PEG). The QD/SiO₂/NH₂/Au^L/Au^S/PEG colloid solution could be clearly imaged via its fluorescence. Its computed tomography (CT) value per unit concentration of Au (M) was 1.2 × 10⁴ HU/M. The QD/SiO₂/NH₂/Au^L/Au^S/PEGs were circulated in amouse through blood vessels, and some of them became trapped and accumulated in the liver and spleen. [ABSTRACT FROM AUTHOR]