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

Abstract

The present work proposes a preparation method for core-shell nanoparticles composed of quantum dots (QDs), SiO2, large Au nanoparticles (AuL), and small Au nanoparticles (AuS). The QDs were silica-coated with a sol-gel method using tetraethyl orthosilicate (QD/SiO2). AuL and AuS 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 AuL and AuS were immobilized on QD/SiO2/NH2 by successively reacting AuL and AuS with QD/SiO2/NH2 (QD/SiO2/NH2/AuL/AuS). Surface modification of QD/SiO2/NH2/AuL/AuS was performed by using polyethylene glycol (PEG) with a thiol group (QD/SiO2/NH2/AuL/AuS/PEG). The QD/SiO2/NH2/AuL/AuS/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/AuL/AuS/PEGs were circulated in a mouse through blood vessels, and some of them became trapped and accumulated in the liver and spleen.