Multifunctional magnetic-fluorescent CdS@Gd–DTPA hierarchical hollow nanospheres: preparation and potential application in drug delivery

Abstract

Nearly monodisperse CdS hierarchical hollow nanospheres have been synthesized on a large scale through a Na₃cit-assisted solution route. The hollow structure has an application as a drug carrier and the CdS building blocks have fluorescent capabilities. The T₁-agent, Gd–DTPA, is then conjugated to the CdS hierarchical hollow nanospheres through N-ethyl-N′-[3-(dimethylamino)propyl]carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling chemistry using surface absorbed Na₃cit molecules as an intermedium. Thus, multifunctional magnetic-fluorescent CdS@Gd–DTPA hierarchical hollow nanospheres are formed, which combine magnetic resonance imaging (MRI), fluorescent imaging and drug delivery into one system. The as-prepared products are characterized in detail by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Fourier transform infrared spectrometry. The room temperature photoluminescent spectra and T₁-weighted maps of the obtained CdS@Gd–DTPA are carried out using a fluorescence spectrophotometer and a 3 T MRI scanner, respectively. The results indicate that the as-prepared product is a potential candidate for simultaneous disease diagnosis and therapy by combining the multiplexing imaging capability.