Fluorescent polystyrene-Fe3O4 composite nanospheres for in vivo imaging and hyperthermia

Abstract

Quantum dots (QD) were immobilized on the surface of a superparamagnetic composite of polyethylene-oxide-modified PS NSs. These QDs have a CdSeTe core and a ZnS shell with a covalently attached, amine-functionalized layer of PEG. About 200μL of a freshly prepared solution of 30 mg NHS and 10 mg EDC of PBS was mixed with 100μL of a suspension containing 2 mg of MNS and 160 pmol of QDs. The reaction mixture was incubated for 12 h at 50°C, cooled to room temperature, and centrifuged at 12 000 rpm for 5 minutes. A drop of QD-NS suspension was smeared on a glass slide for microscopic evaluation using an Olympus BX51 equipped with a fluorescence illumination module. The QD-MNS nanoparticles are clearly visible as individual spherical units spread across the slide. Each particle exhibits intense red-light emission against the dark background, suggesting effective immobilization of QDs on the surfaces of PS-MNS.