Tissue Engineering And Nanotheranostics

“9.61x6.69” b2815 Tissue Engineering and Nanotheranostics

Magnetic Nanohybrids for Magnetic Resonance Imaging 109

CdSe–CdS core–shell nanoparticles and quantum dots (QDs) with

Fe 3 O 4 magnetic nanoparticles (MNPs), and then fabricated Fe 3 O 4 –

QDs@CdSe–CdS using the coassembling process. Finally, polyethylene–

glycol silane conjugated on the surface of nanohybrids to enhance the

surface functionality and biocompatibility. In the synthesis process,

hydrophobic Fe 3 O 4 and QDs was prepared. A surfactant dodecyltrimeth-

ylammonium bromide (DTAB) was used to transfer the phase from

organic to aqueous solution and then poly(vinylpyrrolidone) (PVP) eth-

ylene glycol (EG) solution was employed to stabilize the nanoparticles as

shown in Fig. 4(a). Elemental color mapping results (Fig. 4(b)) demon-

strated the evidence of forming core–shell nanohybrids.

Silica shell was used on MFCSNPs to improve the stability and

biocompatibility in aqueous media and the size of these particles after

coating is about 100 nm as shown in Fig. 4(c) and inset.^33 At room

temperature, these silica-coated MFCSNPs reveal superparamagnet-

ism behavior with a saturation magnetization of 15.2 emu/g.

Basically, two methods have been employed extensively for the syn-

thesis of iron oxide nanoparticles: (1) coprecipitation method and (2)

thermal decomposition of magnetic oleate in non-ionic solvents.

Fig. 3. Various types of core–shell structures: (a) spherical core–shell, (b) nanoma-
tryushka materials, (c) multiple cores in a single shell, (d) moveable core in a hol-
lowshell, (e) hexagonal core–shell and (f) tubular shaped core–shell structure.