Iron oxide particles, nanoparticles

The first clinical human trials using magnetic hyperthermia were reported by Liibbe, et al. [70, 129, 137, 190] who used 100-nm starch-coated iron-oxide particles bound with epirubicin for treatment of advanced solid cancers. Jordan recently reported positive results from ongoing trials of advanced cancer patients who received magnetic nanoparticle hyperthermia in conjunction with conformal external beam radiation therapy [191]. The therapy was well tolerated by the patients and significant increases in the length and quality of life were observed. 

However, we should mention the pioneering work of Chou and Phillips, where metallic iron and iron oxide particles were produced by injecting ferrocene into the afterglow region of a low-pressure, low-power, plasma, generated using a micro-wave power source [160]. This gas phase reaction was carried out as part of an attempt to explore the feasibility of using flow-type microwave plasmas for the production of metal nanoparticles. 

From the electrochemical point of view, an important class of materials is that constituted by aluminosilicates incorporating cobalt, iron, etc., centers. In the case of Fe-based zeolites with Mobil Five structure (FeZSM-5) materials, different forms of iron can coexist. These include isolated ions either in framework positions (isomorphously substituting silicon centers), isolated ions in cationic positions in zeolite channels, binuclear and oligonuclear iron complexes in extra-framework positions, iron oxide nanoparticles (size <2 nm), and large iron oxide particles (FcjOj) in a wide distribution (up to 25 nm in size) located in the surface of the zeolite crystal (Perez-Ramirez et al., 2002). The electrochemistry of such materials will be reviewed in Chapter 8. 

Fig. 10 TEM images of the nanoparticles (a) Janus particles consisting of gold (darker spheres) and iron oxide (brighter spheres)-, (b) homogeneous iron oxide particles (c) gold particles. Scale bars 25 nm. Reprinted with permission from Langmuir [68], Copyright (2006) American Chemical Society...

Preparation of iron oxide magnetic nanoparticles and their encapsulation with polymers in W/0, i.e. inverse microemulsion polymerization, was also applied by O Connor et al. [167]. Inverse microemulsion polymerization was used to prepare submicron hydrophilic magnetic latex containing 5-23 wt% iron oxide. AM and crosslinker MBA were added to an aqueous suspension of previously synthesized iron oxide nanoparticles (6 wt%) this aqueous phase was dispersed in a aerosol OT (sodium l,4-bis(2-ethylhexoxy)-l,4-dioxobutane-2-sulfonate) (AOT)-toluene solution to form a W/O microemulsion, followed by polymerization with AIBN or V-50 as initiator. The particle size (80-180nm)was controlled by tuning the concentration of the water-soluble crosslinker agent as well as the amount of surfactant with respect to water [168]. 

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