Iron Oxide NPs

Figure 4.1 Synthetic scheme for production of iron-oxide NPs using a thermal-decomposition route. From reference [32] with permission.

In one of the early studies of the electrochemistry of discrete electroactive NPs, Marken s group examined iron-oxide NPs. In their first exploration of this area they prepared a-Fe203 using an aqueous hydrolysis route [83]. This produced 4—5 nm diameter cationically charged NPs of a-Fe203 which contained about 2500 Fe centers per NP. Immobilization was achieved by direct adsorption onto cleaned ITO... 

Fig. 10 Processing pathway for obtaining nanocomposite material. (1) Colloidal dispersion of y-Fe203 nanoparticles in hexane. (2) Initial sol with silicon precursor, water, solvents, and iron oxide NPs at ambient conditions, (i) Expanded sol under supercritical conditions with gel composite particles. (4) Dry composite particles. V volume, P pressure, T temperature...

Cell culture substrate can also the influence gene delivery by affecting the occurrence of endocytosis and, thereby, the uptake of DNA-bound NPs by the cells. Hsu et al. [139] observed that the culture of MSCs on chitosan or HA-modified chitosan membranes increased the intracellular uptake of iron oxide NPs ( 5 nm) as well as naked DNA (3.3 kb, 5 mn) by more than fivefold. The increased internalization of NPs was associated with an increase in clathrin-mediated endocytosis on chitosan ( 50%) and in caveolae-mediated endocytosis on chitosan-HA ( 30-40%). In the case of naked DNA, but not iron oxide NPs, macropinocytosis also occurred on both substrates. 

Glycoconjugated chitosan stabilized iron oxide NPs As a multifunctioned nanoprobe [197]... 

PEG-chitosan-coated iron oxide NPs with high saturated magnetization As carriers of 10-hydroxycamptothecin [212]... 

Superparamagnetic iron oxide NPs encapsulated within chitosan Biomedical applications [213]... 

Superparamagnetic iron oxide NPs-loaded chitosan-Unoleic acid nanopeiiticles As an effective hepatocyte-taigeted gene delivery system [223]... 

Similarly, iron oxide NPs confined inside the CNTs channels revealed easier reduction of the oxide at a lower temperature than those supported on the outer wall [129], Even if both in and out NPs exhibit similar conversion, confined NPs displayed higher selectivity to heavier hydrocarbons and were more stable. Cubic iron nitride FeN NPs were synthesized inside or outside CNTs [81]. The FeN confined within the CNTs exhibits higher activity than the nitride iron particles located on the CNT exterior walls in CO hydrogenation. The authors correlated this effect to the smaller particle size and the stronger retention of nitrogen atoms in the cnbic nitride lattice, resnlting in formation of more carbides in than out. 

Iron oxide NPs can be enclosed in a shell (core-shell NPs), such as dextran, lipids, or silica. The porosity of silica allows noncovalent entrapment of many other kinds of probes, such as rhodamine dyes and inorganic complexes, or covalently conjugating probes and/or targeting functions. They can also be doped with other ions, such as luminescent Tb " or Co " in ferrite NPs. 

Hybrid of iron oxide NPs and polyaniline are also prepared by the thermal reaction of Fe(acac)3 in the presence of polyaniline (Scheme 3.32) [79]. The particle size... 

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