Magnetic colloids

L. Cohen-Tannoudji, E. Bertrand, L. Bressy, C. Goubault, J. Baudry, J. Klein, J.-E. Joanny, and J. Bibette Polymer Bridging Probed by Magnetic Colloids. Phys. Rev. Lett. 94, 038301 (2005). 

These two examples show how emulsion-based magnetic colloids can become the essential elements for two apparently very different issues. In fact, this section introduces the basics of using superparamagnetic emulsion-based colloids, and their spontaneous self-assembling ability under a field, as new biosensors. The... 

A. Koenig Study of a Semi-Elexible Polymer with Magnetic Colloids. Ph.D thesis, Paris VI University (2005). 

Doyle, P.S., Futterer, C., Mine, N., Goubault, E., Bibette, J., Viovy, J.L., Self-assembled magnetic colloids for DNA separation in microfluidic devices. Proceedings pTAS 2002 Symposium, 6th Nara, Japan, Nov. 3-7, 2002, 48-50. 

In conclusion, let us estimate the dimensional values of particle parameters and held amplitudes at which the orientational effects discussed would be most pronounced and, hence, observable. For a magnetic colloid (single-domain particles of linear size 10 nm, volume Vm 5 x 10 19 cm3, and magnetization Is 500 G) at room temperature, one hnds p = IsVm 2.5 10 16 erg/G. The magnetic held amplitude that can cause a distinctive orientational nonlinearity is determined by the condition 2,0 > 1> which yields Hq > V i 160 Oe. According to Ref. 152, the actual values and were 500 and 683 Oe, respectively. 

For ferroelectric particles (the same size as in a magnetic colloid) with the spontaneous polarization F 5 x 10 6 C/cm2, we get p = PV 7.5 x 10 15 CGSE units. Hence, the electric held amplitude that satishes the condition 0 > 1 is Eq > 5 CGSE units or 1.5 kV/cm. 

Raman Spectroscopy of Magnetic Colloids in the Presence of Magnetic Field... 

Serna, C.J. and Morales, M.P., Maghemite (y-FcjO,) A versatile magnetic colloidal material. Surf. Colloid Sci., 17. 27, 2004. 

This work will describe a series of magnetic colloidal systems that were specifically developed for an application in ink jet printing technology. This application imposes a certain set of requirements such as particle size 100 + 50A, magnetic moment of 25 emu/g or 35%w Fe O in colloidal dispersion, viscosity of 8-10 cps, non-toxic aqueous system, shelf life of a few years, freeze-thaw stability, fast drying (2 msec) and high optical density of magnetic ink on various papers. 

The second application area of interest is organosols. Organosols involve the use of nonaqueous systems, for example, in making magnetic colloids and recording media, high-technology ceramic composites, and catalyst... 

The cell viability was also represented in in vitro test results when the concentration of magnetic colloid changed. From this result, the magnetic colloids with a concentration of 32 pg/ml that showed the relatively superior cell viability and had the high volume compared to cell numbers were chosen as fluid samples for... 

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