Ferromagnetic nanoparticles (for example Fe3O4) have ability to eliminate inflammatory mediators (tumor necrosis factor α, interleukin-6, interleukin-1β, interleukin-10) from the solutions. Nanoparticles efficiently (up to 91–100 %) eliminate these biologically active molecules. However, these materials have relatively high (up to 84 %)cytotoxicity against the cells in the blood, which greatly limits their applicability to hemosorption. However, this materials can be considered as very promising for the detoxification of cell-free body fluids such as lymph or blood plasma. A promising application is producing of nanocomposite materials with the hemocompatibility polymer matrix which screens surface of the inorganic component.

It was studied and there is an article. But it is in Russian. Link is below

http://www.rae.ru/fs/?section=content&op=show_article&article_id=7981612&lng=en

Ferromagnetic nanoparticles have attracted a lot of study because of the possibility of attaching drug molecules to them and transport them locally to the affected area for healing without damaging healthy cells. However human body does not accept the whole periodic table, not even all the magnetic elements. So far as I know iron is welcome for the human body and that is why a lot of biomedical reasearch concentrate on iron nanoparticles. Fe3O4 is very popular of course. Co is tolerable but Ni is not acceptable. I do not know whether Gd is also acceptable.

I forgot about Mn. In fact we have studied the magnetic properties MnO nanoparticles produced for biomedical applications. Ref: T. Chatterji et al., J. Magn. Magn. Mater. 322, 3333 (2010).

Maghemite nanoparticles (gamma-Fe2O3) are also being used for the drug delivery. Maghemite is non-toxic.

http://pubs.rsc.org/en/Content/ArticleLanding/2013/CC/c3cc39059d#!divAbstract

Magnetic nanoparticles (SPIONs) are promising candidates for applications in biomedical research including drug delivery, magnetic resonance imaging, cell mechanics, hyperthermia, tumor progression, in vivo tracking of stem cells, nucleic acid and cell separation, due to their ultra fine sizes, biocompatibility and superparamagnetic behavior. They are perfect model for high level of accumulation in the target tissues or organ due to their host cell tropism, biophysical nature, and low toxicity.

The magnetic nanoparticles can be used for specific targetting in the case of cancer drug delivery. If the delivery vehicles are decorated with magnetic nanoparticles they can be used for specific site targetting.

For obtaining an increase in temperature into a window of 37 till 46 C it is necesary to have nanoparticles which are not superparamagnetic and in fact the optimization of the shape, size or composition is a fundamental task. You can find also some references within this idea in:

Learning from Nature to Improve the Heat Generation of Iron-Oxide Nanoparticles for Magnetic Hyperthermia Applications, Science Reports Vol.3, Num 1652, pag.1-8(2013)

Adjustable Hyperthermia Response of Self-Assembled Ferromagnetic Fe-MgO Core–Shell Nanoparticles by Tuning Dipole–Dipole Interaction, Advanced Functional Materials 22, 3737-3744(2012)

Influence of dipolar interactions on hyperthermia properties of ferromagnetic particles, Journal of Applied Physics 108, 073918 - 073922 (2010)

I think ferromagnetic nanoparticles can be used in Bio-medical to detect the affected part, which is difficult to reach by detection methods. Even they can be used to detect the cancer cells and also for drug delivery to any part of body.

The original question was about bio-applications of ferromagnetic (well above superparamagnetic) nanoparticles. There are some applications for ferromagnetic nanoparticles . The advantage is larger magnetic response than that for SPION. However, utilization of such ferromagnetic particles is masked by greater thrust on research on SPION. A few applications of larger sized ferromagnetic nanoparticles are discussed by Pankhurst et al. in J. Phys.D Appl. Phys. 36 (2003)R167-R181.

I think that one of the most important applications of magnetic nanoparticles in medicine is the hyperthermia; that is to say, to reach local temperatures of around 45-47 celsius degrees for destroying tumoral cells. For such aim it is applied an oscillating external magnetic field for trying to induce hysteresis loops which are the responsable to produce the heat. The problem is that if we have particles of one radius too small ( less than 45 nm) ,i.e., you have only one magnetic domain per each particle (superparamagnetism) working above the blocking temperature, then you cannot raise the temperature because the loop area is zero. But if you encrease the size too much, thus you have many domains and the effective magnetic moment may be too small in such a form that you haven't heat. This tells you that there is a compromise with sizes and also we could say a similar thing for shapes (anisotropy), materials (without entering in the toxicities), concentrations and so on. The problem is quite complex but very challenging for a physical design.

We have a paper in the JPC-C in my contributions and also its support information for seeing in practice some of these problems and I invite you to see it.

I have browsed your interesting paper in JPC. It is an interesting finding that chain-like assembly of nanomagnetic particles can generate more heat than that for independent nanoparticles. Since chains are in a fluid medium the medium will exhibits what is referred as Brownian type superparamagnetism. Relaxation time of such system will be different from that for ( Neel relaxation time ) intrinsic superparamagnetic state.. And this decides energy barrier on which heating mechanism depend. Question asked was for ferromagnetic single domain nanoparticles ( iron, cobalt) for which hysteresis loop will be broader than that for larger (multi domain) ferromagnetic particles. Your finding suggests that a medium containing chains of SPM (extrinsic as well as intrinsic) has a broader loop than for independent single domain nanomagnetic particles.

Dear Rasbindu,

Thank you very much for your comments on the paper. The main idea is that we have four energies taking place in this phenomenon of hyperthermia: thermal, anisotropy, Zeeman and dipolar interaction among the particles. What we have found is that the last one can be very important if we put the particles interacting in certain arrays as chains because we also increase the anisotropy one which fundamental for the Spefic Absortion Rate (SAR).

Dear Daniel,

It is indeed a very good idea and good findings. For your perusal I am attaching herewith one of our paper relating to biomedical application of nanomagnetic particles.

Dear Rasbindu,

Thank you for your interesting paper, but it seems to be a negative result respect to the possibility of drug delivery using paramagnetic nanoparticles, isn't? Your graph of figure 10 is very clear and in fact it might be because the transport of the particles in blood is not an easy task and to target the tumoral cells perhaps even less.

Yes, our conclusion was that in such a thermo-responsive magnetic material only temperature plays a role in drug release and static magnetic field is only useful for targeting the drug. In a.c. field of appropriate magnitude and frequency , however heating by hypermedia can increase the temperature of such a fluid and can augment drug release. But that is remains to be investigated.

Dear Rasbindu,

Thank you for your explanation and I think that you are closer than us to biomedicine sciences. That is very interesting for us because we are mainly physicists or chemists without to much knowledge in human body. I am going to follow your papers.

Daniel,

You may be surprised to know that i too am a physicist working mainly in optics of magnetic colloids. By chance I was diverted towards this very interesting and useful branch of biomedicine. Fortunately I got good students.

I am attaching herewith with my first paper on biomedical application of nanomagnetic particles. I was earlier consulted for immobilization of biomelecules using ferrofluids.. In my Univeristy in India was not having sufficient facility to pursue this. Hence, During my visit at UK I had discussed possibility to use carbodiamide for this purpose. And we were successful. That was the beginning..

Dear Rasbindu,

Your papers are very interesting. If I have understood you properly, the particles are with three layers which one of them contains a drug to deliver in the tumoral cells. The form to release them is to changes the temperature. Can you make than with an ac external magnetic field?

Yes,that is what I mean. As stated we have yet to try with a.c. field. But for argument sake why this may not work for a.c. field?

Yes, I understand. It makes sense to me that it could work very efficienty with double effect: to release drug and heat the tumour.

In my institute, we want to examine the more effective systems for magnetic nanoparticle-mediated energy transfer to induce tumor necrosis as a primary therapy while minimizing collateral damage to healthy tissue, primarily due to thermal energy diffusion. Our work is focused on the design, optimization and tests of the electromagnetic wave propagation from new more effective applicators for medical applications, above all for hyperthermia cancer.

Check

Article Water dispersible CoFe2O4 nanoparticles with improved colloi...