September 04, 2007

"Warm Ice" may help us achieve a Better Prosthesis

picture of GJ 436, an exoplanetLets face it. We have heard of "hot ice" and now we are discussing "warm ice", before even the cool shock of the former is yet to wear off.

Water is a fascinatingly strange molecule even though its molecular structure is apparently simple, consisting only of 1 oxygen and 2 hydrogen atoms. We will restrict ourselves with the topics relevant here, rather than digressing about the properties of water, in general.

A planet, called GJ 436, situated some 3o light years away from earth, was speculated to contain "hot ice" in it. This Neptune sized exoplanet (extra solar planet) has a surface temperature of about 300 degrees Celsius (centigrade). At this temperature, water should exist in gaseous state. But the high pressure of the planet (due to its high density), let water remain in ice form. (for example, in a pressure cooker, water remains liquid at temperatures exceeding 100 degrees Celsius, due to high pressure inside the cooker).

Exploiting a principle of biophysics, researchers (Alexander Wissner-Gross and E. Kaxiras) at Harvard University, US, have shown it by computer simulation, that by covalently bonding sodium atoms to diamond (an allotrope of carbon), some nanoscale ice would form on its surface. The sodium atoms would allow dipole interactions to occur between adjacent water molecules. A frosty layer of about 2 nm (nanometer=one billionth of a meter) would form over the surface of diamond coating. Thus, while on one hand, you can take the advantage of diamond for its 'wear and tear' resistant properties (for which it is already being used in artificial implants like heart valves, joint replacement prostheses etc.), but also we stand a better chance to ward off any possible thrombus (clot) formation by virtue of the smoothness of the warm ice. This ice is called 'warm ice' since it remains in ice form at our warm body temperature of 37 degrees Celsius. Diamond though corrosion resistant, is prone to induce or aggravate blood clotting and hence it is part of the therapeutic protocol that the patient continues taking anti clotting (blood thinning drugs: e.g. Warfarin, Ticlopidine) drugs to prevent any such calamity. Warm ice may, in future, simply make these anticoagulant drugs unnecessary.

Seems like a cool ending to a hot story!

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