Opposites Attract… Sorta’
The Pollack Laboratory at the University of Washington is a bit unconventional. The web-site is well-maintained and blue in color. Their building appears to cascade down a hill and spill over into a boat club. The grad students seem… happy. (I recommend the “Lab Environment” link on their site.) The fearless leader Dr. Gerald Pollack studied electrical engineering first, then furrowed his brow over some biological enigma and took a lifelong detour. Their tagline is, “Uncovering nature’s deeply held secrets,” and their main subject of research… is water.
Now that’s what I’m talkin’ about.
Open-mindedness being a valued commodity at the Pollack Laboratory, it should not come as a surprise that one of the group’s recent papers attempts to shed light on one of water’s own non-conformities. Everyone knows that opposites attract. This is as obviously true of human relationships as it is of protons and electrons. The corollary is that likes repel, and this is also borne out by experience- except in water.
In water, small particles of like charge are drawn towards one another in apparent refutation of the basic rules of electricity and magnetism, an observation that has been in the literature since the heady days of the transistor. Sticking to their axiomatic guns, leading theorists such as Richard Feynman and Irving Langmuir suggested that intervening “unlike” charges could produce this effect, an idea which led to a successful theory. Despite its explanatory upside, however, there were two challenges outstanding: first, it didn’t appear that anyone had actually observed this mechanism directly in an experiment, and second, explanations as to the sources of the intervening unlike charges were about as rock solid as Cro-Magnon anthropology.
Dr. Pollack and his team were well-positioned to relegate both curiosities to the level of old news because of their novel research into water, and their discovery of the Exclusion Zone. The Exclusion Zone (EZ) is an unexpectedly large zone of water formed near hydrophilic (water-loving) surfaces that possesses gel-like properties, and actively excludes solutes (it has been hypothesized that the EZ also excludes close-mindedness, but… let’s not get over zealous here). Here is a nice video on the lab’s site. Near positively charged surfaces, the EZ takes on a positive charge by donating electrons to the water beyond the EZ. Near negatively charged surfaces it takes on a negative charge by donating protons to the adjacent water.
How it does this exactly is a damn fine question, (the asking of which is reputedly the fastest way to wipe a smile clean off a face at the Pollack Laboratory). Did somebody say we already understand water?
Many beguiling properties of water, particularly water in living matter, may be linked to the novel behavior of the EZ, but as it turns out its also really good for explaining the attraction of like charges in water. The water surrounding such charged particles forms local EZ’s, and expels electrical charges of the opposite sign into the water beyond. In between the two charged particles this then results in a build-up of the intervening opposite charges required by Feynman and Langmuir’s auspicious hunch, and voila, the enigma of a charge source is resolved. The source is the water, and the underlying dynamic is its organization via the formation of the Exclusion Zone. Dr. Pollack’s team was able to experimentally confirm this using pH sensitive dyes and by making sensitive measurements of the electric potential in the region between the charged particles.
The Exclusion Zone has widespread implications for science and, in particular, to our understanding of the dynamics of water in living matter. Because many biomolecules are hydrophilic in nature, including DNA, RNA, specific portions of proteins and enzymes, and those that line the membranes of cells, the EZ suggests that most of the water within the cell is highly structured and liquid crystalline in Nature. So much for the soup idea. The EZ has been implicated in metabolism, photosynthesis, and even the origins of Life.
There are those who would suggest water is a closed case. Thankfully, Johann Grander never met those people until it was too late. Equally thankfully, Gerald Pollack looked those people in the eye and simply furrowed his brow.
Which begs the question: what else does water have up its liquid crystalline sleeve?
© 2010, Michael Mark
Some papers authored by Dr. Gerald Pollack:
Nagornyak, E, Yoo, H and Pollack, GH: Mechanism of attraction between like-charged particles in aqueous solution. Soft Matter, 5, 3850 – 3857, 2009.
Pollack, GH, Figueroa, X and Zhao, Q: Molecules, Water, and Radiant Energy: New Clues for the Origin of Life. Int’l J. Mol Sci 10: 1419 – 1429, 2009.
Pollack, GH and Clegg, J: Unexpected Linkage Between Unstirred Layers, Exclusion Zones, and Water. In: Pollack, G.H. and Chin, W.-C. Phase Transitions in Cell Biology, Springer, pp 143 – 152, 2008.
