February 12, 2019 Tuesday
Bedtime Story
Zeta Potential of Erythrocytes
This peculiar cozy and snug overlay keeps
on happening with successive erythrocytes providing a self-sustaining stability
and thereby leading to this rouleaux formation.
The Brownian motion makes more cells
collide with the stack making the action of fibrinogen through sialic acid on
the surfaces of erythrocytes more probable.
In a Westergren tube the only factor that
resists the erythrocytes from stacking against each other is the zeta potential
or in more simple language the negative charge on the surface of the
erythrocytes.
Zeta potential is a parameter that
determines the stability of colloidal dispersions.
This zeta has nothing to do with the
Riemann zeta function and it is simply a Greek letter that has been adopted by
the colloidal chemists to express net electrical charge contained within the
region bounded by a slipping plane.
Zeta potential thus also becomes applicable
to surfaces of cells where in its value is determined by the net electrical
charge of the molecules exposed at the surface of the cell membrane.
The normal zeta potential of the
erythrocytes is – 15.7 millivolts or mV.
A large chunk of this negative charge is
contributed to by the exposed sialic acid residues in the membrane.
Removal of these residues of sialic acid
from the membranes of the erythrocytes drops down the zeta potential of the
cells to – 6.60 mV.
This Mon Ami is true science and research
where mathematics and physics work in harmony with chemistry to describe
biology.
All that is lacking perhaps is a touch of
mathematical logic in the form of algorithm although most of the processes in
biology generally follow some algorithm as we will see later with our own case.
Blood is naturally a colloid since it is a
mixture that contains microscopically dispersed insoluble particles suspended
throughout.
Though I use the phrase “suspended
particles” in colloid one must not confuse a colloid with a suspension.
In a colloid the diameters of suspended
particles fall in the range of 1 to 1000 nanometers and are visible either
through optical microscopes, ultra-microscopes or electron microscopes.
This means to show that in a colloid the
suspended particles are ultra fine or microscopic and thereby beyond the
resolution of the naked eye.
In a suspension the solid particles are
sufficiently large – may even large enough to be visible through the naked eyes
– so that eventually if left for long would sediment.
In a colloid the suspended particles are
much finer and do not sediment or settle down.
We have differentiated colloid from
suspension.
Stay tuned to the voice of an
average story storytelling chimpanzee or login at http://panarrans.blogspot.com
Good night Mon Ami and my fellow cousin ape.
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Another great educator and a teacher that I am aware of is
Professor Subhashish Chattopadhyay in Bangalore, India.
While I narrate stories, Professor Subhashish an electronic
engineer and a former professor at BARC, does and teaches real mathematics and
physics.
He started the participation of Indian students at the
International Physics Olympiad.
Do visit him here:
All his books can be downloaded for free through this link:
For edutainment and English education of your children, I
recommend this large collection of Halloween Songs for Kids:
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