These are just some quick references on the subject. Perhaps some
researcher can give you a precise and organized answer.
Red blood cells are 7 micrometers.
Platlets are about 2-4 micrometers.
http://www.curriculumpress.co.uk/pdf/newbio/36%20Structure%20and%20function%20of%20blood%20and%20lymph.pdf
http://ect.downstate.edu/courseware/histomanual/cellblood.html
If you consider the size of water and gases:
Molecular diameters: CO2=3.3 A, O2=2.8 A, H2O=3.2 A
(A is for Angstroms = 10^-4 micrometers)
http://www.mit.edu/afs/athena/org/b/biosuit/Chameleon%20Suit/Chameleon%20Suit%20Site%20Visit51.ppt
You probably need to consider the pressures on both sides (no references).
Thoughts on the pulmonary blood-gas barrier
http://ajplung.physiology.org/cgi/content/abstract/285/3/L501
http://newsbureau.upmc.com/tx/Artlung.htm
The University of Pittsburgh Medical Center's Division of
Cardiothoracic Surgery is developing an artificial lung to provide
temporary support for patients with compromised lungs...
Brack Hattler, M.D., Ph.D., professor of surgery and original inventor
of the IMO concept...
Dr. Hattler's patented device is several feet in length and consists
of about 1000 hollow fiber membranes. Oxygen enters these membranes
through an external tube, and flows through the fibers under vacuum
pressure. Oxygen within each fiber diffuses through tiny pores in the
fiber wall into the blood, and is exchanged for carbon dioxide, which
diffuses into the fibers and exits the device through a second tube.
http://www.sciencedaily.com/releases/2001/04/010426070154.htm
Together with bioengineer William J. Federspiel, Ph.D., Dr. Hattler
has created an intravenous respiratory assist device that is easily
inserted through a vein in the leg and positioned into the vena cava,
the major vein returning blood to the heart. It consists of hollow
fiber membranes that introduce oxygen into and remove carbon dioxide
from the body. Key to its design, and a distinction from the device
that failed, is a central balloon within the fibers that can inflate
and deflate at a rate of 300 beats per minute to move the fibers and
mix the blood. This allows for more efficient oxygenation of blood and
removal of carbon dioxide. In essence, respiration takes place even
though the lungs are severely injured and functioning poorly.
The surface area of two lungs is about the size of a tennis court. The
Hattler Catheter has a surface area equivalent to an 8˝ x 11 sheet of
paper and can perform about 50 percent of the gas exchange
requirements of an adult. Blood is exposed to a tiny amount of foreign
biomaterial -- less than a half a square meter -- minimizing the
likelihood that there would be an infection or clotting caused by the
interaction between blood and a synthetic surface, Dr. Hattler
reported.
http://www.pitt.edu/~wfedersp/alhtml.htm
The Artificial Lung Laboratory functions within the environment of the
McGowan Center for Artificial Organ Development at the University of
Pittsburgh Medical Center. The mission of the Laboratory is to
research and develop next generation artificial lung devices (or
oxygenators) which can support patients with acute lung disease, or
bridge patients with chronic lung disease to lung transplantation
(Another Device)
http://www.ananova.com/news/story/sm_607051.html
Dr Robert Bartlett, who led the development team at the University of Michigan...
(Another device)
http://www.tulane.edu/~sbc2003/pdfdocs/0673.PDF
The device consisted of a
0.17 m^2 , 30 cm bundle of microporous hollow
fiber membranes (Celgard Inc. Charlotte, North Carolina)
Celgard Inc.
http://www.celgard.net/index.cfm
http://www.celgard.net/products/hollowfiber.cfm
http://www.celgard.net/products/hfmproperties.cfm
Celgard® Hollow Fiber Property Range
Wall Thickness 10 - 50 µm
Porosity 20 - 40%
Pore Size 0.03 - 0.06 µm
(You might need the hydrophobic properties to prevent water molecules
from flowing through) |
