Processing Oriented Pore Structures Using Ceramic Colloids

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Processing Oriented Pore Structures Using Ceramic
Colloids I. Nettleship, University of Pittsburgh,
DMR 0404874
The colloids used in this project are a mixture
of very small ceramic particles dispersed in
water. They can be used to process ceramics with
oriented pore channels by directional freezing of
ice through the colloid. After the freezing is
complete the ice is sublimed and the resulting
ceramic is heat treated to give it strength.
Water soluble polymers such as poly vinyl alcohol
(PVA) have been added to the colloids and their
effect on the pore shape and pore size has been
studied for the first time. A wide range of
pore sizes, ranging from 5mm to well over 50mm
can be produced just by varying the amount of
PVA. A similarly wide variety of pore shapes,
ranging from lamellar to connected spheres can be
obtained by altering the PVA content while using
the same freezing conditions.
The unique lamellar structure of porous aluminum
oxide is revealed by in-situ sublimation of ice
inside an environmental scanning electron
microscope, performed in collaboration with
Professor Baker at Dartmouth College.
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Ceramic Bone Marrow for Bioreactors Ian
Nettleship , University of Pittsburgh, DMR-0404874
A unique collaboration has been developed with
Professor Gerlachs research group in the McGowan
Institute of Regenerative Medicine at the
University of Pittsburgh. Undergraduate and
graduate students have processed porous ceramics
that mimic the structure of bone marrow. These
ceramics are to be used as cores in bioreactors
developed for the growth of adult bone marrow
stem cells. Such stem cells are of great
interest for the production of blood cells for
the human immune system. Initial cell
compatibility tests for aluminum oxide and
hydroxyapatite ceramics are encouraging and
prototype bioreactors have been constructed for
testing. This collaboration is invaluable to the
students in terms of their ability to understand
these emerging biomedical technologies.
Ceramic cores and a prototype bone marrow reactor
developed in collaboration with Professor
Gerlachs Bioreactor Research Group.