Tissue Engineering of Cartilage - Methods in Molecular Biology: Extracellular Matrix Protocols - page 293

degrading scaffolds fabricated similarly that are composed of PLA or PLA/PGA
co-polymers are also available from Albany International Research Company.

3. Solvent-cast polylactic-glycolic acid (PLGA) and polylactic acid (PLA) foam:

The method described in this chapter is for the fabrication of polymers with
90% porosity. To create polymers with different porosities, alter the ratio of
NaCl:polymer (wt:wt). For example, to obtain a 95% porous scaffold, combine
9.5 parts NaCl and 0.5 parts polymer at a ratio of 9.5:0. Alternatively, maintain a
constant polymer concentration and alter the volume of polymer solution and
NaCl amount to reach the desired porosity.

4. Quenching foam scaffolds (to replace a crystalline structure with an amorphous one):

If a crystalline polymer form is undesirable, (some polymers are brittle when
fabricated in a crystalline form) a polymer can be made more amorphous by
quenching. To quench polymer, proceed as follows.
• Heat oven to above the polymer melting temperature ( T m ).
• Incubate polymer foams containing salt in oven for 1 h.
• Quickly remove polymers from the oven and plunge into liquid nitrogen for at
least 60 s.
• Remove from liquid nitrogen and allow polymers to equilibrate to room tem-
perature. Proceed to leaching step.

5. Construct seeding: Using the method described in this chapter, the efficiency of

cell seeding is between 80-90%.

6. Construct culture: The described methods will routinely result in a relatively

homogeneous tissue containing up to 5% S-GAG, 1% total collagen, and 85%-95%
water of the total construct weight. These are levels that approach the lower lev-
els of normal articular cartilage.

References
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