Seeding Neural Stem Cells on Scaffolds of PGA, PLA, and Their Copolymers

Tissue engineering has arisen to address the extreme shortage of tissues and organs for transplantation and repair. One of the most successful techniques has been the seeding and culturing of cells on three-dimensional biodegradable scaffolds in vitro followed by implantation in vivo ( 1 , 2 ). This technique has been used to treat bladder conditions ( 3 ) and cartilage ( 4 ) and skin ( 5 ) defects, and is being studied for a variety of other applications. While matrices have been made from a host of natural and synthetic materials, there has been particular interest in the biodegradable polymers of poly(glycolic acid) (PGA), poly(lactic acid) (PLA), and their copolymers poly(lactic-co-glycolic acid) (PLGA) Fig. 1 ). This particular family of degradable esters is very attractive for tissue engineering because the members are readily available and can be easily processed into a variety of structures, their degradation can be controlled through the ratio of glycolic acid to lactic acid subunits, and the polymers have already been approved for use in a number of applications by the FDA. Furthermore, recent research has shown this family of polymers to be biocompatible in the brain ( 6 ) and spinal cord ( 7 ).

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