DNA delivery from polymer matrices for tissue engineering

We have proposed engineering tissues by the incorporation and sustained rel ease of plasmids encoding tissue-inductive proteins from polymer matrices. Matrices of poly(lactide-co-glycolide) (PLG) were loaded with plasmid, whic h was subsequently released over a period ranging from days to a month in v itro. Sustained delivery of plasmid DNA from matrices led to the transfecti on of large numbers of cells. Furthermore, in vivo delivery of a plasmid en coding platelet-derived growth factor enhanced matrix deposition and blood vessel formation in the developing tissue. This contrasts with direct injec tion of the plasmid, which did not significantly affect tissue formation. T his method of DNA delivery may find utility in tissue engineering and gene therapy applications.