Conjugation of polyamidoamine dendrimers on biodegradable microparticles for nonviral gene delivery

We report on the preparation and characterization of poly(D, L-lactide-co-glycolide) (PLGA) microparticles with surface-conjugated polyamidoamine (PAMAM) dendrimers of varying generations. The buffering capacity and zeta-potential of the PLGA PAMAM microparticles increased with increasing generation level of the PAMAM dendrimer conjugated. Conjugation of the PAMAM dendrimer to the surface of the PLGA microparticle removed generation-dependent cytotoxicity in HEK293 and COS7 cell lines. PLGA PAMAM pDNA microparticles displayed similar cytotoxicity profiles to unmodified PLGA pDNA microparticles in COS7 cells. A generation three PAMAM dendrimer conjugated to PLGA microparticles significantly increased transfection efficiencies in comparison to unmodified PLGA microparticles.