Correlating cell transfectability and motility on materials with different physico-chemical properties.

Gene delivery into cells can be facilitated by adding plasmid DNA/transfection reagent complexes in culture medium or pre-adsorbing the complexes on the substrate before cell seeding. Using transfection reagents, however, often causes cytotoxicity. Effective delivery of naked plasmid without any transfection reagent remains a challenge. In this study, we cultured human umbilical cord derived mesenchymal stem cells (hMSCs) on different biomaterial substrates with different physico-chemical properties and examined the transfectability of naked plasmid. Specifically, we synthesized a negatively charged polyurethane (PU) to mimic the hyaluronan-modified chitosan (CS-HA) membranes previously found to promote the transfection of naked plasmid. We observed that the PU membranes were as effective as CS-HA membranes in substrate-mediated delivery of naked plasmid into hMSCs. PU membranes with surface microgrooves further increased the gene delivery efficiency to a similar level as the commercial transfection reagent but without the harmful effect. The gene delivery efficiency was associated with the extent of activation of cellular integrins β1 and α5 on different substrates. Moreover, the delivery efficiency was positively correlated with the cell migration rate on various substrates. The substrate-mediated gene delivery by synthetic polymeric substrates supports that integrin activation and cell behavior (e.g. migration and transfectability) changes can be modulated by synthetic polymer surface with microfeatures. The transfection by PU microgrooves is easy, nontoxic, and as effective as the commercial transfection reagent.