Encapsulation of plasmid DNA by triblock copolymer of LEL in 94% DMF + 6% TE. (A) Excess scattered intensity of LEL at different concentrations measured at 90°; (B) Zimm plot of LEL at concentrations of 1.25, 6.24 and 31.2 mg/ml; (C and D) CONTIN analysis of plasmid DNA (hollow circles), LEL (hollow squares) and their mixtures (solid diamonds) at different DNA/LEL weight ratio. The concentration of DNA used in panels C and D is 1 × 10⁻⁵ g/ml.

Incorporation and release of plasmid DNA from electrospun nanofibrous PLGA-based scaffolds. (A) SEM image of electrospun PLGA scaffold with LEL added; (B) Cellular adhesion on PLGA scaffold containing LEL and encapsulated DNA; (C) Gel electrophoresis of DNA samples, lane 1 ladder, lane 2 control plasmid, lanes 3 and 4 released (4 h) plasmid DNA from PLGA scaffold without/with LEL; (D and E) Shows the controlled release of DNA from PLGA scaffold with LEL.

Condensation of plasmid DNA in 94% DMF + 6% TE studied by laser light scattering. (A and B) Shows the Zimm plots of plasmid DNA in 1× TE buffer, and in 94% DMF + 6% TE, respectively. (C) Shows the size distribution of DNA measured by DLS at 90° and 1.0 × 10⁻⁵ g/ml DNA concentration.

Schematic presenting the condensed plasmid DNA, the aggregation of LEL and the encapsulation of DNA by LEL. (A–C) Shows TEM images of DNA in 1× TE buffer, DNA in 94% DMF + 6% TE and encapsulated DNA in 94% DMF + 6% TE, respectively.

Transfection of MC3T3 cells by nanofibrous electrospun scaffolds. (A–D) shows the transfection of DNA released from PLGA without LEL (A), with LEL (B) and the negative (C) and positive (D) controls. Panels E–H show the increased transfection by plating MC3T3 cells directly on a GFP plasmid DNA containing scaffold. (E) Fluorescent image of cells on GFP plasmid DNA containing PLGA/10% block copolymer scaffold 24 h post-plating. Arrowheads indicate representative transfected GFP-expressing cells and arrows indicate non-transfected cells. (F) Light micrograph of cells (shown in E) stained with nuclear fast red. Arrowheads and arrows indicate identical cells in E. (G) Fluorescent image of cells on a control scaffold containing no DNA and indicating no fluorescent (green) cells (arrow). (H) Light micrograph of cells (shown in G) stained with nuclear fast red. Arrow indicates identical cells in G. This transfection efficiency reflected that of cells present only on the exterior surface of the scaffold and not for all cells within the scaffold.' Scale bar: 100 µm in Panels A–D, 10 µm in panels E–H.