Evaluation of Electrospun PCL-PIBMD Meshes Modified with Plasmid Complexes in Vitro and in Vivo

Abstract

Functional artificial vascular meshes from biodegradable polymers have been widely explored for certain tissue engineered meshes. Still, the foreign body reaction and limitation in endothelialization are challenges for such devices. Here, degradable meshes from phase-segregated multiblock copolymers consisting of poly(ε-caprolactone) (PCL) and polydepsipeptide segments are successfully prepared by electrospinning and electrospraying techniques. The pEGFP-ZNF580 plasmid microparticles (MPs-pZNF580) were loaded into the electrospun meshes to enhance endothelialization. These functional meshes were evaluated in vitro and in vivo. The adhesion and proliferation of endothelial cells on the meshes were enhanced in loaded mesh groups. Moreover, the hemocompatibility and the tissue response of the meshes were further tested. The complete tests showed that the vascular meshes modified with MPs-pZNF580 possessed satisfactory performance with an average fiber diameter of 550 ± 160 nm, tensile strength of 27 ± 3 MPa, Young's modulus of 1. 9 ± 0.2 MPa, water contact angle of 95° ± 2°, relative cell number of 122% ± 1% after 7 days of culture, and low blood platelet adhesion as well as weak inflammatory reactions compared to control groups.

Keywords: electrospun meshes; endothelialization; microparticles.

Figure 1

SEM micrographs of electrospun fibrous meshes: (a) PCL-PIBMD meshes; (b) PCL-PIBMD/MPs meshes; and (c) PCL-PIBMD/MPs-pZNF580 meshes. MPs and MPs-pZNF580 were marked by red circles and arrows.

Figure 2

ATR-FTIR of electrospun PCL-PIBMD fibrous meshes.

Figure 3

Stress–strain curves for electrospun PCL-PIBMD, PCL-PIBMD/MPs and PCL-PIBMD/MPs-pZNF580 meshes (a); Mechanical properties were evaluated: (b) Young’s modulus; (c) Tensile strength; and (d) Elongation at break. Error bars represent mean ± standard deviation (SD) (p > 0.05).

Figure 4

(a) EA.hy926 cells density (number of cells/mm²). Error bars represent mean ± standard deviation (SD) (Fisher LSD test was performed to determine statistical significance between groups, * p < 0.05); (b) Fluorescence micrographs of EA.hy926 cells adhesion on PCL-PIBMD, PCL-PIBMD/MPs and PCL-PIBMD/MPs-pZNF580 meshes after 1, 3, and 7 days. Cells without treatment were taken as controls.

Figure 4

(a) EA.hy926 cells density (number of cells/mm²). Error bars represent mean ± standard deviation (SD) (Fisher LSD test was performed to determine statistical significance between groups, * p < 0.05); (b) Fluorescence micrographs of EA.hy926 cells adhesion on PCL-PIBMD, PCL-PIBMD/MPs and PCL-PIBMD/MPs-pZNF580 meshes after 1, 3, and 7 days. Cells without treatment were taken as controls.

Figure 5

The relative cell number of EA.hy926 cells cultured on PCL-PIBMD, PCL-PIBMD/MPs, and PCL-PIBMD/MPs-pZNF580 meshes for 1, 3, and 7 days. Error bars represent mean ± standard deviation (SD) (Fisher LSD test was performed to determine statistical significance between groups, * p < 0.05).

Figure 6

SEM images of platelet adhesion on fibrous meshes: (a) PCL-PIBMD meshes; (b) PCL-PIBMD/MPs meshes; and (c) PCL-PIBMD/MPs-pZNF580 meshes. In the case of PCL-PIBMD, the adhered platelets showed more aggregation, as indicated by red arrows and circles.

Figure 7

H&E micrographs of subcutaneous implanted PCL-PIBMD, PCL-PIBMD/MPs and PCL-PIBMD/MPs-pZNF580 specimens for 7 days. The inflammatory cells were marked by black arrow.