Electrospun gelatin matrices with bioactive pDNA polyplexes

Recent advances in electrospinning are yielding intricate scaffolds for use in regenerative medicine. To explore the possibility of creating bioactive scaffolds with functional gene expression systems, electrospun gelatin mats bearing plasmid DNA (pDNA) polyplexes are explored. The pDNA is first condensed with a lipid-modified polyethylenimine (PEI) to create polyplexes including a poly(aspartic acid) (pAsp) additive, and subsequently electrospun after mixing the polyplexes in gelatin solution. The pDNA polyplexes, 82 nm in size with ζ-potential of +20 mV, are uniformly entrapped in mats with fiber diameter ranging between ~150 and ~350 nm. The additive complexes with pAsp display a significantly higher transfection activity in solution, which was also retained after entrapment in electrospun mats, based on GFP expression to human myoblast (C2C12) and mouse osteoblast cells (MC3T3-E1). Electrospinning of gelatin with polyethylene glycol improves the transfection efficiency, due to increased pDNA entrapment (~71%). To further validate gene-activated mats, a pDNA encoding BMP-2 shows robust alkaline phosphatase (ALP) induction in C2C12 and MC3T3-E1 cells as a marker of osteogenic differentiation. We conclude that creating gelatin fiber mats with bioactive pDNA polyplexes was feasible and such mats could aid in regenerative repair of a wide range of tissues.