Incorporation of DNA/PEI polyplexes into gelatin/chitosan hydrogel scaffolds: a μ-DSC study

Polyplexes between a double-stranded Salmon DNA and hyperbranched poly(ethyleneimine) (PEI) as well as a maltosylated PEI-Mal were incorporated into a gelatin/chitosan hydrogel scaffold. Calorimetric experiments of the polyplexes show a decrease of the melting temperature in presence of PEI and a peak splitting in presence of PEI-Mal, which can be interpreted to a partial compaction of the DNA strands in presence of PEI-Mal. When the polyplexes are incorporated into a gelatin/chitosan scaffold in the swollen state, the DNA melting peaks at 90 and 93 °C, respectively, indicate in both cases the release of the DNA at the surface of the hydrogel scaffold in a more compact form. Specific interactions between the PEI-Mal shell and gelatin are responsible for the tuning of the release properties in presence of the maltose units in the hyperbranched PEI.