Pei Lian Ma1, Marc Lavertu2, Françoise M Winnik3, Michael D Buschmann4. 1. Department of Chemical Engineering and Institute of Biomedical Engineering, Polytechnique Montréal, PO 6079 Succ. Centre-Ville, Montreal, PQ, H3C 3A7, Canada. Electronic address: pei-lian.ma@polymtl.ca. 2. Department of Chemical Engineering and Institute of Biomedical Engineering, Polytechnique Montréal, PO 6079 Succ. Centre-Ville, Montreal, PQ, H3C 3A7, Canada. Electronic address: marc.lavertu@polymtl.ca. 3. Department of Chemistry and Faculty of Pharmacy, Université de Montréal, PO 6128 Succ. Centre-Ville, Montreal, PQ, H3C 3J7, Canada; Department of Chemistry and Faculty of Pharmacy, University of Helsinki, Helsinki, Finland; WPI Materials Nanoarchitectonics Centre, National Institute for Marterials Science, 1-1 Namiki, Tsukuba, Ibaraki, Japan. Electronic address: francoise.winnik@umontreal.ca. 4. Department of Chemical Engineering and Institute of Biomedical Engineering, Polytechnique Montréal, PO 6079 Succ. Centre-Ville, Montreal, PQ, H3C 3A7, Canada. Electronic address: michael.buschmann@polymtl.ca.
Abstract
The stability of DNA/chitosan complexes upon exposure to hyaluronic acid, chondroitin sulfate, and heparin, was assessed by fluorescence spectroscopy to quantify DNA release. Only the highly charged heparin was found to release DNA from the complexes. Complex stability upon exposure to heparin increased with the degree of deacetylation and molecular weight of chitosan and with the ratio of chitosan amino groups to DNA phosphate groups (N/P ratio) in the complexes. Isothermal titration microcalorimetry revealed that among polyanions tested, only heparin has a binding affinity to chitosan approaching that of DNA and can therefore release DNA from the complexes. These results also indicate that anionic components with sufficiently high charge density can induce extracellular or intracellular release of DNA, the former negatively affecting delivery efficiency while the latter is required for gene transfer to occur. Our findings also suggest that increased N/P ratio of the complexes can play an important role in preventing premature dissociation of DNA/polycation complexes upon interaction with anionic components in extracellular milieu.
The stability of DNA/chitosanpan> complexes upon exposure to pan> class="Chemical">hyaluronic acid, chondroitin sulfate, and heparin, was assessed by fluorescence spectroscopy to quantify DNA release. Only the highly charged heparin was found to release DNA from the complexes. Complex stability upon exposure to heparin increased with the degree of deacetylation and molecular weight of chitosan and with the ratio of chitosan amino groups to DNA phosphate groups (N/P ratio) in the complexes. Isothermal titration microcalorimetry revealed that among polyanions tested, only heparin has a binding affinity to chitosan approaching that of DNA and can therefore release DNA from the complexes. These results also indicate that anionic components with sufficiently high charge density can induce extracellular or intracellular release of DNA, the former negatively affecting delivery efficiency while the latter is required for gene transfer to occur. Our findings also suggest that increased N/P ratio of the complexes can play an important role in preventing premature dissociation of DNA/polycation complexes upon interaction with anionic components in extracellular milieu.