Formulation and characterization of biodegradable hyaluronan (HA) gene delivery films

Hyaluronan is a naturally occurring polysaccharide found in the human body. Its unique physical/chemical properties make HA a prospective biomaterial for clinical applications. Gene Delivery coronary stent coating can be formulated using HA. 1% HA (a gel) was used to make the HA and HA-DNA-Protamine films. The films were cross-linked with Adipic dihydrazide. Atomic Force Microscopy (AFM) on the dried films was done to determine a) surface topography at nm- and /spl mu/m-resolution and b) relative Young's Modulus. Results indicated the overnight crosslinked films to have a relatively higher Young's modulus as compared to the 4-hour crosslinked ones. Comparison of the surface topography of the HA-DNA films (with 2.5% and 5% DNA loading) revealed the DNA-Protamine on the film sample. Results of Contact angle measurements indicate that the films with 4-hour crosslinking have smaller contact angles, indicating lesser hydrophobicity than the overnight crosslinked samples. The results obtained from the AFM and contact angle assays thereby suggest that crosslinking of HA and HA-DNA Protamine films renders them more hydrophobic, and thereby more suitable for gene delivery applications.