Controlling porosity and protein release profile of nanofibrillar chitosan scaffolds

Chitosan is an abundantly common, naturally occurring, polysaccharide biopolymer. Its biocompatible, biodegradable, and antimicrobial properties have led to significant research toward biological applications such as drug delivery, artificial tissue scaffolds for functional tissue engineering, and wound-healing dressings. For applications such as tissue scaffolding, formation of highly porous mats of nanometer-sized fibers, such as those fabricated via electrospinning demonstrated high potentials.

In this framework, we have as first objective to control better the scaffold porosity by decreasing the fiber density while keeping enough mechanical performances to be handled and implanted. By playing on the design of the collector used for electrospinning, we have developed structured fiber mats that meet both targeted high porosity and mechanical resistance properties.

In a second objective, strategies have been developed allowing proteins encapsulation within the chitosan scaffolds for locoregional release. The electrospinning process has been optimized in order to preserve the protein integrity and its biological activity. Various release profiles of the protein have been achieved from the structured electrospun scaffolds. A sustained release has been obtained by the use of proteins loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles.

The developed electrospinning process allowing both the precise control of the porosity and of the release profile of a protein will be useful for elaborating porosity and concentration gradients which are critical when developing biomimetic scaffolds aiming to control cell migration and trapping.