Mechanical properties and permeability of porous chitosan-poly(p-dioxanone)/silk fibroin conduits used for peripheral nerve repair.

Some poly(p-dioxanone) (PDO) homopolymers were first synthesized and the selected PDO was conjugated onto chitosan using a group-protecting method to produce chitosan-poly(p-dioxanone) (CH-PDO) copolymers with various PDO percentages changing from around 30 to 60 wt%. The CH-PDO with the PDO content of around 42 wt% was used to blend with prescribed amounts of silk fibroin (SF) to build porous single-lumen conduits that are intended to be used for long-gap peripheral nerve repair. Some genipin-crosslinked CH-PDO/SF conduits were endowed with an average porosity of around 60% in their porous wall, and with changed pore-sizes varying from around 10 to ca. 70 μm using optimized processing conditions. After being degraded in a PBS medium containing a certain amount of lysozyme for various periods up to 8 weeks, some optimal CH-PDO/SF conduits were able to retain their compressive load and deformation recovery at around 59 N/m and 73% in wet state, respectively. In addition, the achieved CH-PDO/SF conduits allowed the permeation of nutritional molecules with various molecular weights while showing a certain ability to prevent cells from infiltrating through the conduit wall. Cell culture confirmed that the optimized CH-PDO/SF conduits were able well supported the growth of rat glioma C6 cells. These results suggest that presently developed CH-PDO/SF conduits have promising potential for long-gap peripheral nerve repair.