Marine polysaccharides (e.g., chitosan, alginate and agarose) meet the requirements of artificial nerve grafting. These include the following: (1) prerequisites of biopolymers used as scaffolds; (2) conditions required by nerve autografts; (3) macroengineering requirements (form, design); (4) microengineering requirements (microgrooves, inclusion filaments); (5) mechanical conditions required by nerve autografts; (6) molecular aspects of peripheral nerve regeneration; space and adherence for: (i) chondroitin sulfate proteoglycans, (ii) neurite outgrowth promoting factors, (iii) neurotrophic factors, (iv) cells; (7) artificial side grafts should be compatible with autologous nerve grafts; (8) spatial distribution of neurotrophic factor gradients; (9) modulation of fibrosis; (10) renewal of luminal fillers. The mechanical stability of chitosan should be increased by adding other polymeric chains and cross-linking. As a result of deacetylation of chitin, chitosan scaffolds have got numerous positively charged free amino groups that provide adherence for growth factors and cells. To modulate fibrosis, heparin cross-linked chitosan microspheres have proved effective for delivering/transplanting cells, heparin and growth factors. To renew luminal fillers, chitosan microspheres may be injected through an indwelling catheter incorporated into the nerve conduit. Agarose and alginate have gained more acceptance as hydrogel lumen fillers. Interacting with positively charged chitosan, negatively charged alginate may form versatile chitosan-calcium-alginate microspheres.
Part of the book: Biological Activities and Application of Marine Polysaccharides