Electrospinning alginate-based nanofibers: From blends to crosslinked low molecular weight alginate-only systems

We report here preparation of nanofibers containing alginate using two different molecular weights (MWs): 37 kDa and 196 kDa. Low MW alginates are attractive for in vivo tissue scaffolds where degradation and clearance from the body are desirable, whereas higher MW alginates are amenable for topical use as wound coverage because of its better mechanical properties. We use polyethylene oxide (PEO) as a carrier material to aid in electrospinning, and relate the solution properties, including entanglement concentration, relaxation time, conductivity, and surface tension, to their ability to be electrospun. In addition, we examine an FDA-approved, nonionic surfactant as a route to enhancing the alginate–PEO ratio (>80:20), and less toxic alternative to Triton X-100 surfactant. Finally, alginate-only nanofibers that are also water-insoluble are obtained by crosslinking the electrospun fibers with calcium and subsequently removing the PEO and surfactants by soaking the nanofibers in water.