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Wet electrospun alginate/gelatin hydrogel nanofibers for 3D cell culture

Majidi, Sara Seidelin, Adamsen, Peter Slemming, Hanif, Muhammad, Zhang, Zhongyang, Wang, Zhiming, Chen, Menglin
International journal of biological macromolecules 2018
alginates, biocompatible materials, biofabrication, cardiomyocytes, cell adhesion, cell culture, cell growth, cell movement, coagulation, crosslinking, cytotoxicity, electrolytes, ethanol, gelatin, humans, hydrogels, ionic strength, nanofibers, polyethylene glycol, porous media, stem cells, surface tension, surfactants, tissue repair, viscoelasticity
Convergence of biological and biofabrication approaches is necessary to progress new biomaterials promoting three dimensional (3D) cell growth and maturation towards tissue regeneration and integration. Here, we have developed a novel approach to fabricate 3D macroporous, alginate/gelatin hydrogel nanofibers (Alg/GelF-MA) which provide superior cell adhesion, motility, proliferation and maturation. Electrospinning process greatly depends on the ionic strength and viscoelastic behavior of the solution. The polyelectrolyte nature of alginate favors intramolecular bundles over intermolecular entanglement, which hinders its electrospinnability. Electrospinning of alginate was achieved by the aid of a supporting polymer, polyethylene oxide and a surfactant, Pluronic®F127. Further, the Ca²⁺ mediated coagulation process of alginate was realized in situ during wet-electrospinning, where the rapid physical crosslink-ability of alginate was applied in conjunction with the jet entrance into the wet electrospinning collector, a coagulation bath. Consequently, the rapid formation of Ca²⁺-alginate complex stabilized the nanofiber morphology. The low surface tension of the non-solvent ethanol used in the bath prevented fiber from dense packing, thus allow the generation of 3D macroporous structure favoring cell motility. The subsequent UV mediated chemical crosslinking further stabilized the Gelatin content in the Alg/GelF-MA hydrogel nanofibers. It is demonstrated that the Alg/GelF-MA nanofibers with low cytotoxicity (below 10%) supported an over 8-fold proliferation of mesenchymal stem cells over 5 weeks and supported the maturation of human iPSC-derived ventricular cardiomyocytes, which significantly outperform cell encapsulated bulk GelF-MA hydrogel. The work provides an insight for rational design and development of 3D cell culture matrix for advancement of stem cell therapy and tissue regeneration.