Precise Printing of Microfiber Scaffold with Gelatin Methacryloyl (GelMA)/Polyethylene Oxide (PEO) Bioink

Gelatin methacryloyl scaffolds with microscale fiber structures own great significance because they can effectively mimic the extracellular matrix environment. Compared with extruding bioprinting, electrospinning technology is more suitable for establishing accurate hydrogel microfibers. However, electrospinning accurate gelatin methacryloyl microfiber remains a big challenge restricted by its bad spinnability. In this paper, polyethylene oxide, which owns promising spinnability, is added into gelatin methacryloyl hydrogel precursor to improve the spinnability of gelatin methacryloyl bioink. A three-dimensional motion platform for electrospinning is designed and built and the spinning process of microfibers under far-electric-field and near-electric-field conditions is systematically studied, respectively. As a result, scaffolds consisted of unordered and ordered microfibers are successfully fabricated under far-electric-field and near-electric field, respectively. In vitro culture experiments of human umbilical vein endothelial cells are carried out using the prepared gelatin methacryloyl microfiber scaffolds. The results show that the cells can easily attach to the microfibers and grow well. Moreover, the gelatin methacryloyl/ polyethylene oxide microfiber scaffold was directly spun on the polycaprolactone mesh scaffold printed by fused modeling printing method. The results showed that the macroscopic ordered and microscopic disordered microfiber scaffold could be successfully established, which could lead to directed cell growth. We believe that this method can effectively solve the problem of hydrogel spinnability and be a powerful tool for various biomedical engineering methods in the future.