Sandwich-type channeled chemical hydrogels manufactured by 3D ink-jet printing under freezing conditions using a photochemical process for human cell cultures

Abstract

This work aims to present the technology of preparing chemical hydrogels for cell culture by printing. It consists in drop-on-drop 3D ink-jet printing under freezing conditions of a solution containing a diacrylic compound (poly(ethylene glycol) diacrylate (PEGDA)) with an initiator (hydrogen peroxide) of photochemically induced polymerization and cross-linking. 3D printing takes place at a low temperature, thanks to which droplets of the solution immediately freeze, allowing the desired structures of the frozen solution to be built. UVC radiation of frozen structures at room temperature and in the presence of oxygen induces simultaneous melting and radical polymerization and cross-linking of PEGDA, resulting in the formation of a firm chemical hydrogel with the same shape as the shape of the printed frozen solution. Discussed are: (i) technological parameters, (ii) reaction mechanism, (iii) sol–gel analysis, (iv) morphology of printed hydrogels and (v) biocompatibility studies with the applied human fibroblasts, human umbilical vein endothelial cells and human neuroblastoma cells. A method for printing sandwich-type channeled structures was developed and shown in application for cell growth. This work demonstrates the feasibility of 3D printing biocompatible chemical hydrogels for cell culture and opens new possibilities for printing hybrid structures for biomedical applications.