Cellulose-based hydrogels with excellent microstructural replication ability and cytocompatibility for microfluidic devices

In the face of challenges in the development of excellent biocompatible materials for microfluidic device fabrication, we demonstrated that cross-linked cellulose (RCC) hydrogel can be used as the bulk material for microchips. The cellulose hydrogel was prepared from cellulose solution dissolved in an 8 wt% LiOH/15 wt% urea aqueous system with cooling by crosslinking with epichlorohydrin. Collagen as a key extracellular matrix component for promoting cell cultivation was cross-linked in the cellulose hydrogel to obtain cellulose–collagen (RCC/C) hybrid hydrogels. The experimental results revealed that cellulose-based hydrogel microchips with well-defined 2D or 3D microstructures possessed excellent structural replication ability, good mechanical properties, and cytocompatibility for cell culture as well as excellent dimensional stability at elevated temperature. The hydrogel, as a transparent microchip material, had no effect on the fluorescence behaviors of FITC-dextran and rhodamine-dextran, leading to the good conjunction with fluorescent detection and imaging. Moreover, collagen could be immobilized in the RCC/C hydrogel scaffold for promoting cell growth and generating stable chemical concentration gradients, leading to superior cytocompatibility. This work provides new hydrogel materials for the microfluidic technology field and mimicks a 3D cell culture microenvironment for cell-based tissue engineering and drug screening.