Biocompatible fabrication of cell-laden calcium alginate microbeads using microfluidic double flow-focusing device

Cell encapsulation based on droplet microfluidics has been widely adopted in single cell researches, and corresponding highly-uniform cell-laden microgels play significant roles in tissue engineering and cell therapy. However, the encapsulation always faces challenges to maintain favorable cell viability. Herein, based on a double flow-focusing regime, cells were encapsulated in biocompatible sodium alginate droplets, and enveloped in oil droplets to form double emulsions. Ca2+ ions in the outer aqueous phase diffused through the oil and introduced the gelation of sodium alginate to form cell encapsulation. This indirect gelation process and the spontaneous detachment of oil helped to keep cell viability well, which was validated by FDA/PI staining tests. (C) 2018 Elsevier B.V. All rights reserved.