Assessing the Impact of Electrohydrodynamic Jetting on Encapsulated Cell Viability, Proliferation, and Ability to Self-Assemble in Three-Dimensional Structures

In this article, we propose a systemic approach to investigate the impact of electrohydrodynamic jetting (EHDJ) encapsulation on viability, proliferation, and functionality of the encapsulated cells. EHDJ consists in applying a high-voltage electrical field between a target substrate and a jetting needle, which is fed with a suspension of cells in a polymeric solution undergoing a sol-gel transition upon contact with the target. The viability, proliferation, and self-assembling ability of SHSY5Y human neuroblastoma cell line encapsulated in 2% alginate microbeads were analyzed by confocal microscopy and DNA quantification assays. In addition, the expression of stress (HSP70B'), apoptotic (CASP3), necrotic (HMGB1), hypoxic (HYOU1, GAPDH), and adhesion (CDH2) markers was measured with reverse transcription quantitative polymerase chain reaction (qPCR). After an initial upregulation of the HSP70B' expression within 24 h, its expression decreased to the negative control level together with a decrease in the expression of CASP3. Any increase in necrotic or hypoxic marker expression was not detected, while a slight upregulation of CDH2 was observed in the first days after encapsulation, followed by its downregulation and stabilization to the control level. Furthermore, cell-laden beads started to self-assemble in three-dimensional (3D) constructs from the 3rd week after encapsulation. The results indicated that the EHDJ encapsulation method had a mild effect on cells, which after a week, fully recovered their proliferation rate and ability to self-assemble into 3D constructs.