Bio-electrospraying: A potentially safe technique for delivering progenitor cells.

Bio-electrospraying is fast becoming an attractive tool for in situ cell delivery into scaffolds for tissue engineering applications, with several cell types been successfully electrosprayed. Bone marrow derived mesenchymal progenitor/stem cells (BMSC), which are an important cell source for tissue engineering, have not been explored in detail and the effect of electrospraying on their "stemness" is not known. This study therefore investigates the effects of electrospraying on BMSC viability, proliferation, and multilineage differentiation potential. Electrospraying a BMSC suspension at flow rate of 6 mL/h and voltages of 7.5-15 kV could successfully generate a continuous, stable and linearly directed electrospray of cells. Morphological observation, trypan blue tests and alamar blue based metabolic assays revealed about 88% of these electrosprayed cells were viable, and proliferated at rates similar to native BMSCs. However, at higher voltages, electrospraying became unstable and reduced cell viability, possibly due to electrical or thermal damage to the cells. BMSCs electrosprayed at 7.5 kV also retained their multipotency and could be successfully differentiated into adipogenic, chondrogenic, and osteogenic lineages, demonstrating similar morphology and gene expression levels as induced native BMSCs. These results indicate that bio-electrospraying could be safely used as a progenitor/stem cell delivery technique for tissue engineering and regenerative medicine applications.