Rheological manipulation for improved reliability in inkjet printing of living cells

In this paper, we investigated the effects of the rheological manipulation on the trajectory of suspended cells during inkjet printing using piezoelectrically actuated nozzles. Suspensions of MCF-7 cells in phosphate-buffered saline (PBS) and 10% w/v Ficoll PM400 in PBS are printed. It is shown that the increased viscosity alters the likelihood of cell deposition as visualized by high-speed imaging. The improved reliability is quantified in cells per drop dispensed, and it is shown that through addition of Ficoll PM400, frequency of cell count per drop closely followed the Poisson distribution which is expected for homogenous suspensions.