Nottrodt, NadineNadineNottrodtHildmann, Tim KonstantinTim KonstantinHildmannLensing, RichardRichardLensingWehner, MartinMartinWehner2022-03-052024-02-232022-03-052017https://publica.fraunhofer.de/handle/publica/250720Single cell printing is an upcoming tool for isolation and positioning of single cells. It can be useful for the development of pharmaceutical test assays. Multiple technologies for cell printing exist, however, most do not allow the contact-free printing of single cells like the laser-induced forward transfer (LIFT) does. Within the current study we investigated the LIFT-process for its influence in cell viability on two molecular biologically relevant cell lines. Two cell lines CHO IFNv wt and BHK cells were printed via LIFT. Cells were given onto a transfer slide consisting of a support layer, a titanium layer and a gelatin layer. A pulsed UV-laser (l=355 nm) evaporates the titanium, which results in the formation of a jet. This transfers gelatin, titanium and a selected cell into a wellplate. Wells containing 20 cells each were used for control. The influence of titanium was shown by pure gelatin lift in the control wells. Cells were analyzed staining living cells after 0h, 24 h and 48 h with neutral red. A successful transfer rate of 80±5% was accomplished. 85±10% of the transferred CHO IFNv cells and 81±6% of the transferred BHK cells survived immediately after lift. After 48 h only 30±5% of the used wells contained living cells. There was no significant difference between the cell types. The growth rate of non-transferred cells was 91% higher for CHO IFNv cells and 31% higher for BHK cells after 48h. The control groups with containing titanium particles showed a reduced growth rate after 48 h compared to the cell suspension without titanium particles too, referring to a growth inhibiting influence of titanium particles. Our results show a promising transfer rate of about 80% with an initial survival rate higher than 80%. After 48 h the number of wells containing living cells decreases significantly. This is partly due to the growth inhibiting effect of titanium, shown in the control experiments. While both cell types show no difference regarding the cell viability after 0h, 24h and 48h, there is a significant difference regarding the growth rate of transferred cells. This leads to the development of a LIFT process without titanium as an absorption layer. Using an infrared laser the transfer layer consisting of hydrogel can be evaporated for the formation of the evaporation bubble.en621journal article