Speaker
Description
Single cell printing techniques are extremely valuable for the precise and controlled construction of tissue precursors. However, existing methods for printing single cells are subject to rheological restrictions. In addition, the high resolution required for printing individual cells conflicts with the desire for time-efficient construction of 3D structures.
This work addresses the question of how both compromises can be overcome by integrating a high-speed single cell printing method with high-resolution drop-on-demand 3D bioprinting.
To this end, a newly developed method of on-demand single cell printing is used. The process combines precise inkjet printing (down to pL range) with a microfluidic cell trap. The cell trap allows single cells to be captured above the nozzle and dispensed on demand. In this way, single cells can be printed at a frequency of > 2 Hz and with an accuracy of less than 5 µm. Due to the inkjet technology, the method is limited to the processing of relatively low-viscosity fluids. In addition, despite the high frequency, the picoliter droplets produced result in low material output, which limits the efficient construction of 3D structures. To solve this problem, the single cell printer head is combined with a drop-based printing process. A piezo-electrically controlled open nozzle printer head is used for this purpose. The drop volume and drop quality can be monitored and controlled with an integrated camera system.
As a result, macroscopic gel structures with a resolution of a few hundred micrometers (DoD) can be produced with intermediate cell layers with single cell resolution (single cell dispensing). The process offers great potential for use in regenerative medicine or the production of miniaturized organ-on-a-chip models.
