Skalenübergreifendes und zellschonendes 3D-Drucken humaner Zellen mittels düsenfreier akustischer Tropfenerzeugung

Jentsch, Stefan; Fischer, Horst (Thesis advisor); Schnakenberg, Uwe (Thesis advisor)

Aachen (2023)
Dissertation / PhD Thesis

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2023

Abstract

A cell-preserving, droplet-based acoustic bioprinting system has been developed for three-dimensional printing of cell-laden hydrogels. The acoustic bioprinting system does not require a nozzle. Thus, wall-induced shear stresses are avoided. It was hypothesized that this would avoid cell damage and that printing at different scales would allow both great flexibility in building three-dimensional constructs and in the number of cells contained. Acoustic droplet ejection was performed using focused ultrasound. The setup of the acoustic bioprinter included six separately controllable and movable axes. Three of each orthogonally arranged axes were combined into an axis system, one for the movement of the building platform and the other for the movement of an ultrasonic transducer. The ultrasonic transducer was positioned below an open reservoir of cells such that the emitted ultrasonic signal ejected individual droplets to a building platform above the reservoirs. Two camera systems were used to determine and control the optimal printing parameters allowing single droplets with a volume of 0.01-3.23 nL and a minimum diameter of 54 μm to be dispensed with high accuracy. The system supported dispensing of different model liquids consisting of glycerol, polyethylene glycol, ethanol, and water over a viscosity range up to 55 mPas. The cells embedded in the hydrogel structures showed a viability of 95.5% after printing. Furthermore, 3D structures on a millimeter scale could be realized using the described technique. In summary, it was shown that the acoustic bioprinting method can be used to place living cells gently and spatially precisely with high printing resolution and adjustable droplet size. In a next step, the method could be combined with microfluidics to 3D print single cells reproducibly.

Institutions

• Division of Materials Science and Engineering [520000]
• [542000-3]