Abstract
BackgroundLaser-assisted bioprinting of multi-cellular replicates in accordance with CAD blueprint may substantially improve our understandings of fundamental aspects of 3 D cell-cell and cell-matrix interactions in vitro. For predictable printing results, a profound knowledge about effects of different processing parameters is essential for realisation of 3 D cell models with well-defined cell densities.MethodsTime-resolved imaging of the hydrogel jet dynamics and quantitative assessment of the dependence of printed droplet diameter on the process characteristics were conducted.ResultsThe existence of a counterjet was visualised, proving the bubble collapsing theory for the jet formation. Furthermore, by adjusting the viscosity and height of the applied hydrogel layer in combination with different laser pulse energies, the printing of volumes in the range of 10 to 7000 picolitres was demonstrated. Additionally, the relationship between the viscosity and the layer thickness at different laser pulse energies on the printed droplet volume was identified.ConclusionsThese findings are essential for the advancement of laser-assisted bioprinting by enabling predictable printing results and the integration of computational methods in the generation of 3 D multi-cellular constructs.
Highlights
Laser-assisted bioprinting of multi-cellular replicates in accordance with CAD blueprint may substantially improve our understandings of fundamental aspects of 3 D cell-cell and cell-matrix interactions in vitro
These findings are essential for the advancement of laser-assisted bioprinting by enabling predictable printing results and the integration of computational methods in the generation of 3 D multi-cellular constructs
Among all bioprinting techniques [1,2,3], laser-assisted bioprinting (LaBP) approaches based on laser-induced forward transfer were demonstrated to possess additional benefits: (i) tiny amounts of different hydrogels with a wide range of rheological characteristics can be printed in a controlled and precise way [4,5,6,7,8], which is important for the realisation of 3 D cell-hydrogel constructs mimicking various stiffnesses of native tissues; (ii) any desired cell amount ranging from single [9] to dozens of cells [10] can be printed without observable damage to pheno- and genotype [7,9,10,11,12]; and (iii) the printing speed depends mainly on the pulse repetition rate of the applied laser
Summary
Laser-assisted bioprinting of multi-cellular replicates in accordance with CAD blueprint may substantially improve our understandings of fundamental aspects of 3 D cell-cell and cell-matrix interactions in vitro. Already demonstrated biological applications reflect the flexibility of this laser printing technique, for instance: (1) generation and differentiation of 3 D stem cell grafts [13], which can be used as in vitro tissue models for the screening of drug effects; (2) assembly of cellular micro arrays of single [11] and multiple [14] cell types for systematic studies of fundamental aspects of cell-cell and cell-environment interaction; (3) computer-controlled seeding of 3 D scaffolds with multiple cell types [15]; and (4) in vivo bioprinting of nano-hydroxyapatite [16]. Laser pulses are focussed through the donor-slide onto the gold layer which is evaporated locally at the focal point This rapid energy deposition leads to the generation of a jet dynamic [17] resulting in the deposition of a tiny hydrogel volume on the collector-slide. Recent studies mainly used glycerol-based fluids to investigate the effects of the laser fluence and fluid properties on the droplet volume [5,8,18] instead of fluids based on fibrin-precursors, which are widely used for bioprinting of different cell types [4,7,13,15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
