Speaker
Description
Extrusion-based bioprinting enables fabrication of living constructs with tissue-like features but poses significant challenges for maintaining post-printing cell viability due to complex mechanical stresses. In this study, we leverage the integrated in-line rheological modules of the RevoBITs Byte 1 bioprinter to directly quantify shear and elongational stresses during printing and correlate these measurements with cellular outcomes.
Two xanthan gum–PEGDA bioinks (3 % and 5 % w/v xanthan) were characterized via rotational and capillary rheometry (CaRheo) with Bagley entrance correction, and with the novel BERIT elongational rheology setup, all seamlessly integrated into the Byte 1 system. Both formulations exhibited pronounced visco-elastic solid like behaviour in shear and elongation; the 5 % ink showed higher oscillatory viscosity throughout the tested regime and exhibited elongational stress plateaus of 400–550 Pa, compared to 300–450 Pa for the 3 % ink. Capillary measurements revealed wall shear stresses of 30–150 Pa for the 3 % ink versus 20–100 Pa for the 5 % ink, despite the latter’s higher rotational viscosity, indicating bioink-specific flow regimes such as plug flow or wall slip in the 5 % formulation.
BJ fibroblast-laden droplets were printed using eight print configurations per bioink (27 G/30 G, 0.5 in/1.5 in) and feedrates (77 μl/min and 154 μl/min). Metabolic activity was assessed immediately (day 0) and at days 1 and 4 post-printing. While bioink handling alone induced notable stress (control vs. printed), cells in the 5 % ink consistently showed up to 30 % higher viability compared to the 3 % ink, suggesting protective effects from reduced local shear gradients. Larger nozzle diameters and shorter lengths further enhanced viability; feedrate remained a minor factor.
Linear regression modeling identified time, xanthan concentration, nozzle diameter, and their interactions as the most significant predictors of metabolic activity. In contrast, nozzle length and feedrate remained minor factors. Gradient analysis within the parameter space highlighted optimal settings for maximal cell health.
By integrating direct in-line rheometry within the Byte 1 bioprinter and correlating stress profiles to biological metrics, this work demonstrates a pathway toward predictive bioprinting workflows, reducing trial-and-error and showcasing the capabilities of RevoBITs’ platform for high-quality tissue fabrication
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