Cascade Pumping Overcomes Hydraulic Resistance and Moderates Shear Conditions for Slow Gelatin Fiber Shaping in Narrow Tubes

Abstract

In microextrusion-based 3D bioprinting, shaping gel fibers online, i.e., in narrow tubes, benefits the structural maintenance after extrusion, but it is challenging for materials possessing slow sol-gel transition dynamics. Gelatin, for example, transforms into thermostable fibers via transglutaminase (TG) reaction in as much as 10 min. It causes dramatic flow resistance accumulation and shear stress increase in fluids moving along narrow tubes, resulting in channel clogging and cell detriments. In this study, we overcome the limitations by adopting cascade pumping and performing in a single peristaltic pump that comprises multi-channel pumping units. The pressure and shear stress reduction by over 1-fold are verified by finite element simulation; continuous gelatin fiber production and patterning in a substrate-free manner are achieved via slow online enzymatic cross-linking. The online fiber shaping can be scaled up by numbering up the pumping units and provides another paradigm for biomanufacturing.

Injectable Mesenchymal Stem Cell‐Laden Matrigel Microspheres for Endometrium Repair and Regeneration

“…The gelation dynamics, mechanical strength, and biocompatibility of gelatin are critical to its application as an injectable gel stabilizer. [35,36] We performed enzymatic crosslinking using TG to shorten the gelation time and increase the strength of gelatin. Figure 4A shows the time-dependent viscosity of our gelatin/TG solution at a shear rate of 10 s -1 ; initially increasing, then decreasing until reaching a plateau.…”

Integrating Engineering, Automation, and Intelligence to Catalyze the Biomedical Translation of Organoids

“…However, hydraulic resistance caused by prolonged incubation may be a challenge. We overcome this by employing cascade pumping, [68] which may allow the production of homogeneous multi-compartment structures or assembloids in a reproducible and high-throughput manner [51,52,69] (Figure 1A).…”