Bioprinting of Collagen Type I and II via Aerosol Jet Printing for the Replication of Dense Collagenous Tissues

Abstract

Collagen has grown increasingly present in bioprinting, however collagen bioprinting has mostly been limited to the extrusion printing of collagen type I to form weak collagen hydrogels. While these weak collagen hydrogels have their applications, synthetic polymers are often required to reinforce gel-laden constructs that aim to replicate dense collagenous tissues found in vivo. In this study, aerosol jet printing (AJP) was used to print and process collagen type I and II into dense constructs with a greater capacity to replicate the dense collagenous ECM found in connective tissues. Collagen type I and II was isolated from animal tissues to form solutions for printing. Collagen type I and II constructs were printed with 576 layers and measured to have average effective elastic moduli of 241.3 ± 94.3 and 196.6 ± 86.0 kPa (±SD), respectively, without any chemical modification. Collagen type II solutions were measured to be less viscous than type I and both collagen type I and II exhibited a drop in viscosity due to AJP. Circular dichroism and SDS-PAGE showed collagen type I to be more vulnerable to structural changes due to the stresses of the aerosol formation step of aerosol jet printing while the collagen type II triple helix was largely unaffected. SEM illustrated that distinct layers remained in the aerosol jet print constructs. The results show that aerosol jet printing should be considered an effective way to process collagen type I and II into stiff dense constructs with suitable mechanical properties for the replication of dense collagenous connective tissues.

Recent Advances in Macroporous Hydrogels for Cell Behavior and Tissue Engineering

“…The type of polymer and viscosity required in different technologies also vary: (1) Extrusion printing is suitable for filament or liquid ink printing with high viscosity (6–30 × 107 mPa·s) [ 147 ]. Such as collagen [ 74 , 75 , 76 ], methacrylamide-modified gelatin (GelMA) [ 77 , 78 , 79 ], decellularized extracellular matrix [ 80 ], and poly(ε-caprolactone) [ 81 ]. (2) Inkjet printing is suitable for liquid ink printing with low viscosity (3.5–12 mPa·s) and needs to be processed again to improve stable structure [ 148 ].…”

3D Bioprinting Using Hydrogels: Cell Inks and Tissue Engineering Applications

“…The other subsections of this image show the wave propagation behavior that could be observed in the completed ventricle, including synchronized contractions, directional action potential propagation, and wall thickening behavior typical of a ventricle [61]. Gibney et al (2021) describe an aerosol jet bioprinting method (AJP) for the printing of dense collagenous tissues [62]. AJP is a printing method that forms an aerosol from an ink and carrier gas, and forces the aerosol to coalesce on a substrate via impaction [62].…”

“…Gibney et al (2021) describe an aerosol jet bioprinting method (AJP) for the printing of dense collagenous tissues [62]. AJP is a printing method that forms an aerosol from an ink and carrier gas, and forces the aerosol to coalesce on a substrate via impaction [62]. This method could provide an interesting means of printing collagen into dense constructs as a substrate for cells, though some sources report that high density collagen constructs can limit cell proliferation, and hinder the ability to differentiate and diffuse waste products [17,63].…”

“…ink and carrier gas, and forces the aerosol to coalesce on a substrate via impaction [62] This method could provide an interesting means of printing collagen into dense constructs as a substrate for cells, though some sources report that high density collagen constructs can limit cell proliferation, and hinder the ability to differentiate and diffuse waste products [17,63]. Conversely, one study shows that fibroblasts cultivated in high-density collagen gels (40 mg/mL) reach high viability over seven days of cultivation [64], underlining the possibility of applying AJP as a novel means of producing substrates for bioprinting Thus, it is clear that further trials are needed.…”

Design, Fabrication, and Testing of a Fully 3D-Printed Pressure Sensor Using a Hybrid Printing Approach

“…AJ ® P ranges from traditional printed electronic (PE) applications to advanced bioelectronic devices and 3D microscale printing. The use of AJ ® P of collagen for tissue engineering applications is also a novel application [ 26 , 27 ].…”