Layer-by-layer ultraviolet assisted extrusion-based (UAE) bioprinting of hydrogel constructs with high aspect ratio for soft tissue engineering applications

Abstract

One of the major challenges in the field of soft tissue engineering using bioprinting is fabricating complex tissue constructs with desired structure integrity and mechanical property. To accomplish such requirements, most of the reported works incorporated reinforcement materials such as poly( ϵ -caprolactone) (PCL) polymer within the 3D bioprinted constructs. Although this approach has made some progress in constructing soft tissue-engineered scaffolds, the mechanical compliance mismatch and long degradation period are not ideal for soft tissue engineering. Herein, we present a facile bioprinting strategy that combines the rapid extrusion-based bioprinting technique with an in-built ultraviolet (UV) curing system to facilitate the layer-by-layer UV curing of bioprinted photo-curable GelMA-based hydrogels to achieve soft yet stable cell-laden constructs with high aspect ratio for soft tissue engineering. GelMA is supplemented with a viscosity enhancer (gellan gum) to improve the bio-ink printability and shape fidelity while maintaining the biocompatibility before crosslinking via a layer-by-layer UV curing process. This approach could eventually fabricate soft tissue constructs with high aspect ratio (length to diameter) of ≥ 5. The effects of UV source on printing resolution and cell viability were also studied. As a proof-of-concept, small building units (3D lattice and tubular constructs) with high aspect ratio are fabricated. Furthermore, we have also demonstrated the ability to perform multi-material printing of tissue constructs with high aspect ratio along both the longitudinal and transverse directions for potential applications in tissue engineering of soft tissues. This layer-by-layer ultraviolet assisted extrusion-based (UAE) Bioprinting may provide a novel strategy to develop soft tissue constructs with desirable structure integrity.

Spheroids of Endothelial Cells and Vascular Smooth Muscle Cells Promote Cell Migration in Hyaluronic Acid and Fibrinogen Composite Hydrogels

“…After the mixture was maintained in an oven at 37°C for 10 min to crosslink the fibrinogen component by thrombin, it was irradiated by 365 nm light (INTELLI-RAY 400, Uvitron, 30 mW/cm 2 ) for 2 min to crosslink the second HA-MA networks, resulting in the composite hydrogels. According to literatures [76] and our own experience, these crosslinking conditions would not influence significantly on the cell viability.…”

One‐Step Photoactivation of a Dual‐Functionalized Bioink as Cell Carrier and Cartilage‐Binding Glue for Chondral Regeneration

“…It was further observed that a high UV irradiation dosage (36 000 mJ cm–2), used as negative control, resulted in 100% chondrocyte death in the proximity of the exposed defect, whereas 40% cell-death was observed in samples irradiated with standard UV dosage (1800 mJ cm–2) typically used to crosslink GelMA (with I2959) hydrogels in a normoxic environment. [ 76 , 77 ] On the other hand, the percentage of normalized live cells in samples irradiated with visible light (14 400 mJ cm–2) was not statistically different to that of cartilage biopsies that were not photoexposed ( Figure 5B ). This was also the case for samples crosslinked with the type I initiator LAP 0.1% w/v, able to initiate the acryloyl-based chain polymerization, upon exposure to a 405 nm light source ( Figure S10, Supporting Information ).…”

Graphene Oxide Induces Ester Bonds Hydrolysis of Poly-l-lactic Acid Scaffold to Accelerate Degradation

“…In this study, GO was introduced into PLLA to accelerate degradation, and three-dimensional porous PLLA/GO scaffolds were prepared by selective laser sintering (SLS)[ 36 ], which is an additive manufacturing method[ 37 ], and can realize the preparation of personalized scaffolds and interconnected porous structures compared to traditional fabrication methods[ 38 - 42 ]. Degradation properties of the PLLA scaffold containing different ratios of GO were studied by observation of degradation morphology and measurement of mass loss.…”