Bioprinting Using Mechanically Robust Core–Shell Cell‐Laden Hydrogel Strands

Abstract

The strand material in extrusion‐based bioprinting determines the microenvironments of the embedded cells and the initial mechanical properties of the constructs. One unmet challenge is the combination of optimal biological and mechanical properties in bioprinted constructs. Here, a novel bioprinting method that utilizes core–shell cell‐laden strands with a mechanically robust shell and an extracellular matrix‐like core has been developed. Cells encapsulated in the strands demonstrate high cell viability and tissue‐like functions during cultivation. This process of bioprinting using core–shell strands with optimal biochemical and biomechanical properties represents a new strategy for fabricating functional human tissues and organs.

Quantifying Oxygen Levels in 3D Bioprinted Cell-Laden Thick Constructs with Perfusable Microchannel Networks

“…One of the hydrogels used in our bioprinted perfusable constructs was Si-HPMC, which is cyto-and biocompatible, as shown in previous works [20,22]. Being a self-setting hydrogel, Si-HPMC does not require UV curing, eliminating the low cell viability after repeated UV exposure required for 3D printing large-size constructs [27]. Two percent Si-HPMC shows a gelling point 30 min after pH neutralization at room temperature, which allows a convenient time window for cell encapsulation under cytocompatible conditions before the gel becomes too viscosity for homogenous cell mixing.…”

From Shape to Function: The Next Step in Bioprinting

“…To enhance its biological activity, alginate is typically blended with more active components. In terms of coaxial printing it can also be coprinted with such components (e.g., collagen, GelMA, and bioactive glass) . In addition, coaxially printed, non‐crosslinked alginate can also be used as a cytocompatible temporary mechanical support, for example when combined with photocurable bioactive polymers, including GelMA, PEGDA‐fibrinogen, methacrylated hyaluronic acid and chondroitin sulfate amino ethyl methacrylate .…”

“…[18,27,40,149,152] Coaxial extrusion can also be used to process materials that exhibit low mechanical stability or long gelation times, such as collagen, Matrigel, fibrin or laminin. [150,153,154] In particular, the coextrusion with mechanically stronger materials can improve their processability while simultaneously increasing the functionality of the resulting constructs. [155,156] As the supply of sufficient nutrients in larger bioprinted tissue constructs is still a significant challenge, [157][158][159][160] coaxial extrusion offers a promising solution as perfusable vascularlike structures can be generated by, for instance, coprinting alginate with a calcium solution for crosslinking ( Figure 5C).…”

“…In addition, coaxially printed, non‐crosslinked alginate can also be used as a cytocompatible temporary mechanical support, for example when combined with photocurable bioactive polymers, including GelMA, PEGDA‐fibrinogen, methacrylated hyaluronic acid and chondroitin sulfate amino ethyl methacrylate . Coaxial extrusion can also be used to process materials that exhibit low mechanical stability or long gelation times, such as collagen, Matrigel, fibrin or laminin . In particular, the coextrusion with mechanically stronger materials can improve their processability while simultaneously increasing the functionality of the resulting constructs …”

“…In terms of coaxial printing it can also be coprinted with such components (e.g., collagen, GelMA, and bioactive glass). [ 27 , 40 , 150 , 151 ] In addition, coaxially printed, noncrosslinked alginate can also be used as a cytocompatible temporary mechanical support, for example when combined with photocurable bioactive polymers, including GelMA, PEGDAfibrinogen, methacrylated hyaluronic acid and chondroitin sulfate amino ethyl methacrylate. [ 18 , 27 , 40 , 149 , 152 ] Coaxial extrusion can also be used to process materials that exhibit low mechanical stability or long gelation times, such as collagen, Matrigel, fibrin or laminin.…”