Bioprinting a Multifunctional Bioink to Engineer Clickable 3D Cellular Niches with Tunable Matrix Microenvironmental Cues

Abstract

The properties of the surrounding cell environment are major determinants of cell response in 3D. However, the ability to unravel how these cues dictate the biological function in bioprinted constructs is limited by the lack of extracellular matrix (ECM)‐mimetic bioinks with fully controllable properties. In this study, a multifunctional bioink that uniquely combines the independent control over the biochemical and biophysical cues that regulate cell fate with the bioorthogonal nature of thiol–norbornene photoclick chemistry is designed for the extrusion bioprinting of bioinspired 3D cellular niches with tunable properties. The bioink rheology is controlled by ionic gelation, being dependent on both the type and content of divalent ions (calcium and barium), while the mechanical and biochemical properties of hydrogels are tailored via a post printing thiol–ene reaction. Bioprinted cell‐adhesive and protease‐degradable hydrogels modulate cell proliferation and ECM deposition in a matrix‐stiffness dependent manner over 14 days of culture regardless of cell spreading, demonstrating the ability to probe the effect of matrix cues on cell response. This bioink can be used as a versatile platform where building blocks can be rationally combined for the bioprinting of functional cell‐ and tissue‐specific constructs with controlled cellular behavior.

3D Bioprinting of Cell‐Laden Hydrogels for Improved Biological Functionality

“…[90] This strategy of combining a first stage of physical crosslinking with a second stage of covalent crosslinking initiated through UV or visible light is perhaps the most ubiquitous method to create dual-crosslinked materials. [91][92][93] Several demon strations have combined a first stage of thermal gelation with a secondary UV crosslinking step (Figure 2B). [94][95][96] This strategy has also been used to print decellularized extracellular matrix (dECM) inks, which have the advantage of containing native bioactive and cell-adhesive domains.…”

Click chemistry for 3D bioprinting

“…3). 101 Matrix stiffness plays a major role in the cellular response of proteinase-degradable 3D hydrogels and controls biochemical and mechanical properties. During the reaction process, norbornene moieties supply rapid chain transfer power and relative polymerization rate due to their high electron density.…”

Robotic in situ bioprinting for cartilage tissue engineering

“…Apart from biochemical cues, the biomechanical properties of bioprinted constructs act as a master regulator of cell fate and tissue morphogenesis [136][137][138][139]. Therefore, bioinks should be designed to match the mechanical properties and anisotropy of native cartilage tissue towards providing an optimal niche for the cells.…”