Aqueous Two‐Phase Emulsion Bioresin for Facile One‐Step 3D Microgel‐Based Bioprinting

Abstract

Microgel assembly as void-forming bioinks in 3D bioprinting has evidenced recent success with a highlighted scaffolding performance of these bottom-up biomaterial systems in supporting the viability and function of the laden cells. Here, a ternary-component aqueous emulsion is established as a one-step strategy to integrate the methacrylated gelatin (GelMA) microgel fabrication and assembly through vat photopolymerization in situ using digital light processing (DLP)-based bioprinting. The as-proposed aqueous emulsion is featured with the partitioning of a secondary photo-crosslinkable polysaccharide, methacrylated galactoglucomannan (GGMMA) derived from plant source in both the dispersed phase of GelMA droplets and the continuous phase of dextran (Dex). As an emulgator, GGMMA renders enhanced stability of the aqueous emulsion bioresins. Strategically, the photo-crosslinkable GGMMA adheres the GelMA microgels that are conveniently converted from emulsion droplets to form hydrogel construct in layer-by-layer curing to accommodate the laden cells directly mixed in the aqueous emulsion. The spatially interconnected void space left by the removal of Dex benefits the cell growth under the guidance of the microgel surface and supports cell colonization within the macroscopic porous hydrogel. This work amends a low-concentration and cost-effective bioresin that is highly applicable for facilely fabricating microgel assembly as a porous hydrogel construct in DLP-based bioprinting.

Bioprinting Macroporous Hydrogel with Aqueous Two‐Phase Emulsion‐Based Bioink: In Vitro Mineralization and Differentiation Empowered by Phosphorylated Cellulose Nanofibrils

“…As expected, the ATPE hydrogels showed enhanced biocompatibility compared to the bulk hydrogels attributed to the macroporous structure that facilitates cell spreading and mass transfer. [7,16] The proliferation and the metabolic activity of cells in p_ATPE hy-drogels were significantly higher than that in the ATPE hydrogels, especially on day 3, indicating faster recovery of the cells (Figure 5a). To evaluate the cell viability post-bioprinting, we performed the live/dead staining on the bioprinted hydrogels, as displayed in Figure 5b.…”

“…[15] Our previous study also demonstrated using a water-soluble non-ionic polysaccharide derivative as an emulgator to improve the emulsion stability by co-partitioning in both GelMA and dextran phases. [16] Another effective strategy is the Pickering emulsion method by applying biocompatible nanoparticles that settle on the interface and form a barrier to prevent droplet coalescence. [13,14] Pickering emulsion could not only improve the stability of the ATPE-based bioinks but also offer multifunctionality by specifically tailoring the nanoparticles.…”

3D printing stretchable and compressible porous structures by polymerizable emulsions for soft robotics

“…Our printed foams were compared with the literature reports for foams that were 3D printed by various technologies (Fig. 5(C)) 15,16,21–24,26,27,30–32,39,47–53 to construct the plot, we searched publications under the keywords “3D printing”, “foams” or/and “porous”, and evaluated only the papers that contained tensile measurements. It should be noted that most publications on photopolymerization-based printing of foams/porous materials result in stiff polymers 37,54 or ceramics 55–57 that cannot elongate and therefore tensile measurements were not reported for.…”

The microparticulate inks for bioprinting applications

“…The printed auricular constructs have high elasticity, high printing accuracy, and low swelling ratio, which can mimic the microenvironment for cartilage regeneration. Wang et al established a one-step strategy to integrate the GelMA microgel fabrication and assembly through vat photopolymerization in situ using DLP bioprinting [ 132 ]. Although bioprinting is appealing for building tissue mimics, precise positioning control of mini-tissue blocks (i.e., spheroids) in 3D space remains challenging.…”