Expanding and optimizing 3D bioprinting capabilities using complementary network bioinks

Abstract

A major challenge in three-dimensional (3D) bioprinting is the limited number of bioinks that fulfill the physicochemical requirements of printing while also providing a desirable environment for encapsulated cells. Here, we address this limitation by temporarily stabilizing bioinks with a complementary thermo-reversible gelatin network. This strategy enables the effective printing of biomaterials that would typically not meet printing requirements, with instrument parameters and structural output largely independent of the base biomaterial. This approach is demonstrated across a library of photocrosslinkable bioinks derived from natural and synthetic polymers, including gelatin, hyaluronic acid, chondroitin sulfate, dextran, alginate, chitosan, heparin, and poly(ethylene glycol). A range of complex and heterogeneous structures are printed, including soft hydrogel constructs supporting the 3D culture of astrocytes. This highly generalizable methodology expands the palette of available bioinks, allowing the biofabrication of constructs optimized to meet the biological requirements of cell culture and tissue engineering.

The rheology of direct and suspended extrusion bioprinting

“…In dEBP, this test is important to understand how quickly the material recovers its pre-extrusion viscosity or moduli such that it will form a stable filament. 44 In sEBP, the thixotropic time, the time taken for the displaced material to recover, is very important to determine if the deposited material will be supported. This will be discussed further in Sec.…”

“…% gelatin was added to a variety of methacrylated biopolymers (alginate, gelatin, chondroitin sulfate, dextran, heparin, and chitosan), and very good shape fidelity was consistently observed following irradiation with UV light. 44 …”

Multi‐Dimensional Printing for Bone Tissue Engineering

“…However, the poor printability of agarose limited its percentage in the hydrogel matrix. By optimizing the ratio of collagen and agarose, 3D-printable hydrogels termed AGx-COLy PCL/PEG In vitro: viability and osteogenic activities of MG63 cells [65] PCL/PANI microparticles In vitro: viability and proliferation of hADSCs [66] PCL/PEDOT In vitro: proliferation of MSCs [67] PEDOT:PSS In vitro: osteogenic activities of MC3T3-E1 cells [68] PEDOT:PSS/GelMA In vitro: viability of C2C12s cells In vivo: biodegradation and biocompatibility in rat [69] Bioprinting Agarose/collagen In vitro: osteogenic differentiation of MSCs [70] Gelatin/hyaluronic acid/chondroitin sulfate/dextran/alginate/ chitosan/heparin/PEG In vitro: osteogenic activity of osteogenic sarcoma cell line (Saos-2) [71] PCL/GelMA/PLGA microparticles In vitro: viability of fibroblasts [72] Inorganic scaffolds Ceramics Ca 2 MgSi 2 O 7 bioceramic/45S5 bioactive glass/photosensitive resin In vitro: viability, proliferation, osteogenic differentiation of hBMSCs and angiogenic activities of HUVECs In vivo: bone and blood vessels regeneration in rabbit femoral defects [73]…”

Natural-Based Hydrogels for Tissue Engineering Applications

“…Thus, new polymeric biomaterials that can overcome these limitations are particularly needed, making reversible hydrogel systems appealing alternatives in this field. Moreover, another potential solution to address the lack of bioinks is the combination of a thermo-responsive gelatin network, which provides excellent extrusion and structural stability during 3D printing, and a photocrosslinkable network, which allows the printed structure to be stabilized by covalent crosslinking [ 178 ]. Furthermore, the dissociation of the thermo-reversible gelatin network does not affect the photocrosslinked network and supports 3D cell culture.…”