Presentation Information
[P03-434]Wood-supported Floating Core-shell Hydrogels for Advanced Culture of Mammalian Cells
○Rio Nozaki1, Rie Utoh1, Masumi Yamada1 (1. Chiba University (Japan))
Keywords:
core-shell hydrogel,3D cell culture,wood carrier,floating culture system,oxgen supply
[Purpose]
In vitro cultivation of mammalian cells is a fundamental process in drug assays, regenerative medicine, and bioproduction. In recent years, hydrogel-based cell encapsulation approaches have been widely reported. In particular, the fabrication of hierarchical hydrogels enables precise control of spatial cell distribution. However, conventional hydrogel-based cell culture approaches often suffer from sedimentation, which leads to hypoxic conditions. While suspension culture by stirring improves oxygen supply, it inevitably causes mechanical damage to both cells and hydrogels. In this study, we propose a floating hydrogel culture system using wood as a low-density carrier, to ensure a stable oxygen supply to encapsulated cells.
[Method]
Two types of wooden materials with different densities, balsa (density: 0.1-0.2 g/cm3) and cypress (density: 0.4-0.5 g/cm3), were used as carriers. The wood was first immersed in a gelation agent solution (BaCl2) to form alginate-based hydrogels. One side of the wood was then brought into contact with a sodium alginate solution with a high mannuronic acid content (Alg-Na, high M) containing HepG2 cells to form a core layer. Subsequently, the wood was immersed in Alg-Na with a high guluronic acid content (high G) to form a shell layer covering both the wood and the core. This design utilizes the soft core layer to allow cell proliferation and the stiff shell layer restricts excessive growth.
[Results]
Core-shell hydrogels were successfully formed on the wood surface. Hydrogel thickness was precisely controlled by adjusting the immersion time and the surface roughness of the wood. Balsa-based hydrogels remained floating near the surface of the culture medium for 14 days, whereas cypress-based hydrogels precipitated immediately. In these hydrogels, HepG2 cells proliferated selectively within the core layer and formed spheroids. Live/Dead assays showed a high cell viability (approximately 99%) after 14 days of culture. Additionally, RT-qPCR analysis revealed distinct differences in gene expression between the balsa-based floating system and the cypress-based sinking system.
[Consideration]
Gene expression analysis suggested that the balsa-based floating hydrogel system enhanced the cell function and suppressed hypoxia. These findings indicate that positioning the hydrogel near the medium-air interface effectively improves oxygen supply to encapsulated cells.
[Conclusion]
The presented wood-supported core-shell hydrogels are expected to be a promising platform for mammalian cell culture, as it enables high cell viability without complex procedure or experimental apparatus. Studies include the optimization of the hydrogel size and composition are ongoing to further improve the cellular functions for various biomedical applications.
In vitro cultivation of mammalian cells is a fundamental process in drug assays, regenerative medicine, and bioproduction. In recent years, hydrogel-based cell encapsulation approaches have been widely reported. In particular, the fabrication of hierarchical hydrogels enables precise control of spatial cell distribution. However, conventional hydrogel-based cell culture approaches often suffer from sedimentation, which leads to hypoxic conditions. While suspension culture by stirring improves oxygen supply, it inevitably causes mechanical damage to both cells and hydrogels. In this study, we propose a floating hydrogel culture system using wood as a low-density carrier, to ensure a stable oxygen supply to encapsulated cells.
[Method]
Two types of wooden materials with different densities, balsa (density: 0.1-0.2 g/cm3) and cypress (density: 0.4-0.5 g/cm3), were used as carriers. The wood was first immersed in a gelation agent solution (BaCl2) to form alginate-based hydrogels. One side of the wood was then brought into contact with a sodium alginate solution with a high mannuronic acid content (Alg-Na, high M) containing HepG2 cells to form a core layer. Subsequently, the wood was immersed in Alg-Na with a high guluronic acid content (high G) to form a shell layer covering both the wood and the core. This design utilizes the soft core layer to allow cell proliferation and the stiff shell layer restricts excessive growth.
[Results]
Core-shell hydrogels were successfully formed on the wood surface. Hydrogel thickness was precisely controlled by adjusting the immersion time and the surface roughness of the wood. Balsa-based hydrogels remained floating near the surface of the culture medium for 14 days, whereas cypress-based hydrogels precipitated immediately. In these hydrogels, HepG2 cells proliferated selectively within the core layer and formed spheroids. Live/Dead assays showed a high cell viability (approximately 99%) after 14 days of culture. Additionally, RT-qPCR analysis revealed distinct differences in gene expression between the balsa-based floating system and the cypress-based sinking system.
[Consideration]
Gene expression analysis suggested that the balsa-based floating hydrogel system enhanced the cell function and suppressed hypoxia. These findings indicate that positioning the hydrogel near the medium-air interface effectively improves oxygen supply to encapsulated cells.
[Conclusion]
The presented wood-supported core-shell hydrogels are expected to be a promising platform for mammalian cell culture, as it enables high cell viability without complex procedure or experimental apparatus. Studies include the optimization of the hydrogel size and composition are ongoing to further improve the cellular functions for various biomedical applications.
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