KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea.
KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea; School of Mechanical Engineering, Korea University, Seoul 02841, Republic of Korea.
Acta Biomater. 2018 Jan;65:185-196. doi: 10.1016/j.actbio.2017.10.045. Epub 2017 Oct 31.
Oxygen availability is a critical factor in regulating cell viability that ultimately contributes to the normal morphogenesis and functionality of human tissues. Among various cell culture platforms, construction of 3D multicellular spheroids based on microwell arrays has been extensively applied to reconstitute in vitro human tissue models due to its precise control of tissue culture conditions as well as simple fabrication processes. However, an adequate supply of oxygen into the spheroidal cellular aggregation still remains one of the main challenges to producing healthy in vitro spheroidal tissue models. Here, we present a novel design for controlling the oxygen distribution in concave microwell arrays. We show that oxygen permeability into the microwell is tightly regulated by varying the poly-dimethylsiloxane (PDMS) bottom thickness of the concave microwells. Moreover, we validate the enhanced performance of the engineered microwell arrays by culturing non-proliferated primary rat pancreatic islet spheroids on varying bottom thickness from 10 μm to 1050 μm. Morphological and functional analyses performed on the pancreatic islet spheroids grown for 14 days prove the long-term stability, enhanced viability, and increased hormone secretion under the sufficient oxygen delivery conditions. We expect our results could provide knowledge on oxygen distribution in 3-dimensional spheroidal cell structures and critical design concept for tissue engineering applications.
In this study, we present a noble design to control the oxygen distribution in concave microwell arrays for the formation of highly functional pancreatic islet spheroids by engineering the bottom of the microwells. Our new platform significantly enhanced oxygen permeability that turned out to improve cell viability and spheroidal functionality compared to the conventional thick-bottomed 3-D culture system. Therefore, we believe that this could be a promising medical biotechnology platform to further develop high-throughput tissue screening system as well as in vivo-mimicking customised 3-D tissue culture systems.
氧气供应是调节细胞活力的关键因素，最终影响人体组织的正常形态发生和功能。在各种细胞培养平台中，基于微井阵列构建 3D 多细胞球体已广泛应用于体外重建人类组织模型，因为它可以精确控制组织培养条件和简单的制造工艺。然而，为了生产健康的体外球体组织模型，向球体细胞聚集物中提供足够的氧气仍然是主要挑战之一。在这里，我们提出了一种控制凹微井阵列中氧气分布的新设计。我们表明，通过改变凹微井的聚二甲基硅氧烷（PDMS）底部厚度，可以紧密调节氧气进入微井的渗透性。此外，我们通过在从 10μm 到 1050μm 的不同底部厚度上培养非增殖的原代大鼠胰岛球体，验证了工程化微井阵列的增强性能。对在充足氧气输送条件下生长 14 天的胰岛球体进行的形态和功能分析证明了其长期稳定性、增强的活力和增加的激素分泌。我们期望我们的结果可以为 3 维球体细胞结构中的氧气分布提供知识，并为组织工程应用提供关键的设计概念。
在这项研究中，我们通过工程化微井的底部，提出了一种控制凹微井阵列中氧气分布的设计，以形成高度功能性的胰岛球体。与传统的厚底 3D 培养系统相比，我们的新平台显著提高了氧气渗透性，从而提高了细胞活力和球体功能。因此，我们相信这可能是一个有前途的医学生物技术平台，可以进一步开发高通量组织筛选系统以及模拟体内环境的定制化 3D 组织培养系统。
