The human intestine is a soft and flexible tissue. Yet the environments traditionally used to culture intestinal cells in the laboratory are strikingly different from those found in the body. Conventional culture platforms are made of synthetic materials that are far stiffer than native intestinal tissue. Could we instead provide cells with an environment that more closely resembles the intestine? A Korean research team has now developed a new cell culture membrane that recreates not only the tissue-specific components of the intestine but also its soft physical environment.
The research team led by Professor Dong Sung Kim of the Department of Mechanical Engineering and Graduate School of Convergence Science and Technology at POSTECH, together with Dr. Hyeonji Kim of the Department of Mechanical Engineering, collaborated with Professor Jaeseung Youn of CHA University School of Medicine, a POSTECH alumnus, and Professor Hyun Jung Kim of Cleveland Clinic to develop a new culture membrane that simultaneously mimics the biochemical composition and physical properties of native intestinal tissue. The study was recently published online in Advanced Healthcare Materials.
Intestinal organoids are miniature, stem cell-derived models of the intestine. Because they reproduce diverse cell types and functions of the native intestine, they are widely used to study intestinal diseases and evaluate drug responses. For greater experimental convenience, cells derived from intestinal organoids can be grown as a flat layer on a thin culture membrane. The problem, however, lies in the membrane itself. Conventional synthetic polymer membranes are much stiffer than native intestinal tissue and fail to fully reproduce its tissue-specific extracellular matrix (ECM). In other words, while the cells may represent the intestine, the environment in which they grow does not.
This difference goes beyond how the culture surface simply "feels." Cells respond not only to biochemical signals such as growth factors and proteins but also to physical cues, including the stiffness and structural properties of their surroundings. Because these physical properties can influence cell proliferation, differentiation, and tissue formation, recreating a physiologically relevant intestinal model requires consideration of both the biochemical composition and physical properties of the native tissue.
The research team therefore sought to integrate both features into a single culture membrane. Using electrospinning, they first fabricated an ultrathin nanofibrous scaffold composed of fibers far thinner than a human hair. They then incorporated decellularized extracellular matrix (dECM) derived from porcine colon tissue, from which cellular components had been removed while preserving extracellular matrix components.
The resulting C-NaDE membrane was designed to combine the structural stability of a nanofibrous scaffold with the tissue-specific biochemical components of colon-derived dECM. Unlike conventional synthetic culture membranes, it also provided a soft physical environment closer to that of native intestinal tissue, allowing cells to experience a microenvironment that more closely resembles their physiological surroundings.
The effects were evident at the cellular level. When human colon organoid-derived epithelial cells were cultured on the newly developed membrane, the researchers observed enhanced characteristics associated with intestinal stem cell maintenance and cell proliferation. Genetic markers associated with certain secretory cell lineages, which are relatively difficult to observe under conventional culture conditions, were also increased. In addition, the resulting epithelial layer exhibited morphological characteristics more closely resembling those of native intestinal tissue.
The key advance of the study lies in moving beyond conventional approaches that primarily focus on supplementing individual proteins or growth factors. Instead, the researchers recreated both the biochemical composition and physical environment in which intestinal cells naturally reside. By integrating tissue-derived biochemical cues with biophysical cues such as physiologically relevant softness, the new membrane helps bridge the gap between conventional synthetic culture substrates and native intestinal tissue.
The technology can also be incorporated into conventional cell culture systems as well as microfluidic organ-on-a-chip platforms. The researchers expect that the membrane could be further developed as a platform for intestinal disease modeling, drug response testing, intestinal barrier assessment, and studies of interactions between the intestinal epithelium and gut microbiota.
Professor Dong Sung Kim of POSTECH said, "Intestinal organoid models offer the advantage of reproducing diverse intestinal cell types, but when they are cultured as a monolayer, they typically rely on synthetic substrates whose biochemical and physical properties differ substantially from those of native tissue." He added, "The significance of this study lies in integrating the tissue-specific components of the intestine and a physiologically relevant physical environment within a single culture membrane."
Professor Jaeseung Youn of CHA University, the first author of the study, said, "Cells respond not only to biochemical factors such as growth factors and proteins but also to physical properties of their surroundings, including stiffness." He explained, "By simultaneously recreating the biochemical and biophysical microenvironment of intestinal tissue, our approach provides a foundation for developing intestinal models that more closely resemble the in vivo environment." He added, "Because the membrane can be incorporated into existing culture systems and microfluidic chips, we expect it to serve as a next-generation platform for intestinal disease research, drug evaluation, and studies of interactions between the gut microbiota and intestinal tissue."
This research was supported by the Mid-Career Researcher Program, the National Research Laboratory (NRL) Program, and the Sejong Science Fellowship Program funded by the Ministry of Science and ICT and the National Research Foundation of Korea, as well as the Korea Health Technology R&D Project funded by the Ministry of Health and Welfare and the Korea Health Industry Development Institute.
