Light-Blocking Nanofiber Membranes Facilitating Physiologically Relevant In Situ Transmigration Assay.

Nanofiber (NF) membranes have demonstrated considerable potential in cellular transmigration studies due to their resemblance to the biophysical properties of basement membranes, enabling cellular behaviors that closely mimic those observed in vivo. Despite their advantages, conventional NF membranes often encounter issues in transmigration assays due to their transparency, which leads to overlapping fluorescent signals from transmigrated and nontransmigrated cells. This overlap complicates the clear differentiation between these cell populations, making the quantitative evaluation of live-cell transmigration challenging.

Scalable production of uniform and mature organoids in a 3D geometrically-engineered permeable membrane.

The application of organoids has been limited by the lack of methods for producing uniformly mature organoids at scale. This study introduces an organoid culture platform, called UniMat, which addresses the challenges of uniformity and maturity simultaneously. UniMat is designed to not only ensure consistent organoid growth but also facilitate an unrestricted supply of soluble factors by a 3D geometrically-engineered, permeable membrane-based platform.

Tissue-scale in vitro epithelial wrinkling and wrinkle-to-fold transition.

Although epithelial folding is commonly studied using in vivo animal models, such models exhibit critical limitations in terms of real-time observation and independent control of experimental parameters. Here, we develop a tissue-scale in vitro epithelial bilayer folding model that incorporates an epithelium and extracellular matrix (ECM) hydrogel, thereby emulating various folding structures found in in vivo epithelial tissue. Beyond mere folding, our in vitro model realizes a hierarchical transition in the epithelial bilayer, shifting from periodic wrinkles to a single deep fold under compression.

Recent Progress in Fabrication of Electrospun Nanofiber Membranes for Developing Physiological In Vitro Organ/Tissue Models.

Nanofiber membranes (NFMs), which have an extracellular matrix-mimicking structure and unique physical properties, have garnered great attention as biomimetic materials for developing physiologically relevant in vitro organ/tissue models. Recent progress in NFM fabrication techniques immensely contributes to the development of NFM-based cell culture platforms for constructing physiological organ/tissue models. However, despite the significance of the NFM fabrication technique, an in-depth discussion of the fabrication technique and its future aspect is insufficient.

Enhanced Differentiation Capacity and Transplantation Efficacy of Insulin-Producing Cell Clusters from Human iPSCs Using Permeable Nanofibrous Microwell-Arrayed Membrane for Diabetes Treatment.

Although pancreatic islet transplantation is a potentially curative treatment for insulin-dependent diabetes, a shortage of donor sources, low differentiation capacity, and transplantation efficacy are major hurdles to overcome before becoming a standard therapy. Stem cell-derived insulin-producing cells (IPCs) are a potential approach to overcoming these limitations. To improve the differentiation capacity of the IPCs, cell cluster formation is crucial to mimic the 3D structure of the islet.

Thin and stretchable extracellular matrix (ECM) membrane reinforced by nanofiber scaffolds for developingbarrier models.

An extracellular matrix (ECM) membrane made up of ECM hydrogels has great potentials to develop a physiologically relevant organ-on-a-chip because of its biochemical and biophysical similarity tobasement membranes (BMs). However, the limited mechanical stability of the ECM hydrogels makes it difficult to utilize the ECM membrane in long-term and dynamic cell/tissue cultures. This study proposes a thin but robust and transparent ECM membrane reinforced with silk fibroin (SF)/polycaprolactone (PCL) nanofibers, which is achieved byself-assembly throughout a freestanding SF/PCL nanofiber scaffold.

A deep and permeable nanofibrous oval-shaped microwell array for the stable formation of viable and functional spheroids.

Despite the potential of a nanofibrous (NF) microwell array as a permeable microwell array to improve the viability and functions of spheroids, thanks to the superior permeability to both gases and solutes, there have still been difficulties regarding the stable formation of spheroids in the NF microwell array due to the low aspect ratio (AR) and the large interspacing between microwells. This study proposes a nanofibrous oval-shaped microwell array, named the NOVA microwell array, with both a high AR and a high well density, enabling us to not only collect cells in the microwell with a high cell seeding efficiency, but also to generate multiple viable and functional spheroids in a uniform and stable manner. To realize a deep NOVA microwell array with a high aspect ratio (AR = 0.

A collagen gel-coated, aligned nanofiber membrane for enhanced endothelial barrier function.

Herein, a collagen gel-coated and aligned nanofiber membrane named Col-ANM is developed, which remarkably improves endothelial barrier function by providing biochemical and topographical cues simultaneously. Col-ANM is fabricated by collagen gel coating process on an aligned polycaprolactone (PCL) nanofiber membrane, which is obtained by a simple electrospinning process adopting a parallel electrode collector. Human umbilical vein endothelial cells (HUVECs) cultured on Col-ANM exhibit remarkably enhanced endothelial barrier function with high expression levels of intercellular junction proteins of ZO-1 and VE-cadherin, a high TEER, and a cellular permeability compared with the artificial porous membranes in commercial cell culture well inserts.

Grayscale mask-assisted photochemical crosslinking for a dense collagen construct with stiffness gradient.

Despite the potential of a collagen construct with a stiffness gradient for investigating cell-extracellular matrix (ECM) stiffness interaction or recapitulating an in vivo tissue interface, it has been developed in a limited way due to the low and poorly controllable mechanical properties of the collagen. This study proposes a novel fabrication process to achieve a compressed collagen construct with a stiffness gradient, named COSDIENT, at a level of ~ 1 MPa while maintaining in vivo ECM-like dense collagen fibrillar structures. The COSDIENT was fabricated by collagen compression followed by grayscale mask-assisted UV-riboflavin crosslinking.