세미나

Stem cell technology has emerged as a powerful tool on the way to ultimate human health and it has been utilized in various biomedical fields 

including regenerative medicine, tissue engineering, and in vitro physiological model systems. 

The key of stem cell technology is guiding the stem cells to have in vivo physiological cellular phenotype, functions, and behaviors. 

Among the various approaches to guide the stem cell fate and behaviors, providing the in vivo-like microenvironments to the stem cells 

based on the nano-/micro manufacturing processes has been highlighted as a promising method for the last decades.

Though the nano-/micro- manufacturing processes have been greatly contributed to developing functional and biomimetic culture scaffolds,

however, it is still difficult but desired to develop an advanced culture scaffold possessing in vivo-like complex microenvironments including biophysical, biochemical, and/or structural cues.

We suggest several nano-manufacturing solutions to develop microphysiological scaffolds providing in vivo-like microenvironments to the stem cells by elaborately utilizing nanofibrous membranes. 

The nanofibrous membranes possessed a nanofibril-like structure, tissue-level stiffness, and high mass permeability that facilitates both exogenous nutrient supply and waste removal.

Furthermore, the nanofiber membrane can also provide in vivo-like biochemical cues because it can be easily immobilized with extracellular matrix (ECM) proteins 

such as collagen, laminin, or fibronectin. 

We fabricated various types of nanofibrous membranes to have functional geometries, such as ultra-thin and freestanding 2D sheets and 3D oval-shaped wells,

which are suitable for reconstructing functional tissue barriers and culturing uniform matured organoids/spheroids, respectively.

An ultra-thin and freestanding 2D nanofibrous membrane, we have developed, possessed not only the in vivo basement membrane (BM)-like biochemical compositions 

but also the biophysical characteristics reminiscent of in vivo BM, including a small thickness (< 5 μm), high permeability (< 9 × 10⁻⁵ cm s⁻¹), a tissue-level stiffness (~ 100 kPa), 

and a nanofibrillar architecture (∼10–100 nm). 

Due to the BM-like biochemical and biophysical cues provided by the nanofiber membrane, induced pluripotent stem cell (iPSC)-derived brain endothelial cells 

formed a blood-brain barrier (BBB) with greatly enhanced physical and metabolic barrier functions compared to the previous artificial plastic membrane. 

A nanofibrous 3D oval-shaped (NOVA) well provided not only a physical wall facilitating cell aggregations 

but also a highly permeable microenvironment promoting exogenous nutrient supply and waste removal. 

The NOVA well was found to have a perichondrium-like permeable microenvironment, 

thereby overcoming the limitation of the conventional conical tube that undermines the chondrogenic differentiation performance due to its impermeable wall. 

The iPSCs were aggregated and nicely differentiated to be a hyaline-like cartilage pellet in the NOVA well while expressing enhanced chondrogenic markers compared to the conventional conical tube. 

Furthermore, the NOVA microwell also enabled the generation of multiplex uniform iPSCs-derived kidney organoids that underwent successful differentiation in a uniform and matured manner, 

based on its optimized physical wall size and permeable microenvironment. 

The advanced culture scaffolds based on nanofibrous membranes exhibited their strengths in reconstituting complex in vivo microenvironments for guiding stem cells. 

They are expected to contribute to reconstructing functional and advanced stem cell-derived organ constructs such as tissue barriers and organoid/spheroid. 

We anticipate that our nanofibrous membrane-based scaffolds will become a powerful platform to accelerate the advancement of regenerative medicine or drug development.