Capillary Force Lithography: A Versatile Tool for Structured Biomaterials Interface Towards Cell and Tissue Engineering

Suh, Kahp-Yang,Park, Min Cheol,Kim, Pilnam WILEY-VCH Verlag 2009 Advanced Functional Materials Vol.19 No.17

<P>This Feature Article aims to provide an in-depth overview of the recently developed molding technologies termed capillary force lithography (CFL) that can be used to control the cellular microenvironment towards cell and tissue engineering. Patterned polymer films provide a fertile ground for controlling various aspects of the cellular microenvironment such as cell–substrate and cell–cell interactions at the micro- and nanoscale. Patterning thin polymer films by molding typically involves several physical forces such as capillary, hydrostatic, and dispersion forces. If these forces are precisely controlled, the polymer films can be molded into the features of a polymeric mold with high pattern fidelity and physical integrity. The patterns can be made either with the substrate surface clearly exposed or unexposed depending on the pattern size and material properties used in the patterning. The former (exposed substrate) can be used to adhere proteins or cells on pre-defined locations of a substrate or within a microfluidic channel using an adhesion-repelling polymer such as poly(ethylene glycol) (PEG)-based polymer and hyaluronic acid (HA). Also, the patterns can be used to co-culture different cells types with molding-assisted layer-by-layer deposition. In comparison, the latter (unexposed substrate) can be used to control the biophysical surrounding of a cell with tailored mechanical properties of the material. The surface micropatterns can be used to engineer cellular and multi-cellular architecture, resulting in changes of the cell shape and the cytoskeletal structures. Also, the nanoscale patterns can be used to affect various aspects of the cellular behavior, such as adhesion, proliferation, migration, and differentiation.</P> <B>Graphic Abstract</B> <P>An in-depth overview of the recently developed molding technology termed capillary force lithography (CFL) that can be used to control the cellular microenvironment is presented in this Feature Article. If physical forces such as capillary, hydrostatic, and dispersion forces are precisely controlled, polymer films can be molded into the features of a polymeric mold with high pattern fidelity and physical integrity. The molding methods presented here can be used to create a structured biomaterials interface as an experimental platform for better understanding cell–substrate interactions in cell biology and tissue-engineering applications. <img src='wiley_img/1616301X-2009-19-17-ADFM200900771-content.gif' alt='wiley_img/1616301X-2009-19-17-ADFM200900771-content'> </P>

Dental-derived cells for regenerative medicine: stem cells, cell reprogramming, and transdifferentiation

조영단,김경화,이용무,구영,설양조 대한치주과학회 2022 Journal of Periodontal & Implant Science Vol.52 No.6

Embryonic stem cells have been a popular research topic in regenerative medicine owing to their pluripotency and applicability. However, due to the difficulty in harvesting them and their low yield efficiency, advanced cell reprogramming technology has been introduced as an alternative. Dental stem cells have entered the spotlight due to their regenerative potential and their ability to be obtained from biological waste generated after dental treatment. Cell reprogramming, a process of reverting mature somatic cells into stem cells, and transdifferentiation, a direct conversion between different cell types without induction of a pluripotent state, have helped overcome the shortcomings of stem cells and raised interest in their regenerative potential. Furthermore, the potential of these cells to return to their original cell types due to their epigenetic memory has reinforced the need to control the epigenetic background for successful management of cellular differentiation. Herein, we discuss all available sources of dental stem cells, the procedures used to obtain these cells, and their ability to differentiate into the desired cells. We also introduce the concepts of cell reprogramming and transdifferentiation in terms of genetics and epigenetics, including DNA methylation, histone modification, and non-coding RNA. Finally, we discuss a novel therapeutic avenue for using dental-derived cells as stem cells, and explain cell reprogramming and transdifferentiation, which are used in regenerative medicine and tissue engineering.

Dental-derived cells for regenerative medicine: stem cells, cell reprogramming, and transdifferentiation

Young-Dan Cho,Kyoung-Hwa Kim,Yong-Moo Lee,Young Ku,Yang-Jo Seol Korean Academy of Periodontology 2022 Journal of Periodontal & Implant Science Vol.52 No.6

Embryonic stem cells have been a popular research topic in regenerative medicine owing to their pluripotency and applicability. However, due to the difficulty in harvesting them and their low yield efficiency, advanced cell reprogramming technology has been introduced as an alternative. Dental stem cells have entered the spotlight due to their regenerative potential and their ability to be obtained from biological waste generated after dental treatment. Cell reprogramming, a process of reverting mature somatic cells into stem cells, and transdifferentiation, a direct conversion between different cell types without induction of a pluripotent state, have helped overcome the shortcomings of stem cells and raised interest in their regenerative potential. Furthermore, the potential of these cells to return to their original cell types due to their epigenetic memory has reinforced the need to control the epigenetic background for successful management of cellular differentiation. Herein, we discuss all available sources of dental stem cells, the procedures used to obtain these cells, and their ability to differentiate into the desired cells. We also introduce the concepts of cell reprogramming and transdifferentiation in terms of genetics and epigenetics, including DNA methylation, histone modification, and non-coding RNA. Finally, we discuss a novel therapeutic avenue for using dental-derived cells as stem cells, and explain cell reprogramming and transdifferentiation, which are used in regenerative medicine and tissue engineering.

DEVS 에이전트 모델과 셀 오토마타를 사용한 유니티엔진 기반의 지진해일 대피 시뮬레이터 개발

이동훈,김동민,주준모,주재우,최선한 한국멀티미디어학회 2020 멀티미디어학회논문지 Vol.23 No.6

Tsunami is a frightful natural disaster that causes severe damages worldwide. To minimize the damage, South Korea has built a tsunami warning system and designated evacuation sites in the east and south coasts. However, such countermeasures have not been verified whether they are adequate to minimize casualties since tsunami rarely occurs in South Korea. Recently, due to increasing earthquakes in the west coast of Japan, the likelihood of South Korea entering the damage area of tsunami rises; thus, in this paper, we develops a simulator based on Unity game engine to simulate the evacuation from tsunami. In order to increase the fidelity of the simulation results, the simulator applies a tsunami simulation model that analyzes coastal inundation based on cellular automata. In addition, the objects included in tsunami evacuation, such as humans, are modeled as an agent model that determines the situation and acts itself, based on the discrete-event system specification (DEVS), a mathematical formalism for describing a discrete event system. The tsunami simulation model and agent models are integrated and visualized in the simulator using Unity game engine. As an example of the use of this simulator, we verify the existing tsunami evacuation site in Gwangalli Beach in Busan and suggest the optimal alternative site minimizing casualties

Highly Moldable Electrospun Clay-Like Fluffy Nanofibers for Three-Dimensional Scaffolds

Lee, Slgirim,Cho, Sunghwan,Kim, Minhee,Jin, Gyuhyung,Jeong, Unyong,Jang, Jae-Hyung American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.2

<P>The development of three-dimensional polymeric systems capable of mimicking the extracellular matrix is critical for advancing tissue engineering. To achieve these objectives, three-dimensional fibrous scaffolds with “clay”-like properties were successfully developed by coaxially electrospinning polystyrene (PS) and poly(ε-caprolactone) (PCL) and selective leaching. As PS is known to be nonbiodegradable and vulnerable to mechanical stress, PS layers present at the outer surface were removed using a “selective leaching” process. The fibrous PCL scaffolds that remained after the leaching step exhibited highly advantageous characteristics as a tissue engineering scaffold, including moldability (i.e., clay-like), flexibility, and three-dimensional structure (i.e., cotton-like). More so, the “clay-like” PCL fibrous scaffolds could be shaped into any desired form, and the microenvironment within the clay scaffolds was highly favorable for cell expansion both in vitro and in vivo. These “electrospun-clay” scaffolds overcome the current limitations of conventional electrospun, sheet-like scaffolds, which are structurally inflexible. Therefore, this work extends the scope of electrospun fibrous scaffolds toward a variety of tissue engineering applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-2/am404627r/production/images/medium/am-2013-04627r_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am404627r'>ACS Electronic Supporting Info</A></P>

Behaviour of Composite Cellular Steel - Concrete Beams at Elevated Temperatures

Vuiyee Bernice Wong,Ian Burgess,Roger Plank 한국강구조학회 2009 International Journal of Steel Structures Vol.9 No.1

The behaviour of composite cellular floor beams is becoming important as such members are increasingly used in multistorey buildings. In the event of fire, this issue becomes increasingly critical, particularly for exposed steelwork. In a fire situation, a composite beam has a much higher perimeter area exposed to fire in its lower web-flange section than in the upper web-flange section, and so the temperature distribution across a composite beam is usually non-uniform. The reduction in fire of the strength and stiffness of the material properties of the perforated steel beam, as well as differential thermal expansion, therefore becomes an important influence on the overall behaviour of the composite beam. The objective of this research is to enhance the level of understanding of the generic behaviour of composite cellular floor beams in fire conditions. In this paper, three-dimensional nonlinear finite element models of composite cellular floor beams have been developed, taking into consideration the influence of the changes in material properties with temperature. Experimental data from furnace tests on cellular composite floor beams obtained from previous research work has been used to validate the FE models. An analytical model based on existing design guides is also presented in this paper. It is concluded that finite element analysis results are in good agreement with the experimental data, and all the failure modes have been accurately predicted. The proposed simplified analytical methods show reasonable agreement with the test and FE results, and are always conservative. The behaviour of composite cellular floor beams is becoming important as such members are increasingly used in multistorey buildings. In the event of fire, this issue becomes increasingly critical, particularly for exposed steelwork. In a fire situation, a composite beam has a much higher perimeter area exposed to fire in its lower web-flange section than in the upper web-flange section, and so the temperature distribution across a composite beam is usually non-uniform. The reduction in fire of the strength and stiffness of the material properties of the perforated steel beam, as well as differential thermal expansion, therefore becomes an important influence on the overall behaviour of the composite beam. The objective of this research is to enhance the level of understanding of the generic behaviour of composite cellular floor beams in fire conditions. In this paper, three-dimensional nonlinear finite element models of composite cellular floor beams have been developed, taking into consideration the influence of the changes in material properties with temperature. Experimental data from furnace tests on cellular composite floor beams obtained from previous research work has been used to validate the FE models. An analytical model based on existing design guides is also presented in this paper. It is concluded that finite element analysis results are in good agreement with the experimental data, and all the failure modes have been accurately predicted. The proposed simplified analytical methods show reasonable agreement with the test and FE results, and are always conservative.

Cellular Engineering with Membrane Fusogenic Liposomes to Produce Functionalized Extracellular Vesicles

Lee, Junsung,Lee, Hyoungjin,Goh, Unbyeol,Kim, Jiyoung,Jeong, Moonkyoung,Lee, Jean,Park, Ji-Ho American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.11

<P>Engineering of extracellular vesicles (EVs) without affecting biological functions remains a challenge, limiting the broad applications of EVs in biomedicine. Here, we report a method to equip EVs with various functional agents, including fluorophores, drugs, lipids, and bio-orthogonal chemicals, in an efficient and controlled manner by engineering parental cells with membrane fusogenic liposomes, while keeping the EVs intact. As a demonstration of how this method can be applied, we prepared EVs containing azide-lipids, and conjugated them with targeting peptides using copper-free click chemistry to enhance targeting efficacy to cancer cells. We believe that this liposome-based cellular engineering method will find utility in studying the biological roles of EVs and delivering therapeutic agents through their innate pathway.</P>

Cellular immunotherapy in multiple myeloma

Manh-Cuong Vo,THANGARAJ JAYA LAKSHMI,정성훈,조덕,박혜성,Tan-Huy Chu,이현주,김형준,김상기,이제정 대한내과학회 2019 The Korean Journal of Internal Medicine Vol.34 No.5

In multiple myeloma (MM), the impaired function of several types of immune cells favors the tumor’s escape from immune surveillance and, therefore, its growth and survival. Tremendous improvements have been made in the treatment of MM over the past decade but cellular immunotherapy using dendritic cells, natural killer cells, and genetically engineered T-cells represent a new therapeutic era. The application of these treatments is growing rapidly, based on their capacity to eradicate MM. In this review, we summarize recent progress in cellular immunotherapy for MM and its future prospects.

Metabolic and Cellular Engineering Strategies for the Production of Natural Products

Dongsoo YANG,Hyunmin EUN,Cindy Pricilia Surya PRABOWO,Sumin CHO,Sang Yup LEE 한국생물공학회 2023 한국생물공학회 학술대회 Vol.2023 No.4

Molecular-Level Interactions between Engineered Materials and Cells

Jang, Yoon-ha,Jin, Xuelin,Shankar, Prabakaran,Lee, Jung Heon,Jo, Kyubong,Lim, Kwang-il MDPI AG 2019 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.20 No.17

<P> Various recent experimental observations indicate that growing cells on engineered materials can alter their physiology, function, and fate. This finding suggests that better molecular-level understanding of the interactions between cells and materials may guide the design and construction of sophisticated artificial substrates, potentially enabling control of cells for use in various biomedical applications. In this review, we introduce recent research results that shed light on molecular events and mechanisms involved in the interactions between cells and materials. We discuss the development of materials with distinct physical, chemical, and biological features, cellular sensing of the engineered materials, transfer of the sensing information to the cell nucleus, subsequent changes in physical and chemical states of genomic DNA, and finally the resulting cellular behavior changes. Ongoing efforts to advance materials engineering and the cell-material interface will eventually expand the cell-based applications in therapies and tissue regenerations. </P>