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Wang Z, Gu P, Wu X. Gecko-inspired bidirectional double-sided adhesives. SOFT MATTER 2014; 10:3301-3310. [PMID: 24637918 DOI: 10.1039/c3sm52921e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A new concept of gecko-inspired double-sided adhesives (DSAs) is presented. The DSAs, constructed by dual-angled (i.e. angled base and angled tip) micro-pillars on both sides of the backplane substrate, are fabricated by combinations of angled etching, mould replication, tip modification, and curing bonding. Two types of DSA, symmetric and antisymmetric (i.e. pillars are patterned symmetrically or antisymmetrically relative to the backplane), are fabricated and studied in comparison with the single-sided adhesive (SSA) counterparts through both non-conformal and conformal tests. Results indicate that the DSAs show controllable and bidirectional adhesion. Combination of the two pillar-layers can either amplify (for the antisymmetric DSA, providing a remarkable and durable adhesion capacity of 25.8 ± 2.8 N cm⁻² and a high anisotropy ratio of ∼8) or counteract (for the symmetric DSA, generating almost isotropic adhesion) the adhesion capacity and anisotropic level of one SSA (capacity of 16.2 ± 1.7 N cm⁻² and anisotropy ratio of ∼6). We demonstrate that these two DSAs can be utilized as a facile fastener for two individual objects and a small-scale delivery setup, respectively, complementing the functionality of the commonly studied SSA. As such, the double-sided patterning is believed to be a new branch in the further development of biomimetic dry adhesives.
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Affiliation(s)
- Zhengzhi Wang
- Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China.
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Bae WG, Kim SM, Choi SJ, Oh SG, Yoon H, Char K, Suh KY. In situ realization of asymmetric ratchet structures within microchannels by directionally guided light transmission and their directional flow behavior. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:2665-2614. [PMID: 24634358 DOI: 10.1002/adma.201305001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/19/2013] [Indexed: 06/03/2023]
Abstract
An asymmetric ratchet structure within microchannels is demonstrated by directionally guided light transmission for controlled liquid flow. A direct and facile method is presented to realize programmed asymmetric structures, which control the fluid direction and speed.
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Affiliation(s)
- Won-Gyu Bae
- School of Mechanical & Aerospace Engineering, Seoul National University, Seoul, 151-742, Republic of Korea; Interdisciplinary Program of Bioengineering, Seoul National University, Seoul, 151-742, Republic of Korea
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Bae WG, Kim HN, Kim D, Park SH, Jeong HE, Suh KY. 25th anniversary article: scalable multiscale patterned structures inspired by nature: the role of hierarchy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:675-700. [PMID: 24353032 DOI: 10.1002/adma.201303412] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/17/2013] [Indexed: 05/03/2023]
Abstract
Multiscale, hierarchically patterned surfaces, such as lotus leaves, butterfly wings, adhesion pads of gecko lizards are abundantly found in nature, where microstructures are usually used to strengthen the mechanical stability while nanostructures offer the main functionality, i.e., wettability, structural color, or dry adhesion. To emulate such hierarchical structures in nature, multiscale, multilevel patterning has been extensively utilized for the last few decades towards various applications ranging from wetting control, structural colors, to tissue scaffolds. In this review, we highlight recent advances in scalable multiscale patterning to bring about improved functions that can even surpass those found in nature, with particular focus on the analogy between natural and synthetic architectures in terms of the role of different length scales. This review is organized into four sections. First, the role and importance of multiscale, hierarchical structures is described with four representative examples. Second, recent achievements in multiscale patterning are introduced with their strengths and weaknesses. Third, four application areas of wetting control, dry adhesives, selectively filtrating membranes, and multiscale tissue scaffolds are overviewed by stressing out how and why multiscale structures need to be incorporated to carry out their performances. Finally, we present future directions and challenges for scalable, multiscale patterned surfaces.
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Affiliation(s)
- Won-Gyu Bae
- Interdisciplinary Program of Bioengineering, Seoul National University, Seoul, 151-742, Republic of Korea
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Park H, Cho H, Kim J, Bang JW, Seo S, Rahmawan Y, Lee DY, Suh KY. Multiscale transfer printing into recessed microwells and on curved surfaces via hierarchical perfluoropolyether stamps. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:52-59. [PMID: 23606663 DOI: 10.1002/smll.201300772] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Indexed: 06/02/2023]
Abstract
A simple method for the formation of multiscale metal patterns is presented using hierarchical polymeric stamps with perfluoropolyether (PFPE). A dual-scale PFPE structure is made via two-step moulding process under partial photocrosslinking conditions. The hierarchical PFPE stamp enables multiscale transfer printing (MTP) of metal pattern in one step within microwells as well as on curved surfaces.
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Affiliation(s)
- Hyunchul Park
- World Class University (WCU) Program on Multiscale Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea
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Kim J, Kim HN, Lim KT, Kim Y, Seonwoo H, Park SH, Lim HJ, Kim DH, Suh KY, Choung PH, Choung YH, Chung JH. Designing nanotopographical density of extracellular matrix for controlled morphology and function of human mesenchymal stem cells. Sci Rep 2013; 3:3552. [PMID: 24352057 PMCID: PMC6506445 DOI: 10.1038/srep03552] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 11/29/2013] [Indexed: 12/14/2022] Open
Abstract
Inspired by ultrastructural analysis of ex vivo human tissues as well as the physiological importance of structural density, we fabricated nanogrooves with 1:1, 1:3, and 1:5 spacing ratio (width:spacing, width = 550 nm). In response to the nanotopographical density, the adhesion, migration, and differentiation of human mesenchymal stem cells (hMSCs) were sensitively controlled, but the proliferation showed no significant difference. In particular, the osteo- or neurogenesis of hMSCs were enhanced at the 1:3 spacing ratio rather than 1:1 or 1:5 spacing ratio, implying an existence of potentially optimized nanotopographical density for stem cell function. Furthermore, such cellular behaviors were positively correlated with several cell morphological indexes as well as the expression of integrin β1 or N-cadherin. Our findings propose that nanotopographical density may be a key parameter for the design and manipulation of functional scaffolds for stem cell-based tissue engineering and regenerative medicine.
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Affiliation(s)
- Jangho Kim
- 1] Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742, Republic of Korea [2]
| | - Hong Nam Kim
- 1] Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-742, Republic of Korea [2]
| | - Ki-Taek Lim
- Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742, Republic of Korea
| | - Yeonju Kim
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, 443-721, Republic of Korea
| | - Hoon Seonwoo
- Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742, Republic of Korea
| | - Soo Hyun Park
- Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742, Republic of Korea
| | - Hye Jin Lim
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, 443-721, Republic of Korea
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Kahp-Yang Suh
- 1] Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-742, Republic of Korea [2]
| | - Pill-Hoon Choung
- Tooth Bioengineering National Research Lab, Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Yun-Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, 443-721, Republic of Korea
| | - Jong Hoon Chung
- 1] Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul, 151-742, Republic of Korea [2] Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-742, Republic of Korea
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56
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Yang HS, Ieronimakis N, Tsui JH, Kim HN, Suh KY, Reyes M, Kim DH. Nanopatterned muscle cell patches for enhanced myogenesis and dystrophin expression in a mouse model of muscular dystrophy. Biomaterials 2013; 35:1478-86. [PMID: 24290810 DOI: 10.1016/j.biomaterials.2013.10.067] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/27/2013] [Indexed: 12/24/2022]
Abstract
Skeletal muscle is a highly organized tissue in which the extracellular matrix (ECM) is composed of highly-aligned cables of collagen with nanoscale feature sizes, and provides structural and functional support to muscle fibers. As such, the transplantation of disorganized tissues or the direct injection of cells into muscles for regenerative therapy often results in suboptimal functional improvement due to a failure to integrate with native tissue properly. Here, we present a simple method in which biodegradable, biomimetic substrates with precisely controlled nanotopography were fabricated using solvent-assisted capillary force lithography (CFL) and were able to induce the proper development and differentiation of primary mononucleated cells to form mature muscle patches. Cells cultured on these nanopatterned substrates were highly-aligned and elongated, and formed more mature myotubes as evidenced by up-regulated expression of the myogenic regulatory factors Myf5, MyoD and myogenin (MyoG). When transplanted into mdx mice models for Duchenne muscular dystrophy (DMD), the proposed muscle patches led to the formation of a significantly greater number of dystrophin-positive muscle fibers, indicating that dystrophin replacement and myogenesis is achievable in vivo with this approach. These results demonstrate the feasibility of utilizing biomimetic substrates not only as platforms for studying the influences of the ECM on skeletal muscle function and maturation, but also to create transplantable muscle cell patches for the treatment of chronic and acute muscle diseases or injuries.
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Affiliation(s)
- Hee Seok Yang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, South Korea
| | - Nicholas Ieronimakis
- Department of Pathology, University of Washington, Seattle, WA 98195, USA; Department of Laboratory Medicine, University of Washington, Seattle, WA 98109, USA
| | - Jonathan H Tsui
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Hong Nam Kim
- School of Mechanical and Aerospace Engineering and the Institute of Bioengineering, Seoul National University, Seoul 151-742, South Korea
| | - Kahp-Yang Suh
- School of Mechanical and Aerospace Engineering and the Institute of Bioengineering, Seoul National University, Seoul 151-742, South Korea
| | - Morayma Reyes
- Department of Pathology, University of Washington, Seattle, WA 98195, USA; Department of Laboratory Medicine, University of Washington, Seattle, WA 98109, USA.
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA.
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57
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Kim MJ, Lee B, Yang K, Park J, Jeon S, Um SH, Kim DI, Im SG, Cho SW. BMP-2 peptide-functionalized nanopatterned substrates for enhanced osteogenic differentiation of human mesenchymal stem cells. Biomaterials 2013; 34:7236-46. [DOI: 10.1016/j.biomaterials.2013.06.019] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 06/12/2013] [Indexed: 01/23/2023]
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Kim J, Kim HN, Lim KT, Kim Y, Pandey S, Garg P, Choung YH, Choung PH, Suh KY, Chung JH. Synergistic effects of nanotopography and co-culture with endothelial cells on osteogenesis of mesenchymal stem cells. Biomaterials 2013; 34:7257-68. [PMID: 23834896 DOI: 10.1016/j.biomaterials.2013.06.029] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/14/2013] [Indexed: 02/08/2023]
Abstract
Inspired by the aligned nanostructures and co-existence of vascular cells and stem cells in human cancellous bone, we quantitatively investigated the relative contributions of nanotopography and co-culture with human umbilical endothelial cells (HUVECs) to the osteogenesis of human mesenchymal stem cells (hMSCs). Although both nanotopography and co-culture independently enhanced the osteogenesis of hMSCs, osteogenesis was further enhanced by the two factors in combination, indicating the importance of synergistic cues in stem cell engineering. Interestingly, nanotopography provided a larger relative contribution to the osteogenesis of hMSCs than did co-culture with HUVECs. Furthermore, the osteogenesis of hMSCs was also affected by the density of parallel nanogrooves, exhibiting a maximum at a 1:3 spacing ratio, as defined as the ratio of ridge width to groove width. Analysis of (i) biochemical soluble factors, (ii) hMSC-substrate interaction and (iii) hMSC-HUVEC interaction suggests that (ii) and (iii) play a crucial role in mediating osteogenic phenotypes.
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Affiliation(s)
- Jangho Kim
- Department of Biosystems & Biomaterials Science and Engineering, Seoul National University, Seoul 151-742, Republic of Korea
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59
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Nge PN, Rogers CI, Woolley AT. Advances in microfluidic materials, functions, integration, and applications. Chem Rev 2013; 113:2550-83. [PMID: 23410114 PMCID: PMC3624029 DOI: 10.1021/cr300337x] [Citation(s) in RCA: 518] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Pamela N. Nge
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Chad I. Rogers
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Adam T. Woolley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
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60
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Kim HN, Jiao A, Hwang NS, Kim MS, Kang DH, Kim DH, Suh KY. Nanotopography-guided tissue engineering and regenerative medicine. Adv Drug Deliv Rev 2013; 65:536-58. [PMID: 22921841 PMCID: PMC5444877 DOI: 10.1016/j.addr.2012.07.014] [Citation(s) in RCA: 253] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 07/19/2012] [Accepted: 07/23/2012] [Indexed: 12/14/2022]
Abstract
Human tissues are intricate ensembles of multiple cell types embedded in complex and well-defined structures of the extracellular matrix (ECM). The organization of ECM is frequently hierarchical from nano to macro, with many proteins forming large scale structures with feature sizes up to several hundred microns. Inspired from these natural designs of ECM, nanotopography-guided approaches have been increasingly investigated for the last several decades. Results demonstrate that the nanotopography itself can activate tissue-specific function in vitro as well as promote tissue regeneration in vivo upon transplantation. In this review, we provide an extensive analysis of recent efforts to mimic functional nanostructures in vitro for improved tissue engineering and regeneration of injured and damaged tissues. We first characterize the role of various nanostructures in human tissues with respect to each tissue-specific function. Then, we describe various fabrication methods in terms of patterning principles and material characteristics. Finally, we summarize the applications of nanotopography to various tissues, which are classified into four types depending on their functions: protective, mechano-sensitive, electro-active, and shear stress-sensitive tissues. Some limitations and future challenges are briefly discussed at the end.
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Affiliation(s)
- Hong Nam Kim
- Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Alex Jiao
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Nathaniel S. Hwang
- School of Chemical and Biological Engineering, Institute for Chemical Processing, Seoul National University, Seoul 151-742, Republic of Korea
| | - Min Sung Kim
- Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Do Hyun Kang
- Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Republic of Korea
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Kahp-Yang Suh
- Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Republic of Korea
- Institute of Biological Engineering, Seoul National University, Seoul 151-742, Republic of Korea
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61
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Bae WG, Choi JH, Suh KY. Pitch-tunable size reduction patterning with a temperature-memory polymer. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:193-198. [PMID: 22997007 DOI: 10.1002/smll.201201554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 07/27/2012] [Indexed: 06/01/2023]
Abstract
A scalable and pitch-tunable size reduction patterning method is introduced by exploiting the temperature memory effect of shape memory polymer and replica molding of UV-curable materials.
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Affiliation(s)
- Won-Gyu Bae
- Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea
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62
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Effect of orientation and density of nanotopography in dermal wound healing. Biomaterials 2012; 33:8782-92. [DOI: 10.1016/j.biomaterials.2012.08.038] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/17/2012] [Indexed: 12/29/2022]
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63
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Pang C, Lee GY, Kim TI, Kim SM, Kim HN, Ahn SH, Suh KY. A flexible and highly sensitive strain-gauge sensor using reversible interlocking of nanofibres. NATURE MATERIALS 2012; 11:795-801. [PMID: 22842511 DOI: 10.1038/nmat3380] [Citation(s) in RCA: 670] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 06/15/2012] [Indexed: 05/21/2023]
Abstract
Flexible skin-attachable strain-gauge sensors are an essential component in the development of artificial systems that can mimic the complex characteristics of the human skin. In general, such sensors contain a number of circuits or complex layered matrix arrays. Here, we present a simple architecture for a flexible and highly sensitive strain sensor that enables the detection of pressure, shear and torsion. The device is based on two interlocked arrays of high-aspect-ratio Pt-coated polymeric nanofibres that are supported on thin polydimethylsiloxane layers. When different sensing stimuli are applied, the degree of interconnection and the electrical resistance of the sensor changes in a reversible, directional manner with specific, discernible strain-gauge factors. The sensor response is highly repeatable and reproducible up to 10,000 cycles with excellent on/off switching behaviour. We show that the sensor can be used to monitor signals ranging from human heartbeats to the impact of a bouncing water droplet on a superhydrophobic surface.
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Affiliation(s)
- Changhyun Pang
- World Class University Program on Multiscale Mechanical Design, Seoul National University, Seoul 151-742, Korea
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64
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Pang C, Kim SM, Rahmawan Y, Suh KY. Beetle-inspired bidirectional, asymmetric interlocking using geometry-tunable nanohairs. ACS APPLIED MATERIALS & INTERFACES 2012; 4:4225-4230. [PMID: 22817617 DOI: 10.1021/am3009289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present bidirectional, asymmetric interlocking behaviors between tilted micro- and nanohair arrays inspired from the actual wing locking device of beetles. The measured shear adhesion force between two identical tilted microhair arrays (1.5 μm radius, 30 μm height) turned out to be higher in the reverse direction than that in the angled direction, suggesting that the directionality of beetle's microtrichia may play a critical role in preventing the elytra from shifting along the middle of insect body. Furthermore, we observed dramatic enhancement of shear adhesion using asymmetric interlocking of various nanohair arrays (tilting angle, δ < 40°). A maximum shear locking force of ∼60 N/cm(2) was measured for the nanohair arrays of 50 nm radius and 1 μm height with a hysteresis as high as ∼3. A simple theoretical model was developed to describe the measured asymmetric adhesion forces and hysteresis, in good agreement with the experimental data.
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Affiliation(s)
- Changhyun Pang
- Division of WCU Multiscale Mechanical Design, Seoul National University, Seoul 151-742, Korea
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65
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Kim JK, Cho HS, Jung HS, Lim K, Kim KB, Choi DG, Jeong JH, Suh KY. Effect of surface tension and coefficient of thermal expansion in 30 nm scale nanoimprinting with two flexible polymer molds. NANOTECHNOLOGY 2012; 23:235303. [PMID: 22595765 DOI: 10.1088/0957-4484/23/23/235303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on nanoimprinting of polymer thin films at 30 nm scale resolution using two types of ultraviolet (UV)-curable, flexible polymer molds: perfluoropolyether (PFPE) and polyurethane acrylate (PUA). It was found that the quality of nanopatterning at the 30 nm scale is largely determined by the combined effects of surface tension and the coefficient of thermal expansion of the polymer mold. In particular, the polar component of surface tension may play a critical role in clean release of the mold, as evidenced by much reduced delamination or broken structures for the less polarized PFPE mold when patterning a relatively hydrophilic PMMA film. In contrast, such problems were not notably observed with a relatively hydrophobic PS film for both polymer molds. In addition, the demolding characteristic was also influenced by the coefficient of thermal expansion so that no delamination or uniformity problems were observed when patterning a UV-curable polymer film at room temperature. These results suggest that a proper polymeric mold material needs to be chosen for patterning polymer films under different surface properties and processing conditions, providing insights into how a clean demolding characteristic can be obtained at 30 nm scale nanopatterning.
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Affiliation(s)
- Jae Kwan Kim
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Korea
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66
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Kim HN, Kang DH, Kim MS, Jiao A, Kim DH, Suh KY. Patterning methods for polymers in cell and tissue engineering. Ann Biomed Eng 2012; 40:1339-55. [PMID: 22258887 PMCID: PMC5439960 DOI: 10.1007/s10439-012-0510-y] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 01/04/2012] [Indexed: 12/23/2022]
Abstract
Polymers provide a versatile platform for mimicking various aspects of physiological extracellular matrix properties such as chemical composition, rigidity, and topography for use in cell and tissue engineering applications. In this review, we provide a brief overview of patterning methods of various polymers with a particular focus on biocompatibility and processability. The materials highlighted here are widely used polymers including thermally curable polydimethyl siloxane, ultraviolet-curable polyurethane acrylate and polyethylene glycol, thermo-sensitive poly(N-isopropylacrylamide) and thermoplastic and conductive polymers. We also discuss how micro- and nanofabricated polymeric substrates of tunable elastic modulus can be used to engineer cell and tissue structure and function. Such synergistic effect of topography and rigidity of polymers may be able to contribute to constructing more physiologically relevant microenvironment.
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Affiliation(s)
- Hong Nam Kim
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea
| | - Do-Hyun Kang
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea
| | - Min Sung Kim
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea
| | - Alex Jiao
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Kahp-Yang Suh
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea
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67
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Kang D, Pang C, Kim SM, Cho HS, Um HS, Choi YW, Suh KY. Shape-controllable microlens arrays via direct transfer of photocurable polymer droplets. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:1709-1715. [PMID: 22388770 DOI: 10.1002/adma.201104507] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 01/13/2012] [Indexed: 05/31/2023]
Abstract
A simple method is presented to form an array of shape-controllable microlenses by partial photocuring of an UV-curable polymer and direct transfer. Using the transferred lens array, nanoscale metal patterns as small as 130-nm gaps are detected under an optical microscope with a distinguishable resolution.
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Affiliation(s)
- Daeshik Kang
- Division of WCU Multiscale Mechanical Design, School of Mechanical and Aerospace Engineering, Seoul National University, Korea
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68
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Kim MS, Kim AY, Jang KJ, Kim JH, Kim JB, Suh KY. Effect of nanogroove geometry on adipogenic differentiation. NANOTECHNOLOGY 2011; 22:494017. [PMID: 22101869 DOI: 10.1088/0957-4484/22/49/494017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present the effect of nanotopographically defined surfaces on adipocyte differentiation using various nanogroove patterns. Parallel nanogroove arrays with equal inter-groove distance (400, 550, 800 nm width) and varying distances (550 nm width with three different spacings of 550, 1100, and 2750 nm) were fabricated by UV-assisted capillary force lithography (CFL) on 18 mm diameter glass coverslips using biocompatible polyurethane (PU)-based material. After coating with fibronectin and subsequent culture of 3T3-L1 preadipocytes, the degree of adipocyte differentiation was determined by Oil Red O staining and adipogenic gene expression. We observed that adipocyte differentiation was slightly but substantially affected by culture on various nanogrooved surfaces. In particular, the cell crawling into nanogrooves contributed substantially to an enhanced level of differentiation with higher contact guidance, suggesting that cell-to-surface interactions would play a role for the adipocyte differentiation.
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Affiliation(s)
- M S Kim
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Korea
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