1
|
Wu Q, Xue R, Zhao Y, Ramsay K, Wang EY, Savoji H, Veres T, Cartmell SH, Radisic M. Automated fabrication of a scalable heart-on-a-chip device by 3D printing of thermoplastic elastomer nanocomposite and hot embossing. Bioact Mater 2024; 33:46-60. [PMID: 38024233 PMCID: PMC10654006 DOI: 10.1016/j.bioactmat.2023.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/11/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
The successful translation of organ-on-a-chip devices requires the development of an automated workflow for device fabrication, which is challenged by the need for precise deposition of multiple classes of materials in micro-meter scaled configurations. Many current heart-on-a-chip devices are produced manually, requiring the expertise and dexterity of skilled operators. Here, we devised an automated and scalable fabrication method to engineer a Biowire II multiwell platform to generate human iPSC-derived cardiac tissues. This high-throughput heart-on-a-chip platform incorporated fluorescent nanocomposite microwires as force sensors, produced from quantum dots and thermoplastic elastomer, and 3D printed on top of a polystyrene tissue culture base patterned by hot embossing. An array of built-in carbon electrodes was embedded in a single step into the base, flanking the microwells on both sides. The facile and rapid 3D printing approach efficiently and seamlessly scaled up the Biowire II system from an 8-well chip to a 24-well and a 96-well format, resulting in an increase of platform fabrication efficiency by 17,5000-69,000% per well. The device's compatibility with long-term electrical stimulation in each well facilitated the targeted generation of mature human iPSC-derived cardiac tissues, evident through a positive force-frequency relationship, post-rest potentiation, and well-aligned sarcomeric apparatus. This system's ease of use and its capacity to gauge drug responses in matured cardiac tissue make it a powerful and reliable platform for rapid preclinical drug screening and development.
Collapse
Affiliation(s)
- Qinghua Wu
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
| | - Ruikang Xue
- Department of Materials, School of Natural Sciences, Faculty of Science and Engineering and The Henry Royce Institute, Royce Hub Building, The University of Manchester, Manchester, UK
| | - Yimu Zhao
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
| | - Kaitlyn Ramsay
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
| | - Erika Yan Wang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Houman Savoji
- Institute of Biomedical Engineering and Department of Pharmacology and Physiology, University of Montreal, Montreal, Quebec, H3T 1J4, Canada
- Research Center, Centre Hospitalier Universitaire Sainte-Justine, Montreal, Quebec, H3T 1C5, Canada
- Montreal TransMedTech Institute, Montreal, Quebec, H3T 1J4, Canada
| | - Teodor Veres
- National Research Council of Canada, Boucherville, QC, J4B 6Y4, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, M5S 3G8, Canada
| | - Sarah H. Cartmell
- Department of Materials, School of Natural Sciences, Faculty of Science and Engineering and The Henry Royce Institute, Royce Hub Building, The University of Manchester, Manchester, UK
| | - Milica Radisic
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3E5, Canada
- Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| |
Collapse
|
2
|
Gu B, Han K, Cao H, Huang X, Li X, Mao M, Zhu H, Cai H, Li D, He J. Heart-on-a-chip systems with tissue-specific functionalities for physiological, pathological, and pharmacological studies. Mater Today Bio 2024; 24:100914. [PMID: 38179431 PMCID: PMC10765251 DOI: 10.1016/j.mtbio.2023.100914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 01/06/2024] Open
Abstract
Recent advances in heart-on-a-chip systems hold great promise to facilitate cardiac physiological, pathological, and pharmacological studies. This review focuses on the development of heart-on-a-chip systems with tissue-specific functionalities. For one thing, the strategies for developing cardiac microtissues on heart-on-a-chip systems that closely mimic the structures and behaviors of the native heart are analyzed, including the imitation of cardiac structural and functional characteristics. For another, the development of techniques for real-time monitoring of biophysical and biochemical signals from cardiac microtissues on heart-on-a-chip systems is introduced, incorporating cardiac electrophysiological signals, contractile activity, and biomarkers. Furthermore, the applications of heart-on-a-chip systems in intelligent cardiac studies are discussed regarding physiological/pathological research and pharmacological assessment. Finally, the future development of heart-on-a-chip toward a higher level of systematization, integration, and maturation is proposed.
Collapse
Affiliation(s)
- Bingsong Gu
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| | - Kang Han
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| | - Hanbo Cao
- Shaanxi Provincial Institute for Food and Drug Control, Xi’ an, 710065, China
| | - Xinxin Huang
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| | - Xiao Li
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| | - Mao Mao
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| | - Hui Zhu
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| | - Hu Cai
- Shaanxi Provincial Institute for Food and Drug Control, Xi’ an, 710065, China
| | - Dichen Li
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| | - Jiankang He
- State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Medical Products Administration (NMPA) Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi'an Jiaotong University, Xi’ an, 710049, China
- National Innovation Platform (Center) for Industry-Education Integration of Medical Technology, Xi'an Jiaotong University, China
| |
Collapse
|
3
|
Velichkova G, Dobreva G. Human pluripotent stem cell-based models of heart development and disease. Cells Dev 2023; 175:203857. [PMID: 37257755 DOI: 10.1016/j.cdev.2023.203857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/16/2023] [Accepted: 05/25/2023] [Indexed: 06/02/2023]
Abstract
The heart is a complex organ composed of distinct cell types, such as cardiomyocytes, cardiac fibroblasts, endothelial cells, smooth muscle cells, neuronal cells and immune cells. All these cell types contribute to the structural, electrical and mechanical properties of the heart. Genetic manipulation and lineage tracing studies in mice have been instrumental in gaining critical insights into the networks regulating cardiac cell lineage specification, cell fate and plasticity. Such knowledge has been of fundamental importance for the development of efficient protocols for the directed differentiation of pluripotent stem cells (PSCs) in highly specialized cardiac cell types. In this review, we summarize the evolution and current advances in protocols for cardiac subtype specification, maturation, and assembly in cardiac microtissues and organoids.
Collapse
Affiliation(s)
- Gabriel Velichkova
- Department of Cardiovascular Genomics and Epigenomics, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Gergana Dobreva
- Department of Cardiovascular Genomics and Epigenomics, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; German Centre for Cardiovascular Research (DZHK), Germany.
| |
Collapse
|
4
|
Sun L, Wang Y, Bian F, Xu D, Zhao Y. Bioinspired optical and electrical dual-responsive heart-on-a-chip for hormone testing. Sci Bull (Beijing) 2023; 68:938-945. [PMID: 37062651 DOI: 10.1016/j.scib.2023.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/13/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023]
Abstract
Heart-on-chips have emerged as a powerful tool to promote the paradigm innovation in cardiac pathological research and drug development. Attempts are focused on improving microphysiological visuals, enhancing bionic characteristics, as well as expanding their biomedical applications. Herein, inspired by the bright feathers of peacock, we present a novel optical and electrical dual-responsive heart-on-a-chip based on cardiomyocytes hybrid bright MXene structural color hydrogels for hormone toxicity evaluation. Such hydrogels with inverse opal nanostructure are generated by using pregel to replicate MXene-decorated colloidal photonic crystal (PhC) array templates. The attendant MXene in the hydrogels could not only enhance the saturation of structural color, but also ensure the composite hydrogel with excellent electroconductivity to facilitate the synergetic beating of their surface cultured cardiomyocytes. In this case, the hydrogels would undergo a synchronous deformation and generate shift in corresponding photonic band gap and structural color, which could be employed as visual signal for self-reporting of the cardiomyocyte mechanics. Based on these features, we demonstrated the practical value of the optical and electrical dual-responsive structural color MXene hydrogels constructed heart-on-a-chip in hormone toxicity testing. These results indicated that the proposed heart-on-a-chip might find broad prospects in drug screening, biological research, and so on.
Collapse
Affiliation(s)
- Lingyu Sun
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing 210023, China
| | - Yu Wang
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Feika Bian
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Dongyu Xu
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Yuanjin Zhao
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing 210023, China; Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou Institute, University of Chinese Academy of Sciences, Zhejiang 325001, China.
| |
Collapse
|
5
|
Abstract
Cardiovascular diseases are a group of heart and blood vessel disorders which remain a leading cause of morbidity and mortality worldwide. Currently, cardiovascular disease research commonly depends on in vivo rodent models and in vitro human cell culture models. Despite their widespread use in cardiovascular disease research, there are some long-standing limitations: animal models often fail to faithfully mimic human response, while traditional cell models ignore the in vivo microenvironment, intercellular communications, and tissue-tissue interactions. The convergence of microfabrication and tissue engineering has given rise to organ-on-a-chip technologies. The organ-on-a-chip is a microdevice containing microfluidic chips, cells, and extracellular matrix to reproduce the physiological processes of a certain part of the human body, and is nowadays considered a promising bridge between in vivo models and in vitro 2D or 3D cell culture models. Considering the difficulty in obtaining human vessel and heart samples, the development of vessel-on-a-chip and heart-on-a-chip systems can guide cardiovascular disease research in the future. In this review, we elaborate methods and materials to fabricate organ-on-a-chip systems and summarize the construction of vessel and heart chips. The construction of vessels-on-a-chip must consider the cyclic mechanical stretch and fluid shear stress, while hemodynamic forces and cardiomyocyte maturation are key factors in building hearts-on-a-chip. We also introduce the application of organs-on-a-chip in cardiovascular disease study.
Collapse
|
6
|
Tang Y, Tian F, Miao X, Wu D, Wang Y, Wang H, You K, Li Q, Zhao S, Wang W. Heart-on-a-chip using human iPSC-derived cardiomyocytes with integrated vascular endothelial layer based on culture patch as a potential platform for drug evaluation. Biofabrication 2022; 15. [PMID: 36195063 DOI: 10.1088/1758-5090/ac975d] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 10/04/2022] [Indexed: 11/12/2022]
Abstract
Many strategies have been adopted to construct in vitro myocardium models, which are of great value to both drug cardiotoxicity evaluation and cardiovascular drug development. Especially the recent rapid development of human induced pluripotent stem cell (hiPSC) technology and the rise of organ-on-a-chip technique provide great potential to achieve more physiologically relevant in vitro models. However, the recapitulation of the key role of the vasculature endothelial layer for the drug action on myocardium in the models is still challenging. In this work, we developed an openable heart-on-a-chip system using highly purified functional hiPSC derived cardiomyocytes (hiPSC-CMs) with integrated a vascular endothelial layer based on our previous proposed culture patch method. The purity and functionality of the differentiated hiPSC-CMs were characterized, which were applied into the lower chamber of the sandwich-structured device to form the CM layer. The integrity and cell morphology of the endothelial layer on culture patch as well as the influence of fluid shear force were studied, which was integrated in between the upper and lower chambers. The constructed heart-on-a-chip was finally applied for drug testing. The effect of two cardiac targeting drugs (isoproterenol and E-4031) directly on the hiPSC-CMs or after penetrating through the endothelial layer under static or dynamic conditions was evaluated. The results demonstrated the significance of vascular layer in the in vitro myocardium models for drug testing, as well as the advantage and potential of the proposed platform for cardiovascular drug evaluation with more human physiological relevance.
Collapse
Affiliation(s)
- Yadong Tang
- Guangdong University of Technology, Higher education mega center, Guangzhou, 510006, CHINA
| | - Feng Tian
- Guangdong University of Technology, Higher education mega center, Guangzhou, Guangdong, 510006, CHINA
| | - Xiaomin Miao
- Guangdong University of Technology, Higher education mega center, Guangzhou, 510006, CHINA
| | - Dianqi Wu
- Guangdong University of Technology, Higher education mega center, Guangzhou, 510006, CHINA
| | - Yaqi Wang
- Guangdong University of Technology, Higher education mega center, Guangzhou, 510006, CHINA
| | - Han Wang
- Guangdong University of Technology, Higher education mega center, Guangzhou, 510006, CHINA
| | - Kai You
- Guangdong Academy of Sciences, Guangdong, Guangzhou, Guangdong, 510070, CHINA
| | - Qinglan Li
- Guangdong University of Technology, Higher education mega center, Guangzhou, 510006, CHINA
| | - Suqing Zhao
- Guangdong University of Technology, Higher education mega center, Guangzhou, 510006, CHINA
| | - Wenlong Wang
- Guangzhou University, Higher education mega center, Guangzhou, 510006, CHINA
| |
Collapse
|
7
|
Veldhuizen J, Chavan R, Moghadas B, Park JG, Kodibagkar VD, Migrino RQ, Nikkhah M. Cardiac ischemia on-a-chip to investigate cellular and molecular response of myocardial tissue under hypoxia. Biomaterials 2022; 281:121336. [PMID: 35026670 PMCID: PMC10440189 DOI: 10.1016/j.biomaterials.2021.121336] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 12/18/2021] [Accepted: 12/24/2021] [Indexed: 12/31/2022]
Abstract
Tissue engineering has enabled the development of advanced and physiologically relevant models of cardiovascular diseases, with advantages over conventional 2D in vitro assays. We have previously demonstrated development of a heart on-a-chip microfluidic model with mature 3D anisotropic tissue formation that incorporates both stem cell-derived cardiomyocytes and cardiac fibroblasts within a collagen-based hydrogel. Using this platform, we herein present a model of myocardial ischemia on-a-chip, that recapitulates ischemic insult through exposure of mature 3D cardiac tissues to hypoxic environments. We report extensive validation and molecular-level analyses of the model in its ability to recapitulate myocardial ischemia in response to hypoxia, demonstrating the 1) induction of tissue fibrosis through upregulation of contractile fibers, 2) dysregulation in tissue contraction through functional assessment, 3) upregulation of hypoxia-response genes and downregulation of contractile-specific genes through targeted qPCR, and 4) transcriptomic pathway regulation of hypoxic tissues. Further, we investigated the complex response of ischemic myocardial tissues to reperfusion, identifying 5) cell toxicity, 6) sustained contractile irregularities, as well as 7) re-establishment of lactate levels and 8) gene expression, in hypoxic tissues in response to ischemia reperfusion injury.
Collapse
Affiliation(s)
- Jaimeson Veldhuizen
- School of Biological and Health Systems Engineering (SBHSE), Arizona State University, Tempe, AZ, 85287, USA
| | - Ramani Chavan
- Center for Personalized Diagnostics (CPD), Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Babak Moghadas
- School of Biological and Health Systems Engineering (SBHSE), Arizona State University, Tempe, AZ, 85287, USA
| | - Jin G Park
- Center for Personalized Diagnostics (CPD), Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Vikram D Kodibagkar
- School of Biological and Health Systems Engineering (SBHSE), Arizona State University, Tempe, AZ, 85287, USA
| | - Raymond Q Migrino
- Phoenix Veterans Affairs Health Care System, Phoenix, AZ, 85012, USA; University of Arizona College of Medicine, Phoenix, AZ, 85004, USA
| | - Mehdi Nikkhah
- School of Biological and Health Systems Engineering (SBHSE), Arizona State University, Tempe, AZ, 85287, USA; Center for Personalized Diagnostics (CPD), Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.
| |
Collapse
|
8
|
Andrysiak K, Stępniewski J, Dulak J. Human-induced pluripotent stem cell-derived cardiomyocytes, 3D cardiac structures, and heart-on-a-chip as tools for drug research. Pflugers Arch 2021; 473:1061-1085. [PMID: 33629131 PMCID: PMC8245367 DOI: 10.1007/s00424-021-02536-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 12/13/2022]
Abstract
Development of new drugs is of high interest for the field of cardiac and cardiovascular diseases, which are a dominant cause of death worldwide. Before being allowed to be used and distributed, every new potentially therapeutic compound must be strictly validated during preclinical and clinical trials. The preclinical studies usually involve the in vitro and in vivo evaluation. Due to the increasing reporting of discrepancy in drug effects in animal and humans and the requirement to reduce the number of animals used in research, improvement of in vitro models based on human cells is indispensable. Primary cardiac cells are difficult to access and maintain in cell culture for extensive experiments; therefore, the human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) became an excellent alternative. This technology enables a production of high number of patient- and disease-specific cardiomyocytes and other cardiac cell types for a large-scale research. The drug effects can be extensively evaluated in the context of electrophysiological responses with a use of well-established tools, such as multielectrode array (MEA), patch clamp, or calcium ion oscillation measurements. Cardiotoxicity, which is a common reason for withdrawing drugs from marketing or rejection at final stages of clinical trials, can be easily verified with a use of hiPSC-CM model providing a prediction of human-specific responses and higher safety of clinical trials involving patient cohort. Abovementioned studies can be performed using two-dimensional cell culture providing a high-throughput and relatively lower costs. On the other hand, more complex structures, such as engineered heart tissue, organoids, or spheroids, frequently applied as co-culture systems, represent more physiological conditions and higher maturation rate of hiPSC-derived cells. Furthermore, heart-on-a-chip technology has recently become an increasingly popular tool, as it implements controllable culture conditions, application of various stimulations and continuous parameters read-out. This paper is an overview of possible use of cardiomyocytes and other cardiac cell types derived from hiPSC as in vitro models of heart in drug research area prepared on the basis of latest scientific reports and providing thorough discussion regarding their advantages and limitations.
Collapse
Affiliation(s)
- Kalina Andrysiak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Jacek Stępniewski
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Józef Dulak
- Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
| |
Collapse
|
9
|
Abstract
Heart diseases have become the main killer threatening human health, and various methods have been developed to study heart disease. Among them, heart-on-a-chip has emerged in recent years as a method for constructing disease (or normal) models in vitro and is considered as a promising tool to study heart diseases. Compared with other methods, the advantages of heart-on-a-chip include the high portability, high throughput, and the capability to mimic microenvironments in vivo. It has shown a great potential in disease mechanism study and drug screening. In this paper, we review the recent advances in heart-on-a-chip, including the fabrication methods (e.g., 3D bioprinting) and biomedical applications. By analyzing the structure of the existing heart-on-a-chip, we proposed that a highly integrated heart-on-a-chip includes four elements: Microfluidic chips, cells/microtissues, microactuators to construct the microenvironment, and microsensors for results readout. Finally, the current challenges and future directions of heart-on-a-chip are discussed.
Collapse
Affiliation(s)
- Qingzhen Yang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an, Shaanxi 710049, P.R. China
- Micro-/Nano-technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, P.R. China
- Research Institute of Xi’an Jiaotong University, Hangzhou, Zhejiang 311215, P.R. China
| | - Zhanfeng Xiao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an, Shaanxi 710049, P.R. China
| | - Xuemeng Lv
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, P.R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an, Shaanxi 710049, P.R. China
| | - Tingting Zhang
- College of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, Xi’an, Shaanxi 710021, P.R. China
| | - Han Liu
- Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases Co-constructed by Henan Province and Education Ministry of P.R. China, Academy of Chinese Medical Sciences, Henan University of Chinese Medicine, Zhengzhou 450016, P.R. China
| |
Collapse
|
10
|
Zhao Y, Rafatian N, Wang EY, Wu Q, Lai BFL, Lu RX, Savoji H, Radisic M. Towards chamber specific heart-on-a-chip for drug testing applications. Adv Drug Deliv Rev 2020; 165-166:60-76. [PMID: 31917972 PMCID: PMC7338250 DOI: 10.1016/j.addr.2019.12.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/26/2019] [Accepted: 12/30/2019] [Indexed: 02/06/2023]
Abstract
Modeling of human organs has long been a task for scientists in order to lower the costs of therapeutic development and understand the pathological onset of human disease. For decades, despite marked differences in genetics and etiology, animal models remained the norm for drug discovery and disease modeling. Innovative biofabrication techniques have facilitated the development of organ-on-a-chip technology that has great potential to complement conventional animal models. However, human organ as a whole, more specifically the human heart, is difficult to regenerate in vitro, in terms of its chamber specific orientation and its electrical functional complexity. Recent progress with the development of induced pluripotent stem cell differentiation protocols, made recapitulating the complexity of the human heart possible through the generation of cells representative of atrial & ventricular tissue, the sinoatrial node, atrioventricular node and Purkinje fibers. Current heart-on-a-chip approaches incorporate biological, electrical, mechanical, and topographical cues to facilitate tissue maturation, therefore improving the predictive power for the chamber-specific therapeutic effects targeting adult human. In this review, we will give a summary of current advances in heart-on-a-chip technology and provide a comprehensive outlook on the challenges involved in the development of human physiologically relevant heart-on-a-chip.
Collapse
Affiliation(s)
- Yimu Zhao
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Naimeh Rafatian
- Division of Cardiology and Peter Munk Cardiac Center, University of Health Network, Toronto, Ontario M5G 2N2, Canada
| | - Erika Yan Wang
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Qinghua Wu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Benjamin F L Lai
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Rick Xingze Lu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Houman Savoji
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Toronto General Research Institute, Toronto, Ontario M5G 2C4, Canada.
| |
Collapse
|
11
|
Schroer A, Pardon G, Castillo E, Blair C, Pruitt B. Engineering hiPSC cardiomyocyte in vitro model systems for functional and structural assessment. Prog Biophys Mol Biol 2019; 144:3-15. [PMID: 30579630 PMCID: PMC6919215 DOI: 10.1016/j.pbiomolbio.2018.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 09/24/2018] [Accepted: 12/04/2018] [Indexed: 02/06/2023]
Abstract
The study of human cardiomyopathies and the development and testing of new therapies has long been limited by the availability of appropriate in vitro model systems. Cardiomyocytes are highly specialized cells whose internal structure and contractile function are sensitive to the local microenvironment and the combination of mechanical and biochemical cues they receive. The complementary technologies of human induced pluripotent stem cell (hiPSC) derived cardiomyocytes (CMs) and microphysiological systems (MPS) allow for precise control of the genetics and microenvironment of human cells in in vitro contexts. These combined systems also enable quantitative measurement of mechanical function and intracellular organization. This review describes relevant factors in the myocardium microenvironment that affect CM structure and mechanical function and demonstrates the application of several engineered microphysiological systems for studying development, disease, and drug discovery.
Collapse
Affiliation(s)
- Alison Schroer
- Departments of Mechanical Engineering and Bioengineering, Stanford University, Stanford, CA, 94305, USA.
| | - Gaspard Pardon
- Departments of Mechanical Engineering and Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Erica Castillo
- Departments of Mechanical Engineering and Bioengineering, Stanford University, Stanford, CA, 94305, USA; Department of Mechanical Engineering, University of California at Santa Barbara, USA
| | - Cheavar Blair
- Departments of Mechanical Engineering and Bioengineering, Stanford University, Stanford, CA, 94305, USA; Department of Mechanical Engineering, University of California at Santa Barbara, USA
| | - Beth Pruitt
- Departments of Mechanical Engineering and Bioengineering, Stanford University, Stanford, CA, 94305, USA; Department of Mechanical Engineering, University of California at Santa Barbara, USA
| |
Collapse
|
12
|
Conant G, Lai BFL, Lu RXZ, Korolj A, Wang EY, Radisic M. High-Content Assessment of Cardiac Function Using Heart-on-a-Chip Devices as Drug Screening Model. Stem Cell Rev Rep 2018; 13:335-346. [PMID: 28429185 DOI: 10.1007/s12015-017-9736-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Drug discovery and development continues to be a challenge to the pharmaceutical industry despite great advances in cell and molecular biology that allow for the design of better targeted therapeutics. Many potential drug compounds fail during the clinical trial due to inefficacy and toxicity that were not predicted during preclinical stages. The fundamental problem lies with the use of traditional drug screening models that still largely rely on the use of cell lines or animal cell monolayers, which leads to lack of predictive power of human tissue and organ response to the drug candidates. More physiologically relevant systems are therefore critical in relieving the burden of high failure rates. Emerging knowledge and techniques in tissue engineering and microfabrication have enabled the development of micro-engineered systems - collectively known as organs-on-chips - that may lead to a paradigm shift in preclinical drug screening assays. In this review we explore the technological advances and challenges in the development of heart-on-a-chip models, by addressing current assessment methods for drug-induced cardiotoxicity and providing a perspective on the modifications that should be implemented to realize the full potential of this system.
Collapse
Affiliation(s)
- Genevieve Conant
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Benjamin Fook Lun Lai
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Rick Xing Ze Lu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Anastasia Korolj
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Erika Yan Wang
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Milica Radisic
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada.
- Toronto General Research Institute, Toronto, ON, Canada.
| |
Collapse
|
13
|
Lozano O, Torres-Quintanilla A, García-Rivas G. Nanomedicine for the cardiac myocyte: Where are we? J Control Release 2017; 271:149-165. [PMID: 29273321 DOI: 10.1016/j.jconrel.2017.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 12/12/2017] [Accepted: 12/17/2017] [Indexed: 02/08/2023]
Abstract
Biomedical achievements in the last few decades, leading to successful therapeutic interventions, have considerably improved human life expectancy. Nevertheless, the increasing load and the still suboptimal outcome for patients with cardiac dysfunction underlines the relevance of continuous research to develop novel therapeutics for these diseases. In this context, the field of nanomedicine has attracted a lot of attention due to the potential novel treatment possibilities, such as controlled and sustained release, tissue targeting, and drug protection from degradation. For cardiac myocytes, which constitute the majority of the heart by mass and are the contractile unit, new options have been explored in terms of the use of nanomaterials (NMs) for therapy, diagnosis, and tissue engineering. This review focuses on the advances of nanomedicine targeted to the cardiac myocyte: first presenting the NMs used and the principal cardiac myocyte-based afflictions, followed by an overview of key advances in the field, including NMs interactions with the cardiac myocyte, therapy delivery, diagnosis based on imaging, and tissue engineering for tissue repair and heart-on-a-chip devices.
Collapse
Affiliation(s)
- Omar Lozano
- Cátedra de Cardiología y Medicina Vascular, Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Mexico; Centro de Investigación Biomédica, Hospital Zambrano-Hellion, Tecnologico de Monterrey, San Pedro Garza-García, Mexico.
| | - Alejandro Torres-Quintanilla
- Cátedra de Cardiología y Medicina Vascular, Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Mexico
| | - Gerardo García-Rivas
- Cátedra de Cardiología y Medicina Vascular, Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Mexico; Centro de Investigación Biomédica, Hospital Zambrano-Hellion, Tecnologico de Monterrey, San Pedro Garza-García, Mexico
| |
Collapse
|
14
|
Zhang YS, Arneri A, Bersini S, Shin SR, Zhu K, Goli-Malekabadi Z, Aleman J, Colosi C, Busignani F, Dell'Erba V, Bishop C, Shupe T, Demarchi D, Moretti M, Rasponi M, Dokmeci MR, Atala A, Khademhosseini A. Bioprinting 3D microfibrous scaffolds for engineering endothelialized myocardium and heart-on-a-chip. Biomaterials 2016; 110:45-59. [PMID: 27710832 DOI: 10.1016/j.biomaterials.2016.09.003] [Citation(s) in RCA: 522] [Impact Index Per Article: 65.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 08/30/2016] [Accepted: 09/03/2016] [Indexed: 02/06/2023]
Abstract
Engineering cardiac tissues and organ models remains a great challenge due to the hierarchical structure of the native myocardium. The need of integrating blood vessels brings additional complexity, limiting the available approaches that are suitable to produce integrated cardiovascular organoids. In this work we propose a novel hybrid strategy based on 3D bioprinting, to fabricate endothelialized myocardium. Enabled by the use of our composite bioink, endothelial cells directly bioprinted within microfibrous hydrogel scaffolds gradually migrated towards the peripheries of the microfibers to form a layer of confluent endothelium. Together with controlled anisotropy, this 3D endothelial bed was then seeded with cardiomyocytes to generate aligned myocardium capable of spontaneous and synchronous contraction. We further embedded the organoids into a specially designed microfluidic perfusion bioreactor to complete the endothelialized-myocardium-on-a-chip platform for cardiovascular toxicity evaluation. Finally, we demonstrated that such a technique could be translated to human cardiomyocytes derived from induced pluripotent stem cells to construct endothelialized human myocardium. We believe that our method for generation of endothelialized organoids fabricated through an innovative 3D bioprinting technology may find widespread applications in regenerative medicine, drug screening, and potentially disease modeling.
Collapse
Affiliation(s)
- Yu Shrike Zhang
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA.
| | - Andrea Arneri
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan 20133, Italy
| | - Simone Bersini
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Cell and Tissue Engineering Lab, IRCCS Istituto Ortopedico Galeazzi, Milan 20161, Italy
| | - Su-Ryon Shin
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA
| | - Kai Zhu
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Cardiac Surgery, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zahra Goli-Malekabadi
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biomedical Engineering, Amirkabir University of Technology, Tehran 64540, Iran
| | - Julio Aleman
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Cristina Colosi
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Chemistry, Sapienza Università di Roma, Rome 00185, Italy
| | - Fabio Busignani
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electronics and Telecommunications, Politecnico di Torino, Torino 10129, Italy
| | - Valeria Dell'Erba
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biomedical Engineering, Politecnico di Torino, Torino 10129, Italy
| | - Colin Bishop
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC 27101, USA
| | - Thomas Shupe
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC 27101, USA
| | - Danilo Demarchi
- Department of Electronics and Telecommunications, Politecnico di Torino, Torino 10129, Italy
| | - Matteo Moretti
- Cell and Tissue Engineering Lab, IRCCS Istituto Ortopedico Galeazzi, Milan 20161, Italy; Swiss Institute for Regnerative Medicine, Lugano 6900, Switzerland; Cardiocentro Ticino, Lugano 6900, Switzerland
| | - Marco Rasponi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan 20133, Italy
| | - Mehmet Remzi Dokmeci
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA
| | - Anthony Atala
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC 27101, USA
| | - Ali Khademhosseini
- Biomaterials Innovation Research Center, Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA; Department of Bioindustrial Technologies, College of Animal Bioscience and Technology, Konkuk University, Seoul 143-701, Republic of Korea; Department of Physics, King Abdulaziz University, Jeddah 21569, Saudi Arabia.
| |
Collapse
|
15
|
Abstract
Heart diseases are one of the main causes of death around the world. The great challenge for scientists is to develop new therapeutic methods for these types of ailments. Stem cells (SCs) therapy could be one of a promising technique used for renewal of cardiac cells and treatment of heart diseases. Conventional in vitro techniques utilized for investigation of heart regeneration do not mimic natural cardiac physiology. Lab-on-a-chip systems may be the solution which could allow the creation of a heart muscle model, enabling the growth of cardiac cells in conditions similar to in vivo conditions. Microsystems can be also used for differentiation of stem cells into heart cells, successfully. It will help better understand of proliferation and regeneration ability of these cells. In this review, we present Heart-on-a-chip systems based on cardiac cell culture and stem cell biology. This review begins with the description of the physiological environment and the functions of the heart. Next, we shortly described conventional techniques of stem cells differentiation into the cardiac cells. This review is mostly focused on describing Lab-on-a-chip systems for cardiac tissue engineering. Therefore, in the next part of this article, the microsystems for both cardiac cell culture and SCs differentiation into cardiac cells are described. The section about SCs differentiation into the heart cells is divided in sections describing biochemical, physical and mechanical stimulations. Finally, we outline present challenges and future research concerning Heart-on-a-chip based on stem cell biology.
Collapse
Affiliation(s)
- Elzbieta Jastrzebska
- Institute of Biotechnology, Department of Microbioanalytics, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Ewelina Tomecka
- Institute of Biotechnology, Department of Microbioanalytics, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Iwona Jesion
- Department of Animal Environment Biology, Faculty of Animal Science, Warsaw University of Life Science, Ciszewskiego 8, 02-786 Warsaw, Poland
| |
Collapse
|