1
|
Zhu M, Wang Q, Gu T, Han Y, Zeng X, Li J, Dong J, Huang H, Qian P. Hydrogel-based microenvironment engineering of haematopoietic stem cells. Cell Mol Life Sci 2023; 80:49. [PMID: 36690903 PMCID: PMC11073069 DOI: 10.1007/s00018-023-04696-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/06/2022] [Accepted: 01/08/2023] [Indexed: 01/25/2023]
Abstract
Haematopoietic Stem cells (HSCs) have the potential for self-renewal and multilineage differentiation, and their behaviours are finely tuned by the microenvironment. HSC transplantation (HSCT) is widely used in the treatment of haematologic malignancies while limited by the quantity of available HSCs. With the development of tissue engineering, hydrogels have been deployed to mimic the HSC microenvironment in vitro. Engineered hydrogels influence HSC behaviour by regulating mechanical strength, extracellular matrix microstructure, cellular ligands and cytokines, cell-cell interaction, and oxygen concentration, which ultimately facilitate the acquisition of sufficient HSCs. Here, we review recent advances in the application of hydrogel-based microenvironment engineering of HSCs, and provide future perspectives on challenges in basic research and clinical practice.
Collapse
Affiliation(s)
- Meng Zhu
- Center of Stem Cell and Regenerative Medicine, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China
| | - Qiwei Wang
- Center of Stem Cell and Regenerative Medicine, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China
| | - Tianning Gu
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China
- Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yingli Han
- Center of Stem Cell and Regenerative Medicine, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China
| | - Xin Zeng
- Center of Stem Cell and Regenerative Medicine, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China
| | - Jinxin Li
- Center of Stem Cell and Regenerative Medicine, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China
| | - Jian Dong
- Center of Stem Cell and Regenerative Medicine, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China
| | - He Huang
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China.
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China.
- Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
| | - Pengxu Qian
- Center of Stem Cell and Regenerative Medicine, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China.
- Institute of Hematology, Zhejiang University and Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Hangzhou, 310058, China.
| |
Collapse
|
2
|
Fabrication and Evaluation of Gellan Gum/Hyaluronic Acid Hydrogel for Retinal Tissue Engineering Biomaterial and the Influence of Substrate Stress Relaxation on Retinal Pigment Epithelial Cells. Molecules 2022; 27:molecules27175512. [PMID: 36080277 PMCID: PMC9458149 DOI: 10.3390/molecules27175512] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
Cell therapies for age-related macular degeneration (AMD) treatment have been developed by integrating hydrogel-based biomaterials. Until now, cell activity has been observed only in terms of the modulus of the hydrogel. In addition, cell behavior has only been observed in the 2D environment of the hydrogel and the 3D matrix. As time-dependent stress relaxation is considered a significant mechanical cue for the control of cellular activities, it is important to optimize hydrogels for retinal tissue engineering (TE) by applying this viewpoint. Herein, a gellan Gum (GG)/Hyaluronic acid (HA) hydrogel was fabricated using a facile physical crosslinking method. The physicochemical and mechanical properties were controlled by forming a different composition of GG and HA. The characterization was performed by conducting a mass swelling study, a sol fraction study, a weight loss test, a viscosity test, an injection force study, a compression test, and a stress relaxation analysis. The biological activity of the cells encapsulated in 3D constructs was evaluated by conducting a morphological study, a proliferation test, a live/dead analysis, histology, immunofluorescence staining, and a gene expression study to determine the most appropriate material for retinal TE biomaterial. Hydrogels with moderate amounts of HA showed improved physicochemical and mechanical properties suitable for injection into the retina. Moreover, the time-dependent stress relaxation property of the GG/HA hydrogel was enhanced when the appropriate amount of HA was loaded. In addition, the cellular compatibility of the GG/HA hydrogel in in vitro experiments was significantly improved in the fast-relaxing hydrogel. Overall, these results demonstrate the remarkable potential of GG/HA hydrogel as an injectable hydrogel for retinal TE and the importance of the stress relaxation property when designing retinal TE hydrogels. Therefore, we believe that GG/HA hydrogel is a prospective candidate for retinal TE biomaterial.
Collapse
|
3
|
Dhakal S, Rotem-Bamberger S, Sejd JR, Sebbagh M, Ronin N, Frey RA, Beitsch M, Batty M, Taler K, Blackerby JF, Inbal A, Stenkamp DL. Selective Requirements for Vascular Endothelial Cells and Circulating Factors in the Regulation of Retinal Neurogenesis. Front Cell Dev Biol 2021; 9:628737. [PMID: 33898420 PMCID: PMC8060465 DOI: 10.3389/fcell.2021.628737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/17/2021] [Indexed: 01/01/2023] Open
Abstract
Development of the vertebrate eye requires signaling interactions between neural and non-neural tissues. Interactions between components of the vascular system and the developing neural retina have been difficult to decipher, however, due to the challenges of untangling these interactions from the roles of the vasculature in gas exchange. Here we use the embryonic zebrafish, which is not yet reliant upon hemoglobin-mediated oxygen transport, together with genetic strategies for (1) temporally-selective depletion of vascular endothelial cells, (2) elimination of blood flow through the circulation, and (3) elimination of cells of the erythroid lineage, including erythrocytes. The retinal phenotypes in these genetic systems were not identical, with endothelial cell-depleted retinas displaying laminar disorganization, cell death, reduced proliferation, and reduced cell differentiation. In contrast, the lack of blood flow resulted in a milder retinal phenotype showing reduced proliferation and reduced cell differentiation, indicating that an endothelial cell-derived factor(s) is/are required for laminar organization and cell survival. The lack of erythrocytes did not result in an obvious retinal phenotype, confirming that defects in retinal development that result from vascular manipulations are not due to poor gas exchange. These findings underscore the importance of the cardiovascular system supporting and controlling retinal development in ways other than supplying oxygen. In addition, these findings identify a key developmental window for these interactions and point to distinct functions for vascular endothelial cells vs. circulating factors.
Collapse
Affiliation(s)
- Susov Dhakal
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Shahar Rotem-Bamberger
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Josilyn R Sejd
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Meyrav Sebbagh
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Nathan Ronin
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ruth A Frey
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Mya Beitsch
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Megan Batty
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States.,Department of Biology, Gonzaga University, Spokane, WA, United States
| | - Kineret Taler
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Jennifer F Blackerby
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States.,Department of Biology, Gonzaga University, Spokane, WA, United States
| | - Adi Inbal
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Deborah L Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| |
Collapse
|
4
|
Hurst J, Fietz A, Tsai T, Joachim SC, Schnichels S. Organ Cultures for Retinal Diseases. Front Neurosci 2020; 14:583392. [PMID: 33324149 PMCID: PMC7724035 DOI: 10.3389/fnins.2020.583392] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/13/2020] [Indexed: 12/18/2022] Open
Abstract
The successful development of novel therapies is closely linked with understanding the underlying pathomechanisms of a disease. To do so, model systems that reflect human diseases and allow for the evaluation of new therapeutic approaches are needed. Yet, preclinical animal studies often have limited success in predicting human physiology, pathology, and therapeutic responses. Moreover, animal testing is facing increasing ethical and bureaucratic hurdles, while human cell cultures are limited in their ability to represent in vivo situations due to the lack of the tissue microenvironment, which may alter cellular responses. To overcome these struggles, organ cultures, especially those of complex organs such as the retina, can be used to study physiological reactions to substances or stressors. Human and animal organ cultures are now well established and recognized. This mini-review discusses how retinal organ cultures can be used to preserve tissue architecture more realistically and therefore better represent disease-related changes. It also shows how molecular biological, biochemical, and histological techniques can be combined to investigate how anatomical localization may alter cellular responses. Examples for the use of retinal organ cultures, including models to study age-related macular degeneration (AMD), retinitis pigmentosa (RP), central artery occlusion (CRAO), and glaucoma are presented, and their advantages and disadvantages are discussed. We conclude that organ cultures significantly improve our understanding of complex retinal diseases and may advance treatment testing without the need for animal testing.
Collapse
Affiliation(s)
- José Hurst
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, Tübingen, Germany
| | - Agnes Fietz
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, Tübingen, Germany
| | - Teresa Tsai
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Stephanie C Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Sven Schnichels
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, Tübingen, Germany
| |
Collapse
|
5
|
Lowen JM, Leach JK. Functionally graded biomaterials for use as model systems and replacement tissues. ADVANCED FUNCTIONAL MATERIALS 2020; 30:1909089. [PMID: 33456431 PMCID: PMC7810245 DOI: 10.1002/adfm.201909089] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Indexed: 05/03/2023]
Abstract
The heterogeneity of native tissues requires complex materials to provide suitable substitutes for model systems and replacement tissues. Functionally graded materials have the potential to address this challenge by mimicking the gradients in heterogeneous tissues such as porosity, mineralization, and fiber alignment to influence strength, ductility, and cell signaling. Advancements in microfluidics, electrospinning, and 3D printing enable the creation of increasingly complex gradient materials that further our understanding of physiological gradients. The combination of these methods enables rapid prototyping of constructs with high spatial resolution. However, successful translation of these gradients requires both spatial and temporal presentation of cues to model the complexity of native tissues that few materials have demonstrated. This review highlights recent strategies to engineer functionally graded materials for the modeling and repair of heterogeneous tissues, together with a description of how cells interact with various gradients.
Collapse
Affiliation(s)
- Jeremy M. Lowen
- Department of Biomedical Engineering, University of California, Davis, CA, 95616
| | - J. Kent Leach
- Department of Biomedical Engineering, University of California, Davis, CA, 95616
- Department of Orthopaedic Surgery, UC Davis Health, Sacramento, CA 95817
| |
Collapse
|
6
|
Schnichels S, Paquet-Durand F, Löscher M, Tsai T, Hurst J, Joachim SC, Klettner A. Retina in a dish: Cell cultures, retinal explants and animal models for common diseases of the retina. Prog Retin Eye Res 2020; 81:100880. [PMID: 32721458 DOI: 10.1016/j.preteyeres.2020.100880] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 12/11/2022]
Abstract
For many retinal diseases, including age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy (DR), the exact pathogenesis is still unclear. Moreover, the currently available therapeutic options are often unsatisfactory. Research designed to remedy this situation heavily relies on experimental animals. However, animal models often do not faithfully reproduce human disease and, currently, there is strong pressure from society to reduce animal research. Overall, this creates a need for improved disease models to understand pathologies and develop treatment options that, at the same time, require fewer or no experimental animals. Here, we review recent advances in the field of in vitro and ex vivo models for AMD, glaucoma, and DR. We highlight the difficulties associated with studies on complex diseases, in which both the initial trigger and the ensuing pathomechanisms are unclear, and then delineate which model systems are optimal for disease modelling. To this end, we present a variety of model systems, ranging from primary cell cultures, over organotypic cultures and whole eye cultures, to animal models. Specific advantages and disadvantages of such models are discussed, with a special focus on their relevance to putative in vivo disease mechanisms. In many cases, a replacement of in vivo research will mean that several different in vitro models are used in conjunction, for instance to analyze and validate causative molecular pathways. Finally, we argue that the analytical decomposition into appropriate cell and tissue model systems will allow making significant progress in our understanding of complex retinal diseases and may furthermore advance the treatment testing.
Collapse
Affiliation(s)
- Sven Schnichels
- University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Germany.
| | - François Paquet-Durand
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Germany
| | - Marina Löscher
- University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Germany
| | - Teresa Tsai
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Germany
| | - José Hurst
- University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Germany
| | - Stephanie C Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Germany
| | - Alexa Klettner
- Department of Ophthalmology, University Medical Center, University of Kiel, Kiel, Germany
| |
Collapse
|
7
|
Lee M, Rizzo R, Surman F, Zenobi-Wong M. Guiding Lights: Tissue Bioprinting Using Photoactivated Materials. Chem Rev 2020; 120:10950-11027. [DOI: 10.1021/acs.chemrev.0c00077] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Mihyun Lee
- Tissue Engineering + Biofabrication HPL J22, ETH Zürich, Otto-Stern-Weg 7, 8093 Zürich, Switzerland
| | - Riccardo Rizzo
- Tissue Engineering + Biofabrication HPL J22, ETH Zürich, Otto-Stern-Weg 7, 8093 Zürich, Switzerland
| | - František Surman
- Tissue Engineering + Biofabrication HPL J22, ETH Zürich, Otto-Stern-Weg 7, 8093 Zürich, Switzerland
| | - Marcy Zenobi-Wong
- Tissue Engineering + Biofabrication HPL J22, ETH Zürich, Otto-Stern-Weg 7, 8093 Zürich, Switzerland
| |
Collapse
|
8
|
Jo H, Yoon M, Gajendiran M, Kim K. Recent Strategies in Fabrication of Gradient Hydrogels for Tissue Engineering Applications. Macromol Biosci 2019; 20:e1900300. [PMID: 31886614 DOI: 10.1002/mabi.201900300] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/08/2019] [Indexed: 12/19/2022]
Abstract
Hydrogels are widely used as scaffold in tissue engineering field because of their ability to mimic the cellular microenvironment. However, mimicking a completely natural cellular environment is complicated due to the differences in various physical and chemical properties of cellular environments. Recently, gradient hydrogels provide excellent heterogeneous environment to mimic the different cellular microenvironments. To create hydrogels with an anisotropic distribution, gradient hydrogels have been widely developed by adopting several gradient generation techniques. Herein, the various gradient hydrogel fabrication techniques, including dual syringe pump systems, microfluidic device, photolithography, diffusion, and bio-printing are summarized. As the effects of gradient 3D hydrogels with stems have been reviewed elsewhere, this review focuses principally on gradient hydrogel fabrication for multi-model tissue regeneration. This review provides new insights into the key points for fabrication of gradient hydrogels for multi-model tissue regeneration.
Collapse
Affiliation(s)
- Heejung Jo
- Department of Bioengineering and Nano-Bioengineering, Incheon National University, Incheon, 22012, Republic of Korea
| | - Minhyuk Yoon
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Mani Gajendiran
- Department of Chemical and Biochemical Engineering, Dongguk University, Seoul, 06420, Republic of Korea
| | - Kyobum Kim
- Department of Chemical and Biochemical Engineering, Dongguk University, Seoul, 06420, Republic of Korea
| |
Collapse
|
9
|
Tavakoli Z, Yazdian F, Tabandeh F, Sheikhpour M. Regenerative medicine as a novel strategy for AMD treatment: a review. Biomed Phys Eng Express 2019; 6:012001. [PMID: 33438587 DOI: 10.1088/2057-1976/ab269a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Age-related macular degeneration (AMD) is known as a major cause of irreversible blindness in elderly adults. The segment of the retina responsible for central vision damages in the disease process. Degeneration of retinal pigmented epithelium (RPE) cells, photoreceptors, and choriocapillaris associated with aging participate for visual loss. In 2010, AMD involved 6.6% of all blindness cases around the world. Some of the researches have evaluated the replacing of damaged RPE in AMD patients by using the cells from various sources. Today, the advancement of RPE differentiation or generation from stem cells has been gained, and currently, clinical trials are testing the efficiency and safety of replacing degenerated RPE with healthy RPE. However, the therapeutic success of RPE transplantation may be restricted unless the transplanted cells can be adhered, distributed and survive for long-term in the transplanted site without any infections. In recent years a variety of scaffold types were used as a carrier for RPE transplantation and AMD treatment. In this review, we have discussed types of scaffolds; natural or synthetic, solid or hydrogel and their results in RPE replacement. Eventually, our aim is highlighting the novel and best scaffold carriers that may have potentially promoting the efficacy of RPE transplantation.
Collapse
Affiliation(s)
- Zahra Tavakoli
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | | | | | | |
Collapse
|
10
|
Fields MA, Del Priore LV, Adelman RA, Rizzolo LJ. Interactions of the choroid, Bruch's membrane, retinal pigment epithelium, and neurosensory retina collaborate to form the outer blood-retinal-barrier. Prog Retin Eye Res 2019; 76:100803. [PMID: 31704339 DOI: 10.1016/j.preteyeres.2019.100803] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 10/26/2019] [Accepted: 10/28/2019] [Indexed: 01/10/2023]
Abstract
The three interacting components of the outer blood-retinal barrier are the retinal pigment epithelium (RPE), choriocapillaris, and Bruch's membrane, the extracellular matrix that lies between them. Although previously reviewed independently, this review integrates these components into a more wholistic view of the barrier and discusses reconstitution models to explore the interactions among them. After updating our understanding of each component's contribution to barrier function, we discuss recent efforts to examine how the components interact. Recent studies demonstrate that claudin-19 regulates multiple aspects of RPE's barrier function and identifies a barrier function whereby mutations of claudin-19 affect retinal development. Co-culture approaches to reconstitute components of the outer blood-retinal barrier are beginning to reveal two-way interactions between the RPE and choriocapillaris. These interactions affect barrier function and the composition of the intervening Bruch's membrane. Normal or disease models of Bruch's membrane, reconstituted with healthy or diseased RPE, demonstrate adverse effects of diseased matrix on RPE metabolism. A stumbling block for reconstitution studies is the substrates typically used to culture cells are inadequate substitutes for Bruch's membrane. Together with human stem cells, the alternative substrates that have been designed offer an opportunity to engineer second-generation culture models of the outer blood-retinal barrier.
Collapse
Affiliation(s)
- Mark A Fields
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, PO Box 208061, New Haven, CT, 06520-8061, USA
| | - Lucian V Del Priore
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, PO Box 208061, New Haven, CT, 06520-8061, USA
| | - Ron A Adelman
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, PO Box 208061, New Haven, CT, 06520-8061, USA
| | - Lawrence J Rizzolo
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, PO Box 208061, New Haven, CT, 06520-8061, USA; Department of Surgery, Yale University School of Medicine, PO Box 208062, New Haven, CT, 06520-8062, USA.
| |
Collapse
|
11
|
Pena CD, Zhang S, Majeska R, Venkatesh T, Vazquez M. Invertebrate Retinal Progenitors as Regenerative Models in a Microfluidic System. Cells 2019; 8:cells8101301. [PMID: 31652654 PMCID: PMC6829900 DOI: 10.3390/cells8101301] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 12/30/2022] Open
Abstract
Regenerative retinal therapies have introduced progenitor cells to replace dysfunctional or injured neurons and regain visual function. While contemporary cell replacement therapies have delivered retinal progenitor cells (RPCs) within customized biomaterials to promote viability and enable transplantation, outcomes have been severely limited by the misdirected and/or insufficient migration of transplanted cells. RPCs must achieve appropriate spatial and functional positioning in host retina, collectively, to restore vision, whereas movement of clustered cells differs substantially from the single cell migration studied in classical chemotaxis models. Defining how RPCs interact with each other, neighboring cell types and surrounding extracellular matrixes are critical to our understanding of retinogenesis and the development of effective, cell-based approaches to retinal replacement. The current article describes a new bio-engineering approach to investigate the migratory responses of innate collections of RPCs upon extracellular substrates by combining microfluidics with the well-established invertebrate model of Drosophila melanogaster. Experiments utilized microfluidics to investigate how the composition, size, and adhesion of RPC clusters on defined extracellular substrates affected migration to exogenous chemotactic signaling. Results demonstrated that retinal cluster size and composition influenced RPC clustering upon extracellular substrates of concanavalin (Con-A), Laminin (LM), and poly-L-lysine (PLL), and that RPC cluster size greatly altered collective migratory responses to signaling from Fibroblast Growth Factor (FGF), a primary chemotactic agent in Drosophila. These results highlight the significance of examining collective cell-biomaterial interactions on bio-substrates of emerging biomaterials to aid directional migration of transplanted cells. Our approach further introduces the benefits of pairing genetically controlled models with experimentally controlled microenvironments to advance cell replacement therapies.
Collapse
Affiliation(s)
- Caroline D Pena
- Department of Biomedical Engineering, City College of New York, New York, NY 10031, USA.
| | - Stephanie Zhang
- Department of Biomedical Engineering, The State University of New York at Binghamton, NY 13902, USA.
| | - Robert Majeska
- Department of Biomedical Engineering, City College of New York, New York, NY 10031, USA.
| | - Tadmiri Venkatesh
- Department of Biology, City College of New York, New York, NY 10031, USA.
| | - Maribel Vazquez
- Department of Biomedical Engineering, Rutgers University, The State University of New Jersey, New Brunswick, NJ 08854, USA.
| |
Collapse
|
12
|
Polybenzyl Glutamate Biocompatible Scaffold Promotes the Efficiency of Retinal Differentiation toward Retinal Ganglion Cell Lineage from Human-Induced Pluripotent Stem Cells. Int J Mol Sci 2019; 20:ijms20010178. [PMID: 30621308 PMCID: PMC6337229 DOI: 10.3390/ijms20010178] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/27/2018] [Accepted: 12/29/2018] [Indexed: 02/06/2023] Open
Abstract
Optic neuropathy is one of the leading causes of irreversible blindness caused by retinal ganglion cell (RGC) degeneration. The development of induced pluripotent stem cell (iPSC)-based therapy opens a therapeutic window for RGC degeneration, and tissue engineering may further promote the efficiency of differentiation process of iPSCs. The present study was designed to evaluate the effects of a novel biomimetic polybenzyl glutamate (PBG) scaffold on culturing iPSC-derived RGC progenitors. The iPSC-derived neural spheres cultured on PBG scaffold increased the differentiated retinal neurons and promoted the neurite outgrowth in the RGC progenitor layer. Additionally, iPSCs cultured on PBG scaffold formed the organoid-like structures compared to that of iPSCs cultured on cover glass within the same culture period. With RNA-seq, we found that cells of the PBG group were differentiated toward retinal lineage and may be related to the glutamate signaling pathway. Further ontological analysis and the gene network analysis showed that the differentially expressed genes between cells of the PBG group and the control group were mainly associated with neuronal differentiation, neuronal maturation, and more specifically, retinal differentiation and maturation. The novel electrospinning PBG scaffold is beneficial for culturing iPSC-derived RGC progenitors as well as retinal organoids. Cells cultured on PBG scaffold differentiate effectively and shorten the process of RGC differentiation compared to that of cells cultured on coverslip. The new culture system may be helpful in future disease modeling, pharmacological screening, autologous transplantation, as well as narrowing the gap to clinical application.
Collapse
|
13
|
Mediating the invasion of smooth muscle cells into a cell-responsive hydrogel under the existence of immune cells. Biomaterials 2018; 180:193-205. [DOI: 10.1016/j.biomaterials.2018.07.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 05/27/2018] [Accepted: 07/11/2018] [Indexed: 01/12/2023]
|
14
|
Shor E, Merdler U, Brosh I, Shoham S, Levenberg S. Induced neuro-vascular interactions robustly enhance functional attributes of engineered neural implants. Biomaterials 2018; 180:1-11. [DOI: 10.1016/j.biomaterials.2018.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/23/2018] [Accepted: 07/01/2018] [Indexed: 12/20/2022]
|
15
|
Yan XZ, van den Beucken JJJP, Yuan C, Jansen JA, Yang F. Spheroid formation and stemness preservation of human periodontal ligament cells on chitosan films. Oral Dis 2018. [DOI: 10.1111/odi.12855] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- X-Z Yan
- Department of Periodontology; School and Hospital of Stomatology; Shanghai Engineering Research Center of Tooth Restoration and Regeneration; Tongji University; Shanghai China
| | - JJJP van den Beucken
- Department of Biomaterials; Radboud University Medical Center; Nijmegen The Netherlands
| | - C Yuan
- College of Materials Science and Engineering; Tongji University; Shanghai China
| | - JA Jansen
- Department of Biomaterials; Radboud University Medical Center; Nijmegen The Netherlands
| | - F Yang
- Department of Biomaterials; Radboud University Medical Center; Nijmegen The Netherlands
| |
Collapse
|
16
|
Yao H, Wang J, Mi S. Photo Processing for Biomedical Hydrogels Design and Functionality: A Review. Polymers (Basel) 2017; 10:E11. [PMID: 30966045 PMCID: PMC6415176 DOI: 10.3390/polym10010011] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/18/2017] [Accepted: 12/19/2017] [Indexed: 01/20/2023] Open
Abstract
A large number of opportunities for biomedical hydrogel design and functionality through photo-processing have stretched the limits of innovation. As both photochemical understanding and engineering technologies continue to develop, more complicated geometries and spatiotemporal manipulations can be realized through photo-exposure, producing multifunctional hydrogels with specific chemical, biological and physical characteristics for the achievement of biomedical goals. This report describes the role that light has recently played in the synthesis and functionalization of biomedical hydrogels and primarily the design of photoresponsive hydrogels via different chemical reactions (photo crosslinking and photo degradation) and conventional light curing processes (micropatterning, stereolithography and two/multiphoton techniques) as well as typical biomedical applications of the hydrogels (cell culture, differentiation and in vivo vascularization) and their promising future.
Collapse
Affiliation(s)
- Hongyi Yao
- Biomanufacturing Engineering Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
| | - Jieqiong Wang
- Biomanufacturing Engineering Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
| | - Shengli Mi
- Biomanufacturing Engineering Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
- Open FIESTA Center, Tsinghua University, Shenzhen 518055, China.
| |
Collapse
|
17
|
Wang S, Dalton PD, Dargaville TR. Spatial Patterning of Hydrogels via 3D Covalent Transfer Stamping from a Fugitive Ink. Macromol Rapid Commun 2017; 39. [DOI: 10.1002/marc.201700564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/03/2017] [Indexed: 01/22/2023]
Affiliation(s)
- Shuang Wang
- Nanotechnology and Molecular Science School of Chemistry Physics and Mechanical Engineering Science and Engineering Faculty Queensland University of Technology 2 George Street Brisbane Queensland 4000 Australia
- Institute of Health and Biomedical Innovation Queensland University of Technology 60 Musk Avenue Kelvin Grove Queensland 4059 Australia
| | - Paul D. Dalton
- Department for Functional Materials in Medicine and Dentistry and Bavarian Polymer Institute Universitätsklinikum Würzburg Pleicherwall 2 D97070 Würzburg Germany
| | - Tim R. Dargaville
- Nanotechnology and Molecular Science School of Chemistry Physics and Mechanical Engineering Science and Engineering Faculty Queensland University of Technology 2 George Street Brisbane Queensland 4000 Australia
- Institute of Health and Biomedical Innovation Queensland University of Technology 60 Musk Avenue Kelvin Grove Queensland 4059 Australia
| |
Collapse
|
18
|
Weil BD, Jenkins MJ, Uddin S, Bracewell DG, Wellings D, Farid SS, Veraitch F. An integrated experimental and economic evaluation of cell therapy affinity purification technologies. Regen Med 2017. [DOI: 10.2217/rme-2016-0156] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Aim: To present an integrated techno-economic analysis assessing the feasibility of affinity purification technologies using the manufacture of induced pluripotent stem cell-derived progenitor photoreceptors for retinal dystrophies as a case study. Materials & methods: Sort purity, progenitor yield and viable cell recovery were investigated for three cell sorting techniques: fluorescent-activated cell sorting (FACS); magnetic-activated cell sorting (MACS); and a novel technology SpheriTech beads. Experimentally derived metrics were incorporated into an advanced bioprocess economics tool to determine cost of goods per dose for each technology. Results & conclusion: Technical and bioprocess benefits were noted with SpheriTech beads which, unlike FACS and MACS, require no cell labeling. This simplifies the bioprocess, reduces cell loss and leaves target cells label free. The economic tool predicted cost drivers and a critical dose (7 × 107 cells per dose) shifting the most cost-effective technology from FACS to MACS. Process optimization is required for SpheriTech to compete economically.
Collapse
Affiliation(s)
- Benjamin D Weil
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, UK
- Royal Free Hospital Campus, Department of Haematology, University College London, Fleet Road, London NW3 2QG, UK
| | - Michael J Jenkins
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, UK
| | - Siddique Uddin
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, UK
| | - Daniel G Bracewell
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, UK
| | - Donald Wellings
- SpheriTech Ltd, The Heath Business & Technical Park, Runcorn, Cheshire WA7 4QX, UK
| | - Suzanne S Farid
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, UK
| | - Farlan Veraitch
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, UK
| |
Collapse
|
19
|
Tam RY, Smith LJ, Shoichet MS. Engineering Cellular Microenvironments with Photo- and Enzymatically Responsive Hydrogels: Toward Biomimetic 3D Cell Culture Models. Acc Chem Res 2017; 50:703-713. [PMID: 28345876 DOI: 10.1021/acs.accounts.6b00543] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Conventional cell culture techniques using 2D polystyrene or glass have provided great insight into key biochemical mechanisms responsible for cellular events such as cell proliferation, differentiation, and cell-cell interactions. However, the physical and chemical properties of 2D culture in vitro are dramatically different than those found in the native cellular microenvironment in vivo. Cells grown on 2D substrates differ significantly from those grown in vivo, and this explains, in part, why many promising drug candidates discovered through in vitro drug screening assays fail when they are translated to in vivo animal or human models. To overcome this obstacle, 3D cell culture using biomimetic hydrogels has emerged as an alternative strategy to recapitulate native cell growth in vitro. Hydrogels, which are water-swollen polymers, can be synthetic or naturally derived. Many methods have been developed to control the physical and chemical properties of the hydrogels to match those found in specific tissues. Compared to 2D culture, cells cultured in 3D gels with the appropriate physicochemical cues can behave more like they naturally do in vivo. While conventional hydrogels involve modifications to the bulk material to mimic the static aspects of the cellular microenvironment, recent progress has focused on using more dynamic hydrogels, the chemical and physical properties of which can be altered with external stimuli to better mimic the dynamics of the native cellular microenvironment found in vivo. In this Account, we describe our progress in designing stimuli-responsive, optically transparent hydrogels that can be used as biomimetic extracellular matrices (ECMs) to study cell differentiation and migration in the context of modeling the nervous system and cancer. Specifically, we developed photosensitive agarose and hyaluronic acid hydrogels that are activated by single or two-photon irradiation for biomolecule immobilization at specific volumes within the 3D hydrogel. By controlling the spatial location of protein immobilization, we created 3D patterns and protein concentration gradients within these gels. We used the latter to study the effect of VEGF-165 concentration gradients on the interactions between endothelial cells and retinal stem cells. Hyaluronic acid (HA) is particularly compelling as it is naturally found in the ECM of many tissues and the tumor microenvironment. We used Diels-Alder click chemistry and cryogelation to alter the chemical and physical properties of these hydrogels. We also designed HA hydrogels to study the invasion of breast cancer cells. HA gels were chemically cross-linked with matrix metalloproteinase (MMP)-degradable peptides that degrade in the presence of cancer cell-secreted MMPs, thus allowing cells to remodel their local microenvironment and invade into HA/MMP-degradable gels.
Collapse
Affiliation(s)
- Roger Y. Tam
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Laura J. Smith
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Institute
of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - Molly S. Shoichet
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Institute
of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| |
Collapse
|
20
|
Hunt NC, Hallam D, Karimi A, Mellough CB, Chen J, Steel DHW, Lako M. 3D culture of human pluripotent stem cells in RGD-alginate hydrogel improves retinal tissue development. Acta Biomater 2017; 49:329-343. [PMID: 27826002 DOI: 10.1016/j.actbio.2016.11.016] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 12/22/2022]
Abstract
No treatments exist to effectively treat many retinal diseases. Retinal pigmented epithelium (RPE) and neural retina can be generated from human embryonic stem cells/induced pluripotent stem cells (hESCs/hiPSCs). The efficacy of current protocols is, however, limited. It was hypothesised that generation of laminated neural retina and/or RPE from hiPSCs/hESCs could be enhanced by three dimensional (3D) culture in hydrogels. hiPSC- and hESC-derived embryoid bodies (EBs) were encapsulated in 0.5% RGD-alginate; 1% RGD-alginate; hyaluronic acid (HA) or HA/gelatin hydrogels and maintained until day 45. Compared with controls (no gel), 0.5% RGD-alginate increased: the percentage of EBs with pigmented RPE foci; the percentage EBs with optic vesicles (OVs) and pigmented RPE simultaneously; the area covered by RPE; frequency of RPE cells (CRALBP+); expression of RPE markers (TYR and RPE65) and the retinal ganglion cell marker, MATH5. Furthermore, 0.5% RGD-alginate hydrogel encapsulation did not adversely affect the expression of other neural retina markers (PROX1, CRX, RCVRN, AP2α or VSX2) as determined by qRT-PCR, or the percentage of VSX2 positive cells as determined by flow cytometry. 1% RGD-alginate increased the percentage of EBs with OVs and/or RPE, but did not significantly influence any other measures of retinal differentiation. HA-based hydrogels had no significant effect on retinal tissue development. The results indicated that derivation of retinal tissue from hESCs/hiPSCs can be enhanced by culture in 0.5% RGD-alginate hydrogel. This RGD-alginate scaffold may be useful for derivation, transport and transplantation of neural retina and RPE, and may also enhance formation of other pigmented, neural or epithelial tissue. STATEMENT OF SIGNIFICANCE The burden of retinal disease is ever growing with the increasing age of the world-wide population. Transplantation of retinal tissue derived from human pluripotent stem cells (PSCs) is considered a promising treatment. However, derivation of retinal tissue from PSCs using defined media is a lengthy process and often variable between different cell lines. This study indicated that alginate hydrogels enhanced retinal tissue development from PSCs, whereas hyaluronic acid-based hydrogels did not. This is the first study to show that 3D culture with a biomaterial scaffold can improve retinal tissue derivation from PSCs. These findings indicate potential for the clinical application of alginate hydrogels for the derivation and subsequent transplantation retinal tissue. This work may also have implications for the derivation of other pigmented, neural or epithelial tissue.
Collapse
Affiliation(s)
- Nicola C Hunt
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
| | - Ayesha Karimi
- Cumberland Infirmary, North Cumbria University Hospitals NHS Trust, Carlisle CA2 7HY, UK
| | - Carla B Mellough
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
| | - Jinju Chen
- School of Mechanical & Systems Engineering, Stephenson Building, Newcastle University, Newcastle upon Tyne, UK.
| | - David H W Steel
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK; Sunderland Eye Infirmary, Queen Alexandra Road, Sunderland SR2 9HP, UK.
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK.
| |
Collapse
|
21
|
Zhu F, Chen Y, Yang S, Wang Q, Liang F, Qu X, Hu Z. Surface patterned hydrogel film as a flexible scaffold for 2D and 3D cell co-culture. RSC Adv 2016. [DOI: 10.1039/c6ra11249h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cell adhesive magnetic silica nano-rods were aligned on glycol chitosan/benzaldehyde capped poly(ethylene oxide) hydrogel surface via dynamic interactions in magnetic field for 2D and 3D cell co-culture.
Collapse
Affiliation(s)
- Feiyan Zhu
- College of Materials Science and Opto-Electronic Technology
- University of Chinese Academy of Sciences
- Beijing 100049
- China
| | - Ying Chen
- State Key Laboratory of Polymer Physics and Chemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Saina Yang
- State Key Laboratory of Polymer Physics and Chemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Qian Wang
- State Key Laboratory of Polymer Physics and Chemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Fuxin Liang
- State Key Laboratory of Polymer Physics and Chemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Xiaozhong Qu
- College of Materials Science and Opto-Electronic Technology
- University of Chinese Academy of Sciences
- Beijing 100049
- China
| | - Zhongbo Hu
- College of Materials Science and Opto-Electronic Technology
- University of Chinese Academy of Sciences
- Beijing 100049
- China
| |
Collapse
|
22
|
Dhakal S, Stevens CB, Sebbagh M, Weiss O, Frey RA, Adamson S, Shelden EA, Inbal A, Stenkamp DL. Abnormal retinal development in Cloche mutant zebrafish. Dev Dyn 2015; 244:1439-1455. [PMID: 26283463 DOI: 10.1002/dvdy.24322] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 08/04/2015] [Accepted: 08/09/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Functions for the early embryonic vasculature in regulating development of central nervous system tissues, such as the retina, have been suggested by in vitro studies and by in vivo manipulations that caused additional ocular vessels to develop. Here, we use an avascular zebrafish embryo, cloche-/- (clo-/-), to begin to identify necessary developmental functions of the ocular vasculature in regulating development and patterning of the neural retina, in vivo. These studies are possible in zebrafish embryos, which do not yet rely upon the vasculature for tissue oxygenation. RESULTS clo-/- embryos lacked early ocular vasculature and were microphthalmic, with reduced retinal cell proliferation and cell survival. Retinas of clo mutants were disorganized, with irregular synaptic layers, mispatterned expression domains of retinal transcription factors, morphologically abnormal Müller glia, reduced differentiation of specific retinal cell types, and sporadically distributed cone photoreceptors. Blockade of p53-mediated cell death did not completely rescue this phenotype and revealed ectopic cones in the inner nuclear layer. clo-/- embryos did not upregulate a molecular marker for hypoxia. CONCLUSIONS The disorganized retinal phenotype of clo-/- embryos is consistent with a neural and glial developmental patterning role for the early ocular vasculature that is independent of its eventual function in gas exchange.
Collapse
Affiliation(s)
- Susov Dhakal
- Department of Biological Sciences, University of Idaho, Moscow, ID USA.,Neuroscience Graduate Program, University of Idaho, Moscow, ID USA
| | - Craig B Stevens
- Department of Biological Sciences, University of Idaho, Moscow, ID USA
| | - Meyrav Sebbagh
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Omri Weiss
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ruth A Frey
- Department of Biological Sciences, University of Idaho, Moscow, ID USA
| | - Seth Adamson
- Department of Biological Sciences, University of Idaho, Moscow, ID USA
| | - Eric A Shelden
- Department of Molecular Biosciences, Washington State University, Pullman, WA USA
| | - Adi Inbal
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Deborah L Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, ID USA.,Neuroscience Graduate Program, University of Idaho, Moscow, ID USA
| |
Collapse
|
23
|
Grim JC, Marozas IA, Anseth KS. Thiol-ene and photo-cleavage chemistry for controlled presentation of biomolecules in hydrogels. J Control Release 2015; 219:95-106. [PMID: 26315818 DOI: 10.1016/j.jconrel.2015.08.040] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/18/2015] [Accepted: 08/20/2015] [Indexed: 12/21/2022]
Abstract
Hydrogels have emerged as promising scaffolds in regenerative medicine for the delivery of biomolecules to promote healing. However, increasing evidence suggests that the context that biomolecules are presented to cells (e.g., as soluble verses tethered signals) can influence their bioactivity. A common approach to deliver biomolecules in hydrogels involves physically entrapping them within the network, such that they diffuse out over time to the surrounding tissues. While simple and versatile, the release profiles in such system are highly dependent on the molecular weight of the entrapped molecule relative to the network structure, and it can be difficult to control the release of two different signals at independent rates. In some cases, supraphysiologically high loadings are used to achieve therapeutic local concentrations, but uncontrolled release can then cause deleterious off-target side effects. In vivo, many growth factors and cytokines are stored in the extracellular matrix (ECM) and released on demand as needed during development, growth, and wound healing. Thus, emerging strategies in biomaterial chemistry have focused on ways to tether or sequester biological signals and engineer these bioactive scaffolds to signal to delivered cells or endogenous cells. While many strategies exist to achieve tethering of peptides, protein, and small molecules, this review focuses on photochemical methods, and their usefulness as a mild reaction that proceeds with fast kinetics in aqueous solutions and at physiological conditions. Photo-click and photo-caging methods are particularly useful because one can direct light to specific regions of the hydrogel to achieve spatial patterning. Recent methods have even demonstrated reversible introduction of biomolecules to mimic the dynamic changes of native ECM, enabling researchers to explore how the spatial and dynamic context of biomolecular signals influences important cell functions. This review will highlight how two photochemical methods have led to important advances in the tissue regeneration community, namely the thiol-ene photo-click reaction for bioconjugation and photocleavage reactions that allow for the removal of protecting groups. Specific examples will be highlighted where these methodologies have been used to engineer hydrogels that control and direct cell function with the aim of inspiring their use in regenerative medicine.
Collapse
Affiliation(s)
- Joseph C Grim
- Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Ian A Marozas
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA; BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Kristi S Anseth
- Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, CO 80309, USA; Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA; BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO 80309, USA.
| |
Collapse
|
24
|
Shoichet M, Wylie R, Aizawa Y, Tam R, Owen S. Three Dimensional Hydrogel Scaffolds and Applications in the CNS. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.13.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Molly Shoichet
- Chemical Engineering and Applied Chemistry University of TorontoTorontoOntarioCanada
- Donnelly Centre for Cellular and Biomolecular Research University of TorontoTorontoOntarioCanada
- Institute of Biomaterials and Biomedical Engineering University of TorontoTorontoOntarioCanada
| | - Ryan Wylie
- Chemical Engineering and Applied Chemistry University of TorontoTorontoOntarioCanada
- Donnelly Centre for Cellular and Biomolecular Research University of TorontoTorontoOntarioCanada
- ChemistryUniversity of TorontoTorontoOntarioCanada
| | - Yukie Aizawa
- Chemical Engineering and Applied Chemistry University of TorontoTorontoOntarioCanada
- Donnelly Centre for Cellular and Biomolecular Research University of TorontoTorontoOntarioCanada
| | - Roger Tam
- Chemical Engineering and Applied Chemistry University of TorontoTorontoOntarioCanada
- Donnelly Centre for Cellular and Biomolecular Research University of TorontoTorontoOntarioCanada
| | - Shawn Owen
- Chemical Engineering and Applied Chemistry University of TorontoTorontoOntarioCanada
- Donnelly Centre for Cellular and Biomolecular Research University of TorontoTorontoOntarioCanada
| |
Collapse
|
25
|
Lienemann PS, Devaud YR, Reuten R, Simona BR, Karlsson M, Weber W, Koch M, Lutolf MP, Milleret V, Ehrbar M. Locally controlling mesenchymal stem cell morphogenesis by 3D PDGF-BB gradients towards the establishment of an in vitro perivascular niche. Integr Biol (Camb) 2015; 7:101-11. [DOI: 10.1039/c4ib00152d] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We report on the creation of a three dimensional biomimetic tissue model that recapitulates the stable PDGF-BB gradient controlling mesenchymal stem cell morphogenetic behavior in the perivascular niche.
Collapse
|
26
|
Yang K, Jung H, Lee HR, Lee JS, Kim SR, Song KY, Cheong E, Bang J, Im SG, Cho SW. Multiscale, hierarchically patterned topography for directing human neural stem cells into functional neurons. ACS NANO 2014; 8:7809-7822. [PMID: 25050736 DOI: 10.1021/nn501182f] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Various biophysical and biochemical factors are important for determining the fate of neural stem cells (NSCs). Among biophysical signals, topographical stimulation by micro/nanopatterns has been applied to control NSC differentiation. In this study, we developed a hierarchically patterned substrate (HPS) platform that can synergistically enhance the differentiation of human NSCs (hNSCs) by simultaneously providing microscale and nanoscale spatial controls to facilitate the alignment of the cytoskeleton and the formation of focal adhesions. The multiscale HPS was fabricated by combining microgroove patterns (groove size: 1.5 μm), prepared by a conventional photolithographic process, and nanopore patterns (pore diameter: 10 nm), prepared from cylinder-forming block copolymer thin films. The hNSCs grown on the HPS exhibited not only a highly aligned, elongated morphology, but also a greatly enhanced differentiation into neuronal and astrocyte lineages, compared to hNSCs on a flat substrate (FS) or single-type patterned substrates [microgroove patterned substrate (MPS) and nanopore patterned substrate (NPS)]. Interestingly, the application of the HPS directed hNSC differentiation toward neurons rather than astrocytes. The expression of focal adhesion proteins in hNSCs was also significantly increased on the HPS compared to the FS, MPS, and NPS, likely a result of the presence of more focal contact points provided by nanopore structures. Inhibition of both β1 integrin-mediated binding and the intracellular Rho-associated protein kinase pathway of hNSCs eliminated the beneficial effects of the HPS on focal adhesion formation and actin filament alignment, which subsequently reduced hNSC differentiation. More importantly, hNSCs on the HPS differentiated into functional neurons exhibiting sodium currents and action potentials. The multiscale, hierarchically patterned topography would be useful for the design of functional biomaterial scaffolds to potentiate NSC therapeutic efficacy.
Collapse
|
27
|
Rossi F, van Griensven M. Polymer Functionalization as a Powerful Tool to Improve Scaffold Performances. Tissue Eng Part A 2014; 20:2043-51. [DOI: 10.1089/ten.tea.2013.0367] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Filippo Rossi
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta,” Politecnico di Milano, Milan, Italy
| | - Martijn van Griensven
- Department of Experimental Trauma Surgery, Clinic for Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| |
Collapse
|
28
|
Gluck JM, Delman C, Chyu J, MacLellan WR, Shemin RJ, Heydarkhan-Hagvall S. Microenvironment influences vascular differentiation of murine cardiovascular progenitor cells. J Biomed Mater Res B Appl Biomater 2014; 102:1730-9. [PMID: 24687591 DOI: 10.1002/jbm.b.33155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 02/13/2014] [Accepted: 03/13/2014] [Indexed: 01/25/2023]
Abstract
We examined the effects of the microenvironment on vascular differentiation of murine cardiovascular progenitor cells (CPCs). We isolated CPCs and seeded them in culture exposed to the various extracellular matrix (ECM) proteins in both two-dimensional (2D) and 3D culture systems. To better understand the contribution of the microenvironment to vascular differentiation, we analyzed endothelial and smooth muscle cell differentiation at both day 7 and day 14. We found that laminin and vitronectin enhanced vascular endothelial cell differentiation while fibronectin enhanced vascular smooth muscle cell differentiation. We also observed that the effects of the 3D electrospun scaffolds were delayed and not noticeable until the later time point (day 14), which may be due to the amount of time necessary for the cells to migrate to the interior of the scaffold. The study characterized the contributions of both ECM proteins and the addition of a 3D culture system to continued vascular differentiation. Additionally, we demonstrated the capability bioengineer a CPC-derived vascular graft.
Collapse
Affiliation(s)
- Jessica M Gluck
- Department of Surgery, Cardiovascular Tissue Engineering Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California; Department of Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | | | | | | | | | | |
Collapse
|
29
|
Battiston KG, Cheung JWC, Jain D, Santerre JP. Biomaterials in co-culture systems: towards optimizing tissue integration and cell signaling within scaffolds. Biomaterials 2014; 35:4465-76. [PMID: 24602569 DOI: 10.1016/j.biomaterials.2014.02.023] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 02/12/2014] [Indexed: 02/07/2023]
Abstract
Most natural tissues consist of multi-cellular systems made up of two or more cell types. However, some of these tissues may not regenerate themselves following tissue injury or disease without some form of intervention, such as from the use of tissue engineered constructs. Recent studies have increasingly used co-cultures in tissue engineering applications as these systems better model the natural tissues, both physically and biologically. This review aims to identify the challenges of using co-culture systems and to highlight different approaches with respect to the use of biomaterials in the use of such systems. The application of co-culture systems to stimulate a desired biological response and examples of studies within particular tissue engineering disciplines are summarized. A description of different analytical co-culture systems is also discussed and the role of biomaterials in the future of co-culture research are elaborated on. Understanding the complex cell-cell and cell-biomaterial interactions involved in co-culture systems will ultimately lead the field towards biomaterial concepts and designs with specific biochemical, electrical, and mechanical characteristics that are tailored towards the needs of distinct co-culture systems.
Collapse
Affiliation(s)
- Kyle G Battiston
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 124 Edward Street, Room 461, Toronto, Ontario, Canada M5G 1G6
| | - Jane W C Cheung
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 124 Edward Street, Room 461, Toronto, Ontario, Canada M5G 1G6
| | - Devika Jain
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 124 Edward Street, Room 461, Toronto, Ontario, Canada M5G 1G6
| | - J Paul Santerre
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 124 Edward Street, Room 461, Toronto, Ontario, Canada M5G 1G6; Department of Biomaterials, Faculty of Dentistry, University of Toronto, 124 Edward Street, Room 464D, Toronto, Ontario, Canada M5G 1G6.
| |
Collapse
|
30
|
Fisher SA, Tam RY, Shoichet MS. Tissue mimetics: engineered hydrogel matrices provide biomimetic environments for cell growth. Tissue Eng Part A 2014; 20:895-8. [PMID: 24417669 DOI: 10.1089/ten.tea.2013.0765] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- Stephanie A Fisher
- 1 Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, University of Toronto , Toronto, Ontario, Canada
| | | | | |
Collapse
|
31
|
Tam RY, Fuehrmann T, Mitrousis N, Shoichet MS. Regenerative therapies for central nervous system diseases: a biomaterials approach. Neuropsychopharmacology 2014; 39:169-88. [PMID: 24002187 PMCID: PMC3857664 DOI: 10.1038/npp.2013.237] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 07/09/2013] [Accepted: 07/12/2013] [Indexed: 02/07/2023]
Abstract
The central nervous system (CNS) has a limited capacity to spontaneously regenerate following traumatic injury or disease, requiring innovative strategies to promote tissue and functional repair. Tissue regeneration strategies, such as cell and/or drug delivery, have demonstrated promising results in experimental animal models, but have been difficult to translate clinically. The efficacy of cell therapy, which involves stem cell transplantation into the CNS to replace damaged tissue, has been limited due to low cell survival and integration upon transplantation, while delivery of therapeutic molecules to the CNS using conventional methods, such as oral and intravenous administration, have been limited by diffusion across the blood-brain/spinal cord-barrier. The use of biomaterials to promote graft survival and integration as well as localized and sustained delivery of biologics to CNS injury sites is actively being pursued. This review will highlight recent advances using biomaterials as cell- and drug-delivery vehicles for CNS repair.
Collapse
Affiliation(s)
- Roger Y Tam
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada,Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada
| | - Tobias Fuehrmann
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada,Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada
| | - Nikolaos Mitrousis
- Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada
| | - Molly S Shoichet
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada,Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada,Department of Chemistry, University of Toronto, Toronto, ON, Canada,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Room 514, Toronto, ON, Canada, Tel: +416 978 1460, Fax: +416 978 4317, E-mail:
| |
Collapse
|
32
|
Unachukwu UJ, Sauane M, Vazquez M, Redenti S. Microfluidic generated EGF-gradients induce chemokinesis of transplantable retinal progenitor cells via the JAK/STAT and PI3kinase signaling pathways. PLoS One 2013; 8:e83906. [PMID: 24376770 PMCID: PMC3871684 DOI: 10.1371/journal.pone.0083906] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/10/2013] [Indexed: 11/18/2022] Open
Abstract
A growing number of studies are evaluating retinal progenitor cell (RPC) transplantation as an approach to repair retinal degeneration and restore visual function. To advance cell-replacement strategies for a practical retinal therapy, it is important to define the molecular and biochemical mechanisms guiding RPC motility. We have analyzed RPC expression of the epidermal growth factor receptor (EGFR) and evaluated whether exposure to epidermal growth factor (EGF) can coordinate motogenic activity in vitro. Using Boyden chamber analysis as an initial high-throughput screen, we determined that RPC motility was optimally stimulated by EGF concentrations in the range of 20-400 ng/ml, with decreased stimulation at higher concentrations, suggesting concentration-dependence of EGF-induced motility. Using bioinformatics analysis of the EGF ligand in a retina-specific gene network pathway, we predicted a chemotactic function for EGF involving the MAPK and JAK-STAT intracellular signaling pathways. Based on targeted inhibition studies, we show that ligand binding, phosphorylation of EGFR and activation of the intracellular STAT3 and PI3kinase signaling pathways are necessary to drive RPC motility. Using engineered microfluidic devices to generate quantifiable steady-state gradients of EGF coupled with live-cell tracking, we analyzed the dynamics of individual RPC motility. Microfluidic analysis, including center of mass and maximum accumulated distance, revealed that EGF induced motility is chemokinetic with optimal activity observed in response to low concentration gradients. Our combined results show that EGFR expressing RPCs exhibit enhanced chemokinetic motility in the presence of low nanomole levels of EGF. These findings may serve to inform further studies evaluating the extent to which EGFR activity, in response to endogenous ligand, drives motility and migration of RPCs in retinal transplantation paradigms.
Collapse
Affiliation(s)
- Uchenna J. Unachukwu
- Biochemistry Doctoral Program, The Graduate School and University Center, City University of New York, New York, New York, United States of America
| | - Moira Sauane
- Department of Biological Sciences, Herbert Lehman College, City University of New York, Bronx, New York, United States of America
| | - Maribel Vazquez
- Department of Biomedical Engineering, City College of New York, City University of New York, New York, New York, United States of America
| | - Stephen Redenti
- Biochemistry Doctoral Program, The Graduate School and University Center, City University of New York, Department of Biological Sciences, Herbert Lehman College, City University of New York, Bronx, New York, United States of America
- * E-mail:
| |
Collapse
|
33
|
Owen SC, Fisher SA, Tam RY, Nimmo CM, Shoichet MS. Hyaluronic acid click hydrogels emulate the extracellular matrix. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:7393-7400. [PMID: 23343008 DOI: 10.1021/la305000w] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Hydrogels are used to create 3D microenvironments with properties that direct cell function. The current study demonstrates the versatility of hyaluronic acid (HA)-based hydrogels with independent control over hydrogel properties such as mechanics, architecture, and the spatial distribution of biological factors. Hydrogels were prepared by reacting furan-modified HA with bis-maleimide-poly(ethylene glycol) in a Diels-Alder click reaction. Biomolecules were photopatterned into the hydrogel by two-photon laser processing, resulting in spatially defined growth factor gradients. The Young's modulus was controlled by either changing the hydrogel concentration or the furan substitution on the HA backbone, thereby decoupling the hydrogel concentration from mechanical properties. Porosity was controlled by cryogelation, and the pore size distribution, by the thaw temperature. The addition of galactose further influenced the porosity, pore size, and Young's modulus of the cryogels. These HA-based hydrogels offer a tunable platform with a diversity of properties for directing cell function, with applications in tissue engineering and regenerative medicine.
Collapse
Affiliation(s)
- Shawn C Owen
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | | | | | | | | |
Collapse
|