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Guarino V, Galizia M, Alvarez-Perez M, Mensitieri G, Ambrosio L. Improving surface and transport properties of macroporous hydrogels for bone regeneration. J Biomed Mater Res A 2014; 103:1095-105. [DOI: 10.1002/jbm.a.35246] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/19/2014] [Accepted: 05/27/2014] [Indexed: 01/10/2023]
Affiliation(s)
- Vincenzo Guarino
- Institute of Polymers, Composite and Biomaterials; National Research Council of Italy, Mostra d'Oltremare Pad. 20, V.le Kennedy 54; 80125 Naples Italy
| | - Michele Galizia
- Department of Chemical, Materials and Industrial Production Engineering; University of Naples Federico II, P.leTecchio 80; 80125 Naples Italy
| | - Marco Alvarez-Perez
- Tissue Bioengineering Laboratory, DEPeI, School of Dentistry, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n C.P. 04510 Coyoacán; Mexico DF Mexico
| | - Giuseppe Mensitieri
- Department of Chemical, Materials and Industrial Production Engineering; University of Naples Federico II, P.leTecchio 80; 80125 Naples Italy
| | - Luigi Ambrosio
- Institute of Polymers, Composite and Biomaterials; National Research Council of Italy, Mostra d'Oltremare Pad. 20, V.le Kennedy 54; 80125 Naples Italy
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Sokic S, Christenson M, Larson J, Papavasiliou G. In Situ Generation of Cell-Laden Porous MMP-Sensitive PEGDA Hydrogels by Gelatin Leaching. Macromol Biosci 2014; 14:731-9. [DOI: 10.1002/mabi.201300406] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/27/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Sonja Sokic
- Department of Biomedical Engineering; Illinois Institute of Technology; 3255 South Dearborn Street Wishnick Hall Room 223 Chicago, IL 60616 USA
| | - Megan Christenson
- Department of Biomedical Engineering; Illinois Institute of Technology; 3255 South Dearborn Street Wishnick Hall Room 223 Chicago, IL 60616 USA
| | - Jeffery Larson
- Department of Biomedical Engineering; Illinois Institute of Technology; 3255 South Dearborn Street Wishnick Hall Room 223 Chicago, IL 60616 USA
| | - Georgia Papavasiliou
- Department of Biomedical Engineering; Illinois Institute of Technology; 3255 South Dearborn Street Wishnick Hall Room 223 Chicago, IL 60616 USA
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53
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Bencherif SA, Braschler TM, Renaud P. Advances in the design of macroporous polymer scaffolds for potential applications in dentistry. J Periodontal Implant Sci 2013; 43:251-61. [PMID: 24455437 PMCID: PMC3891856 DOI: 10.5051/jpis.2013.43.6.251] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 12/22/2013] [Indexed: 12/18/2022] Open
Abstract
A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size, thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissue-engineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications.
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Affiliation(s)
- Sidi A. Bencherif
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, USA
| | - Thomas M. Braschler
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Laboratory of Microsystems, STI-LMIS4, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Philippe Renaud
- Laboratory of Microsystems, STI-LMIS4, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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54
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Bailey BM, Nail LN, Grunlan MA. Continuous gradient scaffolds for rapid screening of cell-material interactions and interfacial tissue regeneration. Acta Biomater 2013; 9:8254-61. [PMID: 23707502 DOI: 10.1016/j.actbio.2013.05.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 04/21/2013] [Accepted: 05/15/2013] [Indexed: 11/28/2022]
Abstract
In tissue engineering, the physical and chemical properties of the scaffold mediates cell behavior, including regeneration. Thus a strategy that permits rapid screening of cell-scaffold interactions is critical. Herein, we have prepared eight "hybrid" hydrogel scaffolds in the form of continuous gradients such that a single scaffold contains spatially varied properties. These scaffolds are based on combining an inorganic macromer (methacrylated star polydimethylsiloxane, PDMSstar-MA) and organic macromer (poly(ethylene glycol)diacrylate, PEG-DA) as well as both aqueous and organic fabrication solvents. Having previously demonstrated its bioactivity and osteoinductivity, PDMSstar-MA is a particularly powerful component to incorporate into instructive gradient scaffolds based on PEG-DA. The following parameters were varied to produce the different gradients or gradual transitions in: (1) the wt.% ratio of PDMSstar-MA to PEG-DA macromers, (2) the total wt.% macromer concentration, (3) the number average molecular weight (Mn) of PEG-DA and (4) the Mn of PDMSstar-MA. Upon dividing each scaffold into four "zones" perpendicular to the gradient, we were able to demonstrate the spatial variation in morphology, bioactivity, swelling and modulus. Among these gradient scaffolds are those in which swelling and modulus are conveniently decoupled. In addition to rapid screening of cell-material interactions, these scaffolds are well suited for regeneration of interfacial tissues (e.g. osteochondral tissues) that transition from one tissue type to another.
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Affiliation(s)
- Brennan M Bailey
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3120, USA
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55
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Loh QL, Choong C. Three-dimensional scaffolds for tissue engineering applications: role of porosity and pore size. TISSUE ENGINEERING PART B-REVIEWS 2013; 19:485-502. [PMID: 23672709 DOI: 10.1089/ten.teb.2012.0437] [Citation(s) in RCA: 1424] [Impact Index Per Article: 129.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Tissue engineering applications commonly encompass the use of three-dimensional (3D) scaffolds to provide a suitable microenvironment for the incorporation of cells or growth factors to regenerate damaged tissues or organs. These scaffolds serve to mimic the actual in vivo microenvironment where cells interact and behave according to the mechanical cues obtained from the surrounding 3D environment. Hence, the material properties of the scaffolds are vital in determining cellular response and fate. These 3D scaffolds are generally highly porous with interconnected pore networks to facilitate nutrient and oxygen diffusion and waste removal. This review focuses on the various fabrication techniques (e.g., conventional and rapid prototyping methods) that have been employed to fabricate 3D scaffolds of different pore sizes and porosity. The different pore size and porosity measurement methods will also be discussed. Scaffolds with graded porosity have also been studied for their ability to better represent the actual in vivo situation where cells are exposed to layers of different tissues with varying properties. In addition, the ability of pore size and porosity of scaffolds to direct cellular responses and alter the mechanical properties of scaffolds will be reviewed, followed by a look at nature's own scaffold, the extracellular matrix. Overall, the limitations of current scaffold fabrication approaches for tissue engineering applications and some novel and promising alternatives will be highlighted.
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Affiliation(s)
- Qiu Li Loh
- Division of Materials Technology, School of Materials Science and Engineering, Nanyang Technological University , Singapore, Singapore
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56
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Köllmer M, Buhrman JS, Zhang Y, Gemeinhart RA. Markers Are Shared Between Adipogenic and Osteogenic Differentiated Mesenchymal Stem Cells. ACTA ACUST UNITED AC 2013; 5:18-25. [PMID: 24013643 DOI: 10.5897/jdbte2013.0065] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The stem cell differentiation paradigm is based on the progression of cells through generations of daughter cells that eventually become restricted and committed to one lineage resulting in fully differentiated cells. Herein, we report on the differentiation of adult human mesenchymal stem cells (hMSCs) towards adipogenic and osteogenic lineages using established protocols. Lineage specific geneswere evaluated by quantitative real-time PCR relative to two reference genes. The expression of osteoblast-associated genes (alkaline phosphatase, osteopontin, and osteocalcin)was detected in hMSCs that underwent adipogenesis. When normalized, the expression of adipocyte marker genes (adiponectin, fatty acid binding protein P4, and leptin) increasedin a time-dependent manner during adipogenic induction. Adiponectin and leptin were also detected in osteoblast-induced cells. Lipid vacuoles that represent the adipocyte phenotype were only present in the adipogenic induction group. Conforming to the heterogeneous nature of hMSCs and the known plasticity between osteogenic and adipogenic lineages, these data indicatea marker overlap between MSC-derived adipocytes and osteoblasts. Weproposea careful consideration of experimental conditions such as investigated timepoints, selected housekeeping genesand the evidence indicating lack of differentiation into other lineageswhen evaluating hMSC differentiation.
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Affiliation(s)
- Melanie Köllmer
- Department of Biopharmaceutical Sciences, University of Illinois, Chicago, IL 60612-7231, USA
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57
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Seidlits SK, Gower RM, Shepard JA, Shea LD. Hydrogels for lentiviral gene delivery. Expert Opin Drug Deliv 2013; 10:499-509. [PMID: 23347508 DOI: 10.1517/17425247.2013.764864] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Gene delivery from hydrogel biomaterials provides a fundamental tool for a variety of clinical applications including regenerative medicine, gene therapy for inherited disorders and drug delivery. The high water content and mild gelation conditions of hydrogels support their use for gene delivery by preserving activity of lentiviral vectors and acting to shield vectors from any host immune response. AREAS COVERED Strategies to control lentiviral entrapment within and retention/release from hydrogels are reviewed. The authors discuss the ability of hydrogel design parameters to control the transgene expression profile and the capacity of hydrogels to protect vectors from (and even modulate) the host immune response. EXPERT OPINION Delivery of genetic vectors from scaffolds provides a unique opportunity to capitalize on the potential synergy between the biomaterial design for cell processes and gene delivery. Hydrogel properties can be tuned to directly control the events that determine the tissue response to controlled gene delivery, which include the extent of cell infiltration, preservation of vector activity and vector retention. While some design parameters have been identified, numerous opportunities for investigation are available in order to develop a complete model relating the biomaterial properties and host response to gene delivery.
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Affiliation(s)
- Stephanie K Seidlits
- Northwestern University, Department of Chemical & Biological Engineering, 2145 Sheridan Rd, Tech Building E-136, Evanston, IL 60208, USA
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58
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Bailey BM, Fei R, Munoz-Pinto D, Hahn MS, Grunlan MA. PDMS(star)-PEG hydrogels prepared via solvent-induced phase separation (SIPS) and their potential utility as tissue engineering scaffolds. Acta Biomater 2012; 8:4324-33. [PMID: 22842033 DOI: 10.1016/j.actbio.2012.07.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 07/10/2012] [Accepted: 07/20/2012] [Indexed: 12/20/2022]
Abstract
Inorganic-organic hydrogels based on methacrylated star polydimethylsiloxane (PDMS(star)-MA) and diacrylated poly(ethylene glycol) (PEG-DA) macromers were prepared via solvent-induced phase separation (SIPS). The macromers were combined in a dichloromethane precursor solution and sequentially photopolymerized, dried and hydrated. The chemical and physical properties of the hydrogels were further tailored by varying the number average molecular weight (M(n)) of PEG-DA (M(n)=3.4k and 6k gmol(-1)) as well as the weight percent ratio of PDMS(star)-MA (M(n)=7k gmol(-1)) to PEG-DA from 0:100 to 20:80. Compared to analogous hydrogels fabricated from aqueous precursor solutions, SIPS produced hydrogels with a macroporous morphology, a more even distribution of PDMS(star)-MA, increased modulus and enhanced degradation rates. The morphology, swelling ratio, mechanical properties, bioactivity, non-specific protein adhesion, controlled introduction of cell adhesion, and cytocompatibility of the hydrogels were characterized. As a result of their tunable properties, this library of hydrogels is useful to study material-guided cell behavior and ultimate tissue regeneration.
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Affiliation(s)
- Brennan M Bailey
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3120, USA
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59
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Building biocompatible hydrogels for tissue engineering of the brain and spinal cord. J Funct Biomater 2012; 3:839-63. [PMID: 24955749 PMCID: PMC4030922 DOI: 10.3390/jfb3040839] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 10/24/2012] [Indexed: 01/07/2023] Open
Abstract
Tissue engineering strategies employing biomaterials have made great progress in the last few decades. However, the tissues of the brain and spinal cord pose unique challenges due to a separate immune system and their nature as soft tissue. Because of this, neural tissue engineering for the brain and spinal cord may require re-establishing biocompatibility and functionality of biomaterials that have previously been successful for tissue engineering in the body. The goal of this review is to briefly describe the distinctive properties of the central nervous system, specifically the neuroimmune response, and to describe the factors which contribute to building polymer hydrogels compatible with this tissue. These factors include polymer chemistry, polymerization and degradation, and the physical and mechanical properties of the hydrogel. By understanding the necessities in making hydrogels biocompatible with tissue of the brain and spinal cord, tissue engineers can then functionalize these materials for repairing and replacing tissue in the central nervous system.
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60
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Su PJ, Tran QA, Fong JJ, Eliceiri KW, Ogle BM, Campagnola PJ. Mesenchymal stem cell interactions with 3D ECM modules fabricated via multiphoton excited photochemistry. Biomacromolecules 2012; 13:2917-25. [PMID: 22876971 DOI: 10.1021/bm300949k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To understand complex micro/nanoscale ECM stem cell interactions, reproducible in vitro models are needed that can strictly recapitulate the relative content and spatial arrangement of native tissue. Additionally, whole ECM proteins are required to most accurately reflect native binding dynamics. To address this need, we use multiphoton excited photochemistry to create 3D whole protein constructs or "modules" to study how the ECM governs stem cell migration. The constructs were created from mixtures of BSA/laminin (LN) and BSA alone, whose comparison afforded studying how the migration dynamics are governed from the combination of morphological and ECM cues. We found that mesenchymal stem cells interacted for significantly longer durations with the BSA/LN constructs than pure BSA, pointing to the importance of binding cues of the LN. Critical to this work was the development of an automated system with feedback based on fluorescence imaging to provide quality control when synthesizing multiple identical constructs.
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Affiliation(s)
- Ping-Jung Su
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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61
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Al-Abboodi A, Fu J, Doran PM, Chan PP. Three-dimensional nanocharacterization of porous hydrogel with ion and electron beams. Biotechnol Bioeng 2012; 110:318-26. [DOI: 10.1002/bit.24612] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/08/2012] [Accepted: 07/10/2012] [Indexed: 11/07/2022]
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62
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Xia Z, Patchan M, Maranchi J, Elisseeff J, Trexler M. Determination of crosslinking density of hydrogels prepared from microcrystalline cellulose. J Appl Polym Sci 2012. [DOI: 10.1002/app.38052] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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63
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Santos E, Hernández RM, Pedraz JL, Orive G. Novel advances in the design of three-dimensional bio-scaffolds to control cell fate: translation from 2D to 3D. Trends Biotechnol 2012; 30:331-41. [DOI: 10.1016/j.tibtech.2012.03.005] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/14/2012] [Accepted: 03/14/2012] [Indexed: 12/15/2022]
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64
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Zorlutuna P, Annabi N, Camci-Unal G, Nikkhah M, Cha JM, Nichol JW, Manbachi A, Bae H, Chen S, Khademhosseini A. Microfabricated biomaterials for engineering 3D tissues. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:1782-804. [PMID: 22410857 PMCID: PMC3432416 DOI: 10.1002/adma.201104631] [Citation(s) in RCA: 269] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Indexed: 05/04/2023]
Abstract
Mimicking natural tissue structure is crucial for engineered tissues with intended applications ranging from regenerative medicine to biorobotics. Native tissues are highly organized at the microscale, thus making these natural characteristics an integral part of creating effective biomimetic tissue structures. There exists a growing appreciation that the incorporation of similar highly organized microscale structures in tissue engineering may yield a remedy for problems ranging from vascularization to cell function control/determination. In this review, we highlight the recent progress in the field of microscale tissue engineering and discuss the use of various biomaterials for generating engineered tissue structures with microscale features. In particular, we will discuss the use of microscale approaches to engineer the architecture of scaffolds, generate artificial vasculature, and control cellular orientation and differentiation. In addition, the emergence of microfabricated tissue units and the modular assembly to emulate hierarchical tissues will be discussed.
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Affiliation(s)
- Pinar Zorlutuna
- Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA 02139, USA
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65
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Desai ES, Tang MY, Ross AE, Gemeinhart RA. Critical factors affecting cell encapsulation in superporous hydrogels. Biomed Mater 2012; 7:024108. [PMID: 22455976 PMCID: PMC3358450 DOI: 10.1088/1748-6041/7/2/024108] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We recently showed that superporous hydrogel (SPH) scaffolds promote long-term stem cell viability and cell driven mineralization when cells were seeded within the pores of pre-fabricated SPH scaffolds. The possibility of cell encapsulation within the SPH matrix during its fabrication was further explored in this study. The impact of each chemical component used in SPH fabrication and each step of the fabrication process on cell viability was systematically examined. Ammonium persulfate, an initiator, and sodium bicarbonate, the gas-generating compound, were the two components having significant toxicity toward encapsulated cells at the concentrations necessary for SPH fabrication. Cell survival rates were 55.7% ± 19.3% and 88.8% ± 9.4% after 10 min exposure to ammonium persulfate and sodium bicarbonate solutions, respectively. In addition, solution pH change via the addition of sodium bicarbonate had significant toxicity toward encapsulated cells with cell survival of only 50.3% ± 2.5%. Despite toxicity of chemical components and the SPH fabrication method, cells still exhibited significant overall survival rates within SPHs of 81.2% ± 6.8% and 67.0% ± 0.9%, respectively, 48 and 72 h after encapsulation. This method of cell encapsulation holds promise for use in vitro and in vivo as a scaffold material for both hydrogel matrix encapsulation and cell seeding within the pores.
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Affiliation(s)
- Esha S Desai
- Department of Biopharmaceutical Sciences, University of Illinois, 833 South Wood Street (MC 865), Chicago, IL 60612-7231
| | - Mary Y Tang
- Department of Biopharmaceutical Sciences, University of Illinois, 833 South Wood Street (MC 865), Chicago, IL 60612-7231
| | - Amy E Ross
- Department of Bioengineering, University of Illinois, Chicago, IL 60607-7052
| | - Richard A Gemeinhart
- Department of Biopharmaceutical Sciences, University of Illinois, 833 South Wood Street (MC 865), Chicago, IL 60612-7231
- Department of Bioengineering, University of Illinois, Chicago, IL 60607-7052
- Department of Ophthalmology and Visual Science, University of Illinois, Chicago, IL 60612-4319
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66
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Köllmer M, Keskar V, Hauk TG, Collins JM, Russell B, Gemeinhart RA. Stem cell-derived extracellular matrix enables survival and multilineage differentiation within superporous hydrogels. Biomacromolecules 2012; 13:963-73. [PMID: 22404228 DOI: 10.1021/bm300332w] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hydrophilic poly(ethylene glycol) diacrylate (PEGDA) hydrogel surfaces resist protein adsorption and are generally thought to be unsuitable for anchorage-dependent cells to adhere. Intriguingly, our previous findings revealed that PEGDA superporous hydrogel scaffolds (SPHs) allow anchorage of bone marrow derived human mesenchymal stem cells (hMSCs) and support their long-term survival. Therefore, we hypothesized that the physicochemical characteristics of the scaffold impart properties that could foster cellular responses. We examined if hMSCs alter their microenvironment to allow cell attachment by synthesizing their own extracellular matrix (ECM) proteins. Immunofluorescence staining revealed extensive expression of collagen type I, collagen type IV, laminin, and fibronectin within hMSC-seeded SPHs by the end of the third week. Whether cultured in serum-free or serum-supplemented medium, hMSC ECM protein gene expression patterns exhibited no substantial changes. The presence of serum proteins is required for initial anchorage of hMSCs within the SPHs but not for the hMSC survival after 24 h. In contrast to 2D expansion on tissue culture plastic (TCP), hMSCs cultured within SPHs proliferate similarly in the presence or absence of serum. To test whether hMSCs retain their undifferentiated state within the SPHs, cell-seeded constructs were cultured for 3 weeks in stem cell maintenance medium and the expression of hMSC-specific cell surface markers were evaluated by flow cytometry. CD105, CD90, CD73, and CD44 were present to a similar extent in the SPH and in 2D monolayer culture. We further demonstrated multilineage potential of hMSCs grown in the PEGDA SPHs, whereby differentiation into osteoblasts, chondrocytes, and adipocytes could be induced. The present study demonstrates the potential of hMSCs to alter the "blank" PEGDA environment to a milieu conducive to cell growth and multilineage differentiation by secreting adhesive ECM proteins within the porous network of the SPH scaffolds.
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Affiliation(s)
- Melanie Köllmer
- Department of Biopharmaceutical Sciences, University of Illinois, Chicago, Illinois 60612-7231, United States
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67
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Guo J, Meng Z, Chen G, Xie D, Chen Y, Wang H, Tang W, Liu L, Jing W, Long J, Guo W, Tian W. Restoration of critical-size defects in the rabbit mandible using porous nanohydroxyapatite-polyamide scaffolds. Tissue Eng Part A 2012; 18:1239-52. [PMID: 22320360 DOI: 10.1089/ten.tea.2011.0503] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Composite nanohydroxyapatite/polyamide (n-HA/PA) biomaterials have been indicated for bone defect reconstruction, where PA is added to enhance the toughness of n-HA. However, a comprehensive understanding of the biological performance of this implant material remains to be determined. In this study, the biological activity of n-HA/PA biomaterials was characterized in vitro by assessing the growth of bone marrow stromal cells (BMSCs), and in an in vivo rabbit model. To evaluate the n-HA/PA performance under different osteogenic conditions in vivo, implants were inserted to critical-size bone defects in the angle and body of the rabbit mandible. To determine the necessity of ectogenic BMSC-n-HA/PA hybrids at different implantation sites, both raw n-HA/PA materials and BMSC-seeded n-HA/PA hybrids were implanted. Bone formation was detected by radiology and histological studies. The results showed that n-HA/PA composites had great bioactivity, demonstrating significant BMSC proliferation, active alkaline phosphatase secretion, and stimulating the expression of osteogenic proteins (bone morphogenetic protein 2 [BMP2], osteoprotegerin [OPG], osteopontin [OPN], collagen type I [Col I], and osteocalcin [OCN]), in comparison to the control (polyethylene). At marrow-rich implantation sites (mandibular body), the amount of new bone formation was significant, but was not enhanced by the presence of BMSCs in the BMSC-n-HA/PA hybrids. However, the BMSC-n-HA/PA hybrids were essential for promoting bone formation in marrow-poor sites (mandibular angle). In conclusion, n-HA/PA biomaterials, which offer the advantage of enhanced mechanical performance over n-HA, exhibit significant bioactivity, including the capacity for bone regeneration at marrow-poor sites when implanted in combination with BMSCs.
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Affiliation(s)
- Jun Guo
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, P.R. China
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68
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Smith AW, Segar CE, Nguyen PK, MacEwan MR, Efimov IR, Elbert DL. Long-term culture of HL-1 cardiomyocytes in modular poly(ethylene glycol) microsphere-based scaffolds crosslinked in the phase-separated state. Acta Biomater 2012; 8:31-40. [PMID: 21920469 DOI: 10.1016/j.actbio.2011.08.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 08/17/2011] [Accepted: 08/24/2011] [Indexed: 01/16/2023]
Abstract
Poly(ethylene glycol) (PEG) microspheres were assembled around HL-1 cardiomyocytes to produce highly porous modular scaffolds. In this study we took advantage of the immiscibility of PEG and dextran to improve upon our previously described modular scaffold fabrication methods. Phase separating the PEG microspheres in dextran solutions caused them to rapidly deswell and crosslink together, eliminating the need for serum protein-based crosslinking. This also led to a dramatic increase in the stiffness of the scaffolds and greatly improved the handling characteristics. HL-1 cardiomyocytes were present during microsphere crosslinking in the cytocompatible dextran solution, exhibiting high cell viability following scaffold formation. Over the course of 2 weeks a 9-fold expansion in cell number was observed. The cardiac functional markers sarcomeric α-actinin and connexin 43 were expressed at 13 and 24 days after scaffold formation. HL-1 cells were spontaneously depolarizing 38 days after scaffold formation, which was visualized by confocal microscopy using a calcium-sensitive dye. Electrical stimulation resulted in synchronization of activation peaks throughout the scaffolds. These findings demonstrate that PEG microsphere scaffolds fabricated in the presence of dextran can support the long-term three-dimensional culture of cells, suggesting applications in cardiovascular tissue engineering.
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Affiliation(s)
- Amanda W Smith
- Department of Biomedical Engineering and Center for Materials Innovation, Washington University, St. Louis, MO 63130, USA
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69
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Aurand ER, Lampe KJ, Bjugstad KB. Defining and designing polymers and hydrogels for neural tissue engineering. Neurosci Res 2011; 72:199-213. [PMID: 22192467 DOI: 10.1016/j.neures.2011.12.005] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 11/07/2011] [Accepted: 12/07/2011] [Indexed: 12/16/2022]
Abstract
The use of biomaterials, such as hydrogels, as neural cell delivery devices is becoming more common in areas of research such as stroke, traumatic brain injury, and spinal cord injury. When reviewing the available research there is some ambiguity in the type of materials used and results are often at odds. This review aims to provide the neuroscience community who may not be familiar with fundamental concepts of hydrogel construction, with basic information that would pertain to neural tissue applications, and to describe the use of hydrogels as cell and drug delivery devices. We will illustrate some of the many tunable properties of hydrogels and the importance of these properties in obtaining reliable and consistent results. It is our hope that this review promotes creative ideas for ways that hydrogels could be adapted and employed for the treatment of a broad range of neurological disorders.
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Affiliation(s)
- Emily R Aurand
- Neuroscience Program, University of Colorado Denver - Anschutz Medical Campus, Aurora, CO 80045, USA.
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70
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Bailey BM, Hui V, Fei R, Grunlan MA. Tuning PEG-DA hydrogel properties via solvent-induced phase separation (SIPS)(). ACTA ACUST UNITED AC 2011; 21:18776-18782. [PMID: 22956857 DOI: 10.1039/c1jm13943f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Poly(ethylene glycol) diacrylate (PEG-DA) hydrogels are widely utilized to probe cell-material interactions and ultimately for a material-guided approach to tissue regeneration. In this study, PEG-DA hydrogels were fabricated via solvent-induced phase separation (SIPS) to obtain hydrogels with a broader range of tunable physical properties including morphology (e.g. porosity), swelling and modulus (G'). In contrast to conventional PEG-DA hydrogels prepared from an aqueous precursor solution, the reported SIPS protocol utilized a dichloromethane (DCM) precursor solution which was sequentially photopolymerized, dried and hydrated. Physical properties were further tailored by varying the PEG-DA wt% concentration (5 wt%-25 wt%) and M(n) (3.4k and 6k g mol (-1)). SIPS produced PEG-DA hydrogels with a macroporous morphology as well as increased G' values versus the corresponding conventional PEG-DA hydrogels. Notably, since the total swelling was not significantly changed versus the corresponding conventional PEG-DA hydrogels, pairs or series of hydrogels represent scaffolds in which morphology and hydration or G' and hydration are uncoupled. In addition, PEG-DA hydrogels prepared via SIPS exhibited enhanced degradation rates.
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Affiliation(s)
- Brennan Margaret Bailey
- Texas A&M University, Department of Biomedical Engineering, Materials Science and Engineering Program, 3120 TAMU College Station, TX, USA. ; Tel: (+979) 845-2406
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71
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Dehghani F, Annabi N. Engineering porous scaffolds using gas-based techniques. Curr Opin Biotechnol 2011; 22:661-6. [DOI: 10.1016/j.copbio.2011.04.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 04/01/2011] [Indexed: 12/18/2022]
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72
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Xu F, Sridharan B, Durmus NG, Wang S, Yavuz AS, Gurkan UA, Demirci U. Living bacterial sacrificial porogens to engineer decellularized porous scaffolds. PLoS One 2011; 6:e19344. [PMID: 21552485 PMCID: PMC3084297 DOI: 10.1371/journal.pone.0019344] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 03/28/2011] [Indexed: 12/31/2022] Open
Abstract
Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types.
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Affiliation(s)
- Feng Xu
- Demirci Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - BanuPriya Sridharan
- Demirci Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Naside Gozde Durmus
- Division of Biology and Medicine, School of Engineering, Brown University, Providence, Rhode Island, United States of America
| | - ShuQi Wang
- Demirci Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ahmet Sinan Yavuz
- Demirci Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Umut Atakan Gurkan
- Demirci Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Utkan Demirci
- Demirci Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Harvard-MIT Health Sciences and Technology, Cambridge, Massashusetts, United States of America
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73
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Huang GY, Zhou LH, Zhang QC, Chen YM, Sun W, Xu F, Lu TJ. Microfluidic hydrogels for tissue engineering. Biofabrication 2011; 3:012001. [DOI: 10.1088/1758-5082/3/1/012001] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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74
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Hwang Y, Sangaj N, Varghese S. Interconnected macroporous poly(ethylene glycol) cryogels as a cell scaffold for cartilage tissue engineering. Tissue Eng Part A 2011; 16:3033-41. [PMID: 20486791 DOI: 10.1089/ten.tea.2010.0045] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Macroporous networks of poly(ethylene glycol) (PEG) with interconnected pores can be created by cryogelation techniques. In this study, we describe the potential application of such PEG cryogels as scaffolds for cartilage tissue engineering. Three-dimensional macroporous cryogels were evaluated for chondrocyte growth and production of cartilage-specific extracellular matrix (ECM). Seeded primary bovine chondrocytes showed homogeneous distribution throughout the cryogels. DNA content suggests continuous cell proliferation over 4 weeks of in vitro culture. Analysis of the composition of cell-secreted ECM showed a culture-time-dependent increase in the amount of glycosaminoglycan and collagen. The production of ECM by chondrocytes was confirmed using scanning electron microscopy analysis. Further histological and immunohistological analysis of the cell-laden scaffold confirmed the presence of accumulated cartilage-specific ECM within the scaffold. The interconnected macroporous network promoted diffusion of cell-secreted matrix within the cryogels. Our results indicated that interconnected macroporous PEG cryogels successfully supported attachment, viability, proliferation, and biosynthetic activity of seeded chondrocytes.
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Affiliation(s)
- Yongsung Hwang
- Materials Science and Engineering Program, University of California–San Diego, La Jolla, California 92093-0412, USA
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75
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Lanasa SM, Hoffecker IT, Bryant SJ. Presence of pores and hydrogel composition influence tensile properties of scaffolds fabricated from well-defined sphere templates. J Biomed Mater Res B Appl Biomater 2010; 96:294-302. [PMID: 21210509 DOI: 10.1002/jbm.b.31765] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 06/30/2010] [Accepted: 07/07/2010] [Indexed: 01/16/2023]
Abstract
Sphere templating is an attractive method to produce porous polymeric scaffolds with well-defined and uniform pore structures for applications in tissue engineering. While high porosity is desired to facilitate cell seeding and enhance nutrient transport, the incorporation of pores will impact gross mechanical properties of tissue scaffolds and will likely be dependent on pore size. The goals of this study were to evaluate the effect of pores, pore diameter, and polymer composition on gross mechanical properties of hydrogels prepared from crosslinked poly(ethylene glycol) (PEG) and poly(2-hydroxyethyl methacrylate) (pHEMA). Sphere templates were fabricated from uncrosslinked poly(methyl methacrylate) spheres sieved between 53-63 and 150-180 μm. Incorporating pores into hydrogels significantly decreased the quasi-static modulus and ultimate tensile stress, but increased the ultimate tensile strain. For pHEMA, decreases in gel crosslinking density and increases in pore diameters followed similar trends. Interestingly, the mechanical properties of porous PEG hydrogels were less sensitive to changes in pore diameter for a given polymer composition. Additionally, pore diameter was shown to affect skeletal myoblast adhesion whereby many cells cultured in porous hydrogels with smaller pores were seen spanning across multiple pores, but lined the inside of larger pores. In summary, incorporation of pores and changes in pore diameter significantly affect the gross mechanical properties, but in a manner that is dependent on gel chemistry, structure, and composition. Together, these findings will help to design better hydrogel scaffolds for applications where gross mechanical properties and porosity are critical.
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Affiliation(s)
- Stephanie M Lanasa
- Department of Chemical and Biological Engineering, The University of Colorado at Boulder, Boulder, Colorado 80309, USA
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76
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Wong VW, Rustad KC, Galvez MG, Neofytou E, Neofyotou E, Glotzbach JP, Januszyk M, Major MR, Sorkin M, Longaker MT, Rajadas J, Gurtner GC. Engineered pullulan-collagen composite dermal hydrogels improve early cutaneous wound healing. Tissue Eng Part A 2010; 17:631-44. [PMID: 20919949 DOI: 10.1089/ten.tea.2010.0298] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
New strategies for skin regeneration are needed to address the significant medical burden caused by cutaneous wounds and disease. In this study, pullulan-collagen composite hydrogel matrices were fabricated using a salt-induced phase inversion technique, resulting in a structured yet soft scaffold for skin engineering. Salt crystallization induced interconnected pore formation, and modification of collagen concentration permitted regulation of scaffold pore size. Hydrogel architecture recapitulated the reticular distribution of human dermal matrix while maintaining flexible properties essential for skin applications. In vitro, collagen hydrogel scaffolds retained their open porous architecture and viably sustained human fibroblasts and murine mesenchymal stem cells and endothelial cells. In vivo, hydrogel-treated murine excisional wounds demonstrated improved wound closure, which was associated with increased recruitment of stromal cells and formation of vascularized granulation tissue. In conclusion, salt-induced phase inversion techniques can be used to create modifiable pullulan-collagen composite dermal scaffolds that augment early wound healing. These novel biomatrices can potentially serve as a structured delivery template for cells and biomolecules in regenerative skin applications.
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Affiliation(s)
- Victor W Wong
- Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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77
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Preparation of three-dimensional interconnected macroporous cellulosic hydrogels for soft tissue engineering. Biomaterials 2010; 31:8141-52. [DOI: 10.1016/j.biomaterials.2010.07.059] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Accepted: 07/13/2010] [Indexed: 01/28/2023]
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78
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Gkioni K, Leeuwenburgh SCG, Douglas TEL, Mikos AG, Jansen JA. Mineralization of hydrogels for bone regeneration. TISSUE ENGINEERING PART B-REVIEWS 2010; 16:577-85. [PMID: 20735319 DOI: 10.1089/ten.teb.2010.0462] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Hydrogels are an important class of highly hydrated polymers that are widely investigated for potential use in soft tissue engineering. Generally, however, hydrogels lack the ability to mineralize, preventing the formation of chemical bonds with hard tissues such as bone. A recent trend in tissue engineering involves the development of hydrogels that possess the capacity to mineralize. The strategy that has attracted most interest has been the incorporation of inorganic phases such as calcium phosphate ceramics and bioglasses into hydrogel matrices. These inorganic particles act as nucleation sites that enable further mineralization, thus improving the mechanical properties of the composite material. A second route to create nucleation sites for calcification of hydrogels involves the use of features from the physiological mineralization process. Examples of these biomimetic mineralization strategies include (1) soaking of hydrogels in solutions that are saturated with respect to calcium phosphate, (2) incorporation of enzymes that catalyze deposition of bone mineral, and (3) incorporation of synthetic analogues to matrix vesicles that are the initial sites of biomineralization. Functionalization of the polymeric hydrogel backbone with negatively charged groups is a third mechanism to promote mineralization in otherwise inert hydrogels. This review summarizes the main strategies that have been developed in the past decade to calcify hydrogel matrices and render these hydrogels suitable for applications in bone regeneration.
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Affiliation(s)
- Katerina Gkioni
- Department of Biomaterials, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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79
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Tzeranis DS, Roy A, So PTC, Yannas IV. An optical method to quantify the density of ligands for cell adhesion receptors in three-dimensional matrices. J R Soc Interface 2010; 7 Suppl 5:S649-61. [PMID: 20671067 PMCID: PMC3024575 DOI: 10.1098/rsif.2010.0321.focus] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 07/09/2010] [Indexed: 12/21/2022] Open
Abstract
The three-dimensional matrix that surrounds cells is an important insoluble regulator of cell phenotypes. Examples of such insoluble surfaces are the extracellular matrix (ECM), ECM analogues and synthetic polymeric biomaterials. Cell-matrix interactions are mediated by cell adhesion receptors that bind to chemical entities (adhesion ligands) on the surface of the matrix. There are currently no established methods to obtain quantitative estimates of the density of adhesion ligands recognized by specific cell adhesion receptors. This article presents a new optical-based methodology for measuring ligands of adhesion receptors on three-dimensional matrices. The study also provides preliminary quantitative results for the density of adhesion ligands of integrins alpha(1)beta(1) and alpha(2)beta(1) on the surface of collagen-based scaffolds, similar to biomaterials that are used clinically to induce regeneration in injured skin and peripheral nerves. Preliminary estimates of the surface density of the ligands of these two major collagen-binding receptors are 5775 +/- 2064 ligands microm(-2) for ligands of alpha(1)beta(1) and 17 084 +/- 5353 ligands microm(-2) for ligands of alpha(2)beta(1). The proposed methodology can be used to quantify the surface chemistry of insoluble surfaces that possess biological activity, such as native tissue ECM and biomaterials, and therefore can be used in cell biology, biomaterials science and regenerative medical studies for quantitative description of a matrix and its effects on cells.
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Affiliation(s)
- Dimitrios S. Tzeranis
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Amit Roy
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Peter T. C. So
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ioannis V. Yannas
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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80
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Chiu YC, Larson JC, Isom A, Brey EM. Generation of Porous Poly(Ethylene Glycol) Hydrogels by Salt Leaching. Tissue Eng Part C Methods 2010; 16:905-12. [DOI: 10.1089/ten.tec.2009.0646] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Yu-Chieh Chiu
- The Pritzker Institute of Biomedical Science and Engineering and Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois
| | - Jeffery C. Larson
- The Pritzker Institute of Biomedical Science and Engineering and Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois
| | - Anthony Isom
- The Pritzker Institute of Biomedical Science and Engineering and Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois
| | - Eric M. Brey
- The Pritzker Institute of Biomedical Science and Engineering and Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois
- Hines Veterans Administration Hospital, Hines, Illinois
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81
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Weir MD, Xu HHK. Human bone marrow stem cell-encapsulating calcium phosphate scaffolds for bone repair. Acta Biomater 2010; 6:4118-26. [PMID: 20451676 DOI: 10.1016/j.actbio.2010.04.029] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/26/2010] [Accepted: 04/30/2010] [Indexed: 01/27/2023]
Abstract
Due to its injectability and excellent osteoconductivity, calcium phosphate cement (CPC) is highly promising for orthopedic applications. However, a literature search revealed no report on human bone marrow mesenchymal stem cell (hBMSC) encapsulation in CPC for bone tissue engineering. The aim of this study was to encapsulate hBMSCs in alginate hydrogel beads and then incorporate them into CPC, CPC-chitosan and CPC-chitosan-fiber scaffolds. Chitosan and degradable fibers were used to mechanically reinforce the scaffolds. After 21 days, that the percentage of live cells and the cell density of hBMSCs inside CPC-based constructs matched those in alginate without CPC, indicating that the CPC setting reaction did not harm the hBMSCs. Alkaline phosphate activity increased by 8-fold after 14 days. Mineral staining, scanning electron microscopy and X-ray diffraction confirmed that apatitic mineral was deposited by the cells. The amount of hBMSC-synthesized mineral in CPC-chitosan-fiber matched that in CPC without chitosan and fibers. Hence, adding chitosan and fibers, which reinforced the CPC, did not compromise hBMSC osteodifferentiation and mineral synthesis. In conclusion, hBMSCs were encapsulated in CPC and CPC-chitosan-fiber scaffolds for the first time. The encapsulated cells remained viable, osteodifferentiated and synthesized bone minerals. These self-setting, hBMSC-encapsulating CPC-based constructs may be promising for bone tissue engineering applications.
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Affiliation(s)
- Michael D Weir
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, 21201, USA
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82
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Annabi N, Nichol JW, Zhong X, Ji C, Koshy S, Khademhosseini A, Dehghani F. Controlling the porosity and microarchitecture of hydrogels for tissue engineering. TISSUE ENGINEERING. PART B, REVIEWS 2010. [PMID: 20121414 DOI: 10.1089/ten.ten.2009.0639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Tissue engineering holds great promise for regeneration and repair of diseased tissues, making the development of tissue engineering scaffolds a topic of great interest in biomedical research. Because of their biocompatibility and similarities to native extracellular matrix, hydrogels have emerged as leading candidates for engineered tissue scaffolds. However, precise control of hydrogel properties, such as porosity, remains a challenge. Traditional techniques for creating bulk porosity in polymers have demonstrated success in hydrogels for tissue engineering; however, often the conditions are incompatible with direct cell encapsulation. Emerging technologies have demonstrated the ability to control porosity and the microarchitectural features in hydrogels, creating engineered tissues with structure and function similar to native tissues. In this review, we explore the various technologies for controlling the porosity and microarchitecture within hydrogels, and demonstrate successful applications of combining these techniques.
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Affiliation(s)
- Nasim Annabi
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, Australia
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83
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Annabi N, Nichol JW, Zhong X, Ji C, Koshy S, Khademhosseini A, Dehghani F. Controlling the porosity and microarchitecture of hydrogels for tissue engineering. TISSUE ENGINEERING. PART B, REVIEWS 2010; 16:371-83. [PMID: 20121414 PMCID: PMC2946907 DOI: 10.1089/ten.teb.2009.0639] [Citation(s) in RCA: 739] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 01/29/2010] [Indexed: 12/19/2022]
Abstract
Tissue engineering holds great promise for regeneration and repair of diseased tissues, making the development of tissue engineering scaffolds a topic of great interest in biomedical research. Because of their biocompatibility and similarities to native extracellular matrix, hydrogels have emerged as leading candidates for engineered tissue scaffolds. However, precise control of hydrogel properties, such as porosity, remains a challenge. Traditional techniques for creating bulk porosity in polymers have demonstrated success in hydrogels for tissue engineering; however, often the conditions are incompatible with direct cell encapsulation. Emerging technologies have demonstrated the ability to control porosity and the microarchitectural features in hydrogels, creating engineered tissues with structure and function similar to native tissues. In this review, we explore the various technologies for controlling the porosity and microarchitecture within hydrogels, and demonstrate successful applications of combining these techniques.
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Affiliation(s)
- Nasim Annabi
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, Australia
| | - Jason W. Nichol
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Xia Zhong
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, Australia
| | - Chengdong Ji
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, Australia
| | - Sandeep Koshy
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Ali Khademhosseini
- Department of Medicine, Center for Biomedical Engineering, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Fariba Dehghani
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, Australia
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84
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Fisher OZ, Khademhosseini A, Langer R, Peppas NA. Bioinspired materials for controlling stem cell fate. Acc Chem Res 2010; 43:419-28. [PMID: 20043634 DOI: 10.1021/ar900226q] [Citation(s) in RCA: 254] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although researchers currently have limited ability to mimic the natural stem cell microenvironment, recent work at the interface of stem biology and biomaterials science has demonstrated that control over stem cell behavior with artificial microenvironments is quite advanced. Embryonic and adult stem cells are potentially useful platforms for tissue regeneration, cell-based therapeutics, and disease-in-a-dish models for drug screening. The major challenge in this field is to reliably control stem cell behavior outside the body. Common biological control schemes often ignore physicochemical parameters that materials scientists and engineers commonly manipulate, such as substrate topography and mechanical and rheological properties. However, with appropriate attention to these parameters, researchers have designed novel synthetic microenvironments to control stem cell behavior in rather unnatural ways. In this Account, we review synthetic microenvironments that aim to overcome the limitations of natural niches rather than to mimic them. A biomimetic stem cell control strategy is often limited by an incomplete understanding of the complex signaling pathways that drive stem cell behavior from early embryogenesis to late adulthood. The stem cell extracellular environment presents a miscellany of competing biological signals that keep the cell in a state of unstable equilibrium. Using synthetic polymers, researchers have designed synthetic microenvironments with an uncluttered array of cell signals, both specific and nonspecific, that are motivated by rather than modeled after biology. These have proven useful in maintaining cell potency, studying asymmetric cell division, and controlling cellular differentiation. We discuss recent research that highlights important biomaterials properties for controlling stem cell behavior, as well as advanced processes for selecting those materials, such as combinatorial and high-throughput screening. Much of this work has utilized micro- and nanoscale fabrication tools for controlling material properties and generating diversity in both two and three dimensions. Because of their ease of synthesis and similarity to biological soft matter, hydrogels have become a biomaterial of choice for generating 3D microenvironments. In presenting these efforts within the framework of synthetic biology, we anticipate that future researchers may exploit synthetic polymers to create microenvironments that control stem cell behavior in clinically relevant ways.
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Affiliation(s)
| | - Ali Khademhosseini
- Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Robert Langer
- David H. Koch Institute for Integrative Cancer Research
- Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology
- Department of Chemical Engineering
| | - Nicholas A. Peppas
- Departments of Chemical Engineering and Biomedical Engineering and Division of Pharmaceutics, The University of Texas at Austin, Austin, Texas 78712
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85
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Keskar V, Gandhi M, Gemeinhart EJ, Gemeinhart RA. Initial evaluation of vascular ingrowth into superporous hydrogels. J Tissue Eng Regen Med 2009; 3:486-90. [PMID: 19526620 DOI: 10.1002/term.183] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
There is a need for new materials and architectures for tissue engineering and regenerative medicine. Based upon our recent results developing novel scaffold architecture, we hypothesized that this new architecture would foster vascularization, a particular need for tissue engineering. We report on the potential of superporous hydrogel (SPH) scaffolds for in vivo cellular infiltration and vascularization. Poly(ethylene glycol) diacrylate (PEGDA) SPH scaffolds were implanted in the dorsum of severe combined immunodeficient (SCID) mice and harvested after 4 weeks of in vivo implantation. The SPHs were visibly red and vascularized, as apparent when compared to the non-porous hydrogel controls, which were macroscopically avascular. Host cell infiltration was observed throughout the SPHs. Blood cells and vascular structures, confirmed through staining for CD34 and smooth muscle alpha-actin, were observed throughout the scaffolds. This novel soft material may be utilized for cell transplantation, tissue engineering and in combination with cell therapies. The neovasularization and limited fibrotic response suggest that the architecture may be conducive to cell survival and rapid vessel development.
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Affiliation(s)
- Vandana Keskar
- Department of Biopharmaceutical Sciences, University of Illinois, Chicago, IL 60612-7231, USA
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