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Wong FSY, Tsang KK, Chan BP, Lo ACY. Both non-coated and polyelectrolytically-coated intraocular collagen-alginate composite gels enhanced photoreceptor survival in retinal degeneration. Biomaterials 2023; 293:121948. [PMID: 36516686 DOI: 10.1016/j.biomaterials.2022.121948] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/09/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Treatments of vision-threatening retinal diseases are often hampered by drug delivery difficulties. Polyelectrolytically-coated alginate encapsulated-cell therapy (ECT) systems have shown therapeutic efficacy through prolonged in vivo drug delivery but still face various biocompatibility, viability, drug delivery and mechanical stability issues in clinical trials. Here, novel, injectable alginate-poly-l-lysine (AP)-coated composite alginate-collagen (CAC) ECT gels were developed for sustained ocular drug delivery, and their long-term performance was compared with non-coated CAC ECT gels. All optimised AP-coated gels (AP1- and AP5.5-CAC ECT: 2 mg/ml collagen, 1.5% high molecular weight alginate, 50,000 cells/gel, with 0.01% or 0.05% poly-l-lysine coating for 5 min, followed by 0.15% alginate coating) and non-coated gels showed effective cell proliferation control, cell viability support and continuous delivery of bioactive glial cell-derived neurotrophic factor (GDNF) with no significant gel degradation in vitro and in rat vitreous. Most importantly, intravitreally injected gels demonstrated therapeutic efficacy in Royal College of Surgeons rats with retinal degeneration, resulting in reduced photoreceptor apoptosis and retinal function loss. At 6 months post-implantation, no host-tissue attachment or ingrowth was detected on the retrieved gels. Non-coated gels were mechanically more stable than AP5.5-coated ones under the current cell loading. This study demonstrated that both coated and non-coated ECT gels can serve as well-controlled, sustained drug delivery platforms for treating posterior eye diseases without immunosuppression.
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Affiliation(s)
- Francisca Siu Yin Wong
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Ken Kin Tsang
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Barbara Pui Chan
- Tissue Engineering Laboratory, Department of Mechanical Engineering, Faculty of Engineering, The University of Hong Kong, Hong Kong, China
| | - Amy Cheuk Yin Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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2
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Mahameed M, Fussenegger M. Engineering autonomous closed-loop designer cells for disease therapy. iScience 2022; 25:103834. [PMID: 35243222 PMCID: PMC8857602 DOI: 10.1016/j.isci.2022.103834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Mohamed Mahameed
- ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Martin Fussenegger
- ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, CH-4058 Basel, Switzerland
- University of Basel, Faculty of Life Science, 4001 Basel, Switzerland
- Corresponding author
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3
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Artificial cells for the treatment of liver diseases. Acta Biomater 2021; 130:98-114. [PMID: 34126265 DOI: 10.1016/j.actbio.2021.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/06/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022]
Abstract
Liver diseases have become an increasing health burden and account for over 2 million deaths every year globally. Standard therapies including liver transplant and cell therapy offer a promising treatment for liver diseases, but they also suffer limitations such as adverse immune reactions and lack of long-term efficacy. Artificial cells that mimic certain functions of a living cell have emerged as a new strategy to overcome some of the challenges that liver cell therapy faces at present. Artificial cells have demonstrated advantages in long-term storage, targeting capability, and tuneable features. This article provides an overview of the recent progress in developing artificial cells and their potential applications in liver disease treatment. First, the design of artificial cells and their biomimicking functions are summarized. Then, systems that mimic cell surface properties are introduced with two concepts highlighted: cell membrane-coated artificial cells and synthetic lipid-based artificial cells. Next, cell microencapsulation strategy is summarized and discussed. Finally, challenges and future perspectives of artificial cells are outlined. STATEMENT OF SIGNIFICANCE: Liver diseases have become an increasing health burden. Standard therapies including liver transplant and cell therapy offer a promising treatment for liver diseases, but they have limitations such as adverse immune reactions and lack of long-term efficacy. Artificial cells that mimic certain functions of a living cell have emerged as a new strategy to overcome some of the challenges that liver cell therapy faces at present. This article provides an overview of the recent progress in developing artificial cells and their potential applications in liver disease treatment, including the design of artificial cells and their biomimicking functions, two systems that mimic cell surface properties (cell membrane-coated artificial cells and synthetic lipid-based artificial cells), and cell microencapsulation strategy. We also outline the challenges and future perspectives of artificial cells.
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4
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A therapeutic vascular conduit to support in vivo cell-secreted therapy. NPJ Regen Med 2021; 6:40. [PMID: 34326344 PMCID: PMC8322381 DOI: 10.1038/s41536-021-00150-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 07/07/2021] [Indexed: 11/08/2022] Open
Abstract
A significant barrier to implementation of cell-based therapies is providing adequate vascularization to provide oxygen and nutrients. Here we describe an approach for cell transplantation termed the Therapeutic Vascular Conduit (TVC), which uses an acellular vessel as a scaffold for a hydrogel sheath containing cells designed to secrete a therapeutic protein. The TVC can be directly anastomosed as a vascular graft. Modeling supports the concept that the TVC allows oxygenated blood to flow in close proximity to the transplanted cells to prevent hypoxia. As a proof-of-principle study, we used erythropoietin (EPO) as a model therapeutic protein. If implanted as an arteriovenous vascular graft, such a construct could serve a dual role as an EPO delivery platform and hemodialysis access for patients with end-stage renal disease. When implanted into nude rats, TVCs containing EPO-secreting fibroblasts were able to increase serum EPO and hemoglobin levels for up to 4 weeks. However, constitutive EPO expression resulted in macrophage infiltration and luminal obstruction of the TVC, thus limiting longer-term efficacy. Follow-up in vitro studies support the hypothesis that EPO also functions to recruit macrophages. The TVC is a promising approach to cell-based therapeutic delivery that has the potential to overcome the oxygenation barrier to large-scale cellular implantation and could thus be used for a myriad of clinical disorders. However, a complete understanding of the biological effects of the selected therapeutic is absolutely essential.
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Joshi DJ, Chitre NM, Bansal A, Murnane KS, D’Souza MJ. Formulation and Characterization of Microcapsules Encapsulating PC12 Cells as a Prospective Treatment Approach for Parkinson's Disease. AAPS PharmSciTech 2021; 22:149. [PMID: 33961149 DOI: 10.1208/s12249-021-02007-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/29/2021] [Indexed: 01/02/2023] Open
Abstract
Parkinson's disease (PD) is the second most common neurological disorder, associated with decreased dopamine levels in the brain. The goal of this study was to assess the potential of a regenerative medicine-based cell therapy approach to increase dopamine levels. In this study, we used rat adrenal pheochromocytoma (PC12) cells that can produce, store, and secrete dopamine. These cells were microencapsulated in the selectively permeable polymer membrane to protect them from immune responses. For fabrication of the microcapsules, we used a modified Buchi spray dryer B-190 that allows for fast manufacturing of microcapsules and is industrially scalable. Size optimization of the microcapsules was performed by systematically varying key parameters of the spraying device. The short- and long-term stabilities of the microcapsules were assessed. In the in vitro study, the cells were found viable for a period of 30 days. Selective permeability of the microcapsules was confirmed via dopamine release assay and micro BCA protein assay. We found that the microcapsules were permeable to the small molecules including dopamine and were impermeable to the large molecules like BSA. Thus, they can provide the protection to the encapsulated cells from the immune cells. Griess's assay confirmed the non-immunogenicity of the microcapsules. These results demonstrate the effective fabrication of microcapsules encapsulating cells using an industrially scalable device. The microcapsules were stable, and the cells were viable inside the microcapsules and were found to release dopamine. Thus, these microcapsules have the potential to serve as the alternative or complementary treatment approach for PD.
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Hajifathaliha F, Mahboubi A, Mohit E, Bolourchian N, Khalaj V, Nematollahi L. Comparison of Linear Poly Ethylene Imine (LPEI) and Poly L-Lysine (PLL) in Fabrication of CHOK 1 Cell-Loaded Multilayer Alginate Microcapsules. Adv Pharm Bull 2020; 10:290-296. [PMID: 32373499 PMCID: PMC7191236 DOI: 10.34172/apb.2020.035] [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: 06/08/2019] [Revised: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 12/26/2022] Open
Abstract
Purpose: Poly l-lysine (PLL) has been introduced as a strengthening covering layer for alginate microcapsules which are the most convenient way for cell encapsulation. Some disadvantages of PLL such as high price and low biocompatibility have prompted scientists to find better alternatives. Linear poly ethylene imine (LPEI), thanks to its highly similar structure to PLL, could be considered as a proper cost-effective alternative. In this study LPEI and PLL were compared as covering layers of cell-loaded alginate-LPEI-alginate (cALA) and alginate-PLL-alginate (cAPA) microcapsules. Methods: In addition to the physico-mechanical properties, the encapsulation efficiency, cell survival post encapsulation, cell viability, and cellular metabolic activity within the microcapsules were evaluated using trypan blue, live/dead cell staining, and MTT test, respectively. Results: Physico-mechanical evaluation of the microcapsules revealed that the cell microencapsulation process did not affect their shape, size, and mechanical stability. Although the encapsulation efficiency for cALA and cAPA was not different (P >0.05), cell survival post encapsulation was higher in cALA than in cAPA (P<0.05) which could be the reason for the higher cell viability and also cellular metabolic activity within these microcapsules in comparison to cAPA. Conclusion: Here, based on these results, ALA could be introduced as a preferable alternative to APA for cell encapsulation.
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Affiliation(s)
- Fariba Hajifathaliha
- Food Safety Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Student Research Committee, Department of Pharmaceutics, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Arash Mahboubi
- Food Safety Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Student Research Committee, Department of Pharmaceutics, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elham Mohit
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Noushin Bolourchian
- Student Research Committee, Department of Pharmaceutics, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Vahid Khalaj
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Leila Nematollahi
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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7
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Haque T, Chen H, Ouyang W, Martoni C, Lawuyi B, Urbanska AM, Urbanska A, Prakash S. Investigation of a New Microcapsule Membrane Combining Alginate, Chitosan, Polyethylene Glycol and Poly-L-Lysine for Cell Transplantation Applications. Int J Artif Organs 2018; 28:631-7. [PMID: 16015573 DOI: 10.1177/039139880502800612] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Microencapsulation of living cells may serve as an alternative therapy for patients requiring organ transplants. One of the limiting factors in the progress of such therapy is attaining a biocompatible and mechanically stable polymer. The current study investigates the potential of a novel membrane combining alginate, chitosan, polyethylene glycol (PEG) and poly-L-lysine (PLL) with the objective of proposing a membrane suitable for cell entrapment that may overcome some of the shortcomings of the widely studied alginate-poly-L-lysine-alginate (APA) capsules. The novel microcapsule was formulated using a 1.5% alginate solution coated with 0.05% chitosan, 0.1% PEG and 0.05% poly-L-lysine with a final layer of 0.1% alginate. Microcapsules having a diameter of 450 ± 30 μm were prepared. Upon citrate treatment, the membrane remained intact and retained its spherical structure. The membrane was able to support liver cell proliferation and the encapsulated cells were capable of secreting proteins. The study demonstrated that the new membrane can be used for cell entrapment. However, further investigations are needed to assess its potential for long term transplantation and usage in the development of bioartificial organs.
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Affiliation(s)
- T Haque
- Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
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8
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Abstract
This method is used to prepare microencapsulation of hepatocytes. The key steps in the protocol are (a) isolation of porcine hepatocytes, followed by (b) production of hepatocytes encapsulation, and (c) evaluation of encapsulations and hepatocytes. This method of collecting porcine hepatocytes was first used in 2003 (Maruyama et al. Cell Transplant 12:593-598, 2003). Cell encapsulation technology was first introduced by Chang (Science 146:524-525, 1964) and later by Lim and Sun in 1980 (Science 210:908-910, 1980). Since then, it has been well adopted in tissue engineering and controlled delivery of biological therapeutics such as bioartificial liver.
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9
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Moran DM, Koniaris LG, Jablonski EM, Cahill PA, Halberstadt CR, McKillop IH. Microencapsulation of Engineered Cells to Deliver Sustained High Circulating Levels of Interleukin-6 to Study Hepatocellular Carcinoma Progression. Cell Transplant 2017; 15:785-98. [PMID: 17269449 DOI: 10.3727/000000006783981477] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Interlukin-6 (IL-6) is a pleitropic cytokine that plays a central role in normal and abnormal hepatic function and response. The aims of the current study were to determine the viability of using cell encapsulation technology to introduce a genetically modified xenogeneic (CHO) cell population to elevate circulating levels of rhIL-6 in a rat model and determine the effects of sustained high rhIL-6 levels on hepatocellular carcinoma (HCC) progression in vivo. An alginate matrix was combined with transfected CHO cells, selected for their ability to synthesize rhIL-6, and used to generate uniform alginate–cell beads. Once encapsulated transfected cells continued to undergo replication, formed colonies within the bead, and synthesized/released large quantities of rhIL-6 into culture medium in vitro. Intraperitoneal implantation of beads into rats resulted in significantly increased circulating and intrahepatic levels of rhIL-6 up to 4 days postimplantation. Prolonged implantation led to the escape of CHO cells from the bead, resulting in a host response and CHO cell death within the bead. Subsequently CHO-IL-6 encapsulated cells were implanted into rats previously inoculated intrahepatically with the H4IIE HCC cell line. These studies demonstrated the maintenance of high circulating/intrahepatic rhIL-6 levels in this model. Despite significantly increased rhIL-6, this technique did not significantly alter the rate of net tumor progression. However, Stat3 activity was significantly increased in both normal liver and HCC tissue resected from animals implanted with CHO-IL-6 cells. Collectively these data demonstrate the short-term viability of using cell encapsulation technology to generate high levels of active circulating and intrahepatic cytokines and raise the possibility of modifying specific signal transduction cascades identified to be important during tumor progression.
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Affiliation(s)
- Diarmuid M Moran
- Department of Biology, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
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10
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Sanberg PR, Greene-Zavertnik C, Davis CD. Article Commentary: Cell Transplantation: The Regenerative Medicine Journal. A Biennial Analysis of Publications. Cell Transplant 2017; 12:815-825. [DOI: 10.3727/000000003771000165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Paul R. Sanberg
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., MDC 78, Tampa, FL 33612
| | - Cathryn Greene-Zavertnik
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., MDC 78, Tampa, FL 33612
| | - Cyndy D. Davis
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., MDC 78, Tampa, FL 33612
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11
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Ma H, Qiao S, Wang Z, Geng S, Zhao Y, Hou X, Tian W, Chen X, Yao L. Microencapsulation of Lefty-secreting engineered cells for pulmonary fibrosis therapy in mice. Am J Physiol Lung Cell Mol Physiol 2017; 312:L741-L747. [PMID: 28213468 DOI: 10.1152/ajplung.00295.2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 11/22/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive disease that causes unremitting deposition of extracellular matrix proteins, thus resulting in distortion of the pulmonary architecture and impaired gas exchange. Associated with high morbidity and mortality, IPF is generally refractory to current pharmacological therapies. Lefty A, a potent inhibitor of transforming growth factor-β signaling, has been shown to have promising antifibrotic ability in vitro for the treatment of renal fibrosis and other potential organ fibroses. Here, we determined whether Lefty A can attenuate bleomycin (BLM)-induced pulmonary fibrosis in vivo based on a novel therapeutic strategy where human embryonic kidney 293 (HEK293) cells are genetically engineered with the Lefty A-associated GFP gene. The engineered HEK293 cells were encapsulated in alginate microcapsules and then subcutaneously implanted in ICR mice that had 1 wk earlier been intratracheally administered BLM to induce pulmonary fibrosis. The severity of fibrosis in lung tissue was assessed using pathological morphology and collagen expression to examine the effect of Lefty A released from the microencapsulated cells. The engineered HEK293 cells with Lefty A significantly reduced the expression of connective tissue growth factor and collagen type I mRNA, lessened the morphological fibrotic effects induced by BLM, and increased the expression of matrix metalloproteinase-9. This illustrates that engineered HEK293 cells with Lefty A can attenuate pulmonary fibrosis in vivo, thus providing a novel method to treat human pulmonary fibrotic disease and other organ fibroses.
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Affiliation(s)
- Hongge Ma
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shupei Qiao
- Bio-X Center, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Zeli Wang
- Bio-X Center, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Shuai Geng
- Department of Pharmacology, Harbin Medical University, Harbin, China; and
| | - Yufang Zhao
- Bio-X Center, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Xiaolu Hou
- Bio-X Center, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Weiming Tian
- Bio-X Center, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Xiongbiao Chen
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lifen Yao
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, China;
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12
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Kleinberger RM, Burke NAD, Zhou C, Stöver HDH. Synthetic polycations with controlled charge density and molecular weight as building blocks for biomaterials. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2016; 27:351-69. [PMID: 26754568 DOI: 10.1080/09205063.2015.1130407] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A series of polycations prepared by RAFT copolymerization of N-(3-aminopropyl)methacrylamide hydrochloride (APM) and N-(2-hydroxypropyl)methacrylamide, with molecular weights of 15 and 40 kDa, and APM content of 10-75 mol%, were tested as building blocks for electrostatically assembled hydrogels such as those used for cell encapsulation. Complexation and distribution of these copolymers within anionic calcium alginate gels, as well as cytotoxicity, cell attachment, and cell proliferation on surfaces grafted with the copolymers were found to depend on composition and molecular weight. Copolymers with lower cationic charge density and lower molecular weight showed less cytotoxicity and cell adhesion, and were more mobile within alginate gels. These findings aid in designing improved polyelectrolyte complexes for use as biomaterials.
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Affiliation(s)
- Rachelle M Kleinberger
- a Department of Chemistry and Chemical Biology , McMaster University , Hamilton , Canada
| | - Nicholas A D Burke
- a Department of Chemistry and Chemical Biology , McMaster University , Hamilton , Canada
| | - Christal Zhou
- a Department of Chemistry and Chemical Biology , McMaster University , Hamilton , Canada
| | - Harald D H Stöver
- a Department of Chemistry and Chemical Biology , McMaster University , Hamilton , Canada
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13
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Effect of Calcium Alginate Microsphere Loaded With Vascular Endothelial Growth Factor on Adipose Tissue Transplantation. Ann Plast Surg 2015; 75:644-51. [DOI: 10.1097/sap.0000000000000201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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de Vos P, Lazarjani HA, Poncelet D, Faas MM. Polymers in cell encapsulation from an enveloped cell perspective. Adv Drug Deliv Rev 2014; 67-68:15-34. [PMID: 24270009 DOI: 10.1016/j.addr.2013.11.005] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 08/26/2013] [Accepted: 11/13/2013] [Indexed: 02/07/2023]
Abstract
In the past two decades, many polymers have been proposed for producing immunoprotective capsules. Examples include the natural polymers alginate, agarose, chitosan, cellulose, collagen, and xanthan and synthetic polymers poly(ethylene glycol), polyvinyl alcohol, polyurethane, poly(ether-sulfone), polypropylene, sodium polystyrene sulfate, and polyacrylate poly(acrylonitrile-sodium methallylsulfonate). The biocompatibility of these polymers is discussed in terms of tissue responses in both the host and matrix to accommodate the functional survival of the cells. Cells should grow and function in the polymer network as adequately as in their natural environment. This is critical when therapeutic cells from scarce cadaveric donors are considered, such as pancreatic islets. Additionally, the cell mass in capsules is discussed from the perspective of emerging new insights into the release of so-called danger-associated molecular pattern molecules by clumps of necrotic therapeutic cells. We conclude that despite two decades of intensive research, drawing conclusions about which polymer is most adequate for clinical application is still difficult. This is because of the lack of documentation on critical information, such as the composition of the polymer, the presence or absence of confounding factors that induce immune responses, toxicity to enveloped cells, and the permeability of the polymer network. Only alginate has been studied extensively and currently qualifies for application. This review also discusses critical issues that are not directly related to polymers and are not discussed in the other reviews in this issue, such as the functional performance of encapsulated cells in vivo. Physiological endocrine responses may indeed not be expected because of the many barriers that the metabolites encounter when traveling from the blood stream to the enveloped cells and back to circulation. However, despite these diffusion barriers, many studies have shown optimal regulation, allowing us to conclude that encapsulated grafts do not always follow nature's course but are still a possible solution for many endocrine disorders for which the minute-to-minute regulation of metabolites is mandatory.
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15
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Rokstad AMA, Lacík I, de Vos P, Strand BL. Advances in biocompatibility and physico-chemical characterization of microspheres for cell encapsulation. Adv Drug Deliv Rev 2014; 67-68:111-30. [PMID: 23876549 DOI: 10.1016/j.addr.2013.07.010] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 06/28/2013] [Accepted: 07/12/2013] [Indexed: 02/06/2023]
Abstract
Cell encapsulation has already shown its high potential and holds the promise for future cell therapies to enter the clinics as a large scale treatment option for various types of diseases. The advancement in cell biology towards this goal has to be complemented with functional biomaterials suitable for cell encapsulation. This cannot be achieved without understanding the close correlation between cell performance and properties of microspheres. The ongoing challenges in the field of cell encapsulation require a critical view on techniques and approaches currently utilized to characterize microspheres. This review deals with both principal subjects of microspheres characterization in the cell encapsulation field: physico-chemical characterization and biocompatibility. The up-to-day knowledge is summarized and discussed with the focus to identify missing knowledge and uncertainties, and to propose the mandatory next steps in characterization of microspheres for cell encapsulation. The primary conclusion of this review is that further success in development of microspheres for cell therapies cannot be accomplished without careful selection of characterization techniques, which are employed in conjunction with biological tests.
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Affiliation(s)
- Anne Mari A Rokstad
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Prinsesse Kristinasgt. 1, N-7491 Trondheim, Norway; The Central Norway Health Authority (RHA), Trondheim, Norway.
| | - Igor Lacík
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dubravska cesta 9, 845 41 Bratislava, Slovakia.
| | - Paul de Vos
- Immunoendocrinology, Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, EA11, 9700 RB Groningen, The Netherlands.
| | - Berit L Strand
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Prinsesse Kristinasgt. 1, N-7491 Trondheim, Norway; Department of Biotechnology, NTNU, Sem Saelandsvei 6/8, N-7491 Trondheim, Norway; The Central Norway Health Authority (RHA), Trondheim, Norway.
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16
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Uchida T, Hazekawa M, Yoshida M, Matsumoto K, Sakai Y. Novel long-acting prostacyclin agonist (ONO-1301) with an angiogenic effect: promoting synthesis of hepatocyte growth factor and increasing cyclic AMP concentration via IP-receptor signaling. J Pharmacol Sci 2013; 123:392-401. [PMID: 24292413 DOI: 10.1254/jphs.13073fp] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The purpose of this study was to evaluate the angiogenic potency of ONO-1301, a novel prostacyclin agonist, using a murine sponge model. Solutions of ONO-1301 or hepatocyte growth factor (HGF), as a positive control, were injected into sponges in the backs of mice, daily for 14 days. Hemoglobin and HGF levels in the sponge were increased for up to 14 days on daily treatment with ONO-1301 while on HGF treatment, they peaked on day 7 and had decreased again by day 14. ONO-1301 also upregulated c-Met expression for 14 days in a dose-dependent manner. When the mice were pretreated with an antibody to HGF or the prostaglandin I (IP)-receptor antagonist CAY10441, the angiogenic effect of ONO-1301 was dramatically reduced. Plasma concentrations of cyclic adenosine monophosphate (cAMP) were increased in a dose-dependent manner by once daily treatment with ONO-1301 for 14 days. This effect was reduced by pretreatment with the IP-receptor antagonist. In conclusion, hemoglobin level was increased by repeated treatment with ONO-1301 for 14 days. It is suggested that ONO-1301 induced angiogenesis by promoting the synthesis of HGF and upregulated c-Met expression, followed by an increase in cAMP concentrations mediated by IP-receptor signaling.
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Affiliation(s)
- Takahiro Uchida
- Department of Clinical Pharmaceutics, Faculty of Pharmaceutical Sciences, Mukogawa Women's University, Japan
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Abstract
Bone is one of the most frequent sites of metastasis in patients with malignancies. Up to 90 % of patients with multiple myeloma, and 60 % to 75 % patients with prostate cancer and breast cancer develop bone metastasis at the later stages of their diseases. Bone metastases are responsible for tremendous morbidity in patients with cancer, including severe bone pain, pathologic fractures, spinal cord and nerve compression syndromes, life-threatening hypercalcemia, and increased mortality. Multiple factors produced by tumor cells or produced by the bone marrow microenvironment in response to tumor cells play important roles in activation of osteoclastic bone resorption and modulation of osteoblastic activity in patients with bone metastasis. In this chapter, we will review the genes that play important roles in bone destruction, tumor growth, and osteoblast activity in bone metastasis and discuss the potential therapies targeting the products of these genes to block both bone destruction and tumor growth.
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Correia CR, Reis RL, Mano JF. Multilayered hierarchical capsules providing cell adhesion sites. Biomacromolecules 2013; 14:743-51. [PMID: 23330726 DOI: 10.1021/bm301833z] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Liquified capsules featuring (i) an external shell by layer-by-layer assembly of poly(l-lysine), alginate, and chitosan, and encapsulating (ii) surface functionalized poly(l-lactic acid) (PLLA) microparticles were developed. We hypothesize that, while the liquified environment enhances the diffusion of essential molecules for cell survival, microparticles dispersed in the liquified core of capsules provide the physical support required for cellular functions of anchorage-dependent cells. The influence of the incorporation of PLL on the regime growth, thickness, and stability was analyzed. Results show a more resistant and thicker film with an exponential build-up growth regime. Moreover, capsules ability to support cell survival was assessed. Capsules containing microparticles revealed an enhanced biological outcome in cell metabolic activity and proliferation, suggesting their potential to boost the development of innovative biomaterial designs for bioencapsulation systems and tissue engineering products.
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Affiliation(s)
- Clara R Correia
- 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho , Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909 Taipas, Guimarães, Portugal
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Artificial Cells. Biomater Sci 2013. [DOI: 10.1016/b978-0-08-087780-8.00071-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
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Paul A, Chen G, Khan A, Rao VTS, Shum-Tim D, Prakash S. Genipin-Cross-Linked Microencapsulated Human Adipose Stem Cells Augment Transplant Retention Resulting in Attenuation of Chronically Infarcted Rat Heart Fibrosis and Cardiac Dysfunction. Cell Transplant 2012; 21:2735-51. [DOI: 10.3727/096368912x637497] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Stem cell transplantation has been widely acknowledged for their immense potential in regenerative medicine. In these procedures, the implanted cells need to maintain both their viability and functional properties for effective therapeutic outcomes. This has long been a subject of major concern and intensive studies. Microencapsulation of stem cells within polymeric microcapsules can be an efficient approach to achieve this goal, particularly for heart diseases. This study reports the use of biocompatible, fluorogenic genipin-cross-linked alginate chitosan (GCAC) microcapsules in delivery of human adipose stem cells (hASCs) with an aim to increase the implant retention in the infarcted myocardium for maximum clinical benefits. In vitro results show, under hypoxic conditions, the microencapsulated cells overexpressed significantly higher amount of biologically active vascular endothelial growth factor (VEGF). We investigated on the in vivo potential using immunocompetent female rats after induction of myocardial infarction. For this, animal groups ( n = 8) received empty control microcapsules, 1.5 × 106 free male hASCs, or 1.5 × 106 microencapsulated male hASCs. Results show significant retention (3.5 times higher) of microencapsulated hASCs compared to free hASCs after 10 weeks of transplantation. Microencapsulated hASCs showed significantly attenuated infarct size compared to free hASCs and empty microcapsule group (21.6% ± 1.1% vs. 27.2% ± 3.1% vs. 33.3% ± 3.2%; p < 0.05), enhanced vasculogenesis, and improved cardiac function (fractional shortening: 24.2% ± 2.1% vs. 19.1% ± 0.5% vs. 12.0% ± 4.0%; p < 0.05). These data suggest that microencapsulated hASCs can contribute significantly to the improvement in cardiac functions. Their greater retentions exhibit reduced fibrosis and cardiac dysfunction in experimental animals. However, further research is needed to fully comprehend the underlying biological and immunological effects of microencapsulated hASCs, which jointly play important roles in cardiac repair.
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Affiliation(s)
- Arghya Paul
- Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Artificial Cells and Organs Research Centre Faculty of Medicine, McGill University, Montreal, Québec, Canada
| | - Guangyong Chen
- Divisions of Cardiac Surgery and Surgical Research, McGill University Health Center, Montreal, Quebec, Canada
| | - Afshan Khan
- Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Artificial Cells and Organs Research Centre Faculty of Medicine, McGill University, Montreal, Québec, Canada
| | - Vijayaraghava T. S. Rao
- Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec, Canada
| | - Dominique Shum-Tim
- Divisions of Cardiac Surgery and Surgical Research, McGill University Health Center, Montreal, Quebec, Canada
| | - Satya Prakash
- Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Artificial Cells and Organs Research Centre Faculty of Medicine, McGill University, Montreal, Québec, Canada
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Ma Y, Zhang Y, Liu Y, Chen L, Li S, Zhao W, Sun G, Li N, Wang Y, Guo X, Lv G, Ma X. Investigation of alginate-ε-poly-L-lysine microcapsules for cell microencapsulation. J Biomed Mater Res A 2012; 101:1265-73. [PMID: 23065714 DOI: 10.1002/jbm.a.34418] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 07/12/2012] [Accepted: 07/30/2012] [Indexed: 11/07/2022]
Abstract
Cell microencapsulation is a promising approach for cell implantation, cell-based gene therapy, and large-scale cell culture. The well-studied α-AP (alginate-α-poly-L-lysine) microcapsules have been restricted to large-scale cell-culture and clinical applications because of high costs and cytotoxic effects in some cases. This study used ε-poly-L-lysine (ε-PLL), a high-biocompatible and low-cost food additives produced by fermentation, to prepare ε-AP (alginate-ε-PLL) microcapsules with various thickness membranes and swelling behaviors. ε-AP microcapsules were permeable to BSA, a standard protein of culture medium. ε-AP-microencapsulated Chinese hamster ovary (CHO) cells proliferated with culture time; no obvious difference with α-AP-microencapsulated CHO cells during the early 19 days. Whereas ε-AP-microencapsulated CHO cells kept higher viability (OD = 0.646 ± 0.012) on the 22nd day and microcapsule strength (integrity rate of 88%) on the 24th day than that of α-AP microcapsules (OD = 0.558 ± 0.025, integrity rate of 80%). ε-AP (alginate-ε-PLL) microcapsules exhibited more superior properties and could lower the costs to broaden the applications of microencapsulation technology.
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Affiliation(s)
- Ying Ma
- Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
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Ma Y, Zhang Y, Wang Y, Wang Q, Tan M, Liu Y, Chen L, Li N, Yu W, Ma X. Study of the effect of membrane thickness on microcapsule strength, permeability, and cell proliferation. J Biomed Mater Res A 2012; 101:1007-15. [DOI: 10.1002/jbm.a.34395] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/12/2012] [Accepted: 07/24/2012] [Indexed: 11/07/2022]
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Rokstad AM, Gustafsson BI, Espevik T, Bakke I, Pfragner R, Svejda B, Modlin IM, Kidd M. Microencapsulation of small intestinal neuroendocrine neoplasm cells for tumor model studies. Cancer Sci 2012; 103:1230-7. [PMID: 22435758 DOI: 10.1111/j.1349-7006.2012.02282.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 03/07/2012] [Accepted: 03/09/2012] [Indexed: 01/26/2023] Open
Abstract
Basic cancer research is dependent on reliable in vitro and in vivo tumor models. The serotonin (5-HT) producing small intestinal neuroendocrine tumor cell line KRJ-1 has been used in in vitro proliferation and secretion studies, but its use in in vivo models has been hampered by problems related to the xeno-barrier and tumor formation. This may be overcome by the encapsulation of tumor cells into alginate microspheres, which can function as bioreactors and protect against the host immune system. We used alginate encapsulation of KRJ-1 cells to achieve long-term functionality, growth and survival. Different conditions, including capsule size, variations in M/G content, gelling ions (Ca(2+) /Ba(2+)) and microcapsule core properties, and variations in KRJ-1 cell condition (single cells/spheroids) were tested. Viability and cell growth was evaluated with MTT, and confocal laser scanner microscopy combined with LIVE/DEAD viability stains. 5-HT secretion was measured to determine functionality. Under all conditions, single cell encapsulation proved unfavorable due to gradual cell death, while encapsulation of aggregates/spheroids resulted in surviving, functional bioreactors. The most ideal spheroids for encapsulation were 200-350 μm. Long-term survival (>30 days) was seen with solid Ca(2+) /Ba(2+) microbeads and hollow microcapsules. Basal 5-HT secretion was increased (sixfold) after hollow microcapsule encapsulation, while Ca(2+) /Ba(2+) microbeads was associated with normal basal secretion and responsiveness to cAMP/PKA activation. In conclusion, encapsulation of KRJ-1 cells into hollow microcapsules produces a bioreactor with a high constitutively activate basal 5-HT secretion, while Ca(2+) /Ba(2+) microbeads provide a more stable bioreactor similar to non-encapsulated cells. Alginate microspheres technology can thus be used to tailor different functional bioreactors for both in vitro and in vivo studies.
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Affiliation(s)
- Anne M Rokstad
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
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Schuller-Petrović S, Pavlović MD, Schuller SS, Schuller-Lukić B, Neuhold N. Early granulomatous foreign body reactions to a novel alginate dermal filler: the system's failure? J Eur Acad Dermatol Venereol 2011; 27:121-3. [PMID: 21929551 DOI: 10.1111/j.1468-3083.2011.04264.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Cutaneous granulomas after a soft filler injection represent one of the worst scenarios for both patient and injector. OBJECTIVES To present clinical and histopathological features of granulomatous nodular reactions induced by a new alginate-based dermal filler (Novabel(®)), and put it in context of the process of injectable soft tissue fillers approval and promotion in the EU. METHODS A case series of four patients injected with Novabel(®) for volume restoration of the face and hands, who developed severe foreign body reactions. RESULTS Four patients injected with Novabel(®) into tear troughs and/or dorsa of hands developed severe granulomatous reactions within months after injections. As we injected with the new filler into a total of 10 patients, a high incidence of 40% of the disfiguring adverse effect was observed. The inadequate response of manufacturer to our reporting the side-effects along with the available data on registration process of dermal fillers confirmed that the area is not well-regulated. CONCLUSIONS The status of dermal fillers as class III medical devices, and the process of their approval and marketing in the EU need to be seriously reconsidered to avoid unnecessary and serious adverse reactions.
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Ranganath SH, Ling Tan A, He F, Wang CH, Krantz WB. Control and enhancement of permselectivity of membrane-based microcapsules for favorable biomolecular transport and immunoisolation. AIChE J 2011. [DOI: 10.1002/aic.12525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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BacMam virus transduced cardiomyoblasts can be used for myocardial transplantation using AP-PEG-A microcapsules: molecular cloning, preparation, and in vitro analysis. J Biomed Biotechnol 2011; 2010:858094. [PMID: 21331169 PMCID: PMC3034997 DOI: 10.1155/2010/858094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2010] [Revised: 09/14/2010] [Accepted: 11/10/2010] [Indexed: 02/01/2023] Open
Abstract
The potential of genetically modified cardiomyoblasts in treating damaged myocardium is well known. However, efficient delivery of these cells is of major concern during treatment. The limiting factors are the massive cell death that occurs soon after their intramyocardial transplantation into the beating heart. To address these problems, we generated recombinant baculoviruses (BacMam viruses) which efficiently transduced cardiomyoblast cells under optimized conditions. These genetically modified cells were then protected in a new polymeric microcapsule using poly-ethylene-glycol (PEG), alginate, and poly-L-lysine (PLL) polymers for efficient delivery. Results showed that microcapsules maintain cell viability and support cell proliferation for at least 30 days. The capsules exhibit strong immunoprotective potential and have high mechanical and osmotic stability with more than 70% intact capsules. The encased transduced cells showed a rapid transgene expression inside the capsule for at least 15 days. However, preclinical studies are needed to further explore its long-term functional benefits.
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Prakash S, Khan A, Paul A. Nanoscaffold based stem cell regeneration therapy: recent advancement and future potential. Expert Opin Biol Ther 2010; 10:1649-61. [PMID: 20954792 DOI: 10.1517/14712598.2010.528387] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Over the past years, extensive research has been directed towards tissue engineering using conventional scaffolds. In-depth studies in this field have led to the realization that in vivo cells interact with the extracellular matrix, composed of nanofibers at sub-micron scale, which not only provides the mechanical support to the cells but also plays a key role in regulation of cellular behavior. This has led to the development of nanofibrous scaffold (NFS) technology which in combination with stem cells is emerging as an important tool in the development of tissue engineering and regenerative medicine. AREAS COVERED IN THIS REVIEW This review summarizes the three methods of nanofibrous scaffold preparation and provides a state-of-the-art update on the recent advancement in the use of nanoscaffolds in stem cell regeneration therapy. WHAT THE READER WILL GAIN The review gives the reader an insight on nanoscaffold based therapy methods, such as how these scaffolds can potentially be designed and used in successful development of stem cell based therapies. TAKE HOME MESSAGE NFS technology when coupled with stem cells and exploited in the right way has a strong potential of being used in stem cell based regenerative medicine.
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Affiliation(s)
- Satya Prakash
- McGill University, Biomedical Engineering, 3775 University Street, Montreal, Quebec, Canada.
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Purcell EK, Singh A, Kipke DR. Alginate composition effects on a neural stem cell-seeded scaffold. Tissue Eng Part C Methods 2010; 15:541-50. [PMID: 19368511 DOI: 10.1089/ten.tec.2008.0302] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The purpose of this study was to evaluate the effects of alginate composition on the neurotrophic factor release, viability, and proliferation of encapsulated neural stem cells (NSCs), as well as on the mechanical stability of the scaffold itself. Four compositions were tested: a high guluronic acid (68%) and a high mannuronic acid (54%) content alginate, with or without a poly-L-lysine (PLL) coating layer. Enzyme-linked immunosorbent assay was used to quantify the release of brain-derived neurotrophic factor, glial-derived neurotrophic factor, and nerve growth factor from the encapsulated cells. All three factors were detected from encapsulated cells only when a high L-guluronic acid alginate without PLL was used. Additionally, capsules with this composition remained intact more frequently when exposed to solutions of low osmolarity, potentially indicating superior mechanical stability. Alginate beads with a PLL-coated, high D-mannuronic acid composition were the most prone to breakage in the osmotic pressure test, and were too fragile for histology and proliferation assays after 1 week in vitro. NSCs survived and proliferated in the three remaining alginate compositions similarly over the 21-day study course irrespective of scaffold condition. NSC-seeded alginate beads with a high L-guluronic acid, non-PLL-coated composition may be useful in the repair of injured nervous tissue, where the mechanism is the secretion of neuroprotective factors. We verify the neuroprotective effects of medium conditioned by NSC-seeded alginate beads on the serum withdrawal-mediated death of PC-12 cells here.
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Affiliation(s)
- Erin K Purcell
- Department of Biomedical Engineering, University of Michigan , Ann Arbor, MI 48109-2099, USA
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Yu CB, Lv GL, Pan XP, Chen YS, Cao HC, Zhang YM, Du WB, Yang SG, Li LJ. In vitro large-scale cultivation and evaluation of microencapsulated immortalized human hepatocytes (HepLL) in roller bottles. Int J Artif Organs 2009; 32:272-81. [PMID: 19569036 DOI: 10.1177/039139880903200504] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIMS Microencapsulated hepatocytes have been proposed as promising bioactive agents for packed-bed or fluidized-bed bioartificial liver assist devices (BLaDs) and for hepatocyte transplantation because of the potential advantages they offer of high mass transport rate and an optimal microenvironment for hepatocyte culture. We developed a large-scale and high-production alginate-chitosan (AC) microcapsule roller bottle culture system for the encapsulation of hepLL immortalized human hepatocytes. In this study, the efficacy of upscaling encapsulated hepLL cells production with roller bottle cultivation was evaluated in vitro. METHODS Microencapsulated hepLL cells were grown at high yield in large-scale roller bottles, with free cells cultured in roller bottle spinners serving as controls. The mechanical stability and the permeability of the AC microcapsules were investigated, and the growth, metabolism and functions of the encapsulated hepLL cells were evaluated as compared to free cells. RESULTS The microcapsules withstood well the shear stress induced by high agitation rates. The microcapsules were permeable to albumin, but prevented the release of immunoglobulins. Culture in roller bottles of immortalized human hepatocytes immobilized in the AC microcapsules improved cell growth, albumin synthesis, ammonia elimination and lidocaine clearance as compared with free cells cultured in roller bottles. CONCLUSIONS Encapsulated hepLL cells may be cultured on a large scale in roller bottles. This makes them possible candidates for use in cell-based liver assist therapies.
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Affiliation(s)
- Cheng-Bo Yu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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Preparation of porous bioactive ceramic microspheres and in vitro osteoblastic culturing for tissue engineering application. Acta Biomater 2009; 5:1725-31. [PMID: 19141374 DOI: 10.1016/j.actbio.2008.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 11/11/2008] [Accepted: 12/05/2008] [Indexed: 11/20/2022]
Abstract
Microparticulates are useful for directly filling defective tissues as well as for delivering cells and bioactive molecules in regenerative medicine. This paper reports on the production of bioactive ceramic microspheres with an interconnected macropore structure. The sol-gel derived calcium silicate powder was homogenized with an oligomeric Camphene melt, which was used as a novel porogen, and spherical-shaped microparticulates were obtained by an oil-in-water emulsion method. A porous structure was generated through the sublimation of Camphene within the calcium silicate-Camphene solidified blend under ambient conditions. The microspheres retained the crystalline phase of apatite and wollastonite during heat treatment and induced calcium phosphate precipitation under a body-simulating medium, showing the characteristics of bone-bioactive materials. Osteoblastic cells were observed to anchor to and spread well over the surface of the porous microspheres, and further to proliferate actively with culturing time. The bioactive and porous microspheres developed are considered potentially useful in the regeneration of hard tissues as a matrix for tissue engineering as well as a direct filling material.
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Genipin Cross-Linked Polymeric Alginate-Chitosan Microcapsules for Oral Delivery: In-Vitro Analysis. INT J POLYM SCI 2009. [DOI: 10.1155/2009/617184] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We have previously reported the preparation of the genipin cross-linked alginate-chitosan (GCAC) microcapsules composed of an alginate core with a genipin cross-linked chitosan membrane. This paper is the further investigation on their structural and physical characteristics. Results showed that the GCAC microcapsules had a smooth and dense surface and a networked interior. Cross-linking by genipin substantially reduced swelling and physical disintegration of microcapsules induced by nongelling ions and calcium sequestrants. Strong resistance to mechanical shear forces and enzymatic degradation was observed. Furthermore, the GCAC membranes were permeable to bovine serum albumin and maintained a molecular weight cutoff at 70 KD, analogous to the widely studied alginate-chitosan, and alginate-poly-L-lysine-alginate microcapsules. The release features and the tolerance of the GCAC microcapsules in the stimulated gastrointestinal environment were also investigated. This GCAC microcapsule formulation offers significant potential as a delivery vehicle for many biomedical applications.
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Breguet V, Vojinovic V, Stockar UV, Marison IW. Enzymatic hydrolysis of organic-core microcapsules to produce aqueous-core microcapsules. J Microencapsul 2008; 25:179-86. [DOI: 10.1080/02652040701843461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Lee HH, Hong SJ, Kim CH, Kim EC, Jang JH, Shin HI, Kim HW. Preparation of hydroxyapatite spheres with an internal cavity as a scaffold for hard tissue regeneration. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:3029-3034. [PMID: 18389344 DOI: 10.1007/s10856-008-3435-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Accepted: 03/11/2008] [Indexed: 05/26/2023]
Abstract
Microparticulates are currently regarded as a useful matrix for the delivery of bioactive molecules and tissue cells. Herein, hydroxyapatite (HA) spherical microparticulates with an internal cavity were produced using an oil-in-water emulsion technique. The HA slurry in the organic solvent was formulated into spherical particles in a water bath containing a surfactant. Rapid evaporation of the solvent helped create a cavity within the microparticulates. The microparticulates were heat-treated at 1,200 degrees C to produce bioactive HA particles with a mean size of approximately 363 microm. Osteoblastic cells were observed to spread and grow favorably over the surface as well as within the cavity of the microparticulates. The currently developed HA microparticulates with an internal cavity are considered to be useful as a scaffolding matrix for bone tissue engineering and direct filling skeletal defects.
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Affiliation(s)
- Hae-Hyoung Lee
- Department of Biomaterials Science, School of Dentistry, Dankook University, Cheonan 330-714, South Korea
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35
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Workman VL, Dunnett SB, Kille P, Palmer DD. On-Chip Alginate Microencapsulation of Functional Cells. Macromol Rapid Commun 2008. [DOI: 10.1002/marc.200700641] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
This manuscript presents hydrogels (HGs) from a tissue engineering perspective being especially written for those who are approaching this field by offering a concise but inclusive review of hydrogel synthesis, properties, characterization methods, and applications.
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Affiliation(s)
- Biancamaria Baroli
- Dipartimento Farmaco Chimico Tecnologico, Università di Cagliari, Via Ospedale, 72, 09124 Cagliari, Italy.
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Nunamaker EA, Purcell EK, Kipke DR. In vivo
stability and biocompatibility of implanted calcium alginate disks. J Biomed Mater Res A 2007; 83:1128-1137. [PMID: 17595019 DOI: 10.1002/jbm.a.31275] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Alginate is a commonly used biomedical hydrogel whose in vivo degradation behavior is only beginning to be understood. The use of alginate in the central nervous system is gaining popularity as an electrode coating, cell encapsulation matrix, and for duraplasty. However, it is necessary to understand how the hydrogel will behave in vivo to aid in the development of alginate for use as a neural interface material. The goal of the current study was to compare the rheological behavior of explanted alginate disks and the inflammatory response to subcutaneously implanted alginate hydrogels over a 3-month period. Specifically, the effects due to (1) in situ gelling, (2) diffusion gelling, and (3) use of a poly-l-lysine (PLL) coating were investigated. While all samples' complex moduli decreased 80% in the first day, in situ gelled alginate was more stable for the first week of implantation. The PLL coating offered some stability increases for diffusion gelled alginate, but the stability in both conditions remained significantly lower than that in in situ gelled alginate. There were no differences in biocompatibility that clearly suggested one gelation method over another. These results indicate that in situ gelation is the preferred method in neural interface applications where stability is the primary concern.
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Affiliation(s)
- Elizabeth A Nunamaker
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2099
| | - Erin K Purcell
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2099
| | - Daryl R Kipke
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2099
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Donati I, Haug IJ, Scarpa T, Borgogna M, Draget KI, Skjåk-Braek G, Paoletti S. Synergistic Effects in Semidilute Mixed Solutions of Alginate and Lactose-Modified Chitosan (Chitlac). Biomacromolecules 2007; 8:957-62. [PMID: 17300173 DOI: 10.1021/bm060856h] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study specifically aimed at preparing and characterizing semidilute binary polymer mixtures of alginate and chitlac which might find an application in the field of cell encapsulation. A polyanion, alginate, and a polycation, a lactose-modified chitosan, were mixed under physiological conditions (pH 7.4 and NaCl 0.15) and at a semidilute concentration avoiding associative phase separation. The mutual solubility was found to be dependent on the charge screening effect of the added NaCl salt, being prevented below 0.05 M NaCl. A comparison with the behavior of the polyanion (alginate) under the same experimental conditions revealed that both the viscosity and the relaxation times of the binary polymer solutions are strongly affected by the presence of the polycation. In particular, the occurrence of electrostatic interactions between the two oppositely charged polysaccharides led to a synergistic effect on the zero-shear viscosity of the solution, which showed a 4.2-fold increase with respect to that of the main component of the solution, i.e., alginate. Moreover, the relaxation time, calculated as the reciprocal of the critical share rate, markedly increased upon reducing the alginate fraction in the binary polysaccharide solution. However, the formation of the soluble complexes and the synergistic effect are reduced upon increasing the concentration of the 1:1 electrolyte. By containing a gel-forming polyanion (alginate, e.g., with Ca(2+) ions) and a bioactive polycation (chitlac, bearing a beta-linked D-galactose), the present system can be regarded as a first step toward the development of biologically active scaffold from polysaccharide mixtures.
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Affiliation(s)
- Ivan Donati
- Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Via Licio Giorgieri 1, I-34127 Trieste, Italy.
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Chen H, Ouyang W, Jones M, Metz T, Martoni C, Haque T, Cohen R, Lawuyi B, Prakash S. Preparation and characterization of novel polymeric microcapsules for live cell encapsulation and therapy. Cell Biochem Biophys 2007; 47:159-68. [PMID: 17406068 DOI: 10.1385/cbb:47:1:159] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 01/15/2023]
Abstract
This article describes the preparation and in vitro characterization of novel genipin cross-linked alginate-chitosan (GCAC) microcapsules that have potential for live cell therapy applications. This microcapsule system, consisting of an alginate core with a covalently cross-linked chitosan membrane, was formed via ionotropic gelation between calcium ions and alginate, followed by chitosan coating by polyelectrolyte complexation and covalent cross-linking of chitosan by naturally derived genipin. Results showed that, using this design concept and the three-step procedure, spherical GCAC microcapsules with improved membrane strength, suppressed capsular swelling, and suitable permeability can be prepared. The suitability of this novel membrane formulation for live cell encapsulation was evaluated, using bacterial Lactobacillus plantarum 80 (pCBH1) (LP80) and mammalian HepG2 as model cells. Results showed that capsular integrity and bacterial cell viability were sustained 6 mo postencapsulation, suggesting the feasibility of using this microcapsule formulation for live bacterial cell encapsulation. The metabolic activity of the encapsulated HepG2 was also investigated. Results suggested the potential capacity of this GCAC microcapsule in cell therapy and the control of cell signaling; however, further research is required.
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Affiliation(s)
- Hongmei Chen
- Department of Biomedical Engineering and Physiology, Artificial Cells and Organs Research Centre, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
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Baruch L, Machluf M. Alginate-chitosan complex coacervation for cell encapsulation: effect on mechanical properties and on long-term viability. Biopolymers 2006; 82:570-9. [PMID: 16552738 DOI: 10.1002/bip.20509] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The use of chitosan in complexation with alginate appears to be a promising strategy for cell microencapsulation, due to the biocompatibility of both polymers and the high mechanical properties attributed by the use of chitosan. The present work focuses on the optimization and characterization of the alginate-chitosan system to achieve long-term cell encapsulation. Microcapsules were prepared from four types of chitosan using one- and two-stage encapsulation procedures. The effect of reaction time and pH on long-term cell viability and mechanical properties of the microcapsules was evaluated. Using the single-stage encapsulation procedure led to increase of at least fourfold in viability compared with the two-stage procedure. Among the four types of chitosan, the use of high molecular weight (MW) chitosan glutamate and low MW chitosan chloride provided high viability levels as well as good mechanical properties, i.e., more than 93% intact capsules. The high viability levels were found to be independent of the reaction conditions when using high MW chitosan. However, when using low MW chitosan, better viability levels (195%) were obtained when using a pH of 6 and a reaction time of 30 min. An alginate-chitosan cell encapsulation system was devised to achieve high cell viability levels as well as to improve mechanical properties, thus holding great potential for future clinical application.
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Affiliation(s)
- Limor Baruch
- The Faculty of Biotechnology, and Food Engineering, The Technion-Israel Institute of Technology, Haifa, Israel
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Rokstad AM, Donati I, Borgogna M, Oberholzer J, Strand BL, Espevik T, Skjåk-Braek G. Cell-compatible covalently reinforced beads obtained from a chemoenzymatically engineered alginate. Biomaterials 2006; 27:4726-37. [PMID: 16750563 DOI: 10.1016/j.biomaterials.2006.05.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Accepted: 05/10/2006] [Indexed: 11/30/2022]
Abstract
A chemoenzymatic strategy has been exploited to make covalently linked alginate beads with high stability. This was achieved by grafting mannuronan (alginate with 100% mannuronic acid (M)) with methacrylate moieties and then performing two enzymatic steps converting M to guluronic acid (G) in alternating sequences (MG-blocks) and in G-blocks. In this way a methacrylate grafted alginate with better gel-forming ability was achieved. Covalent bindings were introduced into the beads by using a photoinitiating system that initiated polymerization of the methacrylate moieties. The covalent links were demonstrated by beads remaining intact after treatment with EDTA. The new chemoenzymatic photocrosslinked (CEPC) beads were compatible with cells with low post-encapsulation ability like C2C12 myoblasts and human pancreatic islets. The islets continued secreting insulin after encapsulation. On contrary, cells with a high post-encapsulation proliferative ability like 293-endo cells died within 2-week post-encapsulation. The exceptional stability and the cell compatibility of the new CEPC beads make them interesting as bioreactors for delivering therapeutic proteins in future applications.
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Affiliation(s)
- Anne Mari Rokstad
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
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Abbah SA, Lu WW, Chan D, Cheung KMC, Liu WG, Zhao F, Li ZY, Leong JCY, Luk KDK. In vitro evaluation of alginate encapsulated adipose-tissue stromal cells for use as injectable bone graft substitute. Biochem Biophys Res Commun 2006; 347:185-91. [PMID: 16815293 DOI: 10.1016/j.bbrc.2006.06.072] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 06/12/2006] [Indexed: 01/08/2023]
Abstract
This study aims to investigate the survival and osteogenic behavior of murine-derived adipose-tissue stromal cells (ATSCs) encapsulated in alginate microcapsules thereby instigating further studies in this cell delivery strategy for in vivo osteogenesis. Cell viability was quantified using a tetrazolium-based assay and osteogenic differentiation was evaluated by both alkaline-phosphatase (ALP) histochemistry and osteocalcin mRNA analysis. Following microencapsulation, cell numbers increased from 3.9 x 10(3) on day 1 to 7.8 x 10(3) on day 7 and maintained excellent viability in the course of 21-day culture. ALP was 6.9, 5.5, and 3.2 times higher than monolayer cultures on days 7, 14, and 21, respectively. In addition, osteocalcin mRNA was detectable in encapsulated cultures earlier (day 14) than monolayer cultures. We conclude that alginate microcapsules can act as three-dimensional matrix for ATSC proliferation and has potential for use as injectable, biodegradable scaffold in bone tissue engineering.
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Affiliation(s)
- S A Abbah
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam
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Mørch YA, Donati I, Strand BL, Skjåk-Braek G. Effect of Ca2+, Ba2+, and Sr2+ on alginate microbeads. Biomacromolecules 2006; 7:1471-80. [PMID: 16677028 DOI: 10.1021/bm060010d] [Citation(s) in RCA: 540] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microcapsules of alginate cross-linked with divalent ions are the most common system for cell immobilization. In this study, we wanted to characterize the effect of different alginates and cross-linking ions on important microcapsule properties. The dimensional stability and gel strength increased for high-G alginate gels when exchanging the traditional Ca2+ ions with Ba2+. The use of Ba2+ decreased the size of alginate beads and reduced the permeability to immunoglobulin G. Strontium gave gels with characteristics lying between calcium and barium. Interestingly, high-M alginate showed an opposite behavior in combination with barium and strontium as these beads were larger than beads of calcium-alginate and tended to swell more, also resulting in increased permeability. Binding studies revealed that different block structures in the alginate bind the ions to a different extent. More specifically, Ca2+ was found to bind to G- and MG-blocks, Ba2+ to G- and M-blocks, and Sr2+ to G-blocks solely.
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Affiliation(s)
- Yrr A Mørch
- Department of Biotechnology, Norwegian University of Science and Technology, Sem Saelands vei 6/8, 7491 Trondheim, Norway.
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Kuijlen JMA, de Haan BJ, Helfrich W, de Boer JF, Samplonius D, Mooij JJA, de Vos P. The efficacy of alginate encapsulated CHO-K1 single chain-TRAIL producer cells in the treatment of brain tumors. J Neurooncol 2006; 78:31-9. [PMID: 16598433 DOI: 10.1007/s11060-005-9071-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 11/03/2005] [Indexed: 10/24/2022]
Abstract
OBJECT Patients with astrocytic tumors in the central nervous system (CNS) have low survival rates despite surgery and radiotherapy. Innovative therapies and strategies must be developed to prolong survival of these patients. The alginate microencapsulation method, used to continuously release a certain cytotoxic agent in the vicinity of the tumor, is such a novel therapeutic strategy. The biological functionality of the apoptosis inducing scFv425:sTRAIL protein, which was released through the microencapsulation method, was studied in vitro. Analysis of the intracerebral biocompatibility of alginate capsules was performed by implantation of empty alginate capsules in the brain of mice. METHOD Chinese Hamster Ovary cells (CHO-K1) were recombinantly engineered to produce the single chain anti-EGFR-sTRAIL protein (scFv425:sTRAIL). The CHO-K1 producer cells were encapsulated in an alginate capsule with a semi-permeable membrane through which the scFv425:sTRAIL protein could be released. RESULTS In vitro studies show maintained biological functionality of the released scFv425:sTRAIL protein. There was no immunological tissue response detectable after intracerebral implantation of the alginate capsules in mice brains. CONCLUSION Biological functionality of the produced scFv425:sTRAIL protein is maintained and intracerebral biocompatibility of the capsules is warranted. Alginate encapsulation of CHO-K1--scFv425:sTRAIL--producer cells and subsequently their intracerebral implantation is technically feasible. This study justifies further in vivo experiments.
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Affiliation(s)
- Jos M A Kuijlen
- Department of Neurosurgery, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30.001, 9700 RB, Groningen, The Netherlands.
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Liu ZC, Chang TMS. Transdifferentiation of bioencapsulated bone marrow cells into hepatocyte-like cells in the 90% hepatectomized rat model. Liver Transpl 2006; 12:566-72. [PMID: 16496278 DOI: 10.1002/lt.20635] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Under specific conditions, bone marrow cells can transdifferentiate into a variety of cell types including hepatocytes. In this study, bioencapsulated bone marrow cells were transplanted intraperitoneally into 90% hepatectomized rats. We then followed the transdifferentiation of the bone marrow cells and the effect of this on liver regeneration in this liver failure model. Bone marrow cells isolated from Wistar rats were bioencapsulated using alginate-polylysine-alginate method. These bioencapsulated bone marrow cells were transplanted intraperitoneally into 90% hepatectomized Wistar rats. Blood chemistry, HGF, liver weight, and survival of the recipient rats were evaluated. Histology and immunocytochemistry were used to analyze the bioencapsulated cells before and 14 days after transplantation. Unlike free bone marrow cells, transplantation of bioencapsulated bone marrow cells improved the survival of 90% hepatectomized rats and improved the blood chemistry with an efficacy similar to that of bioencapsulated hepatocytes or free hepatocytes transplantation. Some bioencapsulated bone marrow cells expressed hepatocytes markers of cytokeratins 8, cytokeratins 18, albumin, and AFP after 2 weeks of transplantation. These results suggest that syngeneic bioencapsulated bone marrow cells can transdifferentiate into hepatocyte-like cells in the peritoneal cavity of 90% hepatectomized rats and increased the survival rates of these rats. In conclusion, these findings suggest the potential for a new alternative to hepatocyte transplantation for cellular therapy of acute liver failure.
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Affiliation(s)
- Zun Chang Liu
- Artificial Cells and Organs Research Center, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
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Maguire T, Novik E, Schloss R, Yarmush M. Alginate-PLL microencapsulation: effect on the differentiation of embryonic stem cells into hepatocytes. Biotechnol Bioeng 2006; 93:581-91. [PMID: 16345081 DOI: 10.1002/bit.20748] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The emergence of hepatocyte based clinical and pharmaceutical technologies, has been limited by the absence of a stable hepatocyte cell source. Embryonic stem cells may represent a potential solution to this cell source limitation problem since they are highly proliferative, renewable, and pluripotent. Although many investigators have described techniques to effectively differentiate stem cells into a variety of mature cell lineages, their practicality is limited by: (1) low yields of fully differentiated cells, (2) absence of large scale processing considerations, and (3) ineffective downstream enrichment protocols. Thus, a differentiation platform that may be modified to induce and sustain differentiated cell function and scaled to increase differentiated cell yield would improve current stem cell differentiation strategies. Microencapsulation provides a vehicle for the discrete control of key cell culture parameters such as the diffusion of growth factors, metabolites, and wastes. In addition, both cell seeding density and bead composition may be manipulated. In order to assess the feasibility of directing stem cell differentiation via microenvironment regulation, we have developed a murine embryonic stem cell (ES) alginate poly-l-lysine microencapsulation hepatocyte differentiation system. Our results indicate that the alginate microenvironment maintains cell viability, is conducive to ES cell differentiation, and maintains differentiated cellular function. This system may ultimately assist in developing scalable stem cell differentiation strategies.
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Affiliation(s)
- Tim Maguire
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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Abstract
BACKGROUND Because standardization of the cell microencapsulation procedure has not yet been achieved, we performed hepatocyte microencapsulation using alginate (ALG)-poly-l-lysine (PLL)-ALG (APA) polymer. METHODS Hepatocytes were microencapsulated using a binozzle air-jet droplet generator. Our study aims were to: (1) clarify how ALG concentration affects the quality of ALG beads; (2) determine how the PLL concentration affects the quality of microcapsules (MCs); (3) ascertain the influence of liquefaction time by sodium citrate (SC) on the quality of the MCs; (4) and clarify how temperature and solution pH, respectively, affect the viability of the hepatocytes inside the MCs. RESULTS The concentration of ALG must be > or = 3% (w/v) to generate droplets with satisfactory homogeneity in size and roundness (P < .01). The total quantity of PLL molecules is the essential component for MCs (P < .01). As our results show, the numeric ratio of PLL (milligrams) to MCs (milliliters) is roughly 25:1. SC incubation for 8 minutes resulted in the proper thickness of the MC wall; however, the time varied according to the size of the MCs (P < .05). Temperature and pH, although both difficult to control, exerted great influences on cell viability: 4 degrees C and pH 7.2 were found to be optimal by this study (P < .05). CONCLUSIONS Concentrations of ALG and PLL exerted decisive effects on the quality and strength of MCs. Higher concentrations were suggested. Because temperature and pH greatly affected cell viability, they must be properly monitored.
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Affiliation(s)
- Y Gao
- Department of General Surgery, First Clinical Hospital of Harbin Medical University, Harbin, China
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Kruyt MC, Persson C, Johansson G, Dhert WJA, de Bruijn JD. Towards Injectable Cell-based Tissue-Engineered Bone: The Effect of Different Calcium Phosphate Microparticles and Pre-Culturing. ACTA ACUST UNITED AC 2006; 12:309-17. [PMID: 16548689 DOI: 10.1089/ten.2006.12.309] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Bone tissue engineering by combining bone marrow stromal cells (BMSCs) with a porous scaffold is a promising technology. Current major challenges are to upscale the technique for clinical application and to improve the handling characteristics. With respect to minimal invasive surgery, moldable and/or injectable formulations are highly preferable. Ceramic microparticles of different HA/TCP formulations (100/0, 70/30, 60/40, 40/60, and 0/100) with varying surface roughness were sieved to select 200 microg aliquots of the 212-300 microm fraction. Goat BMSCs were seeded on different aliquots one week prior to in vivo implantation. These constructs and remaining cells were cultured for one week. By then, the remaining cells were harvested and resuspended in a specific binder: hyaluronic acid, alginate, or blood plasma, combined with aliquots of 60/40 microparticles peroperatively. All constructs were implanted in nude rats (n = 10) and analyzed for their bone yield histomorphometrically after 6 weeks. All precultured constructs showed consistent bone formation of comparable quantity. No significant differences were observed between the different material compositions. Peroperatively prepared constructs hardly showed any bone formation. The present study demonstrated the osteogenic potential of a tissue- engineered bone substitute made of microparticles of various HA/TCP compositions. There was an obvious advantage when the constructs were pre-cultured.
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Affiliation(s)
- Moyo C Kruyt
- Department of Orthopaedics, University Medical Center, Utrecht, The Netherlands.
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Toso C, Mathe Z, Morel P, Oberholzer J, Bosco D, Sainz-Vidal D, Hunkeler D, Buhler LH, Wandrey C, Berney T. Effect of microcapsule composition and short-term immunosuppression on intraportal biocompatibility. Cell Transplant 2005; 14:159-67. [PMID: 15881425 DOI: 10.3727/000000005783983223] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
With higher nutrient and oxygen supply and close contact to blood, the portal vein is a possible alternative to the peritoneal cavity for transplantation of encapsulated cells. Data regarding intraportal biocompatibility of microcapsules are lacking. Microcapsules were built from five alginate types differing in their molar mass and mannuronic/guluronic acid ratios by complex formation with divalent cations (barium or calcium) or mixtures of divalent cations and polycations. They were injected in the portal vein of rats, and cellular and fibrotic pericapsular infiltration thickness was measured 3 and 7 days after implantation. Overgrowth was characterized using various stainings or immunohistochemistry (hematoxylin and eosin, Giemsa, ED-1 for monocyte/macrophage, alpha-actin for myofibroblasts, CD31 for endothelial cells). The impact of short-term immunosuppression (gadolinium-chloride IV 20 mg/kg/day on days--1 and 4 as well as 10 days of rapamycin PO 1 mg/kg/day, tacrolimus PO 3 mg/kg/day, or combinations of rapamycin/tacrolimus or gadolinium/tacrolimus) was further assessed 3, 7, and 42 days after implantation. Overall, overgrowth increased from day 3 to day 7 (p < 0.05). Three and 7 days after implantation, polycation-containing microcapsules induced more reaction than microbeads (p < 0.0001 and p < 0.01). Considering polycation-free beads, barium-alginate induced the weakest reaction. Biocompatibility of microbeads was independent of mannuronic/guluronic acid ratio and molar mass of the alginate. Infiltration was mainly a monocyte/macrophage-rich foreign body reaction, but an eosinophil-containing immunoallergic reaction was also observed. Short-term immunosuppression significantly reduced infiltration in all conditions and up to 42 days after implantation. Biocompatibility after intraportal infusion was best for barium-alginate microbeads and poorest for polycation-containing microcapsules. Short- and long-term overgrowth could be significantly reduced by short-term immunosuppression.
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Affiliation(s)
- Christian Toso
- Centre d'isolement et de transplantation cellulaire, Service de chirurgie viscérale, Hôpital Universitaire, 4, rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland.
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In vitro study of alginate?chitosan microcapsules: an alternative to liver cell transplants for the treatment of liver failure. Biotechnol Lett 2005; 27:317-22. [DOI: 10.1007/s10529-005-0687-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Revised: 01/06/2005] [Accepted: 01/07/2005] [Indexed: 11/26/2022]
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