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Sample records for advanced tissue engineering

  1. Advancing cardiovascular tissue engineering

    PubMed Central

    Truskey, George A.

    2016-01-01

    Cardiovascular tissue engineering offers the promise of biologically based repair of injured and damaged blood vessels, valves, and cardiac tissue. Major advances in cardiovascular tissue engineering over the past few years involve improved methods to promote the establishment and differentiation of induced pluripotent stem cells (iPSCs), scaffolds from decellularized tissue that may produce more highly differentiated tissues and advance clinical translation, improved methods to promote vascularization, and novel in vitro microphysiological systems to model normal and diseased tissue function. iPSC technology holds great promise, but robust methods are needed to further promote differentiation. Differentiation can be further enhanced with chemical, electrical, or mechanical stimuli. PMID:27303643

  2. Advances in Meniscal Tissue Engineering

    PubMed Central

    Longo, Umile Giuseppe; Loppini, Mattia; Forriol, Francisco; Romeo, Giovanni; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Meniscal tears are the most common knee injuries and have a poor ability of healing. In the last few decades, several techniques have been increasingly used to optimize meniscal healing. Current research efforts of tissue engineering try to combine cell-based therapy, growth factors, gene therapy, and reabsorbable scaffolds to promote healing of meniscal defects. Preliminary studies did not allow to draw definitive conclusions on the use of these techniques for routine management of meniscal lesions. We performed a review of the available literature on current techniques of tissue engineering for the management of meniscal tears. PMID:25098366

  3. Advanced Material Strategies for Tissue Engineering Scaffolds

    PubMed Central

    Engelmayr, George C.; Borenstein, Jeffrey T.; Moutos, Franklin T.; Guilak, Farshid

    2010-01-01

    Tissue engineering seeks to restore the function of diseased or damaged tissues through the use of cells and biomaterial scaffolds. It is now apparent that the next generation of functional tissue replacements will require advanced material strategies to achieve many of the important requirements for long-term success. Here we provide representative examples of engineered skeletal and myocardial tissue constructs in which scaffolds were explicitly designed to match native tissue mechanical properties as well as to promote cell alignment. We discuss recent progress in microfluidic devices that can potentially serve as tissue engineering scaffolds, since mass transport via microvascular-like structures will be essential in the development of tissue engineered constructs on the length scale of native tissues. Given the rapid evolution of the field of tissue engineering, it is important to consider the use of advanced materials in light of the emerging role of genetics, growth factors, bioreactors, and other technologies. PMID:20882506

  4. Bone Tissue Engineering: Recent Advances and Challenges

    PubMed Central

    Amini, Ami R.; Laurencin, Cato T.; Nukavarapu, Syam P.

    2013-01-01

    The worldwide incidence of bone disorders and conditions has trended steeply upward and is expected to double by 2020, especially in populations where aging is coupled with increased obesity and poor physical activity. Engineered bone tissue has been viewed as a potential alternative to the conventional use of bone grafts, due to their limitless supply and no disease transmission. However, bone tissue engineering practices have not proceeded to clinical practice due to several limitations or challenges. Bone tissue engineering aims to induce new functional bone regeneration via the synergistic combination of biomaterials, cells, and factor therapy. In this review, we discuss the fundamentals of bone tissue engineering, highlighting the current state of this field. Further, we review the recent advances of biomaterial and cell-based research, as well as approaches used to enhance bone regeneration. Specifically, we discuss widely investigated biomaterial scaffolds, micro- and nano-structural properties of these scaffolds, and the incorporation of biomimetic properties and/or growth factors. In addition, we examine various cellular approaches, including the use of mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), adult stem cells, induced pluripotent stem cells (iPSCs), and platelet-rich plasma (PRP), and their clinical application strengths and limitations. We conclude by overviewing the challenges that face the bone tissue engineering field, such as the lack of sufficient vascularization at the defect site, and the research aimed at functional bone tissue engineering. These challenges will drive future research in the field. PMID:23339648

  5. Distilling complexity to advance cardiac tissue engineering.

    PubMed

    Ogle, Brenda M; Bursac, Nenad; Domian, Ibrahim; Huang, Ngan F; Menasché, Philippe; Murry, Charles E; Pruitt, Beth; Radisic, Milica; Wu, Joseph C; Wu, Sean M; Zhang, Jianyi; Zimmermann, Wolfram-Hubertus; Vunjak-Novakovic, Gordana

    2016-06-01

    The promise of cardiac tissue engineering is in the ability to recapitulate in vitro the functional aspects of a healthy heart and disease pathology as well as to design replacement muscle for clinical therapy. Parts of this promise have been realized; others have not. In a meeting of scientists in this field, five central challenges or "big questions" were articulated that, if addressed, could substantially advance the current state of the art in modeling heart disease and realizing heart repair. PMID:27280684

  6. Tissue engineering advances in spine surgery.

    PubMed

    Makhni, Melvin C; Caldwell, Jon-Michael E; Saifi, Comron; Fischer, Charla R; Lehman, Ronald A; Lenke, Lawrence G; Lee, Francis Y

    2016-03-01

    Autograft, while currently the gold standard for bone grafting, has several significant disadvantages including limited supply, donor site pain, hematoma formation, nerve and vascular injury, and fracture. Bone allografts have their own disadvantages including reduced osteoinductive capability, lack of osteoprogenitor cells, immunogenicity and risk of disease transmission. Thus demand exists for tissue-engineered constructs that can produce viable bone while avoiding the complications associated with human tissue grafts. This review will focus on recent advancements in tissue-engineered bone graft substitutes utilizing nanoscale technology in spine surgery applications. An evaluation will be performed of bone graft substitutes, biomimetic 3D scaffolds, bone morphogenetic protein, mesenchymal stem cells and intervertebral disc regeneration strategies. PMID:26877156

  7. Recent advances in bone tissue engineering scaffolds

    PubMed Central

    Bose, Susmita; Roy, Mangal; Bandyopadhyay, Amit

    2012-01-01

    Bone disorders are of significant concern due to increase in the median age of our population. Traditionally, bone grafts have been used to restore damaged bone. Synthetic biomaterials are now being used as bone graft substitutes. These biomaterials were initially selected for structural restoration based on their biomechanical properties. Later scaffolds were engineered to be bioactive or bioresorbable to enhance tissue growth. Now scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous, biodegradable materials that harbor different growth factors, drugs, genes or stem cells. In this review, we highlight recent advances in bone scaffolds and discuss aspects that still need to be improved. PMID:22939815

  8. Distilling complexity to advance cardiac tissue engineering

    PubMed Central

    Ogle, Brenda M.; Bursac, Nenad; Domian, Ibrahim; Huang, Ngan F; Menasché, Philippe; Murry, Charles; Pruitt, Beth; Radisic, Milica; Wu, Joseph C; Wu, Sean M; Zhang, Jianyi; Zimmermann, Wolfram-Hubertus; Vunjak-Novakovic, Gordana

    2016-01-01

    The promise of cardiac tissue engineering is in the ability to recapitulate in vitro the functional aspects of healthy heart and disease pathology as well as to design replacement muscle for clinical therapy. Parts of this promise have been realized; others have not. In a meeting of scientists in this field, five central challenges or “big questions” were articulated that, if addressed, could substantially advance the current state-of-the-art in modeling heart disease and realizing heart repair. PMID:27280684

  9. Bioreactors Drive Advances in Tissue Engineering

    NASA Technical Reports Server (NTRS)

    2012-01-01

    It was an unlikely moment for inspiration. Engineers David Wolf and Ray Schwarz stopped by their lab around midday. Wolf, of Johnson Space Center, and Schwarz, with NASA contractor Krug Life Sciences (now Wyle Laboratories Inc.), were part of a team tasked with developing a unique technology with the potential to enhance medical research. But that wasn t the focus at the moment: The pair was rounding up colleagues interested in grabbing some lunch. One of the lab s other Krug engineers, Tinh Trinh, was doing something that made Wolf forget about food. Trinh was toying with an electric drill. He had stuck the barrel of a syringe on the bit; it spun with a high-pitched whirr when he squeezed the drill s trigger. At the time, a multidisciplinary team of engineers and biologists including Wolf, Schwarz, Trinh, and project manager Charles D. Anderson, who formerly led the recovery of the Apollo capsules after splashdown and now worked for Krug was pursuing the development of a technology called a bioreactor, a cylindrical device used to culture human cells. The team s immediate goal was to grow human kidney cells to produce erythropoietin, a hormone that regulates red blood cell production and can be used to treat anemia. But there was a major barrier to the technology s success: Moving the liquid growth media to keep it from stagnating resulted in turbulent conditions that damaged the delicate cells, causing them to quickly die. The team was looking forward to testing the bioreactor in space, hoping the device would perform more effectively in microgravity. But on January 28, 1986, the Space Shuttle Challenger broke apart shortly after launch, killing its seven crewmembers. The subsequent grounding of the shuttle fleet had left researchers with no access to space, and thus no way to study the effects of microgravity on human cells. As Wolf looked from Trinh s syringe-capped drill to where the bioreactor sat on a workbench, he suddenly saw a possible solution to both

  10. Nanoscale biomaterial interface modification for advanced tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Safonov, V.; Zykova, A.; Smolik, J.; Rogovska, R.; Donkov, N.; Goltsev, A.; Dubrava, T.; Rassokha, I.; Georgieva, V.

    2012-03-01

    Recently, various stem cells, including mesenchymal stem cells (MSCs), have been found to have considerable potential for application in tissue engineering and future advanced therapies due to their biological capability to differentiate into specific lineages. Modified surface properties, such as composition, nano-roughness and wettability, affect the most important processes at the biomaterial interface. The aim of the present is work is to study the stem cells' (MSCs) adhesive potential, morphology, phenotypical characteristics in in vitro tests, and to distinguish betwen the different factors influencing the cell/biomaterial interaction, such as nano-topography, surface chemistry and surface free energy.

  11. Recent Advances in Application of Biosensors in Tissue Engineering

    PubMed Central

    Paul, Arghya; Lee, Yong-kyu; Jaffa, Ayad A.

    2014-01-01

    Biosensors research is a fast growing field in which tens of thousands of papers have been published over the years, and the industry is now worth billions of dollars. The biosensor products have found their applications in numerous industries including food and beverages, agricultural, environmental, medical diagnostics, and pharmaceutical industries and many more. Even though numerous biosensors have been developed for detection of proteins, peptides, enzymes, and numerous other biomolecules for diverse applications, their applications in tissue engineering have remained limited. In recent years, there has been a growing interest in application of novel biosensors in cell culture and tissue engineering, for example, real-time detection of small molecules such as glucose, lactose, and H2O2 as well as serum proteins of large molecular size, such as albumin and alpha-fetoprotein, and inflammatory cytokines, such as IFN-g and TNF-α. In this review, we provide an overview of the recent advancements in biosensors for tissue engineering applications. PMID:25165697

  12. Recent advances in application of biosensors in tissue engineering.

    PubMed

    Hasan, Anwarul; Nurunnabi, Md; Morshed, Mahboob; Paul, Arghya; Polini, Alessandro; Kuila, Tapas; Al Hariri, Moustafa; Lee, Yong-kyu; Jaffa, Ayad A

    2014-01-01

    Biosensors research is a fast growing field in which tens of thousands of papers have been published over the years, and the industry is now worth billions of dollars. The biosensor products have found their applications in numerous industries including food and beverages, agricultural, environmental, medical diagnostics, and pharmaceutical industries and many more. Even though numerous biosensors have been developed for detection of proteins, peptides, enzymes, and numerous other biomolecules for diverse applications, their applications in tissue engineering have remained limited. In recent years, there has been a growing interest in application of novel biosensors in cell culture and tissue engineering, for example, real-time detection of small molecules such as glucose, lactose, and H2O2 as well as serum proteins of large molecular size, such as albumin and alpha-fetoprotein, and inflammatory cytokines, such as IFN-g and TNF-α. In this review, we provide an overview of the recent advancements in biosensors for tissue engineering applications. PMID:25165697

  13. Transport Advances in Disposable Bioreactors for Liver Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Catapano, Gerardo; Patzer, John F.; Gerlach, Jörg Christian

    Acute liver failure (ALF) is a devastating diagnosis with an overall survival of approximately 60%. Liver transplantation is the therapy of choice for ALF patients but is limited by the scarce availability of donor organs. The prognosis of ALF patients may improve if essential liver functions are restored during liver failure by means of auxiliary methods because liver tissue has the capability to regenerate and heal. Bioartificial liver (BAL) approaches use liver tissue or cells to provide ALF patients with liver-specific metabolism and synthesis products necessary to relieve some of the symptoms and to promote liver tissue regeneration. The most promising BAL treatments are based on the culture of tissue engineered (TE) liver constructs, with mature liver cells or cells that may differentiate into hepatocytes to perform liver-specific functions, in disposable continuous-flow bioreactors. In fact, adult hepatocytes perform all essential liver functions. Clinical evaluations of the proposed BALs show that they are safe but have not clearly proven the efficacy of treatment as compared to standard supportive treatments. Ambiguous clinical results, the time loss of cellular activity during treatment, and the presence of a necrotic core in the cell compartment of many bioreactors suggest that improvement of transport of nutrients, and metabolic wastes and products to or from the cells in the bioreactor is critical for the development of therapeutically effective BALs. In this chapter, advanced strategies that have been proposed over to improve mass transport in the bioreactors at the core of a BAL for the treatment of ALF patients are reviewed.

  14. Corneal Tissue Engineering: Recent Advances and Future Perspectives

    PubMed Central

    Ghezzi, Chiara E.; Rnjak-Kovacina, Jelena

    2015-01-01

    To address the growing need for corneal transplants two main approaches are being pursued: allogenic and synthetic materials. Allogenic tissue from human donors is currently the preferred choice; however, there is a worldwide shortage in donated corneal tissue. In addition, tissue rejection often limits the long-term success of this approach. Alternatively, synthetic homologs to donor corneal grafts are primarily considered temporary replacements until suitable donor tissue becomes available, as they result in a high incidence of graft failure. Tissue engineered cornea analogs would provide effective cornea tissue substitutes and alternatives to address the need to reduce animal testing of commercial products. Recent progress toward these needs is reviewed here, along with future perspectives. PMID:25434371

  15. Graphene and its nanostructure derivatives for use in bone tissue engineering: Recent advances.

    PubMed

    Shadjou, Nasrin; Hasanzadeh, Mohammad

    2016-05-01

    Tissue engineering and regenerative medicine represent areas of increasing interest because of the major progress in cell and organ transplantation, as well as advances in materials science and engineering. Tissue-engineered bone constructs have the potential to alleviate the demand arising from the shortage of suitable autograft and allograft materials for augmenting bone healing. Graphene and its derivatives have attracted much interest for applications in bone tissue engineering. For this purpose, this review focuses on more recent advances in tissue engineering based on graphene-biomaterials from 2013 to May 2015. The purpose of this article was to give a general description of studies of nanostructured graphene derivatives for bone tissue engineering. In this review, we highlight how graphene family nanomaterials are being exploited for bone tissue engineering. Firstly, the main requirements for bone tissue engineering were discussed. Then, the mechanism by which graphene based materials promote new bone formation was explained, following which the current research status of main types of nanostructured scaffolds for bone tissue engineering was reviewed and discussed. In addition, graphene-based bioactive glass, as a potential drug/growth factor carrier, was reviewed which includes the composition-structure-drug delivery relationship and the functional effect on the tissue-stimulation properties. Also, the effect of structural and textural properties of graphene based materials on development of new biomaterials for production of bone implants and bone cements were discussed. Finally, the present review intends to provide the reader an overview of the current state of the graphene based biomaterials in bone tissue engineering, its limitations and hopes as well as the future research trends for this exciting field of science. PMID:26748447

  16. Advancing Tissue Engineering: A Tale of Nano-, Micro-, and Macroscale Integration.

    PubMed

    Leijten, Jeroen; Rouwkema, Jeroen; Zhang, Yu Shrike; Nasajpour, Amir; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2016-04-27

    Tissue engineering has the potential to revolutionize the health care industry. Delivering on this promise requires the generation of efficient, controllable and predictable implants. The integration of nano- and microtechnologies into macroscale regenerative biomaterials plays an essential role in the generation of such implants, by enabling spatiotemporal control of the cellular microenvironment. Here we review the role, function and progress of a wide range of nano- and microtechnologies that are driving the advancements in the field of tissue engineering. PMID:27101419

  17. Review: Advances in Vascular Tissue Engineering Using Protein-Based Biomaterials

    PubMed Central

    Stegemann, Jan P.; Kaszuba, Stephanie N.; Rowe, Shaneen L.

    2008-01-01

    The clinical need for improved blood vessel substitutes, especially in small-diameter applications, drives the field of vascular tissue engineering. The blood vessel has a well-characterized structure and function, but it is a complex tissue, and it has proven difficult to create engineered tissues that are suitable for widespread clinical use. This review is focused on approaches to vascular tissue engineering that use proteins as the primary matrix or “scaffold” material for creating fully biological blood vessel replacements. In particular, this review covers four main approaches to vascular tissue engineering: 1) cell-populated protein hydrogels, 2) cross-linked protein scaffolds, 3) decellularized native tissues, and 4) self-assembled scaffolds. Recent advances in each of these areas are discussed, along with advantages of and drawbacks to these approaches. The first fully biological engineered blood vessels have entered clinical trials, but important challenges remain before engineered vascular tissues will have a wide clinical effect. Cell sourcing and recapitulating the biological and mechanical function of the native blood vessel continue to be important outstanding hurdles. In addition, the path to commercialization for such tissues must be better defined. Continued progress in several complementary approaches to vascular tissue engineering is necessary before blood vessel substitutes can achieve their full potential in improving patient care. PMID:17961004

  18. Cell Microenvironment Engineering and Monitoring for Tissue Engineering and Regenerative Medicine: The Recent Advances

    PubMed Central

    Barthes, Julien; Özçelik, Hayriye; Hindié, Mathilde; Ndreu-Halili, Albana; Hasan, Anwarul

    2014-01-01

    In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells' behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future. PMID:25143954

  19. Cell microenvironment engineering and monitoring for tissue engineering and regenerative medicine: the recent advances.

    PubMed

    Barthes, Julien; Özçelik, Hayriye; Hindié, Mathilde; Ndreu-Halili, Albana; Hasan, Anwarul; Vrana, Nihal Engin

    2014-01-01

    In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells' behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future. PMID:25143954

  20. Novel strategies in tendon and ligament tissue engineering: Advanced biomaterials and regeneration motifs

    PubMed Central

    2010-01-01

    Tendon and ligaments have poor healing capacity and when injured often require surgical intervention. Tissue replacement via autografts and allografts are non-ideal strategies that can lead to future problems. As an alternative, scaffold-based tissue engineering strategies are being pursued. In this review, we describe design considerations and major recent advancements of scaffolds for tendon/ligament engineering. Specifically, we outline native tendon/ligament characteristics critical for design parameters and outcome measures, and introduce synthetic and naturally-derived biomaterials used in tendon/ligament scaffolds. We will describe applications of these biomaterials in advanced tendon/ligament engineering strategies including the utility of scaffold functionalization, cyclic strain, growth factors, and interface considerations. The goal of this review is to compile and interpret the important findings of recent tendon/ligament engineering research in an effort towards the advancement of regenerative strategies. PMID:20727171

  1. Advances in pulmonary therapy and drug development: Lung tissue engineering to lung-on-a-chip.

    PubMed

    Doryab, Ali; Amoabediny, Ghassem; Salehi-Najafabadi, Amir

    2016-01-01

    Lung disease is one of the major causes of death, and the rate of pulmonary diseases has been increasing for decades. Although lung transplantation is the only treatment for majority of patients, this method has been limited due to lack of donors. Therefore, recently, attentions have increased to some new strategies with the aid of tissue engineering and microfluidics techniques not only for the functional analysis, but also for drug screening. In fact, in tissue engineering, the engineered tissue is able to grow by using the patient's own cells without intervention in the immune system. On the other hand, microfluidics devices are applied in order to evaluate drug screenings, function analysis and toxicity. This article reviews new advances in lung tissue engineering and lung-on-a-chip. Furthermore, future directions, difficulties and drawbacks of pulmonary therapy in these areas are discussed. PMID:26875777

  2. Engineered cardiac tissues

    PubMed Central

    Iyer, Rohin K.; Chiu, Loraine L. Y.; Reis, Lewis A.; Radisic, Milica

    2011-01-01

    Cardiac tissue engineering offers the promise of creating functional tissue replacements for use in the failing heart or for in vitro drug screening. The last decade has seen a great deal of progress in this field with new advances in interdisciplinary areas such as developmental biology, genetic engineering, biomaterials, polymer science, bioreactor engineering, and stem cell biology. We review here a selection of the most recent advances in cardiac tissue engineering, including the classical cell-scaffold approaches, advanced bioreactor designs, cell sheet engineering, whole organ decellularization, stem-cell based approaches, and topographical control of tissue organization and function. We also discuss current challenges in the field, such as maturation of stem cell-derived cardiac patches and vascularization. PMID:21530228

  3. Skin tissue engineering advances in severe burns: review and therapeutic applications.

    PubMed

    Chua, Alvin Wen Choong; Khoo, Yik Cheong; Tan, Bien Keem; Tan, Kok Chai; Foo, Chee Liam; Chong, Si Jack

    2016-01-01

    Current advances in basic stem cell research and tissue engineering augur well for the development of improved cultured skin tissue substitutes: a class of products that is still fraught with limitations for clinical use. Although the ability to grow autologous keratinocytes in-vitro from a small skin biopsy into sheets of stratified epithelium (within 3 to 4 weeks) helped alleviate the problem of insufficient donor site for extensive burn, many burn units still have to grapple with insufficient skin allografts which are used as intermediate wound coverage after burn excision. Alternatives offered by tissue-engineered skin dermal replacements to meet emergency demand have been used fairly successfully. Despite the availability of these commercial products, they all suffer from the same problems of extremely high cost, sub-normal skin microstructure and inconsistent engraftment, especially in full thickness burns. Clinical practice for severe burn treatment has since evolved to incorporate these tissue-engineered skin substitutes, usually as an adjunct to speed up epithelization for wound closure and/or to improve quality of life by improving the functional and cosmetic results long-term. This review seeks to bring the reader through the beginnings of skin tissue engineering, the utilization of some of the key products developed for the treatment of severe burns and the hope of harnessing stem cells to improve on current practice. PMID:27574673

  4. Current Advance and Future Prospects of Tissue Engineering Approach to Dentin/Pulp Regenerative Therapy.

    PubMed

    Gong, Ting; Heng, Boon Chin; Lo, Edward Chin Man; Zhang, Chengfei

    2016-01-01

    Recent advances in biomaterial science and tissue engineering technology have greatly spurred the development of regenerative endodontics. This has led to a paradigm shift in endodontic treatment from simply filling the root canal systems with biologically inert materials to restoring the infected dental pulp with functional replacement tissues. Currently, cell transplantation has gained increasing attention as a scientifically valid method for dentin-pulp complex regeneration. This multidisciplinary approach which involves the interplay of three key elements of tissue engineering-stem cells, scaffolds, and signaling molecules-has produced an impressive number of favorable outcomes in preclinical animal studies. Nevertheless, many practical hurdles need to be overcome prior to its application in clinical settings. Apart from the potential health risks of immunological rejection and pathogenic transmission, the lack of a well-established banking system for the isolation and storage of dental-derived stem cells is the most pressing issue that awaits resolution and the properties of supportive scaffold materials vary across different studies and remain inconsistent. This review critically examines the classic triad of tissue engineering utilized in current regenerative endodontics and summarizes the possible techniques developed for dentin/pulp regeneration. PMID:27069484

  5. Advanced Imaging and Tissue Engineering of the Human Limbal Epithelial Stem Cell Niche

    PubMed Central

    Massie, Isobel; Dziasko, Marc; Kureshi, Alvena; Levis, Hannah J.; Morgan, Louise; Neale, Michael; Sheth, Radhika; Tovell, Victoria E.; Vernon, Amanda J.; Funderburgh, James L.; Daniels, Julie T.

    2015-01-01

    The limbal epithelial stem cell niche provides a unique, physically protective environment in which limbal epithelial stem cells reside in close proximity with accessory cell types and their secreted factors. The use of advanced imaging techniques is described to visualize the niche in three dimensions in native human corneal tissue. In addition, a protocol is provided for the isolation and culture of three different cell types, including human limbal epithelial stem cells from the limbal niche of human donor tissue. Finally, the process of incorporating these cells within plastic compressed collagen constructs to form a tissue-engineered corneal limbus is described and how immunohistochemical techniques may be applied to characterize cell phenotype therein. PMID:25388395

  6. Dental Pulp and Dentin Tissue Engineering and Regeneration – Advancement and Challenge

    PubMed Central

    Huang, George T.-J.

    2012-01-01

    Hard tissue is difficult to repair especially dental structures. Tooth enamel is incapable of self-repairing whereas dentin and cememtum can regenerate with limited capacity. Enamel and dentin are commonly under the attack by caries. Extensive forms of caries destroy enamel and dentin and can lead to dental pulp infection. Entire pulp amputation followed by the pulp space disinfection and filled with an artificial rubber-like material is employed to treat the infection --commonly known as root canal or endodontic therapy. Regeneration of dentin relies on having vital pulps; however, regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. With the advent of modern tissue engineering concept and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the recent endeavor on pulp and dentin tissue engineering and regeneration. The prospective outcome of the current advancement and challenge in this line of research will be discussed. PMID:21196351

  7. Current Advance and Future Prospects of Tissue Engineering Approach to Dentin/Pulp Regenerative Therapy

    PubMed Central

    Gong, Ting; Heng, Boon Chin; Lo, Edward Chin Man; Zhang, Chengfei

    2016-01-01

    Recent advances in biomaterial science and tissue engineering technology have greatly spurred the development of regenerative endodontics. This has led to a paradigm shift in endodontic treatment from simply filling the root canal systems with biologically inert materials to restoring the infected dental pulp with functional replacement tissues. Currently, cell transplantation has gained increasing attention as a scientifically valid method for dentin-pulp complex regeneration. This multidisciplinary approach which involves the interplay of three key elements of tissue engineering—stem cells, scaffolds, and signaling molecules—has produced an impressive number of favorable outcomes in preclinical animal studies. Nevertheless, many practical hurdles need to be overcome prior to its application in clinical settings. Apart from the potential health risks of immunological rejection and pathogenic transmission, the lack of a well-established banking system for the isolation and storage of dental-derived stem cells is the most pressing issue that awaits resolution and the properties of supportive scaffold materials vary across different studies and remain inconsistent. This review critically examines the classic triad of tissue engineering utilized in current regenerative endodontics and summarizes the possible techniques developed for dentin/pulp regeneration. PMID:27069484

  8. Tissue engineered periodontal products.

    PubMed

    Bartold, P M; Gronthos, S; Ivanovski, S; Fisher, A; Hutmacher, D W

    2016-02-01

    Attainment of periodontal regeneration is a significant clinical goal in the management of advanced periodontal defects arising from periodontitis. Over the past 30 years numerous techniques and materials have been introduced and evaluated clinically and have included guided tissue regeneration, bone grafting materials, growth and other biological factors and gene therapy. With the exception of gene therapy, all have undergone evaluation in humans. All of the products have shown efficacy in promoting periodontal regeneration in animal models but the results in humans remain variable and equivocal concerning attaining complete biological regeneration of damaged periodontal structures. In the early 2000s, the concept of tissue engineering was proposed as a new paradigm for periodontal regeneration based on molecular and cell biology. At this time, tissue engineering was a new and emerging field. Now, 14 years later we revisit the concept of tissue engineering for the periodontium and assess how far we have come, where we are currently situated and what needs to be done in the future to make this concept a reality. In this review, we cover some of the precursor products, which led to our current position in periodontal tissue engineering. The basic concepts of tissue engineering with special emphasis on periodontal tissue engineering products is discussed including the use of mesenchymal stem cells in bioscaffolds and the emerging field of cell sheet technology. Finally, we look into the future to consider what CAD/CAM technology and nanotechnology will have to offer. PMID:25900048

  9. DENTAL PULP TISSUE ENGINEERING

    PubMed Central

    Demarco, FF; Conde, MCM; Cavalcanti, B; Casagrande, L; Sakai, V; Nör, JE

    2013-01-01

    Dental pulp is a highly specialized mesenchymal tissue, which have a restrict regeneration capacity due to anatomical arrangement and post-mitotic nature of odontoblastic cells. Entire pulp amputation followed by pulp-space disinfection and filling with an artificial material cause loss of a significant amount of dentin leaving as life-lasting sequelae a non-vital and weakened tooth. However, regenerative endodontics is an emerging field of modern tissue engineering that demonstrated promising results using stem cells associated with scaffolds and responsive molecules. Thereby, this article will review the most recent endeavors to regenerate pulp tissue based on tissue engineering principles and providing insightful information to readers about the different aspects enrolled in tissue engineering. Here, we speculate that the search for the ideal combination of cells, scaffolds, and morphogenic factors for dental pulp tissue engineering may be extended over future years and result in significant advances in other areas of dental and craniofacial research. The finds collected in our review showed that we are now at a stage in which engineering a complex tissue, such as the dental pulp, is no longer an unachievable and the next decade will certainly be an exciting time for dental and craniofacial research. PMID:21519641

  10. Neovascularization in Tissue Engineering

    PubMed Central

    Chung, Jennifer C.-Y.; Shum-Tim, Dominique

    2012-01-01

    A prerequisite for successful tissue engineering is adequate vascularization that would allow tissue engineering constructs to survive and grow. Angiogenic growth factors, alone and in combination, have been used to achieve this, and gene therapy has been used as a tool to enable sustained release of these angiogenic proteins. Cell-based therapy using endothelial cells and their precursors presents an alternative approach to tackling this challenge. These studies have occurred on a background of advancements in scaffold design and assays for assessing neovascularization. Finally, several studies have already attempted to translate research in neovascularization to clinical use in the blossoming field of therapeutic angiogenesis. PMID:24710553

  11. Stem cells for regenerative medicine: advances in the engineering of tissues and organs

    NASA Astrophysics Data System (ADS)

    Ringe, Jochen; Kaps, Christian; Burmester, Gerd-Rüdiger; Sittinger, Michael

    2002-07-01

    The adult bone marrow stroma contains a subset of nonhematopoietic cells referred to as mesenchymal stem or mesenchymal progenitor cells (MSC). These cells have the capacity to undergo extensive replication in an undifferentiated state ex vivo. In addition, MSC have the potential to develop either in vitro or in vivo into distinct mesenchymal tissues, including bone, cartilage, fat, tendon, muscle, and marrow stroma, which suggest these cells as an attractive cell source for tissue engineering approaches. The interest in modern biological technologies such as tissue engineering has dramatically increased since it is feasible to isolate living, healthy cells from the body, expand them under cell culture conditions, combine them with biocompatible carrier materials and retransplant them into patients. Therefore, tissue engineering gives the opportunity to generate living substitutes for tissues and organs, which may overcome the drawbacks of classical tissue reconstruction: lacking quality and quantity of autologous grafts, immunogenicity of allogenic grafts and loosening of alloplastic implants. Due to the prerequisite for tissue engineering to ensure a sufficient number of tissue specific cells without donor site morbidity, much attention has been drawn to multipotential progenitor cells such as embryonic stem cells, periosteal cells and mesenchymal stem cells. In this report we review the state of the art in tissue engineering with mesenchymal stem and mesenchymal progenitor cells with emphasis on bone and cartilage reconstruction. Furthermore, several issues of importance, especially with regard to the clinical application of mesenchymal stem cells, are discussed.

  12. Advances in tissue engineering through stem cell-based co-culture.

    PubMed

    Paschos, Nikolaos K; Brown, Wendy E; Eswaramoorthy, Rajalakshmanan; Hu, Jerry C; Athanasiou, Kyriacos A

    2015-05-01

    Stem cells are the future in tissue engineering and regeneration. In a co-culture, stem cells not only provide a target cell source with multipotent differentiation capacity, but can also act as assisting cells that promote tissue homeostasis, metabolism, growth and repair. Their incorporation into co-culture systems seems to be important in the creation of complex tissues or organs. In this review, critical aspects of stem cell use in co-culture systems are discussed. Direct and indirect co-culture methodologies used in tissue engineering are described, along with various characteristics of cellular interactions in these systems. Direct cell-cell contact, cell-extracellular matrix interaction and signalling via soluble factors are presented. The advantages of stem cell co-culture strategies and their applications in tissue engineering and regenerative medicine are portrayed through specific examples for several tissues, including orthopaedic soft tissues, bone, heart, vasculature, lung, kidney, liver and nerve. A concise review of the progress and the lessons learned are provided, with a focus on recent developments and their implications. It is hoped that knowledge developed from one tissue can be translated to other tissues. Finally, we address challenges in tissue engineering and regenerative medicine that can potentially be overcome via employing strategies for stem cell co-culture use. PMID:24493315

  13. Highly conductive stretchable and biocompatible electrode-hydrogel hybrids for advanced tissue engineering.

    PubMed

    Sasaki, Masato; Karikkineth, Bijoy Chandapillai; Nagamine, Kuniaki; Kaji, Hirokazu; Torimitsu, Keiichi; Nishizawa, Matsuhiko

    2014-11-01

    Hydrogel-based, molecular permeable electronic devices are considered to be promising for electrical stimulation and recording of living tissues, either in vivo or in vitro. This study reports the fabrication of the first hydrogel-based devices that remain highly electrically conductive under substantial stretch and bending. Using a simple technique involving a combination of chemical polymerization and electropolymerization of poly (3,4-ethylenedioxythiophene) (PEDOT), a tight bonding of a conductive composite of PEDOT and polyurethane (PU) to an elastic double-network hydrogel is achieved to make fully organic PEDOT/PU-hydrogel hybrids. Their response to repeated bending, mechanical stretching, hydration-dessication cycles, storage in aqueous condition for up to 6 months, and autoclaving is assessed, demonstrating excellent stability, without any mechanical or electrical damage. The hybrids exhibit a high electrical conductivity of up to 120 S cm(-1) at 100% elongation. The adhesion, proliferation, and differentiation of neural and muscle cells cultured on these hybrids are demonstrated, as well as the fabrication of 3D hybrids, advancing the field of tissue engineering with integrated electronics. PMID:24912988

  14. Advanced biomaterial strategies to transplant preformed micro-tissue engineered neural networks into the brain

    NASA Astrophysics Data System (ADS)

    Harris, J. P.; Struzyna, L. A.; Murphy, P. L.; Adewole, D. O.; Kuo, E.; Cullen, D. K.

    2016-02-01

    Objective. Connectome disruption is a hallmark of many neurological diseases and trauma with no current strategies to restore lost long-distance axonal pathways in the brain. We are creating transplantable micro-tissue engineered neural networks (micro-TENNs), which are preformed constructs consisting of embedded neurons and long axonal tracts to integrate with the nervous system to physically reconstitute lost axonal pathways. Approach. We advanced micro-tissue engineering techniques to generate micro-TENNs consisting of discrete populations of mature primary cerebral cortical neurons spanned by long axonal fascicles encased in miniature hydrogel micro-columns. Further, we improved the biomaterial encasement scheme by adding a thin layer of low viscosity carboxymethylcellulose (CMC) to enable needle-less insertion and rapid softening for mechanical similarity with brain tissue. Main results. The engineered architecture of cortical micro-TENNs facilitated robust neuronal viability and axonal cytoarchitecture to at least 22 days in vitro. Micro-TENNs displayed discrete neuronal populations spanned by long axonal fasciculation throughout the core, thus mimicking the general systems-level anatomy of gray matter—white matter in the brain. Additionally, micro-columns with thin CMC-coating upon mild dehydration were able to withstand a force of 893 ± 457 mN before buckling, whereas a solid agarose cylinder of similar dimensions was predicted to withstand less than 150 μN of force. This thin CMC coating increased the stiffness by three orders of magnitude, enabling needle-less insertion into brain while significantly reducing the footprint of previous needle-based delivery methods to minimize insertion trauma. Significance. Our novel micro-TENNs are the first strategy designed for minimally invasive implantation to facilitate nervous system repair by simultaneously providing neuronal replacement and physical reconstruction of long-distance axon pathways in the brain

  15. Advancing functional engineered cardiac tissues toward a preclinical model of human myocardium

    PubMed Central

    Turnbull, Irene C.; Karakikes, Ioannis; Serrao, Gregory W.; Backeris, Peter; Lee, Jia-Jye; Xie, Chaoqin; Senyei, Grant; Gordon, Ronald E.; Li, Ronald A.; Akar, Fadi G.; Hajjar, Roger J.; Hulot, Jean-Sébastien; Costa, Kevin D.

    2014-01-01

    Cardiac experimental biology and translational research would benefit from an in vitro surrogate for human heart muscle. This study investigated structural and functional properties and interventional responses of human engineered cardiac tissues (hECTs) compared to human myocardium. Human embryonic stem cell-derived cardiomyocytes (hESC-CMs, >90% troponin-positive) were mixed with collagen and cultured on force-sensing elastomer devices. hECTs resembled trabecular muscle and beat spontaneously (1.18±0.48 Hz). Microstructural features and mRNA expression of cardiac-specific genes (α-MHC, SERCA2a, and ACTC1) were comparable to human myocardium. Optical mapping revealed cardiac refractoriness with loss of 1:1 capture above 3 Hz, and cycle length dependence of the action potential duration, recapitulating key features of cardiac electrophysiology. hECTs reconstituted the Frank-Starling mechanism, generating an average maximum twitch stress of 660 μN/mm2 at Lmax, approaching values in newborn human myocardium. Dose-response curves followed exponential pharmacodynamics models for calcium chloride (EC50 1.8 mM) and verapamil (IC50 0.61 μM); isoproterenol elicited a positive chronotropic but negligible inotropic response, suggesting sarcoplasmic reticulum immaturity. hECTs were amenable to gene transfer, demonstrated by successful transduction with Ad.GFP. Such 3-D hECTs recapitulate an early developmental stage of human myocardium and promise to offer an alternative preclinical model for cardiology research.—Turnbull, I. C., Karakikes, I., Serrao, G. W., Backeris, P., Lee, J.-J., Xie, C., Senyei, G., Gordon, R. E., Li, R. A., Akar, F. G., Hajjar, R. J., Hulot, J.-S., Costa, K. D. Advancing functional engineered cardiac tissues toward a preclinical model of human myocardium. PMID:24174427

  16. Advances and Prospects in Tissue-Engineered Meniscal Scaffolds for Meniscus Regeneration

    PubMed Central

    Guo, Weimin; Liu, Shuyun; Zhu, Yun; Yu, Changlong; Lu, Shibi; Yuan, Mei; Gao, Yue; Huang, Jingxiang; Yuan, Zhiguo; Peng, Jiang; Wang, Aiyuan; Wang, Yu; Chen, Jifeng; Zhang, Li; Sui, Xiang; Xu, Wenjing; Guo, Quanyi

    2015-01-01

    The meniscus plays a crucial role in maintaining knee joint homoeostasis. Meniscal lesions are relatively common in the knee joint and are typically categorized into various types. However, it is difficult for inner avascular meniscal lesions to self-heal. Untreated meniscal lesions lead to meniscal extrusions in the long-term and gradually trigger the development of knee osteoarthritis (OA). The relationship between meniscal lesions and knee OA is complex. Partial meniscectomy, which is the primary method to treat a meniscal injury, only relieves short-term pain; however, it does not prevent the development of knee OA. Similarly, other current therapeutic strategies have intrinsic limitations in clinical practice. Tissue engineering technology will probably address this challenge by reconstructing a meniscus possessing an integrated configuration with competent biomechanical capacity. This review describes normal structure and biomechanical characteristics of the meniscus, discusses the relationship between meniscal lesions and knee OA, and summarizes the classifications and corresponding treatment strategies for meniscal lesions to understand meniscal regeneration from physiological and pathological perspectives. Last, we present current advances in meniscal scaffolds and provide a number of prospects that will potentially benefit the development of meniscal regeneration methods. PMID:26199629

  17. Neoproteoglycans in tissue engineering

    PubMed Central

    Weyers, Amanda; Linhardt, Robert J.

    2014-01-01

    Proteoglycans, comprised of a core protein to which glycosaminoglycan chains are covalently linked, are an important structural and functional family of macromolecules found in the extracellular matrix. Advances in our understanding of biological interactions have lead to a greater appreciation for the need to design tissue engineering scaffolds that incorporate mimetics of key extracellular matrix components. A variety of synthetic and semisynthetic molecules and polymers have been examined by tissue engineers that serve as structural, chemical and biological replacements for proteoglycans. These proteoglycan mimetics have been referred to as neoproteoglycans and serve as functional and therapeutic replacements for natural proteoglycans that are often unavailable for tissue engineering studies. Although neoproteoglycans have important limitations, such as limited signaling ability and biocompatibility, they have shown promise in replacing the natural activity of proteoglycans through cell and protein binding interactions. This review focuses on the recent in vivo and in vitro tissue engineering applications of three basic types of neoproteoglycan structures, protein–glycosaminoglycan conjugates, nano-glycosaminoglycan composites and polymer–glycosaminoglycan complexes. PMID:23399318

  18. Electrospun multifunctional tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Wang, Chong; Wang, Min

    2014-03-01

    Tissue engineering holds great promises in providing successful treatments of human body tissue loss that current methods are unable to treat or unable to achieve satisfactory clinical outcomes. In scaffold-based tissue engineering, a highperformance scaffold underpins the success of a tissue engineering strategy and a major direction in the field is to create multifunctional tissue engineering scaffolds for enhanced biological performance and for regenerating complex body tissues. Electrospinning can produce nanofibrous scaffolds that are highly desirable for tissue engineering. The enormous interest in electrospinning and electrospun fibrous structures by the science, engineering and medical communities has led to various developments of the electrospinning technology and wide investigations of electrospun products in many industries, including biomedical engineering, over the past two decades. It is now possible to create novel, multicomponent tissue engineering scaffolds with multiple functions. This article provides a concise review of recent advances in the R & D of electrospun multifunctional tissue engineering scaffolds. It also presents our philosophy and research in the designing and fabrication of electrospun multicomponent scaffolds with multiple functions.

  19. [Research advances in the controlled release of growth factor related to blood vessel tissue engineering].

    PubMed

    Wu, Lili; Yuan, Xiaoyan; Yao, Kangde

    2006-08-01

    Growth factors play an important role in cell adhesion and proliferation as well as in tissue regeneration. By incorporating growth factors into polymer scaffolds, controlled release of them can be performed. The release mechanism is varied with the incorporation methods. In this paper, the latest advances in the controlled release of growth factors by blending, hydrogel, microsphere embedding and chemical bonding are reviewed. The potential application of ultrafine fibric embedding in growth factor delivery is described as well. PMID:17002137

  20. Form Follows Function: Advances in Trilayered Structure Replication for Aortic Heart Valve Tissue Engineering

    PubMed Central

    Simionescu, Dan T.; Chen, Joseph; Jaeggli, Michael; Wang, Bo; Liao, Jun

    2013-01-01

    Tissue engineering the aortic heart valve is a challenging endeavor because of the particular hemodynamic and biologic conditions present in the native aortic heart valve. The backbone of an ideal valve substitute should be a scaffold that is strong enough to withstand billions of repetitive bending, flexing and stretching cycles, while also being slowly degradable to allow for remodeling. In this review we highlight three overlooked aspects that might influence the long term durability of tissue engineered valves: replication of the native valve trilayered histoarchitecture, duplication of the three-dimensional shape of the valve and cell integration efforts focused on getting the right number and type of cells to the right place within the valve structure and driving them towards homeostatic maintenance of the valve matrix. We propose that the trilayered structure in the native aortic valve that includes a middle spongiosa layer cushioning the motions of the two external fibrous layers should be our template for creation of novel scaffolds with improved mechanical durability. Furthermore, since cells adapt to micro-loads within the valve structure, we believe that interstitial cell remodeling of the valvular matrix will depend on the accurate replication of the structures and loads, resulting in successful regeneration of the valve tissue and extended durability. PMID:23355946

  1. Research Advances in Tissue Engineering Materials for Sustained Release of Growth Factors

    PubMed Central

    Zhao, Hai-yang; Wu, Jiang; Zhu, Jing-jing; Xiao, Ze-cong; He, Chao-chao; Shi, Hong-xue; Li, Xiao-kun; Yang, Shu-lin; Xiao, Jian

    2015-01-01

    Growth factors are a class of cytokines that stimulate cell growth and are widely used in clinical practice, such as wound healing, revascularization, bone repair, and nervous system disease. However, free growth factors have a short half-life and are instable in vivo. Therefore, the search of excellent carriers to enhance sustained release of growth factors in vivo has become an area of intense research interest. The development of controlled-release systems that protect the recombinant growth factors from enzymatic degradation and provide sustained delivery at the injury site during healing should enhance the growth factor's application in tissue regeneration. Thus, this study reviews current research on commonly used carriers for sustained release of growth factors and their sustained release effects for preservation of their bioactivity and their accomplishment in tissue engineering approaches. PMID:26347885

  2. Current Advances in the Translation of Vascular Tissue Engineering to the Treatment of Pediatric Congenital Heart Disease

    PubMed Central

    Dean, Ethan W.; Udelsman, Brooks; Breuer, Christopher K.

    2012-01-01

    Tissue-engineered vascular grafts (TEVGs) hold great promise for the improvement of outcomes in pediatric patients with congenital cardiac anomalies. Currently used synthetic grafts have several limitations, including thrombogenicity, increased risk of infection, and lack of growth potential. The first pilot clinical trial of TEVGs demonstrated the feasibility of this new technology and revealed an excellent safety profile. However, long-term follow-up from this trial revealed the primary graft-related complication to be stenosis, affecting 16 percent of grafts within 7 years post-implantation. In order to determine the mechanism behind TEVG stenosis and ultimately to create improved second generation TEVGs, our group has returned to the bench to study vascular neotissue formation in a variety of large and small animal models. The purpose of this report is to review the recent advances in the understanding of neotissue formation and vascular tissue engineering. PMID:22737051

  3. [Bone tissue engineering scaffolds].

    PubMed

    Fang, Liru; Weng, Wenjian; Shen, Ge; Han, Gaorong; Santos, J D; Du, Peiyi

    2003-03-01

    Bone tissue engineering may provide an alternative to the repairs to skeletal defects resulting from disease, trauma or surgery. Scaffold has played an important role in bone tissue engineering, which functions as the architecture for bone in growth. In this paper, the authors gave a brief introduction about the requirement of bone tissue engineering scaffold, the key of the design of scaffolds and the current research on this subject. PMID:12744187

  4. Engineering Complex Tissues

    PubMed Central

    MIKOS, ANTONIOS G.; HERRING, SUSAN W.; OCHAREON, PANNEE; ELISSEEFF, JENNIFER; LU, HELEN H.; KANDEL, RITA; SCHOEN, FREDERICK J.; TONER, MEHMET; MOONEY, DAVID; ATALA, ANTHONY; VAN DYKE, MARK E.; KAPLAN, DAVID; VUNJAK-NOVAKOVIC, GORDANA

    2010-01-01

    This article summarizes the views expressed at the third session of the workshop “Tissue Engineering—The Next Generation,” which was devoted to the engineering of complex tissue structures. Antonios Mikos described the engineering of complex oral and craniofacial tissues as a “guided interplay” between biomaterial scaffolds, growth factors, and local cell populations toward the restoration of the original architecture and function of complex tissues. Susan Herring, reviewing osteogenesis and vasculogenesis, explained that the vascular arrangement precedes and dictates the architecture of the new bone, and proposed that engineering of osseous tissues might benefit from preconstruction of an appropriate vasculature. Jennifer Elisseeff explored the formation of complex tissue structures based on the example of stratified cartilage engineered using stem cells and hydrogels. Helen Lu discussed engineering of tissue interfaces, a problem critical for biological fixation of tendons and ligaments, and the development of a new generation of fixation devices. Rita Kandel discussed the challenges related to the re-creation of the cartilage-bone interface, in the context of tissue engineered joint repair. Frederick Schoen emphasized, in the context of heart valve engineering, the need for including the requirements derived from “adult biology” of tissue remodeling and establishing reliable early predictors of success or failure of tissue engineered implants. Mehmet Toner presented a review of biopreservation techniques and stressed that a new breakthrough in this field may be necessary to meet all the needs of tissue engineering. David Mooney described systems providing temporal and spatial regulation of growth factor availability, which may find utility in virtually all tissue engineering and regeneration applications, including directed in vitro and in vivo vascularization of tissues. Anthony Atala offered a clinician’s perspective for functional tissue

  5. Magnetic poly(ε-caprolactone)/iron-doped hydroxyapatite nanocomposite substrates for advanced bone tissue engineering

    PubMed Central

    Gloria, A.; Russo, T.; D'Amora, U.; Zeppetelli, S.; D'Alessandro, T.; Sandri, M.; Bañobre-López, M.; Piñeiro-Redondo, Y.; Uhlarz, M.; Tampieri, A.; Rivas, J.; Herrmannsdörfer, T.; Dediu, V. A.; Ambrosio, L.; De Santis, R.

    2013-01-01

    In biomedicine, magnetic nanoparticles provide some attractive possibilities because they possess peculiar physical properties that permit their use in a wide range of applications. The concept of magnetic guidance basically spans from drug delivery and hyperthermia treatment of tumours, to tissue engineering, such as magneto-mechanical stimulation/activation of cell constructs and mechanosensitive ion channels, magnetic cell-seeding procedures, and controlled cell proliferation and differentiation. Accordingly, the aim of this study was to develop fully biodegradable and magnetic nanocomposite substrates for bone tissue engineering by embedding iron-doped hydroxyapatite (FeHA) nanoparticles in a poly(ε-caprolactone) (PCL) matrix. X-ray diffraction analyses enabled the demonstration that the phase composition and crystallinity of the magnetic FeHA were not affected by the process used to develop the nanocomposite substrates. The mechanical characterization performed through small punch tests has evidenced that inclusion of 10 per cent by weight of FeHA would represent an effective reinforcement. The inclusion of nanoparticles also improves the hydrophilicity of the substrates as evidenced by the lower values of water contact angle in comparison with those of neat PCL. The results from magnetic measurements confirmed the superparamagnetic character of the nanocomposite substrates, indicated by a very low coercive field, a saturation magnetization strictly proportional to the FeHA content and a strong history dependence in temperature sweeps. Regarding the biological performances, confocal laser scanning microscopy and AlamarBlue assay have provided qualitative and quantitative information on human mesenchymal stem cell adhesion and viability/proliferation, respectively, whereas the obtained ALP/DNA values have shown the ability of the nanocomposite substrates to support osteogenic differentiation. PMID:23303218

  6. Magnetic poly(ε-caprolactone)/iron-doped hydroxyapatite nanocomposite substrates for advanced bone tissue engineering.

    PubMed

    Gloria, A; Russo, T; D'Amora, U; Zeppetelli, S; D'Alessandro, T; Sandri, M; Bañobre-López, M; Piñeiro-Redondo, Y; Uhlarz, M; Tampieri, A; Rivas, J; Herrmannsdörfer, T; Dediu, V A; Ambrosio, L; De Santis, R

    2013-03-01

    In biomedicine, magnetic nanoparticles provide some attractive possibilities because they possess peculiar physical properties that permit their use in a wide range of applications. The concept of magnetic guidance basically spans from drug delivery and hyperthermia treatment of tumours, to tissue engineering, such as magneto-mechanical stimulation/activation of cell constructs and mechanosensitive ion channels, magnetic cell-seeding procedures, and controlled cell proliferation and differentiation. Accordingly, the aim of this study was to develop fully biodegradable and magnetic nanocomposite substrates for bone tissue engineering by embedding iron-doped hydroxyapatite (FeHA) nanoparticles in a poly(ε-caprolactone) (PCL) matrix. X-ray diffraction analyses enabled the demonstration that the phase composition and crystallinity of the magnetic FeHA were not affected by the process used to develop the nanocomposite substrates. The mechanical characterization performed through small punch tests has evidenced that inclusion of 10 per cent by weight of FeHA would represent an effective reinforcement. The inclusion of nanoparticles also improves the hydrophilicity of the substrates as evidenced by the lower values of water contact angle in comparison with those of neat PCL. The results from magnetic measurements confirmed the superparamagnetic character of the nanocomposite substrates, indicated by a very low coercive field, a saturation magnetization strictly proportional to the FeHA content and a strong history dependence in temperature sweeps. Regarding the biological performances, confocal laser scanning microscopy and AlamarBlue assay have provided qualitative and quantitative information on human mesenchymal stem cell adhesion and viability/proliferation, respectively, whereas the obtained ALP/DNA values have shown the ability of the nanocomposite substrates to support osteogenic differentiation. PMID:23303218

  7. Tissue engineering of reproductive tissues and organs.

    PubMed

    Atala, Anthony

    2012-07-01

    Regenerative medicine and tissue engineering technology may soon offer new hope for patients with serious injuries and end-stage reproductive organ failure. Scientists are now applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that can restore and maintain normal function in diseased and injured reproductive tissues. In addition, the stem cell field is advancing, and new discoveries in this field will lead to new therapeutic strategies. For example, newly discovered types of stem cells have been retrieved from uterine tissues such as amniotic fluid and placental stem cells. The process of therapeutic cloning and the creation of induced pluripotent cells provide still other potential sources of stem cells for cell-based tissue engineering applications. Although stem cells are still in the research phase, some therapies arising from tissue engineering endeavors that make use of autologous adult cells have already entered the clinic. This article discusses these tissue engineering strategies for various organs in the male and female reproductive tract. PMID:22748231

  8. Therapeutic cloning and tissue engineering.

    PubMed

    Koh, Chester J; Atala, Anthony

    2004-01-01

    A severe shortage of donor organs available for transplantation in the United States leaves patients suffering from diseased and injured organs with few treatment options. Scientists in the field of tissue engineering apply the principles of cell transplantation, material science, and engineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Therapeutic cloning, where the nucleus from a donor cell is transferred into an enucleated oocyte in order to extract pluripotent embryonic stem cells, offers a potentially limitless source of cells for tissue engineering applications. The present chapter reviews recent advances that have occurred in therapeutic cloning and tissue engineering and describes applications of these new technologies that may offer novel therapies for patients with end-stage organ failure. PMID:15094294

  9. Osteochondral tissue engineering.

    PubMed

    Martin, Ivan; Miot, Sylvie; Barbero, Andrea; Jakob, Marcel; Wendt, David

    2007-01-01

    Osteochondral defects (i.e., defects which affect both the articular cartilage and underlying subchondral bone) are often associated with mechanical instability of the joint, and therefore with the risk of inducing osteoarthritic degenerative changes. Current surgical limits in the treatment of complex joint lesions could be overcome by grafting osteochondral composite tissues, engineered by combining the patient's own cells with three-dimensional (3D) porous biomaterials of pre-defined size and shape. Various strategies have been reported for the engineering of osteochondral composites, which result from the use of one or more cell types cultured into single-component or composite scaffolds in a broad spectrum of compositions and biomechanical properties. The variety of concepts and models proposed by different groups for the generation of osteochondral grafts reflects that understanding of the requirements to restore a normal joint function is still poor. In order to introduce the use of engineered osteochondral composites in the routine clinical practice, it will be necessary to comprehensively address a number of critical issues, including those related to the size and shape of the graft to be generated, the cell type(s) and properties of the scaffold(s) to be used, the potential physical conditioning to be applied, the degree of functionality required, and the strategy for a cost-effective manufacturing. The progress made in material science, cell biology, mechanobiology and bioreactor technology will be key to support advances in this challenging field. PMID:16730354

  10. Nanomaterials, Inflammation and Tissue Engineering

    PubMed Central

    Padmanabhan, Jagannath

    2014-01-01

    Nanomaterials exhibit unique properties that are absent in the bulk material because decreasing material size leads to an exponential increase in surface area, surface area to volume ratio, and effective stiffness, resulting in altered physiochemical properties. Diverse categories of nanomaterials such as nanoparticles, nanoporous scaffolds, nanopatterned surfaces, nanofibers and carbon nanotubes can be generated using advanced fabrication and processing techniques. These materials are being increasingly incorporated in tissue engineering scaffolds to facilitate the development of biomimetic substitutes to replace damaged tissues and organs. Long term success of nanomaterials in tissue engineering is contingent upon the inflammatory responses they elicit in vivo. This review seeks to summarize the recent developments in our understanding of biochemical and biophysical attributes of nanomaterials and the inflammatory responses they elicit, with a focus on strategies for nanomaterial design in tissue engineering applications. PMID:25421333

  11. Biomaterials for Tissue Engineering

    PubMed Central

    Lee, Esther J.; Kasper, F. Kurtis; Mikos, Antonios G.

    2013-01-01

    Biomaterials serve as an integral component of tissue engineering. They are designed to provide architectural framework reminiscent of native extracellular matrix in order to encourage cell growth and eventual tissue regeneration. Bone and cartilage represent two distinct tissues with varying compositional and mechanical properties. Despite these differences, both meet at the osteochondral interface. This article presents an overview of current biomaterials employed in bone and cartilage applications, discusses some design considerations, and alludes to future prospects within this field of research. PMID:23820768

  12. "The state of the heart": Recent advances in engineering human cardiac tissue from pluripotent stem cells.

    PubMed

    Sirabella, Dario; Cimetta, Elisa; Vunjak-Novakovic, Gordana

    2015-08-01

    The pressing need for effective cell therapy for the heart has led to the investigation of suitable cell sources for tissue replacement. In recent years, human pluripotent stem cell research expanded tremendously, in particular since the derivation of human-induced pluripotent stem cells. In parallel, bioengineering technologies have led to novel approaches for in vitro cell culture. The combination of these two fields holds potential for in vitro generation of high-fidelity heart tissue, both for basic research and for therapeutic applications. However, this new multidisciplinary science is still at an early stage. Many questions need to be answered and improvements need to be made before clinical applications become a reality. Here we discuss the current status of human stem cell differentiation into cardiomyocytes and the combined use of bioengineering approaches for cardiac tissue formation and maturation in developmental studies, disease modeling, drug testing, and regenerative medicine. PMID:26069271

  13. Advances in Adipose-Derived Stem Cells Isolation, Characterization, and Application in Regenerative Tissue Engineering

    PubMed Central

    Wankhade, Umesh D.; Shen, Michael; Kolhe, Ravindra; Fulzele, Sadanand

    2016-01-01

    Obesity is a complex, multifactorial disease that has been extensively researched in recent times. Obesity is characterized by excess deposition of adipose tissue in response to surplus energy. Despite the negative connotations of adipose tissue (AT), it serves as a critical endocrine organ. Adipose tissue is a source of several adipokines and cytokines which have been deemed important for both normal metabolic function and disease formation. The discoveries of metabolically active brown AT in adult humans and adipose tissue derived stem cells (ADSC) have been key findings in the past decade with potential therapeutic implications. ADSCs represent an enticing pool of multipotent adult stem cells because of their noncontroversial nature, relative abundance, ease of isolation, and expandability. A decade and a half since the discovery of ADSCs, the scientific community is still working to uncover their therapeutic potential in a wide range of diseases. In this review, we provide an overview of the recent developments in the field of ADSCs and examine their potential use in transplantation and cell-based therapies for the regeneration of diseased organs and systems. We also hope to provide perspective on how to best utilize this readily available, powerful pool of stem cells in the future. PMID:26981130

  14. Bioactive glass in tissue engineering

    PubMed Central

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  15. Tissue engineering using adult stem cells.

    PubMed

    Eberli, Daniel; Atala, Anthony

    2006-01-01

    Patients with a variety of diseases may be treated with transplanted tissues and organs. However, there is a shortage of donor tissues and organs, which is worsening yearly because of the aging population. Scientists in the field of tissue engineering are applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. The stem cell field is also advancing rapidly, opening new options for cellular therapy and tissue engineering. The use of adult stem cells for tissue engineering applications is promising. This chapter discusses applications of these new technologies for the engineering of tissues and organs. The first part provides an overview of regenerative medicine and tissue engineering techniques; the second highlights different adult stem cell populations used for tissue regeneration. PMID:17161702

  16. Imaging Strategies for Tissue Engineering Applications

    PubMed Central

    Nam, Seung Yun; Ricles, Laura M.; Suggs, Laura J.

    2015-01-01

    Tissue engineering has evolved with multifaceted research being conducted using advanced technologies, and it is progressing toward clinical applications. As tissue engineering technology significantly advances, it proceeds toward increasing sophistication, including nanoscale strategies for material construction and synergetic methods for combining with cells, growth factors, or other macromolecules. Therefore, to assess advanced tissue-engineered constructs, tissue engineers need versatile imaging methods capable of monitoring not only morphological but also functional and molecular information. However, there is no single imaging modality that is suitable for all tissue-engineered constructs. Each imaging method has its own range of applications and provides information based on the specific properties of the imaging technique. Therefore, according to the requirements of the tissue engineering studies, the most appropriate tool should be selected among a variety of imaging modalities. The goal of this review article is to describe available biomedical imaging methods to assess tissue engineering applications and to provide tissue engineers with criteria and insights for determining the best imaging strategies. Commonly used biomedical imaging modalities, including X-ray and computed tomography, positron emission tomography and single photon emission computed tomography, magnetic resonance imaging, ultrasound imaging, optical imaging, and emerging techniques and multimodal imaging, will be discussed, focusing on the latest trends of their applications in recent tissue engineering studies. PMID:25012069

  17. Calcium phosphate nanocoatings and nanocomposites, part I: recent developments and advancements in tissue engineering and bioimaging.

    PubMed

    Choi, Andy H; Ben-Nissan, Besim

    2015-07-01

    A number of materials have been applied as implant coatings and as tissue regeneration materials. Calcium phosphate holds a special consideration, due to its chemical similarity to human bone and, most importantly, its dissolution characteristics, which allow for bone growth and regeneration. The applications of molecular and nanoscale-based biological materials have been and will continue to play an ever increasing role in enhancing and improving the osseointegration of dental and orthopedic implants. More recently, extensive research efforts have been focused on the development and applications of fluorescent nanoparticles and nanocoatings for in vivo imaging and diagnostics as well as devising methods of adding luminescent or fluorescent capabilities to enhance the in vivo functionality of calcium phosphate-based biomedical materials. PMID:26119630

  18. Biomaterials in tissue engineering.

    PubMed

    Hubbell, J A

    1995-06-01

    Biomaterials play a pivotal role in field of tissue engineering. Biomimetic synthetic polymers have been created to elicit specific cellular functions and to direct cell-cell interactions both in implants that are initially cell-free, which may serve as matrices to conduct tissue regeneration, and in implants to support cell transplantation. Biomimetic approaches have been based on polymers endowed with bioadhesive receptor-binding peptides and mono- and oligosaccharides. These materials have been patterned in two- and three-dimensions to generate model multicellular tissue architectures, and this approach may be useful in future efforts to generate complex organizations of multiple cell types. Natural polymers have also played an important role in these efforts, and recombinant polymers that combine the beneficial aspects of natural polymers with many of the desirable features of synthetic polymers have been designed and produced. Biomaterials have been employed to conduct and accelerate otherwise naturally occurring phenomena, such as tissue regeneration in wound healing in the otherwise healthy subject; to induce cellular responses that might not be normally present, such as healing in a diseased subject or the generation of a new vascular bed to receive a subsequent cell transplant; and to block natural phenomena, such as the immune rejection of cell transplants from other species or the transmission of growth factor signals that stimulate scar formation. This review introduces the biomaterials and describes their application in the engineering of new tissues and the manipulation of tissue responses. PMID:9634795

  19. Whyever bladder tissue engineering clinical applications still remain unusual even though many intriguing technological advances have been reached?

    PubMed Central

    ALBERTI, C.

    2016-01-01

    To prevent problematic outcomes of bowel-based bladder reconstructive surgery, such as prosthetic tumors and systemic metabolic complications, research works, to either regenerate and strengthen failing organ or build organ replacement biosubstitute, have been turned, from 90s of the last century, to both regenerative medicine and tissue engineering. Various types of acellular matrices, naturally-derived materials, synthetic polymers have been used for either “unseeded” (cell free) or autologous “cell seeded” tissue engineering scaffolds. Different categories of cell sources – from autologous differentiated urothelial and smooth muscle cells to natural or laboratory procedure-derived stem cells – have been taken into consideration to reach the construction of suitable “cell seeded” templates. Current clinically validated bladder tissue engineering approaches essentially consist of augmentation cystoplasty in patients suffering from poorly compliant neuropathic bladder. No clinical applications of wholly tissue engineered neobladder have been carried out to radical-reconstructive surgical treatment of bladder malignancies or chronic inflammation-due vesical coarctation. Reliable reasons why bladder tissue engineering clinical applications so far remain unusual, particularly imply the risk of graft ischemia, hence its both fibrous contraction and even worse perforation. Therefore, the achievement of graft vascular network (vasculogenesis) could allow, together with the promotion of host surrounding vessel sprouting (angiogenesis), an effective graft blood supply, so avoiding the ischemia-related serious complications. PMID:27142819

  20. Stereolithography in tissue engineering.

    PubMed

    Skoog, Shelby A; Goering, Peter L; Narayan, Roger J

    2014-03-01

    Several recent research efforts have focused on use of computer-aided additive fabrication technologies, commonly referred to as additive manufacturing, rapid prototyping, solid freeform fabrication, or three-dimensional printing technologies, to create structures for tissue engineering. For example, scaffolds for tissue engineering may be processed using rapid prototyping technologies, which serve as matrices for cell ingrowth, vascularization, as well as transport of nutrients and waste. Stereolithography is a photopolymerization-based rapid prototyping technology that involves computer-driven and spatially controlled irradiation of liquid resin. This technology enables structures with precise microscale features to be prepared directly from a computer model. In this review, use of stereolithography for processing trimethylene carbonate, polycaprolactone, and poly(D,L-lactide) poly(propylene fumarate)-based materials is considered. In addition, incorporation of bioceramic fillers for fabrication of bioceramic scaffolds is reviewed. Use of stereolithography for processing of patient-specific implantable scaffolds is also discussed. In addition, use of photopolymerization-based rapid prototyping technology, known as two-photon polymerization, for production of tissue engineering scaffolds with smaller features than conventional stereolithography technology is considered. PMID:24306145

  1. Multiscale tissue engineering for liver reconstruction

    PubMed Central

    Sudo, Ryo

    2014-01-01

    The liver is a target of in vitro tissue engineering despite its capability to regenerate in vivo. The construction of liver tissues in vitro remains challenging. In this review, conventional 3D cultures of hepatocytes are first discussed. Recent advances in the 3D culturing of liver cells are then summarized in the context of in vitro liver tissue reconstruction at the micro- and macroscales. The application of microfluidics technology to liver tissue engineering has been introduced as a bottom-up approach performed at the microscale, whereas whole-organ bioengineering technology was introduced as a top-down approach performed at the macroscale. Mesoscale approaches are also discussed in considering the integration of micro- and macroscale approaches. Multiple parallel multiscale liver tissue engineering studies are ongoing; however, no tissue-engineered liver that is appropriate for clinical use has yet been realized. The integration of multiscale tissue engineering studies is essential for further understanding of liver reconstruction strategies. PMID:24500493

  2. Soft tissue engineering in craniomaxillofacial surgery

    PubMed Central

    Kim, Roderick Y; Fasi, Anthony C; Feinberg, Stephen E

    2014-01-01

    Craniofacial soft tissue reconstruction may be required following trauma, tumor resection, and to repair congenital deformities. Recent advances in the field of tissue engineering have significantly widened the reconstructive armamentarium of the surgeon. The successful identification and combination of tissue engineering, scaffold, progenitor cells, and physiologic signaling molecules has enabled the surgeon to design, recreate the missing tissue in its near natural form. This has resolved the issues like graft rejection, wound dehiscence, or poor vascularity. Successfully reconstructed tissue through soft tissue engineering protocols would help surgeon to restore the form and function of the lost tissue in its originality. This manuscript intends to provide a glimpse of the basic principle of tissue engineering, contemporary, and future direction of this field as applied to craniofacial surgery. PMID:24987591

  3. [Advances in the research of natural polymeric materials and their derivatives in the manufacture of scaffolds for dermal tissue engineering].

    PubMed

    Li, R; Wang, H; Leng, C Y; Wang, K; Xie, Y

    2016-05-20

    Natural polymeric materials and their derivatives are organic macromolecular compounds which exist in plants, animals, and micro-organisms. They have been widely used in the preparation of scaffolds for skin tissue engineering recently because of their good histocompatibility and degradability, and low immunogenicity. With the improvement of the preparation technics, composite materials are more commonly used to make scaffolds for dermal tissue engineering. This article summarizes the classification and research status of the commonly used natural polymer materials, their derivatives, and composite scaffold materials, as well as makes a prospect of the research trends of dermal scaffold in the future. PMID:27188491

  4. Advanced Engineering Fibers.

    ERIC Educational Resources Information Center

    Edie, Dan D.; Dunham, Michael G.

    1987-01-01

    Describes Clemson University's Advanced Engineered Fibers Laboratory, which was established to provide national leadership and expertise in developing the processing equipment and advance fibers necessary for the chemical, fiber, and textile industries to enter the composite materials market. Discusses some of the laboratory's activities in…

  5. 3D Printing for Tissue Engineering

    PubMed Central

    Jia, Jia; Yao, Hai; Mei, Ying

    2016-01-01

    Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host tissue integration (e.g., cellular infiltration, vascularization, and active remodeling). This review will cover several approaches that have advanced the field of 3D printing through novel fabrication methods of tissue engineering constructs. It will also discuss the applications of synthetic and natural materials for 3D printing facilitated tissue fabrication. PMID:26869728

  6. Advanced engine study program

    NASA Technical Reports Server (NTRS)

    Masters, A. I.; Galler, D. E.; Denman, T. F.; Shied, R. A.; Black, J. R.; Fierstein, A. R.; Clark, G. L.; Branstrom, B. R.

    1993-01-01

    A design and analysis study was conducted to provide advanced engine descriptions and parametric data for space transfer vehicles. The study was based on an advanced oxygen/hydrogen engine in the 7,500 to 50,000 lbf thrust range. Emphasis was placed on defining requirements for high-performance engines capable of achieving reliable and versatile operation in a space environment. Four variations on the expander cycle were compared, and the advantages and disadvantages of each were assessed. Parametric weight, envelope, and performance data were generated over a range of 7,500 to 50,000 lb thrust and a wide range of chamber pressure and nozzle expansion ratio.

  7. Lung tissue engineering.

    PubMed

    Hoganson, David M; Bassett, Erik K; Vacanti, Joseph P

    2014-01-01

    Lung tissue engineering is an emerging field focused on the development of lung replacement devices and tissue to treat patients with end stage lung disease. Microfluidic based lung assist devices have been developed that have biomimetically designed vascular networks that achieve physiologic blood flow. Gas exchange in these devices occurs across a thin respiratory membrane. Designed for intrathoracic implantation as a bridge to transplant or destination therapy, these lung assist devices will allow ambulation and hospital discharge for patients with end stage lung disease. Decellularized lungs subsequently recellularized with epithelial and endothelial cells have been implanted in small animal models with demonstration of initial gas exchange. Further development of these tissues and scaling to large animal models will validate this approach and may be an organ source for lung transplantation. Initial clinical success has been achieved with decellularized tracheal implants using autologous stem cells. Development of microfluidic lung models using similar architecture to the lung assist device technology allows study of lung biology and diseases with manipulation of lung cells and respiratory membrane strain. PMID:24896347

  8. Heart Regeneration with Engineered Myocardial Tissue

    PubMed Central

    Bajpai, Vivek K.; Andreadis, Stelios T.; Murry, Charles E.

    2014-01-01

    Heart disease is the leading cause of morbidity and mortality worldwide, and regenerative therapies that replace damaged myocardium could benefit millions of patients annually. The many cell types in the heart, including cardiomyocytes, endothelial cells, vascular smooth muscle cells, pericytes, and cardiac fibroblasts, communicate via intercellular signaling and modulate each other’s function. Although much progress has been made in generating cells of the cardiovascular lineage from human pluripotent stem cells, a major challenge now is creating the tissue architecture to integrate a microvascular circulation and afferent arterioles into such an engineered tissue. Recent advances in cardiac and vascular tissue engineering will move us closer to the goal of generating functionally mature tissue. Using the biology of the myocardium as the foundation for designing engineered tissue and addressing the challenges to implantation and integration, we can bridge the gap from bench to bedside for a clinically tractable engineered cardiac tissue. PMID:24819474

  9. Biomaterials for vascular tissue engineering

    PubMed Central

    Ravi, Swathi; Chaikof, Elliot L

    2010-01-01

    Cardiovascular disease is the leading cause of mortality in the USA. The limited availability of healthy autologous vessels for bypass grafting procedures has led to the fabrication of prosthetic vascular conduits. While synthetic polymers have been extensively studied as substitutes in vascular engineering, they fall short of meeting the biological challenges at the blood–material interface. Various tissue engineering strategies have emerged to address these flaws and increase long-term patency of vascular grafts. Vascular cell seeding of scaffolds and the design of bioactive polymers for in situ arterial regeneration have yielded promising results. This article describes the advances made in biomaterials design to generate suitable materials that not only match the mechanical properties of native vasculature, but also promote cell growth, facilitate extracellular matrix production and inhibit thrombogenicity. PMID:20017698

  10. Biomaterials for hollow organ tissue engineering.

    PubMed

    Hendow, Eseelle K; Guhmann, Pauline; Wright, Bernice; Sofokleous, Panagiotis; Parmar, Nina; Day, Richard M

    2016-01-01

    Tissue engineering is a rapidly advancing field that is likely to transform how medicine is practised in the near future. For hollow organs such as those found in the cardiovascular and respiratory systems or gastrointestinal tract, tissue engineering can provide replacement of the entire organ or provide restoration of function to specific regions. Larger tissue-engineered constructs often require biomaterial-based scaffold structures to provide support and structure for new tissue growth. Consideration must be given to the choice of material and manufacturing process to ensure the de novo tissue closely matches the mechanical and physiological properties of the native tissue. This review will discuss some of the approaches taken to date for fabricating hollow organ scaffolds and the selection of appropriate biomaterials. PMID:27014369

  11. Advances in combining gene therapy with cell and tissue engineering-based approaches to enhance healing of the meniscus.

    PubMed

    Cucchiarini, M; McNulty, A L; Mauck, R L; Setton, L A; Guilak, F; Madry, H

    2016-08-01

    Meniscal lesions are common problems in orthopaedic surgery and sports medicine, and injury or loss of the meniscus accelerates the onset of knee osteoarthritis (OA). Despite a variety of therapeutic options in the clinics, there is a critical need for improved treatments to enhance meniscal repair. In this regard, combining gene-, cell-, and tissue engineering-based approaches is an attractive strategy to generate novel, effective therapies to treat meniscal lesions. In the present work, we provide an overview of the tools currently available to improve meniscal repair and discuss the progress and remaining challenges for potential future translation in patients. PMID:27063441

  12. Tissue engineering the small intestine.

    PubMed

    Spurrier, Ryan G; Grikscheit, Tracy C

    2013-04-01

    Short bowel syndrome (SBS) results from the loss of a highly specialized organ, the small intestine. SBS and its current treatments are associated with high morbidity and mortality. Production of tissue-engineered small intestine (TESI) from the patient's own cells could restore normal intestinal function via autologous transplantation. Improved understanding of intestinal stem cells and their niche have been coupled with advances in tissue engineering techniques. Originally described by Vacanti et al of Massachusetts General Hospital, TESI has been produced by in vivo implantation of organoid units. Organoid units are multicellular clusters of epithelium and mesenchyme that may be harvested from native intestine. These clusters are loaded onto a scaffold and implanted into the host omentum. The scaffold provides physical support that permits angiogenesis and vasculogenesis of the developing tissue. After a period of 4 weeks, histologic analyses confirm the similarity of TESI to native intestine. TESI contains a differentiated epithelium, mesenchyme, blood vessels, muscle, and nerve components. To date, similar experiments have proved successful in rat, mouse, and pig models. Additional experiments have shown clinical improvement and rescue of SBS rats after implantation of TESI. In comparison with the group that underwent massive enterectomy alone, rats that had surgical anastomosis of TESI to their shortened intestine showed improvement in postoperative weight gain and serum B12 values. Recently, organoid units have been harvested from human intestinal samples and successfully grown into TESI by using an immunodeficient mouse host. Current TESI production yields approximately 3 times the number of cells initially implanted, but improvements in the scaffold and blood supply are being developed in efforts to increase TESI size. Exciting new techniques in stem cell biology and directed cellular differentiation may generate additional sources of autologous intestinal

  13. Two-photon polymerization microfabrication of hydrogels: an advanced 3D printing technology for tissue engineering and drug delivery.

    PubMed

    Xing, Jin-Feng; Zheng, Mei-Ling; Duan, Xuan-Ming

    2015-08-01

    3D printing technology has attracted much attention due to its high potential in scientific and industrial applications. As an outstanding 3D printing technology, two-photon polymerization (TPP) microfabrication has been applied in the fields of micro/nanophotonics, micro-electromechanical systems, microfluidics, biomedical implants and microdevices. In particular, TPP microfabrication is very useful in tissue engineering and drug delivery due to its powerful fabrication capability for precise microstructures with high spatial resolution on both the microscopic and the nanometric scale. The design and fabrication of 3D hydrogels widely used in tissue engineering and drug delivery has been an important research area of TPP microfabrication. The resolution is a key parameter for 3D hydrogels to simulate the native 3D environment in which the cells reside and the drug is controlled to release with optimal temporal and spatial distribution in vitro and in vivo. The resolution of 3D hydrogels largely depends on the efficiency of TPP initiators. In this paper, we will review the widely used photoresists, the development of TPP photoinitiators, the strategies for improving the resolution and the microfabrication of 3D hydrogels. PMID:25992492

  14. Biomaterials for tissue engineering: summary

    NASA Technical Reports Server (NTRS)

    Christenson, L.; Mikos, A. G.; Gibbons, D. F.; Picciolo, G. L.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    This article summarizes presentations and discussion at the workshop "Enabling Biomaterial Technology for Tissue Engineering," which was held during the Fifth World Biomaterials Congress in May 1996. Presentations covered the areas of material substrate architecture, barrier effects, and cellular response, including analysis of biomaterials challenges involved in producing specific tissue-engineered products.

  15. Optical Coherence Tomography in Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Zhao, Youbo; Yang, Ying; Wang, Ruikang K.; Boppart, Stephen A.

    Tissue engineering holds the promise for a therapeutic solution in regenerative medicine. The primary goal of tissue engineering is the development of physiologically functional and biocompatible tissues/organs being implanted for the repair and replacement of damaged or diseased ones. Given the complexity in the developing processes of engineered tissues, which involves multi-dimensional interactions among cells of different types, three-dimensionally constructed scaffolds, and actively intervening bioreactors, a capable real-time imaging tool is critically required for expanding our knowledge about the developing process of desired tissues or organs. It has been recognized that optical coherence tomography (OCT), an emerging noninvasive imaging technique that provides high spatial resolution (up to the cellular level) and three-dimensional imaging capability, is a promising investigative tool for tissue engineering. This chapter discusses the existing and potential applications of OCT in tissue engineering. Example OCT investigations of the three major components of tissue engineering, i.e., cells, scaffolds, and bioreactors are overviewed. Imaging examples of OCT and its enabling functions and variants, e.g., Doppler OCT, polarization-sensitive OCT, optical coherence microscopy are emphasized. Remaining challenges in the application of OCT to tissue engineering are discussed, and the prospective solutions including the combination of OCT with other high-contrast and high-resolution modalities such as two-photon fluorescence microscopy are suggested as well. It is expected that OCT, along with its functional variants, will make important contributions toward revealing the complex cellular dynamics in engineered tissues as well as help us culture demanding tissue/organ implants that will advance regenerative medicine.

  16. New Methods in Tissue Engineering

    PubMed Central

    Sheahan, Timothy P.; Rice, Charles M.; Bhatia, Sangeeta N.

    2015-01-01

    New insights in the study of virus and host biology in the context of viral infection are made possible by the development of model systems that faithfully recapitulate the in vivo viral life cycle. Standard tissue culture models lack critical emergent properties driven by cellular organization and in vivo–like function, whereas animal models suffer from limited susceptibility to relevant human viruses and make it difficult to perform detailed molecular manipulation and analysis. Tissue engineering techniques may enable virologists to create infection models that combine the facile manipulation and readouts of tissue culture with the virus-relevant complexity of animal models. Here, we review the state of the art in tissue engineering and describe how tissue engineering techniques may alleviate some common shortcomings of existing models of viral infection, with a particular emphasis on hepatotropic viruses. We then discuss possible future applications of tissue engineering to virology, including current challenges and potential solutions. PMID:25893203

  17. Engineering tissue from human embryonic stem cells

    PubMed Central

    Metallo, CM; Azarin, SM; Ji, L; De Pablo, JJ; Palecek, SP

    2008-01-01

    Abstract Recent advances in human embryonic stem cell (hESC) biology now offer an alternative cell source for tissue engineers, as these cells are capable of proliferating indefinitely and differentiating to many clinically relevant cell types. Novel culture methods capable of exerting spatial and temporal control over the stem cell microenvironment allow for more efficient expansion of hESCs, and significant advances have been made toward improving our understanding of the biophysical and biochemical cues that direct stem cell fate choices. Effective production of lineage specific progenitors or terminally differentiated cells enables researchers to incorporate hESC derivatives into engineered tissue constructs. Here, we describe current efforts using hESCs as a cell source for tissue engineering applications, highlighting potential advantages of hESCs over current practices as well as challenges which must be overcome. PMID:18194458

  18. Biomimetic Materials for Tissue Engineering

    PubMed Central

    Ma, Peter X

    2008-01-01

    Tissue engineering and regenerative medicine is an exciting research area that aims at regenerative alternatives to harvested tissues for transplantation. Biomaterials play a pivotal role as scaffolds to provide three-dimensional templates and synthetic extracellular-matrix environments for tissue regeneration. It is often beneficial for the scaffolds to mimic certain advantageous characteristics of the natural extracellular matrix, or developmental or would healing programs. This article reviews current biomimetic materials approaches in tissue engineering. These include synthesis to achieve certain compositions or properties similar to those of the extracellular matrix, novel processing technologies to achieve structural features mimicking the extracellular matrix on various levels, approaches to emulate cell-extracellular matrix interactions, and biologic delivery strategies to recapitulate a signaling cascade or developmental/would-healing program. The article also provides examples of enhanced cellular/tissue functions and regenerative outcomes, demonstrating the excitement and significance of the biomimetic materials for tissue engineering and regeneration. PMID:18045729

  19. The Expanding World of Tissue Engineering: The Building Blocks and New Applications of Tissue Engineered Constructs

    PubMed Central

    Zorlutuna, Pinar; Vrana, Nihal Engin; Khademhosseini, Ali

    2013-01-01

    The field of tissue engineering has been growing in the recent years as more products have made it to the market and as new uses for the engineered tissues have emerged, motivating many researchers to engage in this multidisciplinary field of research. Engineered tissues are now not only considered as end products for regenerative medicine, but also have emerged as enabling technologies for other fields of research ranging from drug discovery to biorobotics. This widespread use necessitates a variety of methodologies for production of tissue engineered constructs. In this review, these methods together with their non-clinical applications will be described. First, we will focus on novel materials used in tissue engineering scaffolds; such as recombinant proteins and synthetic, self assembling polypeptides. The recent advances in the modular tissue engineering area will be discussed. Then scaffold-free production methods, based on either cell sheets or cell aggregates will be described. Cell sources used in tissue engineering and new methods that provide improved control over cell behavior such as pathway engineering and biomimetic microenvironments for directing cell differentiation will be discussed. Finally, we will summarize the emerging uses of engineered constructs such as model tissues for drug discovery, cancer research and biorobotics applications. PMID:23268388

  20. Evolving concepts in bone tissue engineering.

    PubMed

    Cowan, Catherine M; Soo, Chia; Ting, Kang; Wu, Benjamin

    2005-01-01

    The field of tissue engineering integrates the latest advances in molecular biology, biochemistry, engineering, material science, and medical transplantation. Researchers in the developing field of regenerative medicine have identified bone tissue engineering as an attractive translational target. Clinical problems requiring bone regeneration are diverse, and no single regeneration approach will likely resolve all defects. Recent advances in the field of tissue engineering have included the use of sophisticated biocompatible scaffolds, new postnatal multipotent cell populations, and the appropriate cellular stimulation. In particular, synthetic polymer scaffolds allow for fast and reproducible construction, while still retaining biocompatible characteristics. These criteria relate to the immediate goal of determining the ideal implant. The search is becoming a reality with widespread availability of biocompatible scaffolds; however, the desired parameters have not been clearly defined. Currently, most research focuses on the use of bone morphogenetic proteins (BMPs), specifically BMP-2 and BMP-7. These proteins induce osteogenic differentiation in vitro, as well as bone defect healing in vivo. Protein-scaffold interactions that enhance BMP binding are of the utmost importance, since prolonged BMP release creates the most osteogenic microenvironment. Transition into clinical studies has had only mild success and relies on large doses of BMPs for bone formation. Advances within the field of bone tissue engineering will likely overcome these challenges and lead to more clinically relevant therapies. PMID:15797456

  1. Current Trends in Bone Tissue Engineering

    PubMed Central

    Péault, Bruno; James, Aaron W.

    2014-01-01

    The development of tissue engineering and regeneration constitutes a new platform for translational medical research. Effective therapies for bone engineering typically employ the coordinated manipulation of cells, biologically active signaling molecules, and biomimetic, biodegradable scaffolds. Bone tissue engineering has become increasingly dependent on the merging of innovations from each of these fields, as they continue to evolve independently. This foreword will highlight some of the most recent advances in bone tissue engineering and regeneration, emphasizing the interconnected fields of stem cell biology, cell signaling biology, and biomaterial research. These include, for example, novel methods for mesenchymal stem cell purification, new methods of Wnt signaling pathway manipulation, and cutting edge computer assisted nanoscale design of bone scaffold materials. In the following special issue, we sought to incorporate these diverse areas of emphasis in order to reflect current trends in the field. PMID:24804256

  2. Chitin Scaffolds in Tissue Engineering

    PubMed Central

    Jayakumar, Rangasamy; Chennazhi, Krishna Prasad; Srinivasan, Sowmya; Nair, Shantikumar V.; Furuike, Tetsuya; Tamura, Hiroshi

    2011-01-01

    Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. PMID:21673928

  3. Silk scaffolds for musculoskeletal tissue engineering.

    PubMed

    Yao, Danyu; Liu, Haifeng; Fan, Yubo

    2016-02-01

    The musculoskeletal system, which includes bone, cartilage, tendon/ligament, and skeletal muscle, is becoming the targets for tissue engineering because of the high need for their repair and regeneration. Numerous factors would affect the use of musculoskeletal tissue engineering for tissue regeneration ranging from cells used for scaffold seeding to the manufacture and structures of materials. The essential function of the scaffolds is to convey growth factors as well as cells to the target site to aid the regeneration of the injury. Among the variety of biomaterials used in scaffold engineering, silk fibroin is recognized as an ideal material for its impressive cytocompatibility, slow biodegradability, and excellent mechanical properties. The current review describes the advances made in the fabrication of silk fibroin scaffolds with different forms such as films, particles, electrospun fibers, hydrogels, three-dimensional porous scaffolds, and their applications in the regeneration of musculoskeletal tissues. PMID:26445979

  4. Polymeric Nanofibers in Tissue Engineering

    PubMed Central

    Dahlin, Rebecca L.; Kasper, F. Kurtis

    2011-01-01

    Polymeric nanofibers can be produced using methods such as electrospinning, phase separation, and self-assembly, and the fiber composition, diameter, alignment, degradation, and mechanical properties can be tailored to the intended application. Nanofibers possess unique advantages for tissue engineering. The small diameter closely matches that of extracellular matrix fibers, and the relatively large surface area is beneficial for cell attachment and bioactive factor loading. This review will update the reader on the aspects of nanofiber fabrication and characterization important to tissue engineering, including control of porous structure, cell infiltration, and fiber degradation. Bioactive factor loading will be discussed with specific relevance to tissue engineering. Finally, applications of polymeric nanofibers in the fields of bone, cartilage, ligament and tendon, cardiovascular, and neural tissue engineering will be reviewed. PMID:21699434

  5. Tissue engineering: A live disc

    NASA Astrophysics Data System (ADS)

    Hukins, David W. L.

    2005-12-01

    A material-cell hybrid device that mimics the anatomic shape of the intervertebral disc has been made and successfully implanted into mice to show that tissue engineering may, in the future, benefit sufferers from back pain.

  6. Commercial considerations in tissue engineering.

    PubMed

    Mansbridge, Jonathan

    2006-10-01

    Tissue engineering is a field with immense promise. Using the example of an early tissue-engineered skin implant, Dermagraft, factors involved in the successful commercial development of devices of this type are explored. Tissue engineering has to strike a balance between tissue culture, which is a resource-intensive activity, and business considerations that are concerned with minimizing cost and maximizing customer convenience. Bioreactor design takes place in a highly regulated environment, so factors to be incorporated into the concept include not only tissue culture considerations but also matters related to asepsis, scaleup, automation and ease of use by the final customer. Dermagraft is an allogeneic tissue. Stasis preservation, in this case cryopreservation, is essential in allogeneic tissue engineering, allowing sterility testing, inventory control and, in the case of Dermagraft, a cellular stress that may be important for hormesis following implantation. Although the use of allogeneic cells provides advantages in manufacturing under suitable conditions, it raises the spectre of immunological rejection. Such rejection has not been experienced with Dermagraft. Possible reasons for this and the vision of further application of allogeneic tissues are important considerations in future tissue-engineered cellular devices. This review illustrates approaches that indicate some of the criteria that may provide a basis for further developments. Marketing is a further requirement for success, which entails understanding of the mechanism of action of the procedure, and is illustrated for Dermagraft. The success of a tissue-engineered product is dependent on many interacting operations, some discussed here, each of which must be performed simultaneously and well. PMID:17005024

  7. Chapter 11: Tissue engineering of peripheral nerves.

    PubMed

    Battiston, Bruno; Raimondo, Stefania; Tos, Pierluigi; Gaidano, Valentina; Audisio, Chiara; Scevola, Anna; Perroteau, Isabelle; Geuna, Stefano

    2009-01-01

    Tissue engineering of peripheral nerves has seen an increasing interest over the last years and, similarly to many other fields of regenerative medicine, great expectations have risen within the general public to its potential clinical application in the treatment of damaged nerves. However, in spite of the scientific advancements, applications to the patients is still very limited and it appears that to optimize the strategy for the tissue engineering of the peripheral nerves in the clinical view, researchers have to strive for a new level of innovation which will bring together (in a multitranslational approach) the main pillars of tissue engineering: namely (1) microsurgery, (2) cell and tissue transplantation, (3) material science, and (4) gene transfer. This review paper provides an overview of these four key approaches to peripheral nerve tissue engineering. While some of these issues will also be specifically addressed in other papers in this special issue on peripheral nerve regeneration of the International Review of Neurobiology, in this paper we will focus on an example of successful translational research in tissue engineering, namely nerve reconstruction by muscle-vein-combined nerve scaffolds. PMID:19682640

  8. Cartilage tissue engineering for degenerative joint disease.

    PubMed

    Nesic, Dobrila; Whiteside, Robert; Brittberg, Mats; Wendt, David; Martin, Ivan; Mainil-Varlet, Pierre

    2006-05-20

    Pain in the joint is often due to cartilage degeneration and represents a serious medical problem affecting people of all ages. Although many, mostly surgical techniques, are currently employed to treat cartilage lesions, none has given satisfactory results in the long term. Recent advances in biology and material science have brought tissue engineering to the forefront of new cartilage repair techniques. The combination of autologous cells, specifically designed scaffolds, bioreactors, mechanical stimulations and growth factors together with the knowledge that underlies the principles of cell biology offers promising avenues for cartilage tissue regeneration. The present review explores basic biology mechanisms for cartilage reconstruction and summarizes the advances in the tissue engineering approaches. Furthermore, the limits of the new methods and their potential application in the osteoarthritic conditions are discussed. PMID:16574268

  9. Scaffolds in Tendon Tissue Engineering

    PubMed Central

    Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair. PMID:22190961

  10. Tissue engineering applications of therapeutic cloning.

    PubMed

    Atala, Anthony; Koh, Chester J

    2004-01-01

    Few treatment options are available for patients suffering from diseased and injured organs because of a severe shortage of donor organs available for transplantation. Therapeutic cloning, where the nucleus from a donor cell is transferred into an enucleated oocyte in order to extract pluripotent embryonic stem cells, offers a potentially limitless source of cells for replacement therapy. Scientists in the field of tissue engineering apply the principles of cell transplantation, material science, and engineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. The present chapter reviews recent advances that have occurred in therapeutic cloning and tissue engineering and describes applications of these new technologies that may offer novel therapies for patients with end-stage organ failure. PMID:15255761

  11. Tissue engineering: state of the art in oral rehabilitation

    PubMed Central

    SCHELLER, E. L.; KREBSBACH, P. H.; KOHN, D. H.

    2009-01-01

    SUMMARY More than 85% of the global population requires repair or replacement of a craniofacial structure. These defects range from simple tooth decay to radical oncologic craniofacial resection. Regeneration of oral and craniofacial tissues presents a formidable challenge that requires synthesis of basic science, clinical science and engineering technology. Identification of appropriate scaffolds, cell sources and spatial and temporal signals (the tissue engineering triad) is necessary to optimize development of a single tissue, hybrid organ or interface. Furthermore, combining the understanding of the interactions between molecules of the extracellular matrix and attached cells with an understanding of the gene expression needed to induce differentiation and tissue growth will provide the design basis for translating basic science into rationally developed components of this tissue engineering triad. Dental tissue engineers are interested in regeneration of teeth, oral mucosa, salivary glands, bone and periodontium. Many of these oral structures are hybrid tissues. For example, engineering the periodontium requires growth of alveolar bone, cementum and the periodontal ligament. Recapitulation of biological development of hybrid tissues and interfaces presents a challenge that exceeds that of engineering just a single tissue. Advances made in dental interface engineering will allow these tissues to serve as model systems for engineering other tissues or organs of the body. This review will begin by covering basic tissue engineering principles and strategic design of functional biomaterials. We will then explore the impact of biomaterials design on the status of craniofacial tissue engineering and current challenges and opportunities in dental tissue engineering. PMID:19228277

  12. Bone tissue engineering in osteoporosis.

    PubMed

    Jakob, Franz; Ebert, Regina; Ignatius, Anita; Matsushita, Takashi; Watanabe, Yoshinobu; Groll, Juergen; Walles, Heike

    2013-06-01

    Osteoporosis is a polygenetic, environmentally modifiable disease, which precipitates into fragility fractures of vertebrae, hip and radius and also confers a high risk of fractures in accidents and trauma. Aging and the genetic molecular background of osteoporosis cause delayed healing and impair regeneration. The worldwide burden of disease is huge and steadily increasing while the average life expectancy is also on the rise. The clinical need for bone regeneration applications, systemic or in situ guided bone regeneration and bone tissue engineering, will increase and become a challenge for health care systems. Apart from in situ guided tissue regeneration classical ex vivo tissue engineering of bone has not yet reached the level of routine clinical application although a wealth of scaffolds and growth factors has been developed. Engineering of complex bone constructs in vitro requires scaffolds, growth and differentiation factors, precursor cells for angiogenesis and osteogenesis and suitable bioreactors in various combinations. The development of applications for ex vivo tissue engineering of bone faces technical challenges concerning rapid vascularization for the survival of constructs in vivo. Recent new ideas and developments in the fields of bone biology, materials science and bioreactor technology will enable us to develop standard operating procedures for ex vivo tissue engineering of bone in the near future. Once prototyped such applications will rapidly be tailored for compromised conditions like vitamin D and sex hormone deficiencies, cellular deficits and high production of regeneration inhibitors, as they are prevalent in osteoporosis and in higher age. PMID:23562167

  13. Keratoconus: Tissue Engineering and Biomaterials

    PubMed Central

    Karamichos, Dimitrios; Hjortdal, Jesper

    2014-01-01

    Keratoconus (KC) is a bilateral, asymmetric, corneal disorder that is characterized by progressive thinning, steepening, and potential scarring. The prevalence of KC is stated to be 1 in 2000 persons worldwide; however, numbers vary depending on size of the study and regions. KC appears more often in South Asian, Eastern Mediterranean, and North African populations. The cause remains unknown, although a variety of factors have been considered. Genetics, cellular, and mechanical changes have all been reported; however, most of these studies have proven inconclusive. Clearly, the major problem here, like with any other ocular disease, is quality of life and the threat of vision loss. While most KC cases progress until the third or fourth decade, it varies between individuals. Patients may experience periods of several months with significant changes followed by months or years of no change, followed by another period of rapid changes. Despite the major advancements, it is still uncertain how to treat KC at early stages and prevent vision impairment. There are currently limited tissue engineering techniques and/or “smart” biomaterials that can help arrest the progression of KC. This review will focus on current treatments and how biomaterials may hold promise for the future. PMID:25215423

  14. Image-guided tissue engineering

    PubMed Central

    Ballyns, Jeffrey J; Bonassar, Lawrence J

    2009-01-01

    Replication of anatomic shape is a significant challenge in developing implants for regenerative medicine. This has lead to significant interest in using medical imaging techniques such as magnetic resonance imaging and computed tomography to design tissue engineered constructs. Implementation of medical imaging and computer aided design in combination with technologies for rapid prototyping of living implants enables the generation of highly reproducible constructs with spatial resolution up to 25 μm. In this paper, we review the medical imaging modalities available and a paradigm for choosing a particular imaging technique. We also present fabrication techniques and methodologies for producing cellular engineered constructs. Finally, we comment on future challenges involved with image guided tissue engineering and efforts to generate engineered constructs ready for implantation. PMID:19583811

  15. Tracheal tissue engineering in rats.

    PubMed

    Jungebluth, Philipp; Haag, Johannes C; Sjöqvist, Sebastian; Gustafsson, Ylva; Beltrán Rodríguez, Antonio; Del Gaudio, Costantino; Bianco, Alessandra; Dehnisch, Ivar; Uhlén, Per; Baiguera, Silvia; Lemon, Greg; Lim, Mei Ling; Macchiarini, Paolo

    2014-09-01

    Tissue-engineered tracheal transplants have been successfully performed clinically. However, before becoming a routine clinical procedure, further preclinical studies are necessary to determine the underlying mechanisms of in situ tissue regeneration. Here we describe a protocol using a tissue engineering strategy and orthotopic transplantation of either natural decellularized donor tracheae or artificial electrospun nanofiber scaffolds into a rat model. The protocol includes details regarding how to assess the scaffolds' biomechanical properties and cell viability before implantation. It is a reliable and reproducible model that can be used to investigate the crucial aspects and pathways of in situ tracheal tissue restoration and regeneration. The model can be established in <6 months, and it may also provide a means to investigate cell-surface interactions, cell differentiation and stem cell fate. PMID:25122525

  16. Advanced expander test bed engine

    NASA Technical Reports Server (NTRS)

    Mitchell, J. P.

    1992-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high pressure expander cycle concept, study system interactions, and conduct studies of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  17. Synthetic biology meets tissue engineering.

    PubMed

    Davies, Jamie A; Cachat, Elise

    2016-06-15

    Classical tissue engineering is aimed mainly at producing anatomically and physiologically realistic replacements for normal human tissues. It is done either by encouraging cellular colonization of manufactured matrices or cellular recolonization of decellularized natural extracellular matrices from donor organs, or by allowing cells to self-organize into organs as they do during fetal life. For repair of normal bodies, this will be adequate but there are reasons for making unusual, non-evolved tissues (repair of unusual bodies, interface to electromechanical prostheses, incorporating living cells into life-support machines). Synthetic biology is aimed mainly at engineering cells so that they can perform custom functions: applying synthetic biological approaches to tissue engineering may be one way of engineering custom structures. In this article, we outline the 'embryological cycle' of patterning, differentiation and morphogenesis and review progress that has been made in constructing synthetic biological systems to reproduce these processes in new ways. The state-of-the-art remains a long way from making truly synthetic tissues, but there are now at least foundations for future work. PMID:27284030

  18. Textile Technologies and Tissue Engineering: A Path Toward Organ Weaving.

    PubMed

    Akbari, Mohsen; Tamayol, Ali; Bagherifard, Sara; Serex, Ludovic; Mostafalu, Pooria; Faramarzi, Negar; Mohammadi, Mohammad Hossein; Khademhosseini, Ali

    2016-04-01

    Textile technologies have recently attracted great attention as potential biofabrication tools for engineering tissue constructs. Using current textile technologies, fibrous structures can be designed and engineered to attain the required properties that are demanded by different tissue engineering applications. Several key parameters such as physiochemical characteristics of fibers, microarchitecture, and mechanical properties of the fabrics play important roles in the effective use of textile technologies in tissue engineering. This review summarizes the current advances in the manufacturing of biofunctional fibers. Different textile methods such as knitting, weaving, and braiding are discussed and their current applications in tissue engineering are highlighted. PMID:26924450

  19. Tissue engineering: current strategies and future directions.

    PubMed

    Olson, Jennifer L; Atala, Anthony; Yoo, James J

    2011-04-01

    Novel therapies resulting from regenerative medicine and tissue engineering technology may offer new hope for patients with injuries, end-stage organ failure, or other clinical issues. Currently, patients with diseased and injured organs are often treated with transplanted organs. However, there is a shortage of donor organs that is worsening yearly as the population ages and as the number of new cases of organ failure increases. Scientists in the field of regenerative medicine and tissue engineering are now applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that can restore and maintain normal function in diseased and injured tissues. In addition, the stem cell field is a rapidly advancing part of regenerative medicine, and new discoveries in this field create new options for this type of therapy. For example, new types of stem cells, such as amniotic fluid and placental stem cells that can circumvent the ethical issues associated with embryonic stem cells, have been discovered. The process of therapeutic cloning and the creation of induced pluripotent cells provide still other potential sources of stem cells for cell-based tissue engineering applications. Although stem cells are still in the research phase, some therapies arising from tissue engineering endeavors that make use of autologous, adult cells have already entered the clinical setting, indicating that regenerative medicine holds much promise for the future. PMID:22111050

  20. Cell and Tissue Engineering for Liver Disease

    PubMed Central

    Bhatia, Sangeeta N.; Underhill, Gregory H.; Zaret, Kenneth S.; Fox, Ira J.

    2015-01-01

    Despite the tremendous hurdles presented by the complexity of the liver’s structure and function, advances in liver physiology, stem cell biology and reprogramming, and the engineering of tissues and devices are accelerating the development of cell-based therapies for treating liver disease and liver failure. This State of the Art Review discusses both the near and long-term prospects for such cell-based therapies and the unique challenges for clinical translation. PMID:25031271

  1. Biomaterials and Stem Cells for Tissue Engineering

    PubMed Central

    Zhang, Zhanpeng; Gupte, Melanie J.; Ma, Peter X.

    2013-01-01

    Importance of the field Organ failure and tissue loss are challenging health issues due to widespread injury, the lack of organs for transplantation, and limitations of conventional artificial implants. The field of tissue engineering aims to provide alternative living substitutes that restore, maintain or improve tissue function. Areas covered in this review In this paper, a wide range of porous scaffolds are reviewed, with an emphasis on phase separation techniques that generate advantageous nanofibrous 3D scaffolds for stem cell-based tissue engineering applications. In addition, methods for presentation and delivery of bioactive molecules to mimic the properties of stem cell niche are summarized. Recent progress in using these bio-instructive scaffolds to support stem cell differentiation and tissue regeneration is also presented. What the reader will gain Stem cells have great clinical potential because of their capability to differentiate into multiple cell types. Biomaterials have served as artificial extracellular environments to regulate stem cell behavior. Biomaterials with various physical, mechanical, and chemical properties can be designed to control stem cell development for regeneration. Take home message The research at the interface of stem cell biology and biomaterials has made and will continue to make exciting advances in tissue engineering. PMID:23327471

  2. “The state of the heart”: Recent advances in engineering human cardiac tissue from pluripotent stem cells

    PubMed Central

    Sirabella, Dario; Cimetta, Elisa; Vunjak-Novakovic, Gordana

    2016-01-01

    The pressing need for effective cell therapy for the heart has led to the investigation of suitable cell sources for tissue replacement. In recent years, human pluripotent stem cell research expanded tremendously, in particular since the derivation of human induced pluripotent stem cells. In parallel, bioengineering technologies have led to novel approaches for in vitro cell culture. The combination of these two fields holds potential for in vitro generation of high-fidelity heart tissue, both for basic research and for therapeutic applications. However, this new multidisciplinary science is still at an early stage. Many questions need to be answered and improvements need to be made before clinical applications become a reality. Here we discuss the current status of human stem cell differentiation into cardiomyocytes and the combined use of bioengineering approaches for cardiac tissue formation and maturation in developmental studies, disease modeling, drug testing and regenerative medicine. PMID:26069271

  3. Quantitative Ultrasound for Nondestructive Characterization of Engineered Tissues and Biomaterials.

    PubMed

    Dalecki, Diane; Mercado, Karla P; Hocking, Denise C

    2016-03-01

    Non-invasive, non-destructive technologies for imaging and quantitatively monitoring the development of artificial tissues are critical for the advancement of tissue engineering. Current standard techniques for evaluating engineered tissues, including histology, biochemical assays and mechanical testing, are destructive approaches. Ultrasound is emerging as a valuable tool for imaging and quantitatively monitoring the properties of engineered tissues and biomaterials longitudinally during fabrication and post-implantation. Ultrasound techniques are rapid, non-invasive, non-destructive and can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, high-frequency quantitative ultrasound techniques can enable volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation. This review provides an overview of ultrasound imaging, quantitative ultrasound techniques, and elastography, with representative examples of applications of these ultrasound-based techniques to the field of tissue engineering. PMID:26581347

  4. Engineering of implantable liver tissues.

    PubMed

    Sakai, Yasuyuki; Nishikawa, M; Evenou, F; Hamon, M; Huang, H; Montagne, K P; Kojima, N; Fujii, T; Niino, T

    2012-01-01

    In this chapter, from the engineering point of view, we introduce the results from our group and related research on three typical configurations of engineered liver tissues; cell sheet-based tissues, sheet-like macroporous scaffold-based tissues, and tissues based on special scaffolds that comprise a flow channel network. The former two do not necessitate in vitro prevascularization and are thus promising in actual human clinical trials for liver diseases that can be recovered by relatively smaller tissue mass. The third approach can implant a much larger mass but is still not yet feasible. In all cases, oxygen supply is the key engineering factor. For the first configuration, direct oxygen supply using an oxygen-permeable polydimethylsiloxane membrane enables various liver cells to exhibit distinct behaviors, complete double layers of mature hepatocytes and fibroblasts, spontaneous thick tissue formation of hepatocarcinoma cells and fetal hepatocytes. Actual oxygen concentration at the cell level can be strictly controlled in this culture system. Using this property, we found that initially low then subsequently high oxygen concentrations were favorable to growth and maturation of fetal cells. For the second configuration, combination of poly-L: -lactic acid 3D scaffolds and appropriate growth factor cocktails provides a suitable microenvironment for the maturation of cells in vitro but the cell growth is limited to a certain distance from the inner surfaces of the macropores. However, implantation to the mesentery leaves of animals allows the cells again to proliferate and pack the remaining spaces of the macroporous structure, suggesting the high feasibility of 3D culture of hepatocyte progenitors for liver tissue-based therapies. For the third configuration, we proposed a design criterion concerning the dimensions of flow channels based on oxygen diffusion and consumption around the channel. Due to the current limitation in the resolution of 3D

  5. Advanced Natural Gas Reciprocating Engine(s)

    SciTech Connect

    Pike, Edward

    2014-03-31

    The objective of the Cummins ARES program, in partnership with the US Department of Energy (DOE), is to develop advanced natural gas engine technologies that increase engine system efficiency at lower emissions levels while attaining lower cost of ownership. The goals of the project are to demonstrate engine system achieving 50% Brake Thermal Efficiency (BTE) in three phases, 44%, 47% and 50% (starting baseline efficiency at 36% BTE) and 0.1 g/bhp-hr NOx system out emissions (starting baseline NOx emissions at 2 – 4 g/bhp-hr NOx). Primary path towards above goals include high Brake Mean Effective Pressure (BMEP), improved closed cycle efficiency, increased air handling efficiency and optimized engine subsystems. Cummins has successfully demonstrated each of the phases of this program. All targets have been achieved through application of a combined set of advanced base engine technologies and Waste Heat Recovery from Charge Air and Exhaust streams, optimized and validated on the demonstration engine and other large engines. The following architectures were selected for each Phase: Phase 1: Lean Burn Spark Ignited (SI) Key Technologies: High Efficiency Turbocharging, Higher Efficiency Combustion System. In production on the 60/91L engines. Over 500MW of ARES Phase 1 technology has been sold. Phase 2: Lean Burn Technology with Exhaust Waste Heat Recovery (WHR) System Key Technologies: Advanced Ignition System, Combustion Improvement, Integrated Waste Heat Recovery System. Base engine technologies intended for production within 2 to 3 years Phase 3: Lean Burn Technology with Exhaust and Charge Air Waste Heat Recovery System Key Technologies: Lower Friction, New Cylinder Head Designs, Improved Integrated Waste Heat Recovery System. Intended for production within 5 to 6 years Cummins is committed to the launch of next generation of large advanced NG engines based on ARES technology to be commercialized worldwide.

  6. Biomaterials in Tooth Tissue Engineering: A Review

    PubMed Central

    Sharma, Sarang; Srivastava, Dhirendra; Grover, Shibani; Sharma, Vivek

    2014-01-01

    Biomaterials play a crucial role in the field of tissue engineering. They are utilized for fabricating frameworks known as scaffolds, matrices or constructs which are interconnected porous structures that establish a cellular microenvironment required for optimal tissue regeneration. Several natural and synthetic biomaterials have been utilized for fabrication of tissue engineering scaffolds. Amongst different biomaterials, polymers are the most extensively experimented and employed materials. They can be tailored to provide good interconnected porosity, large surface area, adequate mechanical strengths, varying surface characterization and different geometries required for tissue regeneration. A single type of material may however not meet all the requirements. Selection of two or more biomaterials, optimization of their physical, chemical and mechanical properties and advanced fabrication techniques are required to obtain scaffold designs intended for their final application. Current focus is aimed at designing biomaterials such that they will replicate the local extra cellular environment of the native organ and enable cell-cell and cell-scaffold interactions at micro level required for functional tissue regeneration. This article provides an insight into the different biomaterials available and the emerging use of nano engineering principles for the construction of bioactive scaffolds in tooth regeneration. PMID:24596804

  7. Hydrogel Composite Materials for Tissue Engineering Scaffolds

    NASA Astrophysics Data System (ADS)

    Shapiro, Jenna M.; Oyen, Michelle L.

    2013-04-01

    Hydrogels are appealing for biomaterials applications due to their compositional similarity with highly hydrated natural biological tissues. However, for structurally demanding tissue engineering applications, hydrogel use is limited by poor mechanical properties. Here, composite materials approaches are considered for improving hydrogel properties while attempting to more closely mimic natural biological tissue structures. A variety of composite material microstructures is explored, based on multiple hydrogel constituents, particle reinforcement, electrospun nanometer to micrometer diameter polymer fibers with single and multiple fiber networks, and combinations of these approaches to form fully three-dimensional fiber-reinforced hydrogels. Natural and synthetic polymers are examined for formation of a range of scaffolds and across a range of engineered tissue applications. Following a discussion of the design and fabrication of composite scaffolds, interactions between living biological cells and composite scaffolds are considered across the full life cycle of tissue engineering from scaffold fabrication to in vivo use. We conclude with a summary of progress in this area to date and make recommendations for continuing research and for advanced hydrogel scaffold development.

  8. Drug releasing systems in cardiovascular tissue engineering

    PubMed Central

    Spadaccio, Cristiano; Chello, Massimo; Trombetta, Marcella; Rainer, Alberto; Toyoda, Yoshiya; Genovese, Jorge A

    2009-01-01

    Abstract Heart disease and atherosclerosis are the leading causes of morbidity and mortality worldwide. The lack of suitable autologous grafts has produced a need for artificial grafts; however, current artificial grafts carry significant limitations, including thrombosis, infection, limited durability and the inability to grow. Tissue engineering of blood vessels, cardiovascular structures and whole organs is a promising approach for creating replacement tissues to repair congenital defects and/or diseased tissues. In an attempt to surmount the shortcomings of artificial grafts, tissue-engineered cardiovascular graft (TECVG), constructs obtained using cultured autologous vascular cells seeded onto a synthetic biodegradable polymer scaffold, have been developed. Autologous TECVGs have the potential advantages of growth, durability, resistance to infection, and freedom from problems of rejection, thrombogenicity and donor scarcity. Moreover polymers engrafted with growth factors, cytokines, drugs have been developed allowing drug-releasing systems capable of focused and localized delivery of molecules depending on the environmental requirements and the milieu in which the scaffold is placed. A broad range of applications for compound-releasing, tissue-engineered grafts have been suggested ranging from drug delivery to gene therapy. This review will describe advances in the development of drug-delivery systems for cardiovascular applications focusing on the manufacturing techniques and on the compounds delivered by these systems to date. PMID:19379142

  9. Advanced rotary engine studies

    NASA Technical Reports Server (NTRS)

    Jones, C.

    1980-01-01

    A review of rotary engine developments relevant to a stratified charge rotary aircraft engine is presented. Advantages in module size and weight, fuel efficiency, reliability, and multi-fuel capability are discussed along with developments in turbocharging, increased mean effective pressure, improved apex seal/trochoid wear surfacing materials, and high strength and temperature aluminum casting alloys. A carbureted prototype aircraft engine is also described.

  10. Advanced rotary engines

    NASA Technical Reports Server (NTRS)

    Jones, C.

    1983-01-01

    The broad objectives of this paper are the following: (1) to summarize the Curtiss-Wright design, development and field testing background in the area of rotary aircraft engines; (2) to briefly summarize past activity and update development work in the area of stratified charge rotary combustion engines; and (3) to discuss the development of a high-performance direct injected unthrottled stratified charge rotary combustion aircraft engine. Efficiency improvements through turbocharging are also discussed.

  11. Biomaterials in myocardial tissue engineering

    PubMed Central

    Reis, Lewis A.; Chiu, Loraine L. Y.; Feric, Nicole; Fu, Lara; Radisic, Milica

    2016-01-01

    Cardiovascular disease is the leading cause of death in the developed world, and as such there is a pressing need for treatment options. Cardiac tissue engineering emerged from the need to develop alternate sources and methods of replacing tissue damaged by cardiovascular diseases, as the ultimate treatment option for many who suffer from end-stage heart failure is a heart transplant. In this review we focus on biomaterial approaches to augment injured or impaired myocardium with specific emphasis on: the design criteria for these biomaterials; the types of scaffolds—composed of natural or synthetic biomaterials, or decellularized extracellular matrix—that have been used to develop cardiac patches and tissue models; methods to vascularize scaffolds and engineered tissue, and finally injectable biomaterials (hydrogels)designed for endogenous repair, exogenous repair or as bulking agents to maintain ventricular geometry post-infarct. The challenges facing the field and obstacles that must be overcome to develop truly clinically viable cardiac therapies are also discussed. PMID:25066525

  12. Tissue-Engineered Kidney Disease Models

    PubMed Central

    DesRochers, Teresa M.; Palma, Erica; Kaplan, David L.

    2014-01-01

    Renal disease represents a major health problem that often results in end-stage renal failure necessitating dialysis and eventually transplantation. Historically these diseases have been studied with patient observation and screening, animal models, and two-dimensional cell culture. In this review, we focus on recent advances in tissue engineered kidney disease models that have the capacity to compensate for the limitations of traditional modalities. The cells and materials utilized to develop these models are discussed and tissue engineered models of polycystic kidney disease, drug-induced nephrotoxicity, and the glomerulus are examined in detail. The application of these models has the potential to direct future disease treatments and preclinical drug development. PMID:24361391

  13. Tissue engineering: an option for esophageal replacement?

    PubMed

    Zani, Augusto; Pierro, Agostino; Elvassore, Nicola; De Coppi, Paolo

    2009-02-01

    Esophageal replacement is required in several pediatric surgical conditions, like long-gap esophageal atresia. Although several techniques have been described to bridge the gap, all of them could be followed by postoperative complications. Esophageal tissue engineering could represent a valid alternative thanks to the recent advances in biomaterial science and cellular biology. Numerous attempts to shape a new esophagus in vitro have been described in the last decade. Herein, we review the main studies on the experimental use of nonabsorbable and absorbable materials as well as the development of cellularized patches. Furthermore, we describe the future perspectives of esophageal tissue engineering characterized by the use of stem cells seeded on new biopolymers. This opens to the construction of a functional allograft that could allow an anatomical replacement that grows with the children and does not severely impair their anatomy. PMID:19103424

  14. Nanofiber Scaffold Gradients for Interfacial Tissue Engineering

    PubMed Central

    Ramalingam, Murugan; Young, Marian F.; Thomas, Vinoy; Sun, Limin; Chow, Laurence C.; Tison, Christopher K.; Chatterjee, Kaushik; Miles, William C.; Simon, Carl G.

    2012-01-01

    We have designed a 2-spinnerette device that can directly electrospin nanofiber scaffolds containing a gradient in composition that can be used to engineer interfacial tissues such as ligament and tendon. Two types of nanofibers are simultaneously electrospun in an overlapping pattern to create a nonwoven mat of nanofibers containing a composition gradient. The approach is an advance over previous methods due to its versatility - gradients can be formed from any materials that can be electrospun. A dye was used to characterize the 2-spinnerette approach and applicability to tissue engineering was demonstrated by fabricating nanofibers with gradients in amorphous calcium phosphate nanoparticles (nACP). Adhesion and proliferation of osteogenic cells (MC3T3-E1 murine pre-osteoblasts) on gradients was enhanced on the regions of the gradients that contained higher nACP content yielding a graded osteoblast response. Since increases in soluble calcium and phosphate ions stimulate osteoblast function, we measured their release and observed significant release from nanofibers containing nACP. The nanofiber-nACP gradients fabricated herein can be applied to generate tissues with osteoblast gradients such as ligaments or tendons. In conclusion, these results introduce a versatile approach for fabricating nanofiber gradients that can have application for engineering graded tissues. PMID:22286209

  15. Multiphasic Scaffolds for Periodontal Tissue Engineering

    PubMed Central

    Ivanovski, S.; Vaquette, C.; Gronthos, S.; Hutmacher, D.W.; Bartold, P.M.

    2014-01-01

    For a successful clinical outcome, periodontal regeneration requires the coordinated response of multiple soft and hard tissues (periodontal ligament, gingiva, cementum, and bone) during the wound-healing process. Tissue-engineered constructs for regeneration of the periodontium must be of a complex 3-dimensional shape and adequate size and demonstrate biomechanical stability over time. A critical requirement is the ability to promote the formation of functional periodontal attachment between regenerated alveolar bone, and newly formed cementum on the root surface. This review outlines the current advances in multiphasic scaffold fabrication and how these scaffolds can be combined with cell- and growth factor–based approaches to form tissue-engineered constructs capable of recapitulating the complex temporal and spatial wound-healing events that will lead to predictable periodontal regeneration. This can be achieved through a variety of approaches, with promising strategies characterized by the use of scaffolds that can deliver and stabilize cells capable of cementogenesis onto the root surface, provide biomechanical cues that encourage perpendicular alignment of periodontal fibers to the root surface, and provide osteogenic cues and appropriate space to facilitate bone regeneration. Progress on the development of multiphasic constructs for periodontal tissue engineering is in the early stages of development, and these constructs need to be tested in large animal models and, ultimately, human clinical trials. PMID:25139362

  16. 3D bioprinting for engineering complex tissues.

    PubMed

    Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho

    2016-01-01

    Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies. PMID:26724184

  17. Kidney diseases and tissue engineering.

    PubMed

    Moon, Kyung Hyun; Ko, In Kap; Yoo, James J; Atala, Anthony

    2016-04-15

    Kidney disease is a worldwide public health problem. Renal failure follows several disease stages including acute and chronic kidney symptoms. Acute kidney injury (AKI) may lead to chronic kidney disease (CKD), which can progress to end-stage renal disease (ESRD) with a mortality rate. Current treatment options are limited to dialysis and kidney transplantation; however, problems such as donor organ shortage, graft failure and numerous complications remain a concern. To address this issue, cell-based approaches using tissue engineering (TE) and regenerative medicine (RM) may provide attractive approaches to replace the damaged kidney cells with functional renal specific cells, leading to restoration of normal kidney functions. While development of renal tissue engineering is in a steady state due to the complex composition and highly regulated functionality of the kidney, cell therapy using stem cells and primary kidney cells has demonstrated promising therapeutic outcomes in terms of restoration of renal functions in AKI and CKD. In this review, basic components needed for successful renal kidney engineering are discussed, and recent TE and RM approaches to treatment of specific kidney diseases will be presented. PMID:26134528

  18. Cardiac Conduction through Engineered Tissue

    PubMed Central

    Choi, Yeong-Hoon; Stamm, Christof; Hammer, Peter E.; Kwaku, Kevin F.; Marler, Jennifer J.; Friehs, Ingeborg; Jones, Mara; Rader, Christine M.; Roy, Nathalie; Eddy, Mau-Thek; Triedman, John K.; Walsh, Edward P.; McGowan, Francis X.; del Nido, Pedro J.; Cowan, Douglas B.

    2006-01-01

    In children, interruption of cardiac atrioventricular (AV) electrical conduction can result from congenital defects, surgical interventions, and maternal autoimmune diseases during pregnancy. Complete AV conduction block is typically treated by implanting an electronic pacemaker device, although long-term pacing therapy in pediatric patients has significant complications. As a first step toward developing a substitute treatment, we implanted engineered tissue constructs in rat hearts to create an alternative AV conduction pathway. We found that skeletal muscle-derived cells in the constructs exhibited sustained electrical coupling through persistent expression and function of gap junction proteins. Using fluorescence in situ hybridization and polymerase chain reaction analyses, myogenic cells in the constructs were shown to survive in the AV groove of implanted hearts for the duration of the animal’s natural life. Perfusion of hearts with fluorescently labeled lectin demonstrated that implanted tissues became vascularized and immunostaining verified the presence of proteins important in electromechanical integration of myogenic cells with surrounding recipient rat cardiomyocytes. Finally, using optical mapping and electrophysiological analyses, we provide evidence of permanent AV conduction through the implant in one-third of recipient animals. Our experiments provide a proof-of-principle that engineered tissue constructs can function as an electrical conduit and, ultimately, may offer a substitute treatment to conventional pacing therapy. PMID:16816362

  19. Clinical translation of controlled protein delivery systems for tissue engineering

    PubMed Central

    Spiller, Kara L.; Vunjak-Novakovic, Gordana

    2013-01-01

    Strategies that utilize controlled release of drugs and proteins for tissue engineering have enormous potential to regenerate damaged organs and tissues. The multiple advantages of controlled release strategies merit overcoming the significant challenges to translation, including high costs and long, difficult regulatory pathways. This review highlights the potential of controlled release of proteins for tissue engineering and regenerative medicine. We specifically discuss treatment modalities that have reached preclinical and clinical trials, with emphasis on controlled release systems for bone tissue engineering, the most advanced application with several products already in clinic. Possible strategies to address translational and regulatory concerns are also discussed. PMID:25787736

  20. Bottom-up tissue engineering

    PubMed Central

    Elbert, Donald L.

    2011-01-01

    Recapitulating the elegant structures formed during development is an extreme synthetic and biological challenge. Great progress has been made in developing materials to support transplanted cells, yet the complexity of tissues is far beyond that found in even the most advanced scaffolds. Self-assembly is a motif used in development and a route for the production of complex materials. Self-assembly of peptides, proteins and other molecules at the nanoscale is promising, but in addition, intriguing ideas are emerging for self-assembly of micron-scale structures. In this brief review, very recent advances in the assembly of micron-scale cell aggregates and microgels will be described and discussed. PMID:21524904

  1. Nano scaffolds and stem cell therapy in liver tissue engineering

    NASA Astrophysics Data System (ADS)

    Montaser, Laila M.; Fawzy, Sherin M.

    2015-08-01

    Tissue engineering and regenerative medicine have been constantly developing of late due to the major progress in cell and organ transplantation, as well as advances in materials science and engineering. Although stem cells hold great potential for the treatment of many injuries and degenerative diseases, several obstacles must be overcome before their therapeutic application can be realized. These include the development of advanced techniques to understand and control functions of micro environmental signals and novel methods to track and guide transplanted stem cells. A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. The application of nanotechnology to stem cell biology would be able to address those challenges. Combinations of stem cell therapy and nanotechnology in tissue engineering and regenerative medicine have achieved significant advances. These combinations allow nanotechnology to engineer scaffolds with various features to control stem cell fate decisions. Fabrication of Nano fiber cell scaffolds onto which stem cells can adhere and spread, forming a niche-like microenvironment which can guide stem cells to proceed to heal damaged tissues. In this paper, current and emergent approach based on stem cells in the field of liver tissue engineering is presented for specific application. The combination of stem cells and tissue engineering opens new perspectives in tissue regeneration for stem cell therapy because of the potential to control stem cell behavior with the physical and chemical characteristics of the engineered scaffold environment.

  2. Hybrid Multicomponent Hydrogels for Tissue Engineering

    PubMed Central

    Jia, Xinqiao; Kiick, Kristi L.

    2009-01-01

    Artificial ECMs that not only closely mimic the hybrid nature of the natural ECM but also provide tunable material properties and enhanced biological functions are attractive candidates for tissue engineering applications. This review summarizes recent advances in developing multicomponent hybrid hydrogels by integrating modular and heterogeneous building blocks into well-defined, multifunctional hydrogel composites. The individual building blocks can be chemically, morphologically, and functionally diverse, and the hybridization can occur at molecular level or microscopic scale. The modular nature of the designs, combined with the potential synergistic effects of the hybrid systems, has resulted in novel hydrogel matrices with robust structure and defined functions. PMID:19107720

  3. Strategies for Whole Lung Tissue Engineering

    PubMed Central

    Calle, Elizabeth A.; Ghaedi, Mahboobe; Sundaram, Sumati; Sivarapatna, Amogh; Tseng, Michelle K.

    2014-01-01

    Recent work has demonstrated the feasibility of using decellularized lung extracellular matrix scaffolds to support the engineering of functional lung tissue in vitro. Rendered acellular through the use of detergents and other reagents, the scaffolds are mounted in organ-specific bioreactors where cells in the scaffold are provided with nutrients and appropriate mechanical stimuli such as ventilation and perfusion. Though initial studies are encouraging, a great deal remains to be done to advance the field and transition from rodent lungs to whole human tissue engineered lungs. To do so, a variety of hurdles must be overcome. In particular, a reliable source of human-sized scaffolds, as well as a method of terminal sterilization of scaffolds, must be identified. Continued research in lung cell and developmental biology will hopefully help identify the number and types of cells that will be required to regenerate functional lung tissue. Finally, bioreactor designs must be improved in order to provide more precise ventilation stimuli and vascular perfusion in order to avoid injury to or death of the cells cultivated within the scaffold. Ultimately, the success of efforts to engineer a functional lung in vitro will critically depend on the ability to create a fully endothelialized vascular network that provides sufficient barrier function and alveolar-capillary surface area to exchange gas at rates compatible with healthy lung function. PMID:24691527

  4. Strategies for whole lung tissue engineering.

    PubMed

    Calle, Elizabeth A; Ghaedi, Mahboobe; Sundaram, Sumati; Sivarapatna, Amogh; Tseng, Michelle K; Niklason, Laura E

    2014-05-01

    Recent work has demonstrated the feasibility of using decellularized lung extracellular matrix scaffolds to support the engineering of functional lung tissue in vitro. Rendered acellular through the use of detergents and other reagents, the scaffolds are mounted in organ-specific bioreactors where cells in the scaffold are provided with nutrients and appropriate mechanical stimuli such as ventilation and perfusion. Though initial studies are encouraging, a great deal remains to be done to advance the field and transition from rodent lungs to whole human tissue engineered lungs. To do so, a variety of hurdles must be overcome. In particular, a reliable source of human-sized scaffolds, as well as a method of terminal sterilization of scaffolds, must be identified. Continued research in lung cell and developmental biology will hopefully help identify the number and types of cells that will be required to regenerate functional lung tissue. Finally, bioreactor designs must be improved in order to provide more precise ventilation stimuli and vascular perfusion in order to avoid injury to or death of the cells cultivated within the scaffold. Ultimately, the success of efforts to engineer a functional lung in vitro will critically depend on the ability to create a fully endothelialized vascular network that provides sufficient barrier function and alveolar-capillary surface area to exchange gas at rates compatible with healthy lung function. PMID:24691527

  5. Tissue engineering therapy for cardiovascular disease.

    PubMed

    Nugent, Helen M; Edelman, Elazer R

    2003-05-30

    The present treatments for the loss or failure of cardiovascular function include organ transplantation, surgical reconstruction, mechanical or synthetic devices, or the administration of metabolic products. Although routinely used, these treatments are not without constraints and complications. The emerging and interdisciplinary field of tissue engineering has evolved to provide solutions to tissue creation and repair. Tissue engineering applies the principles of engineering, material science, and biology toward the development of biological substitutes that restore, maintain, or improve tissue function. Progress has been made in engineering the various components of the cardiovascular system, including blood vessels, heart valves, and cardiac muscle. Many pivotal studies have been performed in recent years that may support the move toward the widespread application of tissue-engineered therapy for cardiovascular diseases. The studies discussed include endothelial cell seeding of vascular grafts, tissue-engineered vascular conduits, generation of heart valve leaflets, cardiomyoplasty, genetic manipulation, and in vitro conditions for optimizing tissue-engineered cardiovascular constructs. PMID:12775655

  6. Tissue engineering and regeneration using biodegradable scaffolds.

    PubMed

    Zhang, X; Zhang, Y

    2015-12-01

    A number of people across the world suffer from various diseases or genetic defects and many of these patients die because of the lack of the availability of ideal tissue substitute and/or treatment. An important aspect of the disease is its association with the loss of tissue function. Many end-stage diseases and/or complete organ failure often require total or partial organ transplantation to restore functionality. However, such transplantation surgeries are not always successful because of the organ/ tissue rejection and also the scarcity of donors. Regenerative medicine and tissue engineering aim to improve or repair the function of a dysfunctional tissue or organ. In spite of the many advances in tissue engineering methods, the field of regenerative medicine still awaits acceptable designs of bioscaffolds that are clinically tenable. Design of scaffolds and the nature of biomaterial used to make the scaffolds dictate cell behavior and function. Several approaches are currently being tried to optimize the design and improve the quality of the biomaterials. Innervation, vascularization and proper cell differentiation that are influenced by the biomaterials, are few challenges that need to be optimized along with the choice of stem cells that can be employed. Extracellular matrix scaffolds have proven to be a better choice for cartilage and bone repair while the fibrin, polyglycolate and polylactate etc are still being developed. Future research and technological innovations are still needed for a better choice of biomaterials that can support the tissue regeneration without causing any immune or inflammatory response from the host and which last for longer periods. PMID:25634586

  7. Nanotechnological strategies for engineering complex tissues

    NASA Astrophysics Data System (ADS)

    Dvir, Tal; Timko, Brian P.; Kohane, Daniel S.; Langer, Robert

    2011-01-01

    Tissue engineering aims at developing functional substitutes for damaged tissues and organs. Before transplantation, cells are generally seeded on biomaterial scaffolds that recapitulate the extracellular matrix and provide cells with information that is important for tissue development. Here we review the nanocomposite nature of the extracellular matrix, describe the design considerations for different tissues and discuss the impact of nanostructures on the properties of scaffolds and their uses in monitoring the behaviour of engineered tissues. We also examine the different nanodevices used to trigger certain processes for tissue development, and offer our view on the principal challenges and prospects of applying nanotechnology in tissue engineering.

  8. Utilizing stem cells for three-dimensional neural tissue engineering.

    PubMed

    Knowlton, Stephanie; Cho, Yongku; Li, Xue-Jun; Khademhosseini, Ali; Tasoglu, Savas

    2016-05-26

    Three-dimensional neural tissue engineering has made great strides in developing neural disease models and replacement tissues for patients. However, the need for biomimetic tissue models and effective patient therapies remains unmet. The recent push to expand 2D neural tissue engineering into the third dimension shows great potential to advance the field. Another area which has much to offer to neural tissue engineering is stem cell research. Stem cells are well known for their self-renewal and differentiation potential and have been shown to give rise to tissues with structural and functional properties mimicking natural organs. Application of these capabilities to 3D neural tissue engineering may be highly useful for basic research on neural tissue structure and function, engineering disease models, designing tissues for drug development, and generating replacement tissues with a patient's genetic makeup. Here, we discuss the vast potential, as well as the current challenges, unique to integration of 3D fabrication strategies and stem cells into neural tissue engineering. We also present some of the most significant recent achievements, including nerve guidance conduits to facilitate better healing of nerve injuries, functional 3D biomimetic neural tissue models, physiologically relevant disease models for research purposes, and rapid and effective screening of potential drugs. PMID:26890524

  9. Advances in engineering plastics

    SciTech Connect

    Leonard, L.

    1997-12-01

    New polymers are being commercialized in record numbers, offering the product designer a new realm of possibilities, and promising tough competition to the traditional engineering resins. Most of the growth is in single-site catalyzed resins. Metallocene (and non-metallocene) single-site catalysts enhance polymer architecture to generate highly uniform molecules, and even permit tailoring new categories of polymers. These new materials include the truly unique aliphatic polyketone, syndiotactic polystyrene (SPS); polyethylene naphthalate (PEN) resins; and novel variations of established polymers. This article provides a closer look at these newcomers to the plastics marketplace, with an emphasis on their properties and potential applications.

  10. Textile Processes for Engineering Tissues with Biomimetic Architectures and Properties.

    PubMed

    Fallahi, Afsoon; Khademhosseini, Ali; Tamayol, Ali

    2016-09-01

    Textile technologies in which fibers containing biological factors and cells are formed and assembled into constructs with biomimetic properties have attracted significant attention in the field of tissue engineering. This Forum article highlights the most prominent advances of the field in the areas of fiber fabrication and construct engineering. PMID:27499277

  11. Tumor Engineering: The Other Face of Tissue Engineering

    SciTech Connect

    Ghajar, Cyrus M; Bissell, Mina J

    2010-03-09

    Advances in tissue engineering have been accomplished for years by employing biomimetic strategies to provide cells with aspects of their original microenvironment necessary to reconstitute a unit of both form and function for a given tissue.We believe that the most critical hallmark of cancer is loss of integration of architecture and function; thus, it stands to reason that similar strategies could be employed to understand tumor biology. In this commentary, we discuss work contributed by Fischbach-Teschl and colleagues to this special issue of Tissue Engineering in the context of 'tumor engineering', that is, the construction of complex cell culture models that recapitulate aspects of the in vivo tumor microenvironment to study the dynamics of tumor development, progression, and therapy on multiple scales. We provide examples of fundamental questions that could be answered by developing such models, and encourage the continued collaboration between physical scientists and life scientists not only for regenerative purposes, but also to unravel the complexity that is the tumor microenvironment. In 1993, Vacanti and Langer cast a spotlight on the growing gap between patients in need of organ transplants and the amount of available donor organs; they reaffirmed that tissue engineering could eventually address this problem by 'applying principles of engineering and the life sciences toward the development of biological substitutes. Mortality figures and direct health care costs for cancer patients rival those of patients who experience organ failure. Cancer is the second leading cause of death in the United States (Source: American Cancer Society) and it is estimated that direct medical costs for cancer patients approach $100B yearly in the United States alone (Source: National Cancer Institute). In addition, any promising therapy that emerges from the laboratory costs roughly $1.7B to take from bench to bedside. Whereas we have indeed waged war on cancer, the

  12. The coming of age of musculoskeletal tissue engineering and regeneration

    PubMed Central

    Tuan, Rocky S.

    2016-01-01

    Standfirst Tissue engineering and regenerative medicine have advanced rapidly towards the development of therapeutic solutions for musculoskeletal disorders. In 2012, breakthroughs have been made in the guidance of adult stem cell homing, the tissue regenerative activity of stem-cell-derived extracellular matrix has been tested, and novel, mechanically superior biomaterials have been fabricated. PMID:23321611

  13. Turbine pyrometry for advanced engines

    NASA Astrophysics Data System (ADS)

    Atkinson, W. H.; Strange, R. R.

    1987-06-01

    The turbine pyrometry requirements for advanced engine designs are examined. The practical use of current optical pyrometer systems is limited to situations where the reflected radiation comprises not more than 50 percent of the total signal. Alternative approaches, including techniques known as 'Advanced Dual Spectral Area Pyrometer', 'Active Pyrometry', passive synchronous detection pyrometry, and techniques that use thermographic phosphors, are discussed. It is suggested that the methods that use thermographic phosphors at low temperatures can be extended to high temperatures and gas turbine engine environment and can be adapted to the vane scanning pyrometer application.

  14. Microfluidic systems for stem cell-based neural tissue engineering.

    PubMed

    Karimi, Mahdi; Bahrami, Sajad; Mirshekari, Hamed; Basri, Seyed Masoud Moosavi; Nik, Amirala Bakhshian; Aref, Amir R; Akbari, Mohsen; Hamblin, Michael R

    2016-07-01

    Neural tissue engineering aims at developing novel approaches for the treatment of diseases of the nervous system, by providing a permissive environment for the growth and differentiation of neural cells. Three-dimensional (3D) cell culture systems provide a closer biomimetic environment, and promote better cell differentiation and improved cell function, than could be achieved by conventional two-dimensional (2D) culture systems. With the recent advances in the discovery and introduction of different types of stem cells for tissue engineering, microfluidic platforms have provided an improved microenvironment for the 3D-culture of stem cells. Microfluidic systems can provide more precise control over the spatiotemporal distribution of chemical and physical cues at the cellular level compared to traditional systems. Various microsystems have been designed and fabricated for the purpose of neural tissue engineering. Enhanced neural migration and differentiation, and monitoring of these processes, as well as understanding the behavior of stem cells and their microenvironment have been obtained through application of different microfluidic-based stem cell culture and tissue engineering techniques. As the technology advances it may be possible to construct a "brain-on-a-chip". In this review, we describe the basics of stem cells and tissue engineering as well as microfluidics-based tissue engineering approaches. We review recent testing of various microfluidic approaches for stem cell-based neural tissue engineering. PMID:27296463

  15. Tissue engineered small-diameter vascular grafts.

    PubMed

    Schmedlen, Rachael H; Elbjeirami, Wafa M; Gobin, Andrea S; West, Jennifer L

    2003-10-01

    Arterial occlusive disease remains the leading cause of death in western countries and often requires vascular reconstructive surgery. The limited supply of suitable small-diameter vascular grafts has led to the development of tissue engineered blood vessel substitutes. Many different approaches have been examined, including natural scaffolds containing one or more ECM proteins and degradable polymeric scaffolds. For optimal graft development, many efforts have modified the culture environment to enhance ECM synthesis and organization using bioreactors under physiologic conditions and biochemical supplements. In the past couple of decades, a great deal of progress on TEVGs has been made. Many challenges remain and are being addressed, particularly with regard to the prevention of thrombosis and the improvement of graft mechanical properties. To develop a patent TEVG that grossly resembles native tissue, required culture times in most studies exceed 8 weeks. Even with further advances in the field, TEVGs will likely not be used in emergency situations because of the time necessary to allow for cell expansion, ECM production and organization, and attainment of desired mechanical strength. Furthermore, TEVGs will probably require the use of autologous tissue to prevent an immunogenic response, unless advances in immune acceptance render allogenic and xenogenic tissue use feasible. TEVGs have not yet been subjected to clinical trials, which will determine the efficacy of such grafts in the long term. Finally, off-the-shelf availability and cost will become the biggest hurdles in the development of a feasible TEVG product. Although many obstacles exist in the effort to develop a small-diameter TEVG, the potential benefits of such an achievement are exciting. In the near future, a nonthrombogenic TEVG with sufficient mechanical strength may be developed for clinical trials. Such a graft will have the minimum characteristics of biological tissue necessary to remain patent

  16. Advanced diesel engineering and operation

    SciTech Connect

    Haddad, S.D.

    1988-01-01

    This state-of-the-art text/reference addresses advanced aspects of the design and operation of diesel engines. It is the only book to provide a comprehensive account of the adiabatic (or ceramic) diesel engine, aircraft and locomotive diesels (including both four-stroke and two-stroke configurations), an up-to-date analysis of torsional vibration shafts. Treats diesel engine vehicle noise, couplings and test instrumentation, and includes an excellent survey of fuel injection systems. All chapters are fully illustrated, most with supporting data. Contains an extensive, current bibliography.

  17. Tissue engineering of cultured skin substitutes.

    PubMed

    Horch, Raymund E; Kopp, Jürgen; Kneser, Ulrich; Beier, Justus; Bach, Alexander D

    2005-01-01

    Skin replacement has been a challenging task for surgeons ever since the introduction of skin grafts by Reverdin in 1871. Recently, skin grafting has evolved from the initial autograft and allograft preparations to biosynthetic and tissue-engineered living skin replacements. This has been fostered by the dramatically improved survival rates of major burns where the availability of autologous normal skin for grafting has become one of the limiting factors. The ideal properties of a temporary and a permanent skin substitute have been well defined. Tissue-engineered skin replacements: cultured autologous keratinocyte grafts, cultured allogeneic keratinocyte grafts, autologous/allogeneic composites, acellular biological matrices, and cellular matrices including such biological substances as fibrin sealant and various types of collagen, hyaluronic acid etc. have opened new horizons to deal with such massive skin loss. In extensive burns it has been shown that skin substitution with cultured grafts can be a life-saving measure where few alternatives exist. Future research will aim to create skin substitutes with cultured epidermis that under appropriate circumstances may provide a wound cover that could be just as durable and esthetically acceptable as conventional split-thickness skin grafts. Genetic manipulation may in addition enhance the performance of such cultured skin substitutes. If cell science, molecular biology, genetic engineering, material science and clinical expertise join their efforts to develop optimized cell culture techniques and synthetic or biological matrices then further technical advances might well lead to the production of almost skin like new tissue-engineered human skin products resembling natural human skin. PMID:16202208

  18. Advanced Natural Gas Reciprocating Engine(s)

    SciTech Connect

    Kwok, Doris; Boucher, Cheryl

    2009-09-30

    Energy independence and fuel savings are hallmarks of the nation’s energy strategy. The advancement of natural gas reciprocating engine power generation technology is critical to the nation’s future. A new engine platform that meets the efficiency, emissions, fuel flexibility, cost and reliability/maintainability targets will enable American manufacturers to have highly competitive products that provide substantial environmental and economic benefits in the US and in international markets. Along with Cummins and Waukesha, Caterpillar participated in a multiyear cooperative agreement with the Department of Energy to create a 50% efficiency natural gas powered reciprocating engine system with a 95% reduction in NOx emissions by the year 2013. This platform developed under this agreement will be a significant contributor to the US energy strategy and will enable gas engine technology to remain a highly competitive choice, meeting customer cost of electricity targets, and regulatory environmental standard. Engine development under the Advanced Reciprocating Engine System (ARES) program was divided into phases, with the ultimate goal being approached in a series of incremental steps. This incremental approach would promote the commercialization of ARES technologies as soon as they emerged from development and would provide a technical and commercial foundation of later-developing technologies. Demonstrations of the Phase I and Phase II technology were completed in 2004 and 2008, respectively. Program tasks in Phase III included component and system development and testing from 2009-2012. Two advanced ignition technology evaluations were investigated under the ARES program: laser ignition and distributed ignition (DIGN). In collaboration with Colorado State University (CSU), a laser ignition system was developed to provide ignition at lean burn and high boost conditions. Much work has been performed in Caterpillar’s DIGN program under the ARES program. This work

  19. Advanced Technology for Engineering Education

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K. (Compiler); Malone, John B. (Compiler)

    1998-01-01

    This document contains the proceedings of the Workshop on Advanced Technology for Engineering Education, held at the Peninsula Graduate Engineering Center, Hampton, Virginia, February 24-25, 1998. The workshop was jointly sponsored by the University of Virginia's Center for Advanced Computational Technology and NASA. Workshop attendees came from NASA, other government agencies, industry and universities. The objectives of the workshop were to assess the status of advanced technologies for engineering education and to explore the possibility of forming a consortium of interested individuals/universities for curriculum reform and development using advanced technologies. The presentations covered novel delivery systems and several implementations of new technologies for engineering education. Certain materials and products are identified in this publication in order to specify adequately the materials and products that were investigated in the research effort. In no case does such identification imply recommendation or endorsement of products by NASA, nor does it imply that the materials and products are the only ones or the best ones available for this purpose. In many cases equivalent materials and products are available and would probably produce equivalent results.

  20. Vascular Tissue Engineering: Building Perfusable Vasculature for Implantation

    PubMed Central

    Gui, Liqiong; Niklason, Laura E.

    2014-01-01

    Tissue and organ replacement is required when there are no alternative therapies available. Although vascular tissue engineering was originally developed to meet the clinical demands of small-diameter vascular conduits as bypass grafts, it has evolved into a highly advanced field where perfusable vasculatures are generated for implantation. Herein, we review several cutting-edge techniques that have led to implantable human blood vessels in clinical trials, the novel approaches that build complex perfusable microvascular networks in functional tissues, the use of stem cells to generate endothelial cells for vascularization, as well as the challenges in bringing vascular tissue engineering technologies into the clinics. PMID:24533306

  1. Bone Tissue Engineering: Past-Present-Future.

    PubMed

    Quarto, Rodolfo; Giannoni, Paolo

    2016-01-01

    Bone is one of the few tissues to display a true potential for regeneration. Fracture healing is an obvious example where regeneration occurs through tightly regulated sequences of molecular and cellular events which recapitulate tissue formation seen during embryogenesis. Still in some instances, bone regeneration does not occur properly (i.e. critical size lesions) and an appropriate therapeutic intervention is necessary. Successful replacement of bone by tissue engineering will likely depend on the recapitulation of this flow of events. In fact, bone regeneration requires cross-talk between microenvironmental factors and cells; for example, resident mesenchymal progenitors are recruited and properly guided by soluble and insoluble signaling molecules. Tissue engineering attempts to reproduce and to mimic this natural milieu by delivering cells capable of differentiating into osteoblasts, inducing growth factors and biomaterials to support cellular attachment, proliferation, migration, and matrix deposition. In the last two decades, a significant effort has been made by the scientific community in the development of methods and protocols to repair and regenerate tissues such as bone, cartilage, tendons, and ligaments. In this same period, great advancements have been achieved in the biology of stem cells and on the mechanisms governing "stemness". Unfortunately, after two decades, effective clinical translation does not exist, besides a few limited examples. Many years have passed since cell-based regenerative therapies were first described as "promising approaches", but this definition still engulfs the present literature. Failure to envisage translational cell therapy applications in routine medical practice evidences the existence of unresolved scientific and technical struggles, some of which still puzzle researchers in the field and are presented in this chapter. PMID:27236664

  2. Tumor Engineering: The Other Face of Tissue Engineering

    PubMed Central

    2010-01-01

    Advances in tissue engineering have been accomplished for years by employing biomimetic strategies to provide cells with aspects of their original microenvironment necessary to reconstitute a unit of both form and function for a given tissue. We believe that the most critical hallmark of cancer is loss of integration of architecture and function; thus, it stands to reason that similar strategies could be employed to understand tumor biology. In this commentary, we discuss work contributed by Fischbach-Teschl and colleagues to this special issue of Tissue Engineering in the context of ‘tumor engineering’, that is, the construction of complex cell culture models that recapitulate aspects of the in vivo tumor microenvironment to study the dynamics of tumor development, progression, and therapy on multiple scales. We provide examples of fundamental questions that could be answered by developing such models, and encourage the continued collaboration between physical scientists and life scientists not only for regenerative purposes, but also to unravel the complexity that is the tumor microenvironment. PMID:20214448

  3. Stem cells and tissue engineering: past, present, and future.

    PubMed

    Polak, Julia M; Bishop, Anne E

    2006-04-01

    Tissue engineering is an interdisciplinary field that brings together the principles of the life sciences and medicine with those of engineering. The increase in its development over the past decade has resulted from a variety of factors; advances in genomics and proteomics, the advent of new biomaterials as potential templates for tissue growth, improvements in bioreactor design, and increased understanding of healing processes. Possibly the greatest contribution has come from our increased knowledge and understanding of stem cell biology, which is paving the way for the generation of unlimited cells of specific phenotypes for incorporation into engineered tissue constructs. Thus, tissue engineering approaches for expanding and engrafting the differentiated progeny of embryonic, fetal, or adult stem cells have major potential for tissue repair and will make a major contribution to medicine in the 21st century. PMID:16831937

  4. Three-dimensional bioprinting in tissue engineering and regenerative medicine.

    PubMed

    Gao, Guifang; Cui, Xiaofeng

    2016-02-01

    With the advances of stem cell research, development of intelligent biomaterials and three-dimensional biofabrication strategies, highly mimicked tissue or organs can be engineered. Among all the biofabrication approaches, bioprinting based on inkjet printing technology has the promises to deliver and create biomimicked tissue with high throughput, digital control, and the capacity of single cell manipulation. Therefore, this enabling technology has great potential in regenerative medicine and translational applications. The most current advances in organ and tissue bioprinting based on the thermal inkjet printing technology are described in this review, including vasculature, muscle, cartilage, and bone. In addition, the benign side effect of bioprinting to the printed mammalian cells can be utilized for gene or drug delivery, which can be achieved conveniently during precise cell placement for tissue construction. With layer-by-layer assembly, three-dimensional tissues with complex structures can be printed using converted medical images. Therefore, bioprinting based on thermal inkjet is so far the most optimal solution to engineer vascular system to the thick and complex tissues. Collectively, bioprinting has great potential and broad applications in tissue engineering and regenerative medicine. The future advances of bioprinting include the integration of different printing mechanisms to engineer biphasic or triphasic tissues with optimized scaffolds and further understanding of stem cell biology. PMID:26466597

  5. Vascularized Bone Tissue Engineering: Approaches for Potential Improvement

    PubMed Central

    Nguyen, Lonnissa H.; Annabi, Nasim; Nikkhah, Mehdi; Bae, Hojae; Binan, Loïc; Park, Sangwon; Kang, Yunqing

    2012-01-01

    Significant advances have been made in bone tissue engineering (TE) in the past decade. However, classical bone TE strategies have been hampered mainly due to the lack of vascularization within the engineered bone constructs, resulting in poor implant survival and integration. In an effort toward clinical success of engineered constructs, new TE concepts have arisen to develop bone substitutes that potentially mimic native bone tissue structure and function. Large tissue replacements have failed in the past due to the slow penetration of the host vasculature, leading to necrosis at the central region of the engineered tissues. For this reason, multiple microscale strategies have been developed to induce and incorporate vascular networks within engineered bone constructs before implantation in order to achieve successful integration with the host tissue. Previous attempts to engineer vascularized bone tissue only focused on the effect of a single component among the three main components of TE (scaffold, cells, or signaling cues) and have only achieved limited success. However, with efforts to improve the engineered bone tissue substitutes, bone TE approaches have become more complex by combining multiple strategies simultaneously. The driving force behind combining various TE strategies is to produce bone replacements that more closely recapitulate human physiology. Here, we review and discuss the limitations of current bone TE approaches and possible strategies to improve vascularization in bone tissue substitutes. PMID:22765012

  6. A Review of Three-Dimensional Printing in Tissue Engineering.

    PubMed

    Sears, Nick A; Seshadri, Dhruv R; Dhavalikar, Prachi S; Cosgriff-Hernandez, Elizabeth

    2016-08-01

    Recent advances in three-dimensional (3D) printing technologies have led to a rapid expansion of applications from the creation of anatomical training models for complex surgical procedures to the printing of tissue engineering constructs. In addition to achieving the macroscale geometry of organs and tissues, a print layer thickness as small as 20 μm allows for reproduction of the microarchitectures of bone and other tissues. Techniques with even higher precision are currently being investigated to enable reproduction of smaller tissue features such as hepatic lobules. Current research in tissue engineering focuses on the development of compatible methods (printers) and materials (bioinks) that are capable of producing biomimetic scaffolds. In this review, an overview of current 3D printing techniques used in tissue engineering is provided with an emphasis on the printing mechanism and the resultant scaffold characteristics. Current practical challenges and technical limitations are emphasized and future trends of bioprinting are discussed. PMID:26857350

  7. Tissue engineering a fetal membrane.

    PubMed

    Mi, Shengli; David, Anna L; Chowdhury, Bipasha; Jones, Roanne Razalia; Hamley, Ian William; Squires, Adam M; Connon, Che John

    2012-02-01

    The aim of this study was to construct an artificial fetal membrane (FM) by combination of human amniotic epithelial stem cells (hAESCs) and a mechanically enhanced collagen scaffold containing encapsulated human amniotic stromal fibroblasts (hASFs). Such a tissue-engineered FM may have the potential to plug structural defects in the amniotic sac after antenatal interventions, or to prevent preterm premature rupture of the FM. The hAESCs and hASFs were isolated from human fetal amniotic membrane (AM). Magnetic cell sorting was used to enrich the hAESCs by positive ATP-binding cassette G2 selection. We investigated the use of a laminin/fibronectin (1:1)-coated compressed collagen gel as a novel scaffold to support the growth of hAESCs. A type I collagen gel was dehydrated to form a material mimicking the mechanical properties and ultra-structure of human AM. hAESCs successfully adhered to and formed a monolayer upon the biomimetic collagen scaffold. The resulting artificial membrane shared a high degree of similarity in cell morphology, protein expression profiles, and structure to normal fetal AM. This study provides the first line of evidence that a compacted collagen gel containing hASFs could adequately support hAESCs adhesion and differentiation to a degree that is comparable to the normal human fetal AM in terms of structure and maintenance of cell phenotype. PMID:21919796

  8. Advanced engineering environment pilot project.

    SciTech Connect

    Schwegel, Jill; Pomplun, Alan R.; Abernathy, Rusty

    2006-10-01

    The Advanced Engineering Environment (AEE) is a concurrent engineering concept that enables real-time process tooling design and analysis, collaborative process flow development, automated document creation, and full process traceability throughout a product's life cycle. The AEE will enable NNSA's Design and Production Agencies to collaborate through a singular integrated process. Sandia National Laboratories and Parametric Technology Corporation (PTC) are working together on a prototype AEE pilot project to evaluate PTC's product collaboration tools relative to the needs of the NWC. The primary deliverable for the project is a set of validated criteria for defining a complete commercial off-the-shelf (COTS) solution to deploy the AEE across the NWC.

  9. Biomimetic strategies for engineering composite tissues.

    PubMed

    Lee, Nancy; Robinson, Jennifer; Lu, Helen

    2016-08-01

    The formation of multiple tissue types and their integration into composite tissue units presents a frontier challenge in regenerative engineering. Tissue-tissue synchrony is crucial in providing structural support for internal organs and enabling daily activities. This review highlights the state-of-the-art in composite tissue scaffold design, and explores how biomimicry can be strategically applied to avoid over-engineering the scaffold. Given the complexity of biological tissues, determining the most relevant parameters for recapitulating native structure-function relationships through strategic biomimicry will reduce the burden for clinical translation. It is anticipated that these exciting efforts in composite tissue engineering will enable integrative and functional repair of common soft tissue injuries and lay the foundation for total joint or limb regeneration. PMID:27010653

  10. Cell-Based Strategies for Meniscus Tissue Engineering

    PubMed Central

    Niu, Wei; Guo, Weimin; Han, Shufeng; Zhu, Yun; Liu, Shuyun; Guo, Quanyi

    2016-01-01

    Meniscus injuries remain a significant challenge due to the poor healing potential of the inner avascular zone. Following a series of studies and clinical trials, tissue engineering is considered a promising prospect for meniscus repair and regeneration. As one of the key factors in tissue engineering, cells are believed to be highly beneficial in generating bionic meniscus structures to replace injured ones in patients. Therefore, cell-based strategies for meniscus tissue engineering play a fundamental role in meniscal regeneration. According to current studies, the main cell-based strategies for meniscus tissue engineering are single cell type strategies; cell coculture strategies also were applied to meniscus tissue engineering. Likewise, on the one side, the zonal recapitulation strategies based on mimicking meniscal differing cells and internal architectures have received wide attentions. On the other side, cell self-assembling strategies without any scaffolds may be a better way to build a bionic meniscus. In this review, we primarily discuss cell seeds for meniscus tissue engineering and their application strategies. We also discuss recent advances and achievements in meniscus repair experiments that further improve our understanding of meniscus tissue engineering. PMID:27274735

  11. Ethical considerations in tissue engineering research: Case studies in translation.

    PubMed

    Baker, Hannah B; McQuilling, John P; King, Nancy M P

    2016-04-15

    Tissue engineering research is a complex process that requires investigators to focus on the relationship between their research and anticipated gains in both knowledge and treatment improvements. The ethical considerations arising from tissue engineering research are similarly complex when addressing the translational progression from bench to bedside, and investigators in the field of tissue engineering act as moral agents at each step of their research along the translational pathway, from early benchwork and preclinical studies to clinical research. This review highlights the ethical considerations and challenges at each stage of research, by comparing issues surrounding two translational tissue engineering technologies: the bioartificial pancreas and a tissue engineered skeletal muscle construct. We present relevant ethical issues and questions to consider at each step along the translational pathway, from the basic science bench to preclinical research to first-in-human clinical trials. Topics at the bench level include maintaining data integrity, appropriate reporting and dissemination of results, and ensuring that studies are designed to yield results suitable for advancing research. Topics in preclinical research include the principle of "modest translational distance" and appropriate animal models. Topics in clinical research include key issues that arise in early-stage clinical trials, including selection of patient-subjects, disclosure of uncertainty, and defining success. The comparison of these two technologies and their ethical issues brings to light many challenges for translational tissue engineering research and provides guidance for investigators engaged in development of any tissue engineering technology. PMID:26282436

  12. Oxygen Releasing Biomaterials for Tissue Engineering

    PubMed Central

    Camci-Unal, Gulden; Alemdar, Neslihan; Annabi, Nasim; Khademhosseini, Ali

    2013-01-01

    Due to the increasing demand to generate thick and vascularized tissue engineered constructs, novel strategies are currently being developed. An emerging example is the generation of oxygen-releasing biomaterials to tackle mass transport and diffusion limitations within engineered tissue-like constructs. Biomaterials containing oxygen releasing molecules can be fabricated in various forms such as, hybrid thin films, microparticles, or three dimensional (3D) scaffolds. In this perspective, we will summarize various oxygen-releasing reagents and their potential applications in regenerative engineering. Moreover, we will review the main approaches to fabricate oxygen-releasing biomaterials for a range of tissue engineering applications. PMID:23853426

  13. Mesoscopic Fluorescence Molecular Tomography for Evaluating Engineered Tissues.

    PubMed

    Ozturk, Mehmet S; Chen, Chao-Wei; Ji, Robin; Zhao, Lingling; Nguyen, Bao-Ngoc B; Fisher, John P; Chen, Yu; Intes, Xavier

    2016-03-01

    Optimization of regenerative medicine strategies includes the design of biomaterials, development of cell-seeding methods, and control of cell-biomaterial interactions within the engineered tissues. Among these steps, one paramount challenge is to non-destructively image the engineered tissues in their entirety to assess structure, function, and molecular expression. It is especially important to be able to enable cell phenotyping and monitor the distribution and migration of cells throughout the bulk scaffold. Advanced fluorescence microscopic techniques are commonly employed to perform such tasks; however, they are limited to superficial examination of tissue constructs. Therefore, the field of tissue engineering and regenerative medicine would greatly benefit from the development of molecular imaging techniques which are capable of non-destructive imaging of three-dimensional cellular distribution and maturation within a tissue-engineered scaffold beyond the limited depth of current microscopic techniques. In this review, we focus on an emerging depth-resolved optical mesoscopic imaging technique, termed laminar optical tomography (LOT) or mesoscopic fluorescence molecular tomography (MFMT), which enables longitudinal imaging of cellular distribution in thick tissue engineering constructs at depths of a few millimeters and with relatively high resolution. The physical principle, image formation, and instrumentation of LOT/MFMT systems are introduced. Representative applications in tissue engineering include imaging the distribution of human mesenchymal stem cells embedded in hydrogels, imaging of bio-printed tissues, and in vivo applications. PMID:26645079

  14. Tissue engineering in the rheumatic diseases

    PubMed Central

    Ringe, Jochen; Sittinger, Michael

    2009-01-01

    Diseases such as degenerative or rheumatoid arthritis are accompanied by joint destruction. Clinically applied tissue engineering technologies like autologous chondrocyte implantation, matrix-assisted chondrocyte implantation, or in situ recruitment of bone marrow mesenchymal stem cells target the treatment of traumatic defects or of early osteoarthritis. Inflammatory conditions in the joint hamper the application of tissue engineering during chronic joint diseases. Here, most likely, cartilage formation is impaired and engineered neocartilage will be degraded. Based on the observations that mesenchymal stem cells (a) develop into joint tissues and (b) in vitro and in vivo show immunosuppressive and anti-inflammatory qualities indicating a transplant-protecting activity, these cells are prominent candidates for future tissue engineering approaches for the treatment of rheumatic diseases. Tissue engineering also provides highly organized three-dimensional in vitro culture models of human cells and their extracellular matrix for arthritis research. PMID:19232063

  15. Cardiovascular tissue engineering: state of the art.

    PubMed

    Vara, Dina S; Salacinski, Henryk J; Kannan, Ruben Y; Bordenave, Laurence; Hamilton, George; Seifalian, Alexander M

    2005-12-01

    In patients requiring coronary or peripheral vascular bypass procedures, autogenous arterial or vein grafts remain as the conduit of choice even in the case of redo patients. It is in this class of redo patients that often natural tissue of suitable quality becomes unavailable; so that prosthetic material is then used. Prosthetic grafts are liable to fail due to graft occlusion caused by surface thrombogenicity and lack of elasticity. To prevent this, seeding of the graft lumen with endothelial cells has been undertaken and recent clinical studies have evidenced patency rates approaching reasonable vein grafts. Recent advances have also looked at developing a completely artificial biological graft engineered from the patient's cells with surface and viscoelastic properties similar to autogenous vessels. This review encompasses both endothelialisation of grafts and the construction of biological cardiovascular conduits. PMID:16364812

  16. Cartilage Tissue Engineering: What Have We Learned in Practice?

    PubMed

    Doran, Pauline M

    2015-01-01

    Many technologies that underpin tissue engineering as a research field were developed with the aim of producing functional human cartilage in vitro. Much of our practical experience with three-dimensional cultures, tissue bioreactors, scaffold materials, stem cells, and differentiation protocols was gained using cartilage as a model system. Despite these advances, however, generation of engineered cartilage matrix with the composition, structure, and mechanical properties of mature articular cartilage has not yet been achieved. Currently, the major obstacles to synthesis of clinically useful cartilage constructs are our inability to control differentiation to the extent needed, and the failure of engineered and host tissues to integrate after construct implantation. The aim of this chapter is to distil from the large available body of literature the seminal approaches and experimental techniques developed for cartilage tissue engineering and to identify those specific areas requiring further research effort. PMID:26445827

  17. Generating new blood flow: integrating developmental biology and tissue engineering.

    PubMed

    Krenning, Guido; Moonen, Jan-Renier A J; van Luyn, Marja J A; Harmsen, Martin C

    2008-11-01

    Vascular tissue engineering aims to restore blood flow by seeding artificial tubular scaffolds with endothelial and smooth muscle cells, thus creating bioartificial blood vessels. Herein, the progenitors of smooth muscle and endothelial cells hold great promise because they efficiently differentiate and harbor longevity. In this review, we describe a novel tissue engineering approach that uses current insights from developmental biology, that is, progenitor cell plasticity, and the latest advances in biomaterial design. We focus specifically on developmental processes that regulate progenitor cell (trans)differentiation and offer a platform for the integration of these molecular clues into biomaterial design. We propose a novel engineering paradigm for the creation of a small-diameter blood vessel wherein progenitor cell differentiation and tissue organization are instructed by the biomaterial solely. With this review, we emphasize the power of integrating developmental biology and material science for vascular tissue engineering. PMID:19345319

  18. Advanced fuel chemistry for advanced engines.

    SciTech Connect

    Taatjes, Craig A.; Jusinski, Leonard E.; Zador, Judit; Fernandes, Ravi X.; Miller, James A.

    2009-09-01

    Autoignition chemistry is central to predictive modeling of many advanced engine designs that combine high efficiency and low inherent pollutant emissions. This chemistry, and especially its pressure dependence, is poorly known for fuels derived from heavy petroleum and for biofuels, both of which are becoming increasingly prominent in the nation's fuel stream. We have investigated the pressure dependence of key ignition reactions for a series of molecules representative of non-traditional and alternative fuels. These investigations combined experimental characterization of hydroxyl radical production in well-controlled photolytically initiated oxidation and a hybrid modeling strategy that linked detailed quantum chemistry and computational kinetics of critical reactions with rate-equation models of the global chemical system. Comprehensive mechanisms for autoignition generally ignore the pressure dependence of branching fractions in the important alkyl + O{sub 2} reaction systems; however we have demonstrated that pressure-dependent 'formally direct' pathways persist at in-cylinder pressures.

  19. Advanced System for Process Engineering

    1992-02-01

    ASPEN (Advanced System for Process Engineering) is a state of the art process simulator and economic evaluation package which was designed for use in engineering fossil energy conversion processes. ASPEN can represent multiphase streams including solids, and handle complex substances such as coal. The system can perform steady state material and energy balances, determine equipment size and cost, and carry out preliminary economic evaluations. It is supported by a comprehensive physical property system for computationmore » of major properties such as enthalpy, entropy, free energy, molar volume, equilibrium ratio, fugacity coefficient, viscosity, thermal conductivity, and diffusion coefficient for specified phase conditions; vapor, liquid, or solid. The properties may be computed for pure components, mixtures, or components in a mixture, as appropriate. The ASPEN Input Language is oriented towards process engineers.« less

  20. Animal Models for Adipose Tissue Engineering

    PubMed Central

    Uthamanthil, Rajesh; Beahm, Elisabeth; Frye, Cindy

    2008-01-01

    Abstract There is a critical need for adequate reconstruction of soft tissue defects resulting from tumor resection, trauma, and congenital abnormalities. To be sure, adipose tissue engineering strategies offer promising solutions. However, before clinical translation can occur, efficacy must be proven in animal studies. The aim of this review is to provide an overview of animal models currently employed for adipose tissue engineering. PMID:18544014

  1. Amelogenin in Enamel Tissue Engineering

    PubMed Central

    2016-01-01

    In this chapter the basic premises, the recent findings and the future challenges in the use of amelogenin for enamel tissue engineering are being discoursed on. Results emerging from the experiments performed to assess the fundamental physicochemical mechanisms of the interaction of amelogenin, the main protein of the enamel matrix, and the growing crystals of apatite, are mentioned, alongside a moderately comprehensive literature review of the subject at hand. The clinical importance of understanding this protein/mineral interaction at the nanoscale are highlighted as well as the potential for tooth enamel to act as an excellent model system for studying some of the essential aspects of biomineralization processes in general. The dominant paradigm stating that amelogenin directs the uniaxial growth of apatite crystals in enamel by slowing down the growth of (hk0) faces on which it adheres is being questioned based on the results demonstrating the ability of amelogenin to promote the nucleation and crystal growth of apatite under constant titration conditions designed to mimic those present in the developing enamel matrix. The role of numerous minor components of the enamel matrix is being highlighted as essential and impossible to compensate for by utilizing its more abundant ingredients only. It is concluded that the three major aspects of amelogenesis outlined hereby – (1) the assembly of amelogenin and other enamel matrix proteins, (2) the proteolytic activity, and (3) crystallization – need to be in precise synergy with each other in order for the grounds for the proper imitation of amelogenesis in the lab to be created. PMID:26545753

  2. Amelogenin in Enamel Tissue Engineering.

    PubMed

    Uskoković, Vuk

    2015-01-01

    In this chapter the basic premises, the recent findings and the future challenges in the use of amelogenin for enamel tissue engineering are being discoursed on. Results emerging from the experiments performed to assess the fundamental physicochemical mechanisms of the interaction of amelogenin, the main protein of the enamel matrix, and the growing crystals of apatite, are mentioned, alongside a moderately comprehensive literature review of the subject at hand. The clinical importance of understanding this protein/mineral interaction at the nanoscale are highlighted as well as the potential for tooth enamel to act as an excellent model system for studying some of the essential aspects of biomineralization processes in general. The dominant paradigm stating that amelogenin directs the uniaxial growth of apatite crystals in enamel by slowing down the growth of (hk0) faces on which it adheres is being questioned based on the results demonstrating the ability of amelogenin to promote the nucleation and crystal growth of apatite under constant titration conditions designed to mimic those present in the developing enamel matrix. The role of numerous minor components of the enamel matrix is being highlighted as essential and impossible to compensate for by utilizing its more abundant ingredients only. It is concluded that the three major aspects of amelogenesis outlined hereby--(1) the assembly of amelogenin and other enamel matrix proteins, (2) the proteolytic activity, and (3) crystallization--need to be in precise synergy with each other in order for the grounds for the proper imitation of amelogenesis in the lab to be created. PMID:26545753

  3. Capillary force lithography for cardiac tissue engineering.

    PubMed

    Macadangdang, Jesse; Lee, Hyun Jung; Carson, Daniel; Jiao, Alex; Fugate, James; Pabon, Lil; Regnier, Michael; Murry, Charles; Kim, Deok-Ho

    2014-01-01

    Cardiovascular disease remains the leading cause of death worldwide(1). Cardiac tissue engineering holds much promise to deliver groundbreaking medical discoveries with the aims of developing functional tissues for cardiac regeneration as well as in vitro screening assays. However, the ability to create high-fidelity models of heart tissue has proven difficult. The heart's extracellular matrix (ECM) is a complex structure consisting of both biochemical and biomechanical signals ranging from the micro- to the nanometer scale(2). Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering(3-5). A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling(2). Unfortunately, few methods have been able to mimic the organization of ECM fibers down to the nanometer scale. Recent advancements in nanofabrication techniques, however, have enabled the design and fabrication of scalable scaffolds that mimic the in vivo structural and substrate stiffness cues of the ECM in the heart(6-9). Here we present the development of two reproducible, cost-effective, and scalable nanopatterning processes for the functional alignment of cardiac cells using the biocompatible polymer poly(lactide-co-glycolide) (PLGA)(8) and a polyurethane (PU) based polymer. These anisotropically nanofabricated substrata (ANFS) mimic the underlying ECM of well-organized, aligned tissues and can be used to investigate the role of nanotopography on cell morphology and function(10-14). Using a nanopatterned (NP) silicon master as a template, a polyurethane acrylate (PUA) mold is fabricated. This PUA mold is then used to pattern the PU or PLGA hydrogel via UV-assisted or solvent-mediated capillary force lithography (CFL), respectively(15,16). Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip

  4. Advanced engineering environment collaboration project.

    SciTech Connect

    Lamph, Jane Ann; Pomplun, Alan R.; Kiba, Grant W.; Dutra, Edward G.; Dankiewicz, Robert J.; Marburger, Scot J.

    2008-12-01

    The Advanced Engineering Environment (AEE) is a model for an engineering design and communications system that will enhance project collaboration throughout the nuclear weapons complex (NWC). Sandia National Laboratories and Parametric Technology Corporation (PTC) worked together on a prototype project to evaluate the suitability of a portion of PTC's Windchill 9.0 suite of data management, design and collaboration tools as the basis for an AEE. The AEE project team implemented Windchill 9.0 development servers in both classified and unclassified domains and used them to test and evaluate the Windchill tool suite relative to the needs of the NWC using weapons project use cases. A primary deliverable was the development of a new real time collaborative desktop design and engineering process using PDMLink (data management tool), Pro/Engineer (mechanical computer aided design tool) and ProductView Lite (visualization tool). Additional project activities included evaluations of PTC's electrical computer aided design, visualization, and engineering calculations applications. This report documents the AEE project work to share information and lessons learned with other NWC sites. It also provides PTC with recommendations for improving their products for NWC applications.

  5. Tendon Tissue Engineering: Progress, Challenges, and Translation to the Clinic

    PubMed Central

    Shearn, Jason T.; Kinneberg, Kirsten R.C.; Dyment, Nathaniel A.; Galloway, Marc T.; Kenter, Keith; Wylie, Christopher; Butler, David L.

    2013-01-01

    The tissue engineering field has made great strides in understanding how different aspects of tissue engineered constructs (TECs) and the culture process affect final tendon repair. However, there remain significant challenges in developing strategies that will lead to a clinically effective and commercially successful product. In an effort to increase repair quality, a better understanding of normal development, and how it differs from adult tendon healing, may provide strategies to improve tissue engineering. As tendon tissue engineering continues to improve, the field needs to employ more clinically relevant models of tendon injury such as degenerative tendons. We need to translate successes to larger animal models to begin exploring the clinical implications of our treatments. By advancing the models used to validate our TECs, we can help convince our toughest customer, the surgeon, that our products will be clinically efficacious. As we address these challenges in musculoskeletal tissue engineering, the field still needs to address the commercialization of products developed in the laboratory. TEC commercialization faces numerous challenges because each injury and patient is unique. This review aims to provide tissue engineers with a summary of important issues related to engineering tendon repairs and potential strategies for producing clinically successful products. PMID:21625053

  6. The Cummins advanced turbocompound diesel engine evaluation

    NASA Technical Reports Server (NTRS)

    Hoehne, J. L.; Werner, J. R.

    1982-01-01

    An advanced turbocompound diesel engine program was initiated to improve the tank mileage of the turbocompound engine by 5% over the vehicle test engines. Engine improvements could be realized by increasing the available energy of the exhaust gas at the turbine inlet, incorporating gas turbine techniques into improving the turbomachinery efficiencies, and through refined engine system optimization. The individual and cumulative performance gains achieved with the advanced turbocompound engine improvements are presented.

  7. Myocardial tissue engineering for cardiac repair.

    PubMed

    Pecha, Simon; Eschenhagen, Thomas; Reichenspurner, Hermann

    2016-03-01

    The number of patients with heart failure is increasing in the aging population. Heart transplantation remains the only curative treatment option for patients with end-stage heart failure. Because of an organ donor shortage, new organ-independent treatment options are necessary. Different approaches to cardiac repair therapies have been developed and optimized in recent years. One of these promising approaches is myocardial tissue engineering, which refers to the creation of 3-dimensional engineered heart tissue in vitro. This perspective provides an overview of different approaches to tissue engineering, including essentials to improve tissue quality and choice of ideal cell source, as well as an overview of in vitro and in vivo studies. Several hurdles that have to be overcome before clinical application of engineered heart tissue might become a realistic scenario are also addressed. PMID:26856673

  8. Pulp and dentin tissue engineering and regeneration: current progress

    PubMed Central

    Huang, George TJ

    2009-01-01

    Dental pulp tissue is vulnerable to infection. Entire pulp amputation followed by pulp-space disinfection and filling with an artificial rubber-like material is employed to treat the infection – commonly known as root-canal therapy. Regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. However, with the advent of the concept of modern tissue engineering and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the early attempts to regenerate pulp tissue and the current endeavor of pulp and dentin tissue engineering, and regeneration. The prospective outcome of the current advancement in this line of research will be discussed. PMID:19761395

  9. Pulp and dentin tissue engineering and regeneration: current progress.

    PubMed

    Huang, George T J

    2009-09-01

    Dental pulp tissue is vulnerable to infection. Entire pulp amputation followed by pulp-space disinfection and filling with an artificial rubber-like material is employed to treat the infection - commonly known as root-canal therapy. Regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. However, with the advent of the concept of modern tissue engineering and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the early attempts to regenerate pulp tissue and the current endeavor of pulp and dentin tissue engineering, and regeneration. The prospective outcome of the current advancement in this line of research will be discussed. PMID:19761395

  10. Protein–Hydrogel Interactions in Tissue Engineering: Mechanisms and Applications

    PubMed Central

    Zustiak, Silviya P.; Wei, Yunqian

    2013-01-01

    Recent advances in our understanding of the sophistication of the cellular microenvironment and the dynamics of tissue remodeling during development, disease, and regeneration have increased our appreciation of the current challenges facing tissue engineering. As this appreciation advances, we are better equipped to approach problems in the biology and therapeutics of even more complex fields, such as stem cells and cancer. To aid in these studies, as well as the established areas of tissue engineering, including cardiovascular, musculoskeletal, and neural applications, biomaterials scientists have developed an extensive array of materials with specifically designed chemical, mechanical, and biological properties. Herein, we highlight an important topic within this area of biomaterials research, protein–hydrogel interactions. Due to inherent advantages of hydrated scaffolds for soft tissue engineering as well as specialized bioactivity of proteins and peptides, this field is well-posed to tackle major needs within emerging areas of tissue engineering. We provide an overview of the major modes of interactions between hydrogels and proteins (e.g., weak forces, covalent binding, affinity binding), examples of applications within growth factor delivery and three-dimensional scaffolds, and finally future directions within the area of hydrogel–protein interactions that will advance our ability to control the cell–biomaterial interface. PMID:23150926

  11. Preclinical imaging in bone tissue engineering.

    PubMed

    Ventura, Manuela; Boerman, Otto C; de Korte, Chris; Rijpkema, Mark; Heerschap, Arend; Oosterwijk, Egbert; Jansen, John A; Walboomers, X Frank

    2014-12-01

    Since X-rays were discovered, in 1895, and since the first radiological image of a hand, bone tissue has been the subject of detailed medical imaging. However, advances in bone engineering, including the increased complexity of implant scaffolds, currently also underline the limits of X-ray imaging. Therefore, advanced follow-up imaging methods are pivotal to develop. The field of noninvasive, high-sensitivity, and high-resolution anatomical and functional imaging techniques (optical, ultrasound, positron emission tomography, single-photon emission computed tomography, magnetic resonance, etc.) offers a wide variety of tools that potentially could be considered as alternatives, or at least supportive, to the most commonly used X-ray computed tomography. Moreover, dedicated preclinical scanners have become available, with sensitivity and resolution even higher than clinical scanners, thus favoring a quick translation from preclinical to clinical applications. Furthermore, the armamentarium of bone-specific probes and contrast agents for each of this imaging modalities is constantly growing. This review focuses on such preclinical imaging tools, each with its respective strengths and weaknesses, used alone or in combination. Especially, multimodal imaging will dramatically contribute to improve the knowledge on bone healing regenerative processes. PMID:24720381

  12. Cell-scaffold interaction within engineered tissue.

    PubMed

    Chen, Haiping; Liu, Yuanyuan; Jiang, Zhenglong; Chen, Weihua; Yu, Yongzhe; Hu, Qingxi

    2014-05-01

    The structure of a tissue engineering scaffold plays an important role in modulating tissue growth. A novel gelatin-chitosan (Gel-Cs) scaffold with a unique structure produced by three-dimensional printing (3DP) technology combining with vacuum freeze-drying has been developed for tissue-engineering applications. The scaffold composed of overall construction, micro-pore, surface morphology, and effective mechanical property. Such a structure meets the essential design criteria of an ideal engineered scaffold. The favorable cell-matrix interaction supports the active biocompatibility of the structure. The structure is capable of supporting cell attachment and proliferation. Cells seeded into this structure tend to maintain phenotypic shape and secreted large amounts of extracellular matrix (ECM) and the cell growth decreased the mechanical properties of scaffold. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique structure, which acts to support cell growth. PMID:24631290

  13. 3-dimensional bioprinting for tissue engineering applications.

    PubMed

    Gu, Bon Kang; Choi, Dong Jin; Park, Sang Jun; Kim, Min Sup; Kang, Chang Mo; Kim, Chun-Ho

    2016-01-01

    The 3-dimensional (3D) printing technologies, referred to as additive manufacturing (AM) or rapid prototyping (RP), have acquired reputation over the past few years for art, architectural modeling, lightweight machines, and tissue engineering applications. Among these applications, tissue engineering field using 3D printing has attracted the attention from many researchers. 3D bioprinting has an advantage in the manufacture of a scaffold for tissue engineering applications, because of rapid-fabrication, high-precision, and customized-production, etc. In this review, we will introduce the principles and the current state of the 3D bioprinting methods. Focusing on some of studies that are being current application for biomedical and tissue engineering fields using printed 3D scaffolds. PMID:27114828

  14. Liposomes in tissue engineering and regenerative medicine

    PubMed Central

    Monteiro, Nelson; Martins, Albino; Reis, Rui L.; Neves, Nuno M.

    2014-01-01

    Liposomes are vesicular structures made of lipids that are formed in aqueous solutions. Structurally, they resemble the lipid membrane of living cells. Therefore, they have been widely investigated, since the 1960s, as models to study the cell membrane, and as carriers for protection and/or delivery of bioactive agents. They have been used in different areas of research including vaccines, imaging, applications in cosmetics and tissue engineering. Tissue engineering is defined as a strategy for promoting the regeneration of tissues for the human body. This strategy may involve the coordinated application of defined cell types with structured biomaterial scaffolds to produce living structures. To create a new tissue, based on this strategy, a controlled stimulation of cultured cells is needed, through a systematic combination of bioactive agents and mechanical signals. In this review, we highlight the potential role of liposomes as a platform for the sustained and local delivery of bioactive agents for tissue engineering and regenerative medicine approaches. PMID:25401172

  15. Nanostructured Capsules for Cartilage Tissue Engineering.

    PubMed

    Correia, Clara R; Reis, Rui L; Mano, João F

    2015-01-01

    Polymeric multilayered capsules (PMCs) have found great applicability in bioencapsulation, an evolving branch of tissue engineering and regenerative medicine. Here, we describe the production of hierarchical PMCs composed by an external multilayered membrane by layer-by-layer assembly of poly(L-lysine), alginate, and chitosan. The core of the PMCs is liquified and encapsulates human adipose stem cells and surface-functionalized collagen II-TGF-β3 poly(L-lactic acid) microparticles for cartilage tissue engineering. PMID:26445839

  16. Cell Patterning for Liver Tissue Engineering via Dielectrophoretic Mechanisms

    PubMed Central

    Yahya, Wan Nurlina Wan; Kadri, Nahrizul Adib; Ibrahim, Fatimah

    2014-01-01

    Liver transplantation is the most common treatment for patients with end-stage liver failure. However, liver transplantation is greatly limited by a shortage of donors. Liver tissue engineering may offer an alternative by providing an implantable engineered liver. Currently, diverse types of engineering approaches for in vitro liver cell culture are available, including scaffold-based methods, microfluidic platforms, and micropatterning techniques. Active cell patterning via dielectrophoretic (DEP) force showed some advantages over other methods, including high speed, ease of handling, high precision and being label-free. This article summarizes liver function and regenerative mechanisms for better understanding in developing engineered liver. We then review recent advances in liver tissue engineering techniques and focus on DEP-based cell patterning, including microelectrode design and patterning configuration. PMID:24991941

  17. Bioreactor Development for Lung Tissue Engineering

    PubMed Central

    Panoskaltsis-Mortari, Angela

    2015-01-01

    Rationale Much recent interest in lung bioengineering by pulmonary investigators, industry and the organ transplant field has seen a rapid growth of bioreactor development ranging from the microfluidic scale to the human-sized whole lung systems. A comprehension of the findings from these models is needed to provide the basis for further bioreactor development. Objective The goal was to comprehensively review the current state of bioreactor development for the lung. Methods A search using PubMed was done for published, peer-reviewed papers using the keywords “lung” AND “bioreactor” or “bioengineering” or “tissue engineering” or “ex vivo perfusion”. Main Results Many new bioreactors ranging from the microfluidic scale to the human-sized whole lung systems have been developed by both academic and commercial entities. Microfluidic, lung-mimic and lung slice cultures have the advantages of cost-efficiency and high throughput analyses ideal for pharmaceutical and toxicity studies. Perfused/ventilated rodent whole lung systems can be adapted for mid-throughput studies of lung stem/progenitor cell development, cell behavior, understanding and treating lung injury and for preliminary work that can be translated to human lung bioengineering. Human-sized ex vivo whole lung bioreactors incorporating perfusion and ventilation are amenable to automation and have been used for whole lung decellularization and recellularization. Clinical scale ex vivo lung perfusion systems have been developed for lung preservation and reconditioning and are currently being evaluated in clinical trials. Conclusions Significant advances in bioreactors for lung engineering have been made at both the microfluidic and the macro scale. The most advanced are closed systems that incorporate pressure-controlled perfusion and ventilation and are amenable to automation. Ex vivo lung perfusion systems have advanced to clinical trials for lung preservation and reconditioning. The biggest

  18. Advanced System for Process Engineering

    1998-09-14

    PRO ASPEN/PC1.0 (Advanced System for Process Engineering) is a state of the art process simulator and economic evaluation package which was designed for use in engineering fossil energy conversion processes and has been ported to run on a PC. PRO ASPEN/PC1.0 can represent multiphase streams including solids, and handle complex substances such as coal. The system can perform steady state material and energy balances, determine equipment size and cost, and carry out preliminary economic evaluations.more » It is supported by a comprehensive physical property system for computation of major properties such as enthalpy, entropy, free energy, molar volume, equilibrium ratio, fugacity coefficient, viscosity, thermal conductivity, and diffusion coefficient for specified phase conditions; vapor, liquid, or solid. The properties may be computed for pure components, mixtures, or components in a mixture, as appropriate. The PRO ASPEN/PC1.0 Input Language is oriented towards process engineers.« less

  19. Engineering cell attachments to scaffolds in cartilage tissue engineering

    NASA Astrophysics Data System (ADS)

    Steward, Andrew J.; Liu, Yongxing; Wagner, Diane R.

    2011-04-01

    One of the challenges of tissue engineering, a promising cell-based treatment for damaged or diseased cartilage, is designing the scaffold that provides structure while the tissue regenerates. In addition to the scaffold material's biocompatibility, mechanical properties, and ease of manufacturing, scaffold interactions with the cells must also be considered. In cartilage tissue engineering, a range of scaffolds with various degrees of cell attachment have been proposed, but the attachment density and type have yet to be optimized. Several techniques have been developed to modulate cell adhesion to the scaffold. These studies suggest that the need for cell attachment in cartilage tissue engineering may vary with cell type, stage of differentiation, culture condition, and scaffold material. Further studies will elucidate the role of cell attachment in cartilage regeneration and enhance efforts to engineer cell-based cartilage therapies.

  20. Tissue Engineering Chamber Promotes Adipose Tissue Regeneration in Adipose Tissue Engineering Models Through Induced Aseptic Inflammation

    PubMed Central

    Peng, Zhangsong; Dong, Ziqing; Chang, Qiang; Zhan, Weiqing; Zeng, Zhaowei; Zhang, Shengchang

    2014-01-01

    Tissue engineering chamber (TEC) makes it possible to generate significant amounts of mature, vascularized, stable, and transferable adipose tissue. However, little is known about the role of the chamber in tissue engineering. Therefore, to investigate the role of inflammatory response and the change in mechanotransduction started by TEC after implantation, we placed a unique TEC model on the surface of the groin fat pads in rats to study the expression of cytokines and tissue development in the TEC. The number of infiltrating cells was counted, and vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1) expression levels in the chamber at multiple time points postimplantation were analyzed by enzyme-linked immunosorbent assay. Tissue samples were collected at various time points and labeled for specific cell populations. The result showed that new adipose tissue formed in the chamber at day 60. Also, the expression of MCP-1 and VEGF in the chamber decreased slightly from an early stage as well as the number of the infiltrating cells. A large number of CD34+/perilipin− perivascular cells could be detected at day 30. Also, the CD34+/perilipin+ adipose precursor cell numbers increased sharply by day 45 and then decreased by day 60. CD34−/perilipin+ mature adipocytes were hard to detect in the chamber content at day 30, but their number increased and then peaked at day 60. Ki67-positive cells could be found near blood vessels and their number decreased sharply over time. Masson's trichrome showed that collagen was the dominant component of the chamber content at early stage and was replaced by newly formed small adipocytes over time. Our findings suggested that the TEC implantation could promote the proliferation of adipose precursor cells derived from local adipose tissue, increase angiogenesis, and finally lead to spontaneous adipogenesis by inducing aseptic inflammation and changing local mechanotransduction. PMID:24559078

  1. Tissue Engineering: Step Ahead in Maxillofacial Reconstruction

    PubMed Central

    Rai, Raj; Raval, Rushik; Khandeparker, Rakshit Vijay Sinai; Chidrawar, Swati K; Khan, Abdul Ahad; Ganpat, Makne Sachin

    2015-01-01

    Within the precedent decade, a new field of “tissue engineering” or “tissue regeneration” emerge that offers an innovative and exhilarating substitute for maxillofacial reconstruction. It offers a new option to supplement existing treatment regimens for reconstruction/regeneration of the oral and craniofacial complex, which includes the teeth, periodontium, bones, soft tissues (oral mucosa, conjunctiva, skin), salivary glands, and the temporomandibular joint (bone and cartilage), as well as blood vessels, muscles, tendons, and nerves. Tissue engineering is based on harvesting the stem cells which are having potential to form an organ. Harvested cells are then transferred into scaffolds that are manufactured in a laboratory to resemble the structure of the desired tissue to be replaced. This article reviews the principles of tissue engineering and its various applications in oral and maxillofacial surgery. PMID:26435634

  2. Tissue engineered constructs for peripheral nerve surgery

    PubMed Central

    Johnson, P. J.; Wood, M. D.; Moore, A. M.; Mackinnon, S. E.

    2013-01-01

    Summary Background Tissue engineering has been defined as “an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ”. Traumatic peripheral nerve injury resulting in significant tissue loss at the zone of injury necessitates the need for a bridge or scaffold for regenerating axons from the proximal stump to reach the distal stump. Methods A review of the literature was used to provide information on the components necessary for the development of a tissue engineered peripheral nerve substitute. Then, a comprehensive review of the literature is presented composed of the studies devoted to this goal. Results Extensive research has been directed toward the development of a tissue engineered peripheral nerve substitute to act as a bridge for regenerating axons from the proximal nerve stump seeking the distal nerve. Ideally this nerve substitute would consist of a scaffold component that mimics the extracellular matrix of the peripheral nerve and a cellular component that serves to stimulate and support regenerating peripheral nerve axons. Conclusions The field of tissue engineering should consider its challenge to not only meet the autograft “gold standard” but also to understand what drives and inhibits nerve regeneration in order to surpass the results of an autograft. PMID:24385980

  3. Tissue engineering and regenerative medicine: concepts for clinical application.

    PubMed

    Atala, Anthony

    2004-01-01

    Patients suffering from diseased and injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs that is worsening yearly given the aging population. Scientists in the field of regenerative medicine and tissue engineering apply the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Therapeutic cloning, where the nucleus from a donor cell is transferred into an enucleated oocyte in order to extract pluripotent embryonic stem cells, offers a potentially limitless source of cells for tissue engineering applications. The stem cell field is also advancing rapidly, opening new options for therapy. This paper reviews recent advances that have occurred in regenerative medicine and describes applications of these new technologies that may offer novel therapies for patients with end-stage organ failure. PMID:15256042

  4. Tissue engineering: from research to dental clinics

    PubMed Central

    Rosa, Vinicius; Bona, Alvaro Della; Cavalcanti, Bruno Neves; Nör, Jacques Eduardo

    2013-01-01

    Tissue engineering is an interdisciplinary field that combines the principles of engineering, material and biological sciences toward the development of therapeutic strategies and biological substitutes that restore, maintain, replace or improve biological functions. The association of biomaterials, stem cells, growth and differentiation factors have yielded the development of new treatment opportunities in most of the biomedical areas, including Dentistry. The objective of this paper is to present the principles underlying tissue engineering and the current scenario, the challenges and the perspectives of this area in Dentistry. Significance The growth of tissue engineering as a research field have provided a novel set of therapeutic strategies for biomedical applications. The emerging knowledge arisen from studies in the dental area may translate into new methods for caring or improving the alternatives used to treat patients in the daily clinic. PMID:22240278

  5. Advanced General Aviation Turbine Engine (GATE) study

    NASA Technical Reports Server (NTRS)

    Smith, R.; Benstein, E. H.

    1979-01-01

    The small engine technology requirements suitable for general aviation service in the 1987 to 1988 time frame were defined. The market analysis showed potential United States engines sales of 31,500 per year providing that the turbine engine sales price approaches current reciprocating engine prices. An optimum engine design was prepared for four categories of fixed wing aircraft and for rotary wing applications. A common core approach was derived from the optimum engines that maximizes engine commonality over the power spectrum with a projected price competitive with reciprocating piston engines. The advanced technology features reduced engine cost, approximately 50 percent compared with current technology.

  6. Engineering complex orthopaedic tissues via strategic biomimicry.

    PubMed

    Qu, Dovina; Mosher, Christopher Z; Boushell, Margaret K; Lu, Helen H

    2015-03-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, wherein overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g., bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g., bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g., bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  7. Engineering Complex Orthopaedic Tissues via Strategic Biomimicry

    PubMed Central

    Qu, Dovina; Mosher, Christopher Z.; Boushell, Margaret K.; Lu, Helen H.

    2014-01-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, whereby overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g. bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g. bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g. bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  8. Genetically Engineered Immunotherapy for Advanced Cancer

    Cancer.gov

    In this trial, doctors will collect T lymphocytes from patients with advanced mesothelin-expressing cancer and genetically engineer them to recognize mesothelin. The gene-engineered cells will be multiplied and infused into the patient to fight the cancer

  9. New engine and advanced component design

    SciTech Connect

    Not Available

    1990-01-01

    This book contains the proceedings on new engine and advance component design. Topics covered include: development of low emission high performance four valve engines, the effect of engine build options on powerplant inertias, silicon nitride turbocharger rotor for high performance automotive engines and development of Toyota reflex Burn (TRB) system in DI diesel.

  10. New Era in Health Care: Tissue Engineering

    PubMed Central

    Parveen, S; Krishnakumar, K; Sahoo, SK

    2006-01-01

    Abstract Tissue engineering is a rapidly expanding field, which applies the principles and methods of physical sciences, life sciences and engineering to understand physiological and pathological systems and to modify and create cells and tissues for therapeutic applications. It has emerged as a rapidly expanding ‘interdisciplinary field’ that is a significant potential alternative wherein tissue and organ failure is addressed by implanting natural, synthetic, or semi synthetic tissue or organ mimics that grow into the required functionality or that are fully functional from the start. This review presents in a comprehensive manner the various considerations for the reconstruction of various tissues and organs as well as the various applications of this young emerging field in different disciplines. PMID:24692857

  11. The potential impact of bone tissue engineering in the clinic.

    PubMed

    Mishra, Ruchi; Bishop, Tyler; Valerio, Ian L; Fisher, John P; Dean, David

    2016-09-01

    Bone tissue engineering (BTE) intends to restore structural support for movement and mineral homeostasis, and assist in hematopoiesis and the protective functions of bone in traumatic, degenerative, cancer, or congenital malformation. While much effort has been put into BTE, very little of this research has been translated to the clinic. In this review, we discuss current regenerative medicine and restorative strategies that utilize tissue engineering approaches to address bone defects within a clinical setting. These approaches involve the primary components of tissue engineering: cells, growth factors and biomaterials discussed briefly in light of their clinical relevance. This review also presents upcoming advanced approaches for BTE applications and suggests a probable workpath for translation from the laboratory to the clinic. PMID:27549369

  12. Programmed electronic advance for engines

    SciTech Connect

    Dogadko, P.

    1987-03-03

    An ignition advance control is described for an internal combustion engine including a crankshaft, a throttle control, and at least one cylinder, the ignition advance control comprising a spark ignition circuit associated with the cylinder and including trigger means operative to cause an ignition spark, means for generating a control pulse associated with the cylinder, latch means for enabling the trigger means in response to generation of the control pulse, means for generating a constant plurality of sequentially occurring electrical reference pulses during each revolution of the crankshaft, means for counting the reference pulses developed during each revolution of the crankshaft, means for firing the enabled trigger means in response to the counting means counting a predetermined number of the reference pulses to cause the ignition spark at a predetermined ignition point in each revolution of the crankshaft, means for sensing the position of the throttle control, and means responsive to the throttle sensing means for varying the predetermined number of reference pulses solely in accordance with the position of the throttle control to vary the predetermined ignition point as appropriate for the position of the throttle control.

  13. Bioreactors for connective tissue engineering: design and monitoring innovations.

    PubMed

    El Haj, A J; Hampson, K; Gogniat, G

    2009-01-01

    The challenges for the tissue engineering of connective tissue lie in creating off-the-shelf tissue constructs which are capable of providing organs for transplantation. These strategies aim to grow a complex tissue with the appropriate mechanical integrity necessary for functional load bearing. Monolayer culture systems lack correlation with the in vivo environment and the naturally occur ring cell phenotypes. Part of the development of more recent models is to create growth environments or bioreactors which enable three-dimensional culture. Evidence suggests that in order to grow functional load-bearing tissues in a bioreactor, the cells must experience mechanical loading stimuli similar to that experienced in vivo which sets out the requirements for mechanical loading bioreactors. An essential part of developing new bioreactors for tissue growth is identifying ways of routinely and continuously measuring neo-tissue formation and in order to fully identify the successful generation of a tissue implant, the appropriate on-line monitoring must be developed. New technologies are being developed to advance our efforts to grow tissue ex vivo. The bioreactor is a critical part of these developments in supporting growth of biological implants and combining this with new advances in the detection of tissue formation allows us to refine our protocols and move nearer to off-the-shelf implants for clinical applications. PMID:19290498

  14. Bioreactors for Connective Tissue Engineering: Design and Monitoring Innovations

    NASA Astrophysics Data System (ADS)

    Haj, A. J. El; Hampson, K.; Gogniat, G.

    The challenges for the tissue engineering of connective tissue lie in creating off-the-shelf tissue constructs which are capable of providing organs for transplantation. These strategies aim to grow a complex tissue with the appropri ate mechanical integrity necessary for functional load bearing. Monolayer culture systems lack correlation with the in vivo environment and the naturally occur ring cell phenotypes. Part of the development of more recent models is to create growth environments or bioreactors which enable three-dimensional culture. Evidence suggests that in order to grow functional load-bearing tissues in a bioreactor, the cells must experience mechanical loading stimuli similar to that experienced in vivo which sets out the requirements for mechanical loading bioreactors. An essential part of developing new bioreactors for tissue growth is identifying ways of routinely and continuously measuring neo-tissue formation and in order to fully identify the successful generation of a tissue implant, the appropriate on-line monitoring must be developed. New technologies are being developed to advance our efforts to grow tissue ex vivo. The bioreactor is a critical part of these develop ments in supporting growth of biological implants and combining this with new advances in the detection of tissue formation allows us to refine our protocols and move nearer to off-the-shelf implants for clinical applications.

  15. Engineering Superficial Zone Features in Tissue Engineered Cartilage

    PubMed Central

    Chen, Tony; Hilton, Matthew J.; Brown, Edward B.; Zuscik, Michael J.; Awad, Hani A.

    2013-01-01

    A major challenge in cartilage tissue engineering is the need to recreate the native tissue's anisotropic extracellular matrix structure. This anisotropy has important mechanical and biological consequences and could be crucial for integrative repair. Here we report that hydrodynamic conditions that mimic the motion-induced flow fields in between the articular surfaces in the synovial joint induce the formation of a distinct superficial layer in tissue engineered cartilage hydrogels, with enhanced production of cartilage matrix proteoglycan and type II collagen. Moreover, the flow stimulation at the surface induces the production of the surface zone protein Proteoglycan 4 (aka PRG4 or lubricin). Analysis of second harmonic generation signature of collagen in this superficial layer reveals a highly aligned fibrillar matrix that resembles the alignment pattern in native tissue's surface zone, suggesting that mimicking synovial fluid flow at the cartilage surface in hydrodynamic bioreactors could be key to creating engineered cartilage with superficial zone features. PMID:23239161

  16. Systemic Therapy for Advanced Soft Tissue Sarcoma.

    PubMed

    Sheng, Jennifer Y; Movva, Sujana

    2016-10-01

    Soft tissue sarcomas are rare tumors that present with distant metastasis in up to 10% of patients. Survival has improved significantly because of advancements in histologic classification and improved management approaches. Older agents such as doxorubicin, ifosfamide, gemcitabine, and paclitaxel continue to demonstrate objective response rates from 18% to 25%. Newer agents such as trabectedin, eribulin, aldoxorubicin, and olaratumab have demonstrated improvements in progression-free survival, overall survival, or toxicity profiles. Future studies on treatment of advanced soft tissue sarcoma will continue to concentrate on reducing toxicity, personalization of therapy, and targeting novel pathways. PMID:27542647

  17. Growing Tissues in Real and Simulated Microgravity: New Methods for Tissue Engineering

    PubMed Central

    Wehland, Markus; Pietsch, Jessica; Aleshcheva, Ganna; Wise, Petra; van Loon, Jack; Ulbrich, Claudia; Magnusson, Nils E.; Infanger, Manfred; Bauer, Johann

    2014-01-01

    Tissue engineering in simulated (s-) and real microgravity (r-μg) is currently a topic in Space medicine contributing to biomedical sciences and their applications on Earth. The principal aim of this review is to highlight the advances and accomplishments in the field of tissue engineering that could be achieved by culturing cells in Space or by devices created to simulate microgravity on Earth. Understanding the biology of three-dimensional (3D) multicellular structures is very important for a more complete appreciation of in vivo tissue function and advancing in vitro tissue engineering efforts. Various cells exposed to r-μg in Space or to s-μg created by a random positioning machine, a 2D-clinostat, or a rotating wall vessel bioreactor grew in the form of 3D tissues. Hence, these methods represent a new strategy for tissue engineering of a variety of tissues, such as regenerated cartilage, artificial vessel constructs, and other organ tissues as well as multicellular cancer spheroids. These aggregates are used to study molecular mechanisms involved in angiogenesis, cancer development, and biology and for pharmacological testing of, for example, chemotherapeutic drugs or inhibitors of neoangiogenesis. Moreover, they are useful for studying multicellular responses in toxicology and radiation biology, or for performing coculture experiments. The future will show whether these tissue-engineered constructs can be used for medical transplantations. Unveiling the mechanisms of microgravity-dependent molecular and cellular changes is an up-to-date requirement for improving Space medicine and developing new treatment strategies that can be translated to in vivo models while reducing the use of laboratory animals. PMID:24597549

  18. Growing tissues in real and simulated microgravity: new methods for tissue engineering.

    PubMed

    Grimm, Daniela; Wehland, Markus; Pietsch, Jessica; Aleshcheva, Ganna; Wise, Petra; van Loon, Jack; Ulbrich, Claudia; Magnusson, Nils E; Infanger, Manfred; Bauer, Johann

    2014-12-01

    Tissue engineering in simulated (s-) and real microgravity (r-μg) is currently a topic in Space medicine contributing to biomedical sciences and their applications on Earth. The principal aim of this review is to highlight the advances and accomplishments in the field of tissue engineering that could be achieved by culturing cells in Space or by devices created to simulate microgravity on Earth. Understanding the biology of three-dimensional (3D) multicellular structures is very important for a more complete appreciation of in vivo tissue function and advancing in vitro tissue engineering efforts. Various cells exposed to r-μg in Space or to s-μg created by a random positioning machine, a 2D-clinostat, or a rotating wall vessel bioreactor grew in the form of 3D tissues. Hence, these methods represent a new strategy for tissue engineering of a variety of tissues, such as regenerated cartilage, artificial vessel constructs, and other organ tissues as well as multicellular cancer spheroids. These aggregates are used to study molecular mechanisms involved in angiogenesis, cancer development, and biology and for pharmacological testing of, for example, chemotherapeutic drugs or inhibitors of neoangiogenesis. Moreover, they are useful for studying multicellular responses in toxicology and radiation biology, or for performing coculture experiments. The future will show whether these tissue-engineered constructs can be used for medical transplantations. Unveiling the mechanisms of microgravity-dependent molecular and cellular changes is an up-to-date requirement for improving Space medicine and developing new treatment strategies that can be translated to in vivo models while reducing the use of laboratory animals. PMID:24597549

  19. The materials used in bone tissue engineering

    SciTech Connect

    Tereshchenko, V. P. Kirilova, I. A.; Sadovoy, M. A.; Larionov, P. M.

    2015-11-17

    Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.

  20. The materials used in bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Tereshchenko, V. P.; Kirilova, I. A.; Sadovoy, M. A.; Larionov, P. M.

    2015-11-01

    Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.

  1. Cell Encapsulation in Biodegradable Hydrogels for Tissue Engineering Applications

    PubMed Central

    Nicodemus, Garret D.

    2008-01-01

    Abstract Encapsulating cells in biodegradable hydrogels offers numerous attractive features for tissue engineering, including ease of handling, a highly hydrated tissue-like environment for cell and tissue growth, and the ability to form in vivo. Many properties important to the design of a hydrogel scaffold, such as swelling, mechanical properties, degradation, and diffusion, are closely linked to the crosslinked structure of the hydrogel, which is controlled through a variety of different processing conditions. Degradation may be tuned by incorporating hydrolytically or enzymatically labile segments into the hydrogel or by using natural biopolymers that are susceptible to enzymatic degradation. Because cells are present during the gelation process, the number of suitable chemistries and formulations are limited. In this review, we describe important considerations for designing biodegradable hydrogels for cell encapsulation and highlight recent advances in material design and their applications in tissue engineering. PMID:18498217

  2. Nanostructured Biomaterials for Tissue Engineered Bone Tissue Reconstruction

    PubMed Central

    Chiara, Gardin; Letizia, Ferroni; Lorenzo, Favero; Edoardo, Stellini; Diego, Stomaci; Stefano, Sivolella; Eriberto, Bressan; Barbara, Zavan

    2012-01-01

    Bone tissue engineering strategies are emerging as attractive alternatives to autografts and allografts in bone tissue reconstruction, in particular thanks to their association with nanotechnologies. Nanostructured biomaterials, indeed, mimic the extracellular matrix (ECM) of the natural bone, creating an artificial microenvironment that promotes cell adhesion, proliferation and differentiation. At the same time, the possibility to easily isolate mesenchymal stem cells (MSCs) from different adult tissues together with their multi-lineage differentiation potential makes them an interesting tool in the field of bone tissue engineering. This review gives an overview of the most promising nanostructured biomaterials, used alone or in combination with MSCs, which could in future be employed as bone substitutes. Recent works indicate that composite scaffolds made of ceramics/metals or ceramics/polymers are undoubtedly more effective than the single counterparts in terms of osteoconductivity, osteogenicity and osteoinductivity. A better understanding of the interactions between MSCs and nanostructured biomaterials will surely contribute to the progress of bone tissue engineering. PMID:22312283

  3. Composite tissue engineering on polycaprolactone nanofiber scaffolds.

    PubMed

    Reed, Courtney R; Han, Li; Andrady, Anthony; Caballero, Montserrat; Jack, Megan C; Collins, James B; Saba, Salim C; Loboa, Elizabeth G; Cairns, Bruce A; van Aalst, John A

    2009-05-01

    Tissue engineering has largely focused on single tissue-type reconstruction (such as bone); however, the basic unit of healing in any clinically relevant scenario is a compound tissue type (such as bone, periosteum, and skin). Nanofibers are submicron fibrils that mimic the extracellular matrix, promoting cellular adhesion, proliferation, and migration. Stem cell manipulation on nanofiber scaffolds holds significant promise for future tissue engineering. This work represents our initial efforts to create the building blocks for composite tissue reflecting the basic unit of healing. Polycaprolactone (PCL) nanofibers were electrospun using standard techniques. Human foreskin fibroblasts, murine keratinocytes, and periosteal cells (4-mm punch biopsy) harvested from children undergoing palate repair were grown in appropriate media on PCL nanofibers. Human fat-derived mesenchymal stem cells were osteoinduced on PCL nanofibers. Cell growth was assessed with fluorescent viability staining; cocultured cells were differentiated using antibodies to fibroblast- and keratinocyte-specific surface markers. Osteoinduction was assessed with Alizarin red S. PCL nanofiber scaffolds supported robust growth of fibroblasts, keratinocytes, and periosteal cells. Cocultured periosteal cells (with fibroblasts) and keratinocytes showed improved longevity of the keratinocytes, though growth of these cell types was randomly distributed throughout the scaffold. Robust osteoinduction was noted on PCL nanofibers. Composite tissue engineering using PCL nanofiber scaffolds is possible, though the major obstacles to the trilaminar construct are maintaining an appropriate interface between the tissue types and neovascularization of the composite structure. PMID:19387150

  4. Application of polarization OCT in tissue engineering

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Ahearne, Mark; Bagnaninchi, Pierre O.; Hu, Bin; Hampson, Karen; El Haj, Alicia J.

    2008-02-01

    For tissue engineering of load-bearing tissues, such as bone, tendon, cartilage, and cornea, it is critical to generate a highly organized extracellular matrix. The major component of the matrix in these tissues is collagen, which usually forms a highly hierarchical structure with increasing scale from fibril to fiber bundles. These bundles are ordered into a 3D network to withstand forces such as tensile, compressive or shear. To induce the formation of organized matrix and create a mimic body environment for tissue engineering, in particular, tendon tissue engineering, we have fabricated scaffolds with features to support the formation of uniaxially orientated collagen bundles. In addition, mechanical stimuli were applied to stimulate tissue formation and matrix organization. In parallel, we seek a nondestructive tool to monitor the changes within the constructs in response to these external stimulations. Polarizationsensitive optical coherence tomography (PSOCT) is a non-destructive technique that provides functional imaging, and possesses the ability to assess in depth the organization of tissue. In this way, an engineered tissue construct can be monitored on-line, and correlated with the application of different stimuli by PSOCT. We have constructed a PSOCT using a superluminescent diode (FWHM 52nm) in this study and produced two types of tendon constructs. The matrix structural evolution under different mechanical stimulation has been evaluated by the PSOCT. The results in this study demonstrate that PSOCT was a powerful tool enabling us to monitor non-destructively and real time the progressive changes in matrix organization and assess the impact of various stimuli on tissue orientation and growth.

  5. Tissue Engineered Strategies for Pseudoarthrosis

    PubMed Central

    Longo, Umile Giuseppe; Trovato, Ugo; Loppini, Mattia; Rizzello, Giacomo; Khan, Wasim Sardar; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Numerous classification systems of non-union have been proposed based on: presence or absence of infection, radiographic features, clinical findings, biologic activity, location and shape. The management of pseudarthrosis is strongly related to the type of non-union (infected versus uninfected, atrophic versus hypertrophic). Surgical management of pseudarthrosis is generally effective with a success rate ranging from 75 to 100%. Nevertheless, in a relatively high number of instances several combined treatments are required for the fracture healing. The current gold standard to stimulate the bone regeneration is represented by the revision surgery with the application of autologous bone grafts. However, several approaches have been described to promote and enhance the bone tissue regeneration, including extracorporeal shock wave therapy (ESWT), ultrasound, electromagnetic, bone morphogenic proteins (BMPs) and platelet-rich-plasma (PRP). The aim of the present study was to perform a systematic review of the literature evaluating the current therapies to promote and enhance the bone tissue healing. The systematic review was performed according to PRISMA guidelines with a PRISMA checklist and algorithm. Limitations of the present systematic review are mainly related to the scanty quality of the studies available in the literature. Although the therapies previously described for the management of patients with non-unions seems to be effective, the limitations of the included studies, especially the extensive clinical heterogeneity, make not possible to provide clear recommendations regarding the application of these approaches. The problems remain the need to better understand the most effective treatment options, subject to surgical stabilization as a first step. PMID:23248729

  6. Stem Cell-based Tissue Engineering Approaches for Musculoskeletal Regeneration

    PubMed Central

    Brown, Patrick T.; Handorf, Andrew M.; Jeon, Won Bae; Li, Wan-Ju

    2014-01-01

    The field of regenerative medicine and tissue engineering is an ever evolving field that holds promise in treating numerous musculoskeletal diseases and injuries. An important impetus in the development of the field was the discovery and implementation of stem cells. The utilization of mesenchymal stem cells, and later embryonic and induced pluripotent stem cells, opens new arenas for tissue engineering and presents the potential of developing stem cell-based therapies for disease treatment. Multipotent and pluripotent stem cells can produce various lineage tissues, and allow for derivation of a tissue that may be comprised of multiple cell types. As the field grows, the combination of biomaterial scaffolds and bioreactors provides methods to create an environment for stem cells that better represent their microenvironment for new tissue formation. As technologies for the fabrication of biomaterial scaffolds advance, the ability of scaffolds to modulate stem cell behavior advances as well. The composition of scaffolds could be of natural or synthetic materials and could be tailored to enhance cell self-renewal and/or direct cell fates. In addition to biomaterial scaffolds, studies of tissue development and cellular microenvironments have determined other factors, such as growth factors and oxygen tension, that are crucial to the regulation of stem cell activity. The overarching goal of stem cell-based tissue engineering research is to precisely control differentiation of stem cells in culture. In this article, we review current developments in tissue engineering, focusing on several stem cell sources, induction factors including growth factors, oxygen tension, biomaterials, and mechanical stimulation, and the internal and external regulatory mechanisms that govern proliferation and differentiation. PMID:23432679

  7. Airway tissue engineering for congenital laryngotracheal disease.

    PubMed

    Maughan, Elizabeth; Lesage, Flore; Butler, Colin R; Hynds, Robert E; Hewitt, Richard; Janes, Sam M; Deprest, Jan A; Coppi, Paolo De

    2016-06-01

    Regenerative medicine offers hope of a sustainable solution for severe airway disease by the creation of functional, immunocompatible organ replacements. When considering fetuses and newborns, there is a specific spectrum of airway pathologies that could benefit from cell therapy and tissue engineering applications. While hypoplastic lungs associated with congenital diaphragmatic hernia (CDH) could benefit from cellular based treatments aimed at ameliorating lung function, patients with upper airway obstruction could take advantage from a de novo tissue engineering approach. Moreover, the international acceptance of the EXIT procedure as a means of securing the precarious neonatal airway, together with the advent of fetal surgery as a method of heading off postnatal co-morbidities, offers the revolutionary possibility of extending the clinical indication for tissue-engineered airway transplantation to infants affected by diverse severe congenital laryngotracheal malformations. This article outlines the necessary basic components for regenerative medicine solutions in this potential clinical niche. PMID:27301606

  8. Extracellular Matrix Revisited: Roles in Tissue Engineering

    PubMed Central

    2016-01-01

    The extracellular matrix (ECM) is a heterogeneous, connective network composed of fibrous glycoproteins that coordinate in vivo to provide the physical scaffolding, mechanical stability, and biochemical cues necessary for tissue morphogenesis and homeostasis. This review highlights some of the recently raised aspects of the roles of the ECM as related to the fields of biophysics and biomedical engineering. Fundamental aspects of focus include the role of the ECM as a basic cellular structure, for novel spontaneous network formation, as an ideal scaffold in tissue engineering, and its essential contribution to cell sheet technology. As these technologies move from the laboratory to clinical practice, they are bound to shape the vast field of tissue engineering for medical transplantations. PMID:27230457

  9. Update in Facial Nerve Paralysis: Tissue engineering and new technologies

    PubMed Central

    Langhals, Nicholas B.; Urbanchek, Melanie G.; Ray, Amrita; Brenner, Michael J.

    2014-01-01

    Purpose of review To present recent advances in treatment of facial paralysis, emphasizing emerging technologies. This review will summarize the current state of the art in the management of facial paralysis and discuss advances in nerve regeneration, facial reanimation, and use of novel biomaterials. The review includes surgical innovations in re-innervation and reanimation as well as progress with bioelectrical interfaces. Recent Findings The past decade has witnessed major advances in understanding of nerve injury and approaches for management. Key innovations include strategies to accelerate nerve regeneration, provide tissue-engineered constructs that may replace nonfunctional nerves, approaches to influence axonal guidance, limiting of donor-site morbidity, and optimization of functional outcomes. Approaches to muscle transfer continue to evolve, and new technologies allow for electrical nerve stimulation and use of artificial tissues. Summary The fields of biomedical engineering and facial reanimation increasingly intersect, with innovative surgical approaches complementing a growing array of tissue engineering tools. The goal of treatment remains the predictable restoration of natural facial movement, with acceptable morbidity and long-term stability. Advances in bioelectrical interfaces and nanotechnology hold promise for widening the window for successful treatment intervention and for restoring both lost neural inputs and muscle function. PMID:24979369

  10. Electrical stimulation systems for cardiac tissue engineering

    PubMed Central

    Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

    2009-01-01

    We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures. PMID:19180087

  11. Mechanostimulation Protocols for Cardiac Tissue Engineering

    PubMed Central

    Govoni, Marco; Muscari, Claudio; Guarnieri, Carlo; Giordano, Emanuele

    2013-01-01

    Owing to the inability of self-replacement by a damaged myocardium, alternative strategies to heart transplantation have been explored within the last decades and cardiac tissue engineering/regenerative medicine is among the present challenges in biomedical research. Hopefully, several studies witness the constant extension of the toolbox available to engineer a fully functional, contractile, and robust cardiac tissue using different combinations of cells, template bioscaffolds, and biophysical stimuli obtained by the use of specific bioreactors. Mechanical forces influence the growth and shape of every tissue in our body generating changes in intracellular biochemistry and gene expression. That is why bioreactors play a central role in the task of regenerating a complex tissue such as the myocardium. In the last fifteen years a large number of dynamic culture devices have been developed and many results have been collected. The aim of this brief review is to resume in a single streamlined paper the state of the art in this field. PMID:23936858

  12. Bioactive polymers for cardiac tissue engineering

    NASA Astrophysics Data System (ADS)

    Wall, Samuel Thomas

    2007-05-01

    Prevalent in the US and worldwide, acute myocardial infarctions (AMI) can cause ischemic injuries to the heart that persist and lead to progressive degradation of the organ. Tissue engineering techniques exploiting biomaterials present a hopeful means of treating these injuries, either by mechanically stabilizing the injured ventricle, or by fostering cell growth to replace myocytes lost to damage. This thesis describes the development and testing of a synthetic extracellular matrix for cardiac tissue engineering applications. The first stage of this process was using an advanced finite element model of an injured ovine left ventricle to evaluate the potential benefits of injecting synthetic materials into the heart. These simulations indicated that addition of small amounts non-contractile material (on the order of 1--5% total wall volume) to infarct border zone regions reduced pathological systolic fiber stress to levels near those found in normal remote regions. Simulations also determined that direct addition to the infarct itself caused increases in ventricle ejection fraction while the underlying performance of the pump, ascertained by the Starling relation, was not improved. From these theoretical results, biomaterials were developed specifically for injection into the injured myocardium, and were characterized and tested for their mechanical properties and ability to sustain the proliferation of a stem cell population suitable for transplantation. Thermoresponsive synthetic copolymer hydrogels consisting of N-isopropylacrylamide and acrylic acid, p(NIPAAm-co-AAc), crosslinked with protease degradable amino acid sequences and modified with integrin binding ligands were synthesized, characterized in vitro, and used for myocardial implantation. These injectable materials could maintain a population of bone marrow derived mesenchymal stem cells in both two dimensional and three dimensional culture, and when tested in vivo in a murine infarct model they

  13. Biomechanics of engineered heart valve tissues.

    PubMed

    Sacks, Michael S

    2006-01-01

    The vast majority of prosthetic valve designs are either mechanical prosthesis and bioprosthetic heart valves (BHV). Mechanical prostheses are fabricated from synthetic materials, mainly pyrolytic carbon leaflets mounted in a titanium frame. Tissue engineering (TE) offers the potential to create cardiac replacement structures containing living cells, which has the potential for growth and remodeling, overcoming the limitations of current pediatric heart valve devices. The purpose of this paper is to present a review of the structure-strength relationships for native and engineered heart valve tissues. PMID:17946864

  14. Bone mechanobiology, gravity and tissue engineering: effects and insights.

    PubMed

    Ruggiu, Alessandra; Cancedda, Ranieri

    2015-12-01

    Bone homeostasis strongly depends on fine tuned mechanosensitive regulation signals from environmental forces into biochemical responses. Similar to the ageing process, during spaceflights an altered mechanotransduction occurs as a result of the effects of bone unloading, eventually leading to loss of functional tissue. Although spaceflights represent the best environment to investigate near-zero gravity effects, there are major limitations for setting up experimental analysis. A more feasible approach to analyse the effects of reduced mechanostimulation on the bone is represented by the 'simulated microgravity' experiments based on: (1) in vitro studies, involving cell cultures studies and the use of bioreactors with tissue engineering approaches; (2) in vivo studies, based on animal models; and (3) direct analysis on human beings, as in the case of the bed rest tests. At present, advanced tissue engineering methods allow investigators to recreate bone microenvironment in vitro for mechanobiology studies. This group and others have generated tissue 'organoids' to mimic in vitro the in vivo bone environment and to study the alteration cells can go through when subjected to unloading. Understanding the molecular mechanisms underlying the bone tissue response to mechanostimuli will help developing new strategies to prevent loss of tissue caused by altered mechanotransduction, as well as identifying new approaches for the treatment of diseases via drug testing. This review focuses on the effects of reduced gravity on bone mechanobiology by providing the up-to-date and state of the art on the available data by drawing a parallel with the suitable tissue engineering systems. PMID:25052837

  15. BIOMIMETIC GRADIENT HYDROGELS FOR TISSUE ENGINEERING

    PubMed Central

    Sant, Shilpa; Hancock, Matthew J.; Donnelly, Joseph P.; Iyer, Dharini; Khademhosseini, Ali

    2011-01-01

    During tissue morphogenesis and homeostasis, cells experience various signals in their environments, including gradients of physical and chemical cues. Spatial and temporal gradients regulate various cell behaviours such as proliferation, migration, and differentiation during development, inflammation, wound healing, and cancer. One of the goals of functional tissue engineering is to create microenvironments that mimic the cellular and tissue complexity found in vivo by incorporating physical, chemical, temporal, and spatial gradients within engineered three-dimensional (3D) scaffolds. Hydrogels are ideal materials for 3D tissue scaffolds that mimic the extracellular matrix (ECM). Various techniques from material science, microscale engineering, and microfluidics are used to synthesise biomimetic hydrogels with encapsulated cells and tailored microenvironments. In particular, a host of methods exist to incorporate micrometer to centimetre scale chemical and physical gradients within hydrogels to mimic the cellular cues found in vivo. In this review, we draw on specific biological examples to motivate hydrogel gradients as tools for studying cell–material interactions. We provide a brief overview of techniques to generate gradient hydrogels and showcase their use to study particular cell behaviours in two-dimensional (2D) and 3D environments. We conclude by summarizing the current and future trends in gradient hydrogels and cell–material interactions in context with the long-term goals of tissue engineering. PMID:21874065

  16. Recombinant protein scaffolds for tissue engineering.

    PubMed

    Werkmeister, Jerome A; Ramshaw, John A M

    2012-02-01

    New biological materials for tissue engineering are now being developed using common genetic engineering capabilities to clone and express a variety of genetic elements that allow cost-effective purification and scaffold fabrication from these recombinant proteins, peptides or from chimeric combinations of these. The field is limitless as long as the gene sequences are known. The utility is dependent on the ease, product yield and adaptability of these protein products to the biomedical field. The development of recombinant proteins as scaffolds, while still an emerging technology with respect to commercial products, is scientifically superior to current use of natural materials or synthetic polymer scaffolds, in terms of designing specific structures with desired degrees of biological complexities and motifs. In the field of tissue engineering, next generation scaffolds will be the key to directing appropriate tissue regeneration. The initial period of biodegradable synthetic scaffolds that provided shape and mechanical integrity, but no biological information, is phasing out. The era of protein scaffolds offers distinct advantages, particularly with the combination of powerful tools of molecular biology. These include, for example, the production of human proteins of uniform quality that are free of infectious agents and the ability to make suitable quantities of proteins that are found in low quantity or are hard to isolate from tissue. For the particular needs of tissue engineering scaffolds, fibrous proteins like collagens, elastin, silks and combinations of these offer further advantages of natural well-defined structural scaffolds as well as endless possibilities of controlling functionality by genetic manipulation. PMID:22262725

  17. Tissue engineering and regenerative medicine: manufacturing challenges.

    PubMed

    Williams, D J; Sebastine, I M

    2005-12-01

    Tissue engineering and regenerative medicine are interdisciplinary fields that apply principles of engineering and life sciences to develop biological substitutes, typically composed of biological and synthetic components, that restore, maintain or improve tissue function. Many tissue engineering technologies are still at a laboratory or pre-commercial scale. The short review paper describes the most significant manufacturing and bio-process challenges inherent in the commercialisation and exploitation of the exciting results emerging from the biological and clinical laboratories exploring tissue engineering and regenerative medicine. A three-generation road map of the industry has been used to structure a view of these challenges and to define where the manufacturing community can contribute to the commercial success of the products from these emerging fields. The first-generation industry is characterised by its demonstrated clinical applications and products in the marketplace, the second is characterised by emerging clinical applications, and the third generation is characterised by aspirational clinical applications. The paper focuses on the cost reduction requirement of the first generation of the industry to allow more market penetration and consequent patient impact. It indicates the technological requirements, for instance the creation of three-dimensional tissue structures, and value chain issues in the second generation of the industry. The third-generation industry challenges lie in fundamental biological and clinical science. The paper sets out a road map of these generations to identify areas for research. PMID:16441181

  18. BIOMIMETIC GRADIENT HYDROGELS FOR TISSUE ENGINEERING.

    PubMed

    Sant, Shilpa; Hancock, Matthew J; Donnelly, Joseph P; Iyer, Dharini; Khademhosseini, Ali

    2010-12-01

    During tissue morphogenesis and homeostasis, cells experience various signals in their environments, including gradients of physical and chemical cues. Spatial and temporal gradients regulate various cell behaviours such as proliferation, migration, and differentiation during development, inflammation, wound healing, and cancer. One of the goals of functional tissue engineering is to create microenvironments that mimic the cellular and tissue complexity found in vivo by incorporating physical, chemical, temporal, and spatial gradients within engineered three-dimensional (3D) scaffolds. Hydrogels are ideal materials for 3D tissue scaffolds that mimic the extracellular matrix (ECM). Various techniques from material science, microscale engineering, and microfluidics are used to synthesise biomimetic hydrogels with encapsulated cells and tailored microenvironments. In particular, a host of methods exist to incorporate micrometer to centimetre scale chemical and physical gradients within hydrogels to mimic the cellular cues found in vivo. In this review, we draw on specific biological examples to motivate hydrogel gradients as tools for studying cell-material interactions. We provide a brief overview of techniques to generate gradient hydrogels and showcase their use to study particular cell behaviours in two-dimensional (2D) and 3D environments. We conclude by summarizing the current and future trends in gradient hydrogels and cell-material interactions in context with the long-term goals of tissue engineering. PMID:21874065

  19. MicroRNAs in skin tissue engineering.

    PubMed

    Miller, Kyle J; Brown, David A; Ibrahim, Mohamed M; Ramchal, Talisha D; Levinson, Howard

    2015-07-01

    35.2 million annual cases in the U.S. require clinical intervention for major skin loss. To meet this demand, the field of skin tissue engineering has grown rapidly over the past 40 years. Traditionally, skin tissue engineering relies on the "cell-scaffold-signal" approach, whereby isolated cells are formulated into a three-dimensional substrate matrix, or scaffold, and exposed to the proper molecular, physical, and/or electrical signals to encourage growth and differentiation. However, clinically available bioengineered skin equivalents (BSEs) suffer from a number of drawbacks, including time required to generate autologous BSEs, poor allogeneic BSE survival, and physical limitations such as mass transfer issues. Additionally, different types of skin wounds require different BSE designs. MicroRNA has recently emerged as a new and exciting field of RNA interference that can overcome the barriers of BSE design. MicroRNA can regulate cellular behavior, change the bioactive milieu of the skin, and be delivered to skin tissue in a number of ways. While it is still in its infancy, the use of microRNAs in skin tissue engineering offers the opportunity to both enhance and expand a field for which there is still a vast unmet clinical need. Here we give a review of skin tissue engineering, focusing on the important cellular processes, bioactive mediators, and scaffolds. We further discuss potential microRNA targets for each individual component, and we conclude with possible future applications. PMID:25953499

  20. Peptide Amphiphiles in Corneal Tissue Engineering

    PubMed Central

    Miotto, Martina; Gouveia, Ricardo M.; Connon, Che J.

    2015-01-01

    The increasing interest in effort towards creating alternative therapies have led to exciting breakthroughs in the attempt to bio-fabricate and engineer live tissues. This has been particularly evident in the development of new approaches applied to reconstruct corneal tissue. The need for tissue-engineered corneas is largely a response to the shortage of donor tissue and the lack of suitable alternative biological scaffolds preventing the treatment of millions of blind people worldwide. This review is focused on recent developments in corneal tissue engineering, specifically on the use of self-assembling peptide amphiphiles for this purpose. Recently, peptide amphiphiles have generated great interest as therapeutic molecules, both in vitro and in vivo. Here we introduce this rapidly developing field, and examine innovative applications of peptide amphiphiles to create natural bio-prosthetic corneal tissue in vitro. The advantages of peptide amphiphiles over other biomaterials, namely their wide range of functions and applications, versatility, and transferability are also discussed to better understand how these fascinating molecules can help solve current challenges in corneal regeneration. PMID:26258796

  1. Articular cartilage: from formation to tissue engineering.

    PubMed

    Camarero-Espinosa, Sandra; Rothen-Rutishauser, Barbara; Foster, E Johan; Weder, Christoph

    2016-05-26

    Hyaline cartilage is the nonlinear, inhomogeneous, anisotropic, poro-viscoelastic connective tissue that serves as friction-reducing and load-bearing cushion in synovial joints and is vital for mammalian skeletal movements. Due to its avascular nature, low cell density, low proliferative activity and the tendency of chondrocytes to de-differentiate, cartilage cannot regenerate after injury, wear and tear, or degeneration through common diseases such as osteoarthritis. Therefore severe damage usually requires surgical intervention. Current clinical strategies to generate new tissue include debridement, microfracture, autologous chondrocyte transplantation, and mosaicplasty. While articular cartilage was predicted to be one of the first tissues to be successfully engineered, it proved to be challenging to reproduce the complex architecture and biomechanical properties of the native tissue. Despite significant research efforts, only a limited number of studies have evolved up to the clinical trial stage. This review article summarizes the current state of cartilage tissue engineering in the context of relevant biological aspects, such as the formation and growth of hyaline cartilage, its composition, structure and biomechanical properties. Special attention is given to materials development, scaffold designs, fabrication methods, and template-cell interactions, which are of great importance to the structure and functionality of the engineered tissue. PMID:26923076

  2. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based scaffolds for tissue engineering

    PubMed Central

    Chang, H.M.; Wang, Z.H.; Luo, H.N.; Xu, M.; Ren, X.Y.; Zheng, G.X.; Wu, B.J.; Zhang, X.H.; Lu, X.Y.; Chen, F.; Jing, X.H.; Wang, L.

    2014-01-01

    Development and selection of an ideal scaffold is of importance for tissue engineering. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biocompatible bioresorbable copolymer that belongs to the polyhydroxyalkanoate family. Because of its good biocompatibility, PHBHHx has been widely used as a cell scaffold for tissue engineering. This review focuses on the utilization of PHBHHx-based scaffolds in tissue engineering. Advances in the preparation, modification, and application of PHBHHx scaffolds are discussed. PMID:25003631

  3. Stem cells and scaffolds for vascularizing engineered tissue constructs.

    PubMed

    Luong, E; Gerecht, S

    2009-01-01

    The clinical impact of tissue engineering depends upon our ability to direct cells to form tissues with characteristic structural and mechanical properties from the molecular level up to organized tissue. Induction and creation of functional vascular networks has been one of the main goals of tissue engineering either in vitro, for the transplantation of prevascularized constructs, or in vivo, for cellular organization within the implantation site. In most cases, tissue engineering attempts to recapitulate certain aspects of normal development in order to stimulate cell differentiation and functional tissue assembly. The induction of tissue growth generally involves the use of biodegradable and bioactive materials designed, ideally, to provide a mechanical, physical, and biochemical template for tissue regeneration. Human embryonic stem cells (hESCs), derived from the inner cell mass of a developing blastocyst, are capable of differentiating into all cell types of the body. Specifically, hESCs have the capability to differentiate and form blood vessels de novo in a process called vasculogenesis. Human ESC-derived endothelial progenitor cells (EPCs) and endothelial cells have substantial potential for microvessel formation, in vitro and in vivo. Human adult EPCs are being isolated to understand the fundamental biology of how these cells are regulated as a population and to explore whether these cells can be differentiated and reimplanted as a cellular therapy in order to arrest or even reverse damaged vasculature. This chapter focuses on advances made toward the generation and engineering of functional vascular tissue, focusing on both the scaffolds - the synthetic and biopolymer materials - and the cell sources - hESCs and hEPCs. PMID:19082932

  4. Stem Cells and Scaffolds for Vascularizing Engineered Tissue Constructs

    NASA Astrophysics Data System (ADS)

    Luong, E.; Gerecht, S.

    The clinical impact of tissue engineering depends upon our ability to direct cells to form tissues with characteristic structural and mechanical properties from the molecular level up to organized tissue. Induction and creation of functional vascular networks has been one of the main goals of tissue engineering either in vitro, for the transplantation of prevascularized constructs, or in vivo, for cellular organization within the implantation site. In most cases, tissue engineering attempts to recapitulate certain aspects of normal development in order to stimulate cell differentiation and functional tissue assembly. The induction of tissue growth generally involves the use of biodegradable and bioactive materials designed, ideally, to provide a mechanical, physical, and biochemical template for tissue regeneration. Human embryonic stem cells (hESCs), derived from the inner cell mass of a developing blastocyst, are capable of differentiating into all cell types of the body. Specifically, hESCs have the capability to differentiate and form blood vessels de novo in a process called vasculogenesis. Human ESC-derived endothelial progenitor cells (EPCs) and endothelial cells have substantial potential for microvessel formation, in vitro and in vivo. Human adult EPCs are being isolated to understand the fundamental biology of how these cells are regulated as a population and to explore whether these cells can be differentiated and reimplanted as a cellular therapy in order to arrest or even reverse damaged vasculature. This chapter focuses on advances made toward the generation and engineering of functional vascular tissue, focusing on both the scaffolds - the synthetic and biopolymer materials - and the cell sources - hESCs and hEPCs.

  5. Outlook for Tissue Engineering of the Tympanic Membrane.

    PubMed

    Villar-Fernandez, Maria A; Lopez-Escamez, Jose A

    2015-01-21

    Tympanic membrane perforation is a common problem leading to hearing loss. Despite the autoregenerative activity of the eardrum, chronic perforations require surgery using different materials, from autologous tissue - fascia, cartilage, fat or perichondrium - to paper patch. However, both, surgical procedures (myringoplasty or tympanoplasty) and the materials employed, have a number of limitations. Therefore, the advances in this field are incorporating the principles of tissue engineering, which includes the use of scaffolds, biomolecules and cells. This discipline allows the development of new biocompatible materials that reproduce the structure and mechanical properties of the native tympanic membrane, while it seeks to implement new therapeutic approaches that can be performed in an outpatient setting. Moreover, the creation of an artificial tympanic membrane commercially available would reduce the duration of the surgery and costs. The present review analyzes the current treatment of tympanic perforations and examines the techniques of tissue engineering, either to develop bioartificial constructs, or for tympanic regeneration by using different scaffold materials, bioactive molecules and cells. Finally, it considers the aspects regarding the design of scaffolds, release of biomolecules and use of cells that must be taken into account in the tissue engineering of the eardrum. The possibility of developing new biomaterials, as well as constructs commercially available, makes tissue engineering a discipline with great potential, capable of overcoming the drawbacks of current surgical procedures. PMID:26557361

  6. Outlook for Tissue Engineering of the Tympanic Membrane

    PubMed Central

    Villar-Fernandez, Maria A.; Lopez-Escamez, Jose A.

    2015-01-01

    Tympanic membrane perforation is a common problem leading to hearing loss. Despite the autoregenerative activity of the eardrum, chronic perforations require surgery using different materials, from autologous tissue - fascia, cartilage, fat or perichondrium - to paper patch. However, both, surgical procedures (myringoplasty or tympanoplasty) and the materials employed, have a number of limitations. Therefore, the advances in this field are incorporating the principles of tissue engineering, which includes the use of scaffolds, biomolecules and cells. This discipline allows the development of new biocompatible materials that reproduce the structure and mechanical properties of the native tympanic membrane, while it seeks to implement new therapeutic approaches that can be performed in an outpatient setting. Moreover, the creation of an artificial tympanic membrane commercially available would reduce the duration of the surgery and costs. The present review analyzes the current treatment of tympanic perforations and examines the techniques of tissue engineering, either to develop bioartificial constructs, or for tympanic regeneration by using different scaffold materials, bioactive molecules and cells. Finally, it considers the aspects regarding the design of scaffolds, release of biomolecules and use of cells that must be taken into account in the tissue engineering of the eardrum. The possibility of developing new biomaterials, as well as constructs commercially available, makes tissue engineering a discipline with great potential, capable of overcoming the drawbacks of current surgical procedures. PMID:26557361

  7. Dentin Matrix Proteins in Bone Tissue Engineering

    PubMed Central

    Ravindran, Sriram

    2016-01-01

    Dentin and bone are mineralized tissue matrices comprised of collagen fibrils and reinforced with oriented crystalline hydroxyapatite. Although both tissues perform different functionalities, they are assembled and orchestrated by mesenchymal cells that synthesize both collagenous and noncollagenous proteins albeit in different proportions. The dentin matrix proteins (DMPs) have been studied in great detail in recent years due to its inherent calcium binding properties in the extracellular matrix resulting in tissue calcification. Recent studies have shown that these proteins can serve both as intracellular signaling proteins leading to induction of stem cell differentiation and also function as nucleating proteins in the extracellular matrix. These properties make the DMPs attractive candidates for bone and dentin tissue regeneration. This chapter will provide an overview of the DMPs, their functionality and their proven and possible applications with respect to bone tissue engineering. PMID:26545748

  8. Variable cycle engines for advanced supersonic transports

    NASA Technical Reports Server (NTRS)

    Howlett, R. A.; Kozlowski, H.

    1975-01-01

    Variable Cycle Engines being studied for advanced commercial supersonic transports show potential for significant environmental and economic improvements relative to 1st generation SST engines. The two most promising concepts are: a Variable Stream Control Engine and a Variable Cycle Engine with a rear flow-control valve. Each concept utilizes variable components and separate burners to provide independent temperature and velocity control for two coannular flow streams. Unique fuel control techniques are combined with cycle characteristics that provide low fuel consumption, similar to a turbojet engine, for supersonic operation. This is accomplished while retaining the good subsonic performance features of a turbofan engine. A two-stream coannular nozzle shows potential to reduce jet noise to below FAR Part 36 without suppressors. Advanced burner concepts have the potential for significant reductions in exhaust emissions. In total, these unique engine concepts have the potential for significant overall improvements to the environmental and economic characteristics of advanced supersonic transports.

  9. Stem cells used for cardiovascular tissue engineering.

    PubMed

    Siepe, Matthias; Akhyari, Payam; Lichtenberg, Artur; Schlensak, Christian; Beyersdorf, Friedhelm

    2008-08-01

    Stem cell research and tissue engineering have become leading fields in basic research worldwide. Especially in cardiovascular medicine, initial reports on the potential of using stem cells to recover cardiac function and replace organ subunits such as heart valves seemed to offer the promise of widespread clinical use in the near future. However, the broad application of this new therapy failed due to safety and efficacy concerns. Due in part to the initial reports, major basic research efforts were undertaken to explore the specific cell types in greater detail and identify their mechanisms of supporting function, resulting in remarkable new findings in stem cell biology. For example, the notion of resident human cardiac stem cells has disproved the earlier supposition that the human heart is a finitely differentiated organ without the intrinsic potential for regeneration. Furthermore, new technologies emerged to produce pluripotent cells without the ethical and immunological drawbacks of embryonic stem cells (for instance by nuclear transfer). Other autologous cell sources are presently under investigation in myocardial tissue engineering. For tissue engineering of heart valves and small calibre vessels, the use of autologous endothelial (precursor) cells may be the optimal means of seeding a biological or artificial scaffold. It is important that ongoing basic and clinical research in cardiovascular surgery might explore the potential of different cell types either using tissue engineering constructs or in cell transplantation approaches. PMID:18468449

  10. Cell–scaffold interaction within engineered tissue

    SciTech Connect

    Chen, Haiping; Liu, Yuanyuan Jiang, Zhenglong; Chen, Weihua; Yu, Yongzhe; Hu, Qingxi

    2014-05-01

    The structure of a tissue engineering scaffold plays an important role in modulating tissue growth. A novel gelatin–chitosan (Gel–Cs) scaffold with a unique structure produced by three-dimensional printing (3DP) technology combining with vacuum freeze-drying has been developed for tissue-engineering applications. The scaffold composed of overall construction, micro-pore, surface morphology, and effective mechanical property. Such a structure meets the essential design criteria of an ideal engineered scaffold. The favorable cell–matrix interaction supports the active biocompatibility of the structure. The structure is capable of supporting cell attachment and proliferation. Cells seeded into this structure tend to maintain phenotypic shape and secreted large amounts of extracellular matrix (ECM) and the cell growth decreased the mechanical properties of scaffold. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique structure, which acts to support cell growth. - Highlights: • The scaffold is not only for providing a surface for cell residence but also for determining cell phenotype and retaining structural integrity. • The mechanical property of scaffold can be affected by activities of cell. • The scaffold provides a microenvironment for cell attachment, growth, and migration.

  11. Tailored Carbon Nanotubes for Tissue Engineering Applications

    PubMed Central

    Veetil, Jithesh V.; Ye, Kaiming

    2008-01-01

    A decade of aggressive researches on carbon nanotubes (CNTs) has paved way for extending these unique nanomaterials into a wide range of applications. In the relatively new arena of nanobiotechnology, a vast majority of applications are based on CNTs, ranging from miniaturized biosensors to organ regeneration. Nevertheless, the complexity of biological systems poses a significant challenge in developing CNT-based tissue engineering applications. This review focuses on the recent developments of CNT-based tissue engineering, where the interaction between living cells/tissues and the nanotubes have been transformed into a variety of novel techniques. This integration has already resulted in a revaluation of tissue engineering and organ regeneration techniques. Some of the new treatments that were not possible previously become reachable now. Because of the advent of surface chemistry, the CNT’s biocompatibility has been significantly improved, making it possible to serve as tissue scaffolding materials to enhance the organ regeneration. The superior mechanic strength and chemical inert also makes it ideal for blood compatible applications, especially for cardiopulmonary bypass surgery. The applications of CNTs in these cardiovascular surgeries led to a remarkable improvement in mechanical strength of implanted catheters and reduced thrombogenecity after surgery. Moreover, the functionalized CNTs have been extensively explored for in vivo targeted drug or gene delivery, which could potentially improve the efficiency of many cancer treatments. However, just like other nanomaterials, the cytotoxicity of CNTs has not been well established. Hence, more extensive cytotoxic studies are warranted while converting the hydrophobic CNTs into biocompatible nanomaterials. PMID:19496152

  12. Injectable Biomaterials for Adipose Tissue Engineering

    PubMed Central

    Young, D. Adam; Christman, Karen L.

    2012-01-01

    Adipose tissue engineering has recently gained significant attention from materials scientists as a result of the exponential growth of soft tissue filler procedures being performed within the clinic. While several injectable materials are currently being marketed for filling subcutaneous voids, they often face limited longevity due to rapid resorption. Their inability to encourage natural adipose formation or ingrowth necessitates repeated injections for a prolonged effect, and thus classifies them as temporary fillers. As a result, a significant need for injectable materials that not only act as fillers, but also promote in vivo adipogenesis is beginning to be realized. This review will discuss the advantages and disadvantages of commercially available soft tissue fillers. It will then summarize the current state of research using injectable synthetic materials, biopolymers, and extracellular matrix-derived materials for adipose tissue engineering. Furthermore, the successful attributes observed across each of these materials will be outlined along with a discussion of the current difficulties and future directions for adipose tissue engineering. PMID:22456805

  13. Vascularization in bone tissue engineering constructs

    PubMed Central

    Mercado-Pagán, Ángel E.; Stahl, Alexander M.; Shanjani, Yaser; Yang, Yunzhi

    2016-01-01

    Vascularization of large bone grafts is one of the main challenges of bone tissue engineering (BTE), and has held back the clinical translation of engineered bone constructs for two decades so far. The ultimate goal of vascularized BTE constructs is to provide a bone environment rich in functional vascular networks to achieve efficient osseointegration and accelerate restoration of function after implantation. To attain both structural and vascular integration of the grafts, a large number of biomaterials, cells, and biological cues have been evaluated. This review will present biological considerations for bone function restoration, contemporary approaches for clinical salvage of large bone defects and their limitations, state-of-the-art research on the development of vascularized bone constructs, and perspectives on evaluating and implementing novel BTE grafts in clinical practice. Success will depend on achieving full graft integration at multiple hierarchical levels, both between the individual graft components as well as between the implanted constructs and their surrounding host tissues. The paradigm of vascularized tissue constructs could not only revolutionize the progress of bone tissue engineering, but could also be readily applied to other fields in regenerative medicine for the development of new innovative vascularized tissue designs. PMID:25616591

  14. Esophageal tissue engineering: Current status and perspectives.

    PubMed

    Poghosyan, T; Catry, J; Luong-Nguyen, M; Bruneval, P; Domet, T; Arakelian, L; Sfeir, R; Michaud, L; Vanneaux, V; Gottrand, F; Larghero, J; Cattan, P

    2016-02-01

    Tissue engineering, which consists of the combination and in vivo implantation of elements required for tissue remodeling toward a specific organ phenotype, could be an alternative for classical techniques of esophageal replacement. The current hybrid approach entails creation of an esophageal substitute composed of an acellular matrix and autologous epithelial and muscle cells provides the most successful results. Current research is based on the use of mesenchymal stem cells, whose potential for differentiation and proangioogenic, immune-modulator and anti-inflammatory properties are important assets. In the near future, esophageal substitutes could be constructed from acellular "intelligent matrices" that contain the molecules necessary for tissue regeneration; this should allow circumvention of the implantation step and still obtain standardized in vivo biological responses. At present, tissue engineering applications to esophageal replacement are limited to enlargement plasties with absorbable, non-cellular matrices. Nevertheless, the application of existing clinical techniques for replacement of other organs by tissue engineering in combination with a multiplication of translational research protocols for esophageal replacement in large animals should soon pave the way for health agencies to authorize clinical trials. PMID:26711880

  15. Tissue engineering and regenerative medicine in applied research: a year in review of 2014.

    PubMed

    Lin, Xunxun; Huang, Jia; Shi, Yuan; Liu, Wei

    2015-04-01

    Tissue engineering and regenerative medicine (TERM) remains to be one of the fastest growing fields, which covers a wide scope of topics of both basic and applied biological researches. This overview article summarized the advancements in applied researches of TERM area, including stem cell-mediated tissue regeneration, material science, and TERM clinical trial. These achievements demonstrated the great potential of clinical regenerative therapy of tissue/organ disease or defect through stem cells and tissue engineering approaches. PMID:25588683

  16. Tissue Engineering by Intrinsic Vascularization in an In Vivo Tissue Engineering Chamber.

    PubMed

    Zhan, Weiqing; Marre, Diego; Mitchell, Geraldine M; Morrison, Wayne A; Lim, Shiang Y

    2016-01-01

    In reconstructive surgery, there is a clinical need for an alternative to the current methods of autologous reconstruction which are complex, costly and trade one defect for another. Tissue engineering holds the promise to address this increasing demand. However, most tissue engineering strategies fail to generate stable and functional tissue substitutes because of poor vascularization. This paper focuses on an in vivo tissue engineering chamber model of intrinsic vascularization where a perfused artery and a vein either as an arteriovenous loop or a flow-through pedicle configuration is directed inside a protected hollow chamber. In this chamber-based system angiogenic sprouting occurs from the arteriovenous vessels and this system attracts ischemic and inflammatory driven endogenous cell migration which gradually fills the chamber space with fibro-vascular tissue. Exogenous cell/matrix implantation at the time of chamber construction enhances cell survival and determines specificity of the engineered tissues which develop. Our studies have shown that this chamber model can successfully generate different tissues such as fat, cardiac muscle, liver and others. However, modifications and refinements are required to ensure target tissue formation is consistent and reproducible. This article describes a standardized protocol for the fabrication of two different vascularized tissue engineering chamber models in vivo. PMID:27286267

  17. Chitosan-based scaffolds for bone tissue engineering

    PubMed Central

    Levengood, Sheeny Lan; Zhang, Miqin

    2014-01-01

    Bone defects requiring grafts to promote healing are frequently occurring and costly problems in health care. Chitosan, a biodegradable, naturally occurring polymer, has drawn considerable attention in recent years as scaffolding material in tissue engineering and regenerative medicine. Chitosan is especially attractive as a bone scaffold material because it supports the attachment and proliferation of osteoblast cells as well as formation of mineralized bone matrix. In this review, we discuss the fundamentals of bone tissue engineering and the unique properties of chitosan as a scaffolding material to treat bone defects for hard tissue regeneration. We present the common methods for fabrication and characterization of chitosan scaffolds, and discuss the influence of material preparation and addition of polymeric or ceramic components or biomolecules on chitosan scaffold properties such as mechanical strength, structural integrity, and functional bone regeneration. Finally, we highlight recent advances in development of chitosan-based scaffolds with enhanced bone regeneration capability. PMID:24999429

  18. Tissue Engineering and Regenerative Repair in Wound Healing

    PubMed Central

    Hu, Michael S.; Maan, Zeshaan N.; Wu, Jen-Chieh; Rennert, Robert C.; Hong, Wan Xing; Lai, Tiffany S.; Cheung, Alexander T. M.; Walmsley, Graham G.; Chung, Michael T.; McArdle, Adrian; Longaker, Michael T.; Lorenz, H. Peter

    2014-01-01

    Wound healing is a highly evolved defense mechanism against infection and further injury. It is a complex process involving multiple cell types and biological pathways. Mammalian adult cutaneous wound healing is mediated by a fibroproliferative response leading to scar formation. In contrast, early to mid-gestational fetal cutaneous wound healing is more akin to regeneration and occurs without scar formation. This early observation has led to extensive research seeking to unlock the mechanism underlying fetal scarless regenerative repair. Building upon recent advances in biomaterials and stem cell applications, tissue engineering approaches are working towards a recapitulation of this phenomenon. In this review, we describe the elements that distinguish fetal scarless and adult scarring wound healing, and discuss current trends in tissue engineering aimed at achieving scarless tissue regeneration. PMID:24788648

  19. [Cell sources for cardiovascular tissue engineering].

    PubMed

    Klopsch, C; Donndorf, P; Kaminski, A; Ma, N; Steinhoff, G

    2011-04-01

    Numerous studies have confirmed that stem cell therapy has significant potential for the regeneration of congenital and acquired heart diseases. The utilization of embryonic stem cells and induced pluripotent stem cells promises a possible generation and regeneration of all cardiovascular structures. On the one hand fetal and adult stem cells, e.g. endothelial progenitors, mesenchymal, hematopoietic, cardiac stem cells and myoblasts, possess limited potential for multilinear differentiation. On the other hand these cells have high paracrin activity and support with well-confirmed safety the reconstruction and formation of cardiovascular structures. On the visionary track towards an autonomously functioning autologous heart generated by tissue engineering, vascular, valvular and myocardial tissues have already been successfully created. This manuscript describes the possible stem cell sources for cardiovascular tissue engineering and evaluates their potency and safety from a medical and ethical point of view employing the data from systematic reviews (Medline database) and own investigations. PMID:21424292

  20. Tissue Engineered Airways: A Prospects Article.

    PubMed

    Bogan, Stephanie L; Teoh, Gui Zhen; Birchall, Martin A

    2016-07-01

    An ideal tracheal scaffold must withstand luminal collapse yet be flexible, have a sufficient degree of porosity to permit vascular and cellular ingrowth, but also be airtight and must facilitate growth of functional airway epithelium to avoid infection and aid in mucocilliary clearance. Finally, the scaffold must also be biocompatible to avoid implant rejection. Over the last 40 years, efforts to design and manufacture the airway have been undertaken worldwide but success has been limited and far apart. As a result, tracheal resection with primary repair remains the Gold Standard of care for patients presenting with airway disorders and malignancies. However, the maximum resectable length of the trachea is restricted to 30% of the total length in children or 50% in adults. Attempts to provide autologous grafts for human application have also been disappointing for a host of different reasons, including lack of implant integration, insufficient donor organs, and poor mechanical strength resulting in an unmet clinical need. The two main approaches researchers have taken to address this issue have been the development of synthetic scaffolds and the use of decellularized organs. To date, a number of different decellularization techniques and a variety of materials, including polyglycolic acid (PGA) and nanocomposite polymers have been explored. The findings thus far have shown great promise, however, there remain a significant number of caveats accompanying each approach. That being said, the possibilities presented by these two approaches could be combined to produce a highly successful, clinically viable hybrid scaffold. This article aims to highlight advances in airway tissue engineering and provide an overview of areas to explore and utilize in accomplishing the aim of developing an ideal tracheal prosthesis. J. Cell. Biochem. 117: 1497-1505, 2016. © 2016 Wiley Periodicals, Inc. PMID:26853803

  1. Ocular tissue engineering: current and future directions.

    PubMed

    Karamichos, D

    2015-01-01

    Tissue engineering (TE) is a concept that was first emerged in the early 1990s to provide solutions to severe injured tissues and/or organs [1]. The dream was to be able to restore and replace the damaged tissue with an engineered version which would ultimately help overcome problems such as donor shortages, graft rejections, and inflammatory responses following transplantation. While an incredible amount of progress has been made, suggesting that TE concept is viable, we are still not able to overcome major obstacles. In TE, there are two main strategies that researchers have adopted: (1) cell-based, where cells are been manipulated to create their own environment before transplanted to the host, and (2) scaffold-based, where an extracellular matrix is created to mimic in vivo structures. TE approaches for ocular tissues are available and have indeed come a long way, over the last decades; however more clinically relevant ocular tissue substitutes are needed. Figure 1 highlights the importance of TE in ocular applications and indicates the avenues available based on each tissue.[...]. PMID:25695336

  2. Development of multilayer constructs for tissue engineering.

    PubMed

    Bettahalli, N M S; Groen, N; Steg, H; Unadkat, H; de Boer, J; van Blitterswijk, C A; Wessling, M; Stamatialis, D

    2014-02-01

    The rapidly developing field of tissue engineering produces living substitutes that restore, maintain or improve the function of tissues or organs. In contrast to standard therapies, the engineered products become integrated within the patient, affording a potentially permanent and specific cure of the disease, injury or impairment. Despite the great progress in the field, development of clinically relevantly sized tissues with complex architecture remains a great challenge. This is mostly due to limitations of nutrient and oxygen delivery to the cells and limited availability of scaffolds that can mimic the complex tissue architecture. This study presents the development of a multilayer tissue construct by rolling pre-seeded electrospun sheets [(prepared from poly (l-lactic acid) (PLLA) seeded with C2C12 pre-myoblast cells)] around a porous multibore hollow fibre (HF) membrane and its testing using a bioreactor. Important elements of this study are: 1) the medium permeating through the porous walls of multibore HF acts as an additional source of nutrients and oxygen to the cells, which exerts low shear stress (controllable by trans membrane pressure); 2) application of dynamic perfusion through the HF lumen and around the 3D construct to achieve high cell proliferation and homogenous cell distribution across the layers, and 3) cell migration occurs within the multilayer construct (shown using pre-labeled C2C12 cells), illustrating the potential of using this concept for developing thick and more complex tissues. PMID:22499264

  3. Periodontal tissue engineering strategies based on nonoral stem cells.

    PubMed

    Requicha, João Filipe; Viegas, Carlos Alberto; Muñoz, Fernando; Reis, Rui Luís; Gomes, Manuela Estima

    2014-01-01

    Periodontal disease is an inflammatory disease which constitutes an important health problem in humans due to its enormous prevalence and life threatening implications on systemic health. Routine standard periodontal treatments include gingival flaps, root planning, application of growth/differentiation factors or filler materials and guided tissue regeneration. However, these treatments have come short on achieving regeneration ad integrum of the periodontium, mainly due to the presence of tissues from different embryonic origins and their complex interactions along the regenerative process. Tissue engineering (TE) aims to regenerate damaged tissue by providing the repair site with a suitable scaffold seeded with sufficient undifferentiated cells and, thus, constitutes a valuable alternative to current therapies for the treatment of periodontal defects. Stem cells from oral and dental origin are known to have potential to regenerate these tissues. Nevertheless, harvesting cells from these sites implies a significant local tissue morbidity and low cell yield, as compared to other anatomical sources of adult multipotent stem cells. This manuscript reviews studies describing the use of non-oral stem cells in tissue engineering strategies, highlighting the importance and potential of these alternative stem cells sources in the development of advanced therapies for periodontal regeneration. PMID:24293355

  4. Engineered whole organs and complex tissues.

    PubMed

    Badylak, Stephen F; Weiss, Daniel J; Caplan, Arthur; Macchiarini, Paolo

    2012-03-10

    End-stage organ failure is a key challenge for the medical community because of the ageing population and the severe shortage of suitable donor organs available. Equally, injuries to or congenital absence of complex tissues such as the trachea, oesophagus, or skeletal muscle have few therapeutic options. A new approach to treatment involves the use of three-dimensional biological scaffolds made of allogeneic or xenogeneic extracellular matrix derived from non-autologous sources. These scaffolds can act as an inductive template for functional tissue and organ reconstruction after recellularisation with autologous stem cells or differentiated cells. Such an approach has been used successfully for the repair and reconstruction of several complex tissues such as trachea, oesophagus, and skeletal muscle in animal models and human beings, and, guided by appropriate scientific and ethical oversight, could serve as a platform for the engineering of whole organs and other tissues. PMID:22405797

  5. Engineering visualization utilizing advanced animation

    NASA Technical Reports Server (NTRS)

    Sabionski, Gunter R.; Robinson, Thomas L., Jr.

    1989-01-01

    Engineering visualization is the use of computer graphics to depict engineering analysis and simulation in visual form from project planning through documentation. Graphics displays let engineers see data represented dynamically which permits the quick evaluation of results. The current state of graphics hardware and software generally allows the creation of two types of 3D graphics. The use of animated video as an engineering visualization tool is presented. The engineering, animation, and videography aspects of animated video production are each discussed. Specific issues include the integration of staffing expertise, hardware, software, and the various production processes. A detailed explanation of the animation process reveals the capabilities of this unique engineering visualization method. Automation of animation and video production processes are covered and future directions are proposed.

  6. 3D printing of functional biomaterials for tissue engineering.

    PubMed

    Zhu, Wei; Ma, Xuanyi; Gou, Maling; Mei, Deqing; Zhang, Kang; Chen, Shaochen

    2016-08-01

    3D printing is emerging as a powerful tool for tissue engineering by enabling 3D cell culture within complex 3D biomimetic architectures. This review discusses the prevailing 3D printing techniques and their most recent applications in building tissue constructs. The work associated with relatively well-known inkjet and extrusion-based bioprinting is presented with the latest advances in the fields. Emphasis is put on introducing two relatively new light-assisted bioprinting techniques, including digital light processing (DLP)-based bioprinting and laser based two photon polymerization (TPP) bioprinting. 3D bioprinting of vasculature network is particularly discussed for its foremost significance in maintaining tissue viability and promoting functional maturation. Limitations to current bioprinting approaches, as well as future directions of bioprinting functional tissues are also discussed. PMID:27043763

  7. Cell sheet approach for tissue engineering and regenerative medicine.

    PubMed

    Matsuura, Katsuhisa; Utoh, Rie; Nagase, Kenichi; Okano, Teruo

    2014-09-28

    After the biotech medicine era, regenerative medicine is expected to be an advanced medicine that is capable of curing patients with difficult-to-treat diseases and physically impaired function. Our original scaffold-free cell sheet-based tissue engineering technology enables transplanted cells to be engrafted for a long time, while fully maintaining their viability. This technology has already been applied to various diseases in the clinical setting, including the cornea, esophagus, heart, periodontal ligament, and cartilage using autologous cells. Transplanted cell sheets not only replace the injured tissue and compensate for impaired function, but also deliver growth factors and cytokines in a spatiotemporal manner over a prolonged period, which leads to promotion of tissue repair. Moreover, the integration of stem cell biology and cell sheet technology with sufficient vascularization opens possibilities for fabrication of human three-dimensional vascularized dense and intact tissue grafts for regenerative medicine to parenchymal organs. PMID:24858800

  8. Cardiac tissue engineering in magnetically actuated scaffolds

    NASA Astrophysics Data System (ADS)

    Sapir, Yulia; Polyak, Boris; Cohen, Smadar

    2014-01-01

    Cardiac tissue engineering offers new possibilities for the functional and structural restoration of damaged or lost heart tissue by applying cardiac patches created in vitro. Engineering such functional cardiac patches is a complex mission, involving material design on the nano- and microscale as well as the application of biological cues and stimulation patterns to promote cell survival and organization into a functional cardiac tissue. Herein, we present a novel strategy for creating a functional cardiac patch by combining the use of a macroporous alginate scaffold impregnated with magnetically responsive nanoparticles (MNPs) and the application of external magnetic stimulation. Neonatal rat cardiac cells seeded within the magnetically responsive scaffolds and stimulated by an alternating magnetic field of 5 Hz developed into matured myocardial tissue characterized by anisotropically organized striated cardiac fibers, which preserved its features for longer times than non-stimulated constructs. A greater activation of AKT phosphorylation in cardiac cell constructs after applying a short-term (20 min) external magnetic field indicated the efficacy of magnetic stimulation to actuate at a distance and provided a possible mechanism for its action. Our results point to a synergistic effect of magnetic field stimulation together with nanoparticulate features of the scaffold surface as providing the regenerating environment for cardiac cells driving their organization into functionally mature tissue.

  9. Multimodal evaluation of tissue-engineered cartilage.

    PubMed

    Mansour, Joseph M; Welter, Jean F

    2013-02-01

    Tissue engineering (TE) has promise as a biological solution and a disease modifying treatment for arthritis. Although cartilage can be generated by TE, substantial inter- and intra-donor variability makes it impossible to guarantee optimal, reproducible results. TE cartilage must be able to perform the functions of native tissue, thus mechanical and biological properties approaching those of native cartilage are likely a pre-requisite for successful implantation. A quality-control assessment of these properties should be part of the implantation release criteria for TE cartilage. Release criteria should certify that selected tissue properties have reached certain target ranges, and should be predictive of the likelihood of success of an implant in vivo. Unfortunately, it is not currently known which properties are needed to establish release criteria, nor how close one has to be to the properties of native cartilage to achieve success. Achieving properties approaching those of native cartilage requires a clear understanding of the target properties and reproducible assessment methodology. Here, we review several main aspects of quality control as it applies to TE cartilage. This includes a look at known mechanical and biological properties of native cartilage, which should be the target in engineered tissues. We also present an overview of the state of the art of tissue assessment, focusing on native articular and TE cartilage. Finally, we review the arguments for developing and validating non-destructive testing methods for assessing TE products. PMID:23606823

  10. Ceramic Technology for Advanced Heat Engines Project

    SciTech Connect

    Not Available

    1990-08-01

    The Ceramic Technology For Advanced Heat Engines Project was developed by the Department of Energy's Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Advanced Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the Department of Energy (DOE), National Aeronautics and Space Administration (NASA), and Department of Defense (DOD) advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The objective of the project is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on structural ceramics for advanced gas turbine and diesel engines, ceramic hearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines.

  11. Angiogenesis, cell differentiation and cell survival in tissue engineering and cancer research

    PubMed Central

    Tilkorn, Daniel Johannes

    2015-01-01

    Recent medical advances lead to a growing demand for tissue engineering and regenerative medicine in the future. Tissue engineering and regenerative medicine aim to create substitute tissue or restore lost or impaired tissue by combining biological science with engineering techniques, whereas cancer research faces the challenge to identify and hinder aberrant and uncontrolled cell growth. These two seemingly opposing fields of research share fundamental communalities. This review focuses on the shared underlying biological processes. Exploring these mechanisms of tissue growth and homeostasis from different angles will allow for creative novel approaches for both areas of research. PMID:26504737

  12. 3D Printing and Biofabrication for Load Bearing Tissue Engineering.

    PubMed

    Jeong, Claire G; Atala, Anthony

    2015-01-01

    Cell-based direct biofabrication and 3D bioprinting is becoming a dominant technological platform and is suggested as a new paradigm for twenty-first century tissue engineering. These techniques may be our next step in surpassing the hurdles and limitations of conventional scaffold-based tissue engineering, and may offer the industrial potential of tissue engineered products especially for load bearing tissues. Here we present a topically focused review regarding the fundamental concepts, state of the art, and perspectives of this new technology and field of biofabrication and 3D bioprinting, specifically focused on tissue engineering of load bearing tissues such as bone, cartilage, osteochondral and dental tissue engineering. PMID:26545741

  13. Electrospun Nanofibers for Neural and Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Xia, Younan

    2009-03-01

    Electrospinning has been exploited for almost one century to process polymers and other materials into nanofibers with controllable compositions, diameters, porosities, and porous structures for a variety of applications. Owing to its small size, high porosity, and large surface area, a nonwoven mat of electrospun nanofibers can serve as an ideal scaffold to mimic the extra cellular matrix for cell attachment and nutrient transportation. The nanofiber itself can also be functionalized through encapsulation or attachment of bioactive species such as extracellular matrix proteins, enzymes, and growth factors. In addition, the nanofibers can be further assembled into a variety of arrays or architectures by manipulating their alignment, stacking, or folding. All these attributes make electrospinning a powerful tool for generating nanostructured materials for a range of biomedical applications that include controlled release, drug delivery, and tissue engineering. This talk will focus on the use of electrospun nanofibers as scaffolds for neural and bone tissue engineering.

  14. Cardiac tissue engineering using perfusion bioreactor systems

    PubMed Central

    Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

    2009-01-01

    This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

  15. Advances in engineering science, volume 1

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Proceedings from a conference on engineering advances are presented, including materials science, fracture mechanics, and impact and vibration testing. The tensile strength and moisture transport of laminates are also discussed.

  16. Thermal Inkjet Printing in Tissue Engineering and Regenerative Medicine

    PubMed Central

    Cui, Xiaofeng; Boland, Thomas; D’Lima, Darryl D.; Lotz, Martin K.

    2013-01-01

    With the advantages of high throughput, digital control, and highly accurate placement of cells and biomaterial scaffold to the desired 2D and 3D locations, bioprinting has great potential to develop promising approaches in translational medicine and organ replacement. The most recent advances in organ and tissue bioprinting based on the thermal inkjet printing technology are described in this review. Bioprinting has no or little side effect to the printed mammalian cells and it can conveniently combine with gene transfection or drug delivery to the ejected living systems during the precise placement for tissue construction. With layer-by-layer assembly, 3D tissues with complex structures can be printed using scanned CT or MRI images. Vascular or nerve systems can be enabled simultaneously during the organ construction with digital control. Therefore, bioprinting is the only solution to solve this critical issue in thick and complex tissues fabrication with vascular system. Collectively, bioprinting based on thermal inkjet has great potential and broad applications in tissue engineering and regenerative medicine. This review article introduces some important patents related to bioprinting living systems and the bioprinting in tissue engineering field. PMID:22436025

  17. Thermal inkjet printing in tissue engineering and regenerative medicine.

    PubMed

    Cui, Xiaofeng; Boland, Thomas; D'Lima, Darryl D; Lotz, Martin K

    2012-08-01

    With the advantages of high throughput, digital control, and highly accurate placement of cells and biomaterial scaffold to the desired 2D and 3D locations, bioprinting has great potential to develop promising approaches in translational medicine and organ replacement. The most recent advances in organ and tissue bioprinting based on the thermal inkjet printing technology are described in this review. Bioprinting has no or little side effect to the printed mammalian cells and it can conveniently combine with gene transfection or drug delivery to the ejected living systems during the precise placement for tissue construction. With layer-by-layer assembly, 3D tissues with complex structures can be printed using scanned CT or MRI images. Vascular or nerve systems can be enabled simultaneously during the organ construction with digital control. Therefore, bioprinting is the only solution to solve this critical issue in thick and complex tissues fabrication with vascular system. Collectively, bioprinting based on thermal inkjet has great potential and broad applications in tissue engineering and regenerative medicine. This review article introduces some important patents related to bioprinting of living systems and the applications of bioprinting in tissue engineering field. PMID:22436025

  18. Advanced materials for aircraft engine applications.

    PubMed

    Backman, D G; Williams, J C

    1992-02-28

    A review of advances for aircraft engine structural materials and processes is presented. Improved materials, such as superalloys, and the processes for making turbine disks and blades have had a major impact on the capability of modern gas turbine engines. New structural materials, notably composites and intermetallic materials, are emerging that will eventually further enhance engine performance, reduce engine weight, and thereby enable new aircraft systems. In the future, successful aerospace manufacturers will combine product design and materials excellence with improved manufacturing methods to increase production efficiency, enhance product quality, and decrease the engine development cycle time. PMID:17817782

  19. Vascularization in bone tissue engineering constructs.

    PubMed

    Mercado-Pagán, Ángel E; Stahl, Alexander M; Shanjani, Yaser; Yang, Yunzhi

    2015-03-01

    Vascularization of large bone grafts is one of the main challenges of bone tissue engineering (BTE), and has held back the clinical translation of engineered bone constructs for two decades so far. The ultimate goal of vascularized BTE constructs is to provide a bone environment rich in functional vascular networks to achieve efficient osseointegration and accelerate restoration of function after implantation. To attain both structural and vascular integration of the grafts, a large number of biomaterials, cells, and biological cues have been evaluated. This review will present biological considerations for bone function restoration, contemporary approaches for clinical salvage of large bone defects and their limitations, state-of-the-art research on the development of vascularized bone constructs, and perspectives on evaluating and implementing novel BTE grafts in clinical practice. Success will depend on achieving full graft integration at multiple hierarchical levels, both between the individual graft components as well as between the implanted constructs and their surrounding host tissues. The paradigm of vascularized tissue constructs could not only revolutionize the progress of BTE, but could also be readily applied to other fields in regenerative medicine for the development of new innovative vascularized tissue designs. PMID:25616591

  20. Novel detergent for whole organ tissue engineering.

    PubMed

    Kawasaki, Takanori; Kirita, Yuhei; Kami, Daisuke; Kitani, Tomoya; Ozaki, Chisa; Itakura, Yoko; Toyoda, Masashi; Gojo, Satoshi

    2015-10-01

    Whole organ tissue engineering for various organs, including the heart, lung, liver, and kidney, has demonstrated promising results for end-stage organ failure. However, the sodium dodecyl sulfate (SDS)-based protocol for standard decellularization has drawbacks such as clot formation in vascularized transplantation and poor cell engraftment in recellularization procedures. Preservation of the surface milieu of extracellular matrices (ECMs) might be crucial for organ generation based on decellularization/recellularization engineering. We examined a novel detergent, sodium lauryl ether sulfate (SLES), to determine whether it could overcome the drawbacks associated with SDS using rat heart and kidney. Both organs were perfused in an antegrade fashion with either SLES or SDS. Although immunohistochemistry for collagen I, IV, laminin, and fibronectin showed similar preservation in both detergents, morphological analysis using scanning electron microscopy and an assay of glycosaminoglycan content on ECMs showed that SLES-treated tissues had better-preserved ECMs than SDS-treated tissues. Mesenteric transplantation revealed SLES did not induce significant inflammation, as opposed to SDS. Platelet adhesion to decellularized tissues was significantly reduced with SLES. Overall, SLES could replace older detergents such as SDS in the decellularization process for generation of transplantable recellularized organs. PMID:25850947

  1. Cell interactions in bone tissue engineering

    PubMed Central

    Pirraco, R P; Marques, A P; Reis, R L

    2010-01-01

    Abstract Bone fractures, where the innate regenerative bone response is compromised, represent between 4 and 8 hundred thousands of the total fracture cases, just in the United States. Bone tissue engineering (TE) brought the notion that, in cases such as those, it was preferable to boost the healing process of bone tissue instead of just adding artificial parts that could never properly replace the native tissue. However, despite the hype, bone TE so far could not live up to its promises and new bottom-up approaches are needed. The study of the cellular interactions between the cells relevant for bone biology can be of essential importance to that. In living bone, cells are in a context where communication with adjacent cells is almost permanent. Many fundamental works have been addressing these communications nonetheless, in a bone TE approach, the 3D perspective, being part of the microenvironment of a bone cell, is as crucial. Works combining the study of cell-to-cell interactions in a 3D environment are not as many as expected. Therefore, the bone TE field should not only gain knowledge from the field of fundamental Biology but also contribute for further understanding the biology of bone. In this review, a summary of the main works in the field of bone TE, aiming at studying cellular interactions in a 3D environment, and how they contributed towards the development of a functional engineered bone tissue, is presented. PMID:20050963

  2. [Tissue engineered skin and regenerative wound repair].

    PubMed

    Han, Chun-mao; Wang, Xin-gang

    2013-04-01

    Various skin defects resulting from mechanical injury, burns, chronic ulcers, and resection of tumor etc. are very common in clinic. The traditional treatment measure, such as grafting of autologous split-thickness skin remains the gold standard. However, its limitations are obvious, such as shortage of donor sites, creation of new injury, and scar formation. To realize regenerative or scarless repair of tissue defects has always been the dream of human being. The advent of tissue engineered skin (TES) provides an ideal access to tissue regeneration. After decades of development, several kinds of TES products have been developed and used in clinic, with promising effects. However, a large number of basic scientific problems regarding TES, as well as difficulties in translation of basic research to bedside should be taken into serious consideration. This article presents a comprehensive overview of strategies of construction of TES, the role of TES in regenerative wound repair, and its opportunities and challenges. PMID:23985197

  3. Oxygen Delivering Biomaterials for Tissue Engineering

    PubMed Central

    Farris, Ashley L.; Rindone, Alexandra N.; Grayson, Warren L.

    2016-01-01

    Tissue engineering (TE) has provided promising strategies for regenerating tissue defects, but few TE approaches have been translated for clinical applications. One major barrier in TE is providing adequate oxygen supply to implanted tissue scaffolds, since oxygen diffusion from surrounding vasculature in vivo is limited to the periphery of the scaffolds. Moreover, oxygen is also an important signaling molecule for controlling stem cell differentiation within TE scaffolds. Various technologies have been developed to increase oxygen delivery in vivo and enhance the effectiveness of TE strategies. Such technologies include hyperbaric oxygen therapy, perfluorocarbon- and hemoglobin-based oxygen carriers, and oxygen-generating, peroxide-based materials. Here, we provide an overview of the underlying mechanisms and how these technologies have been utilized for in vivo TE applications. Emerging technologies and future prospects for oxygen delivery in TE are also discussed to evaluate the progress of this field towards clinical translation. PMID:27453782

  4. Developing High-Frequency Quantitative Ultrasound Techniques to Characterize Three-Dimensional Engineered Tissues

    NASA Astrophysics Data System (ADS)

    Mercado, Karla Patricia E.

    Tissue engineering holds great promise for the repair or replacement of native tissues and organs. Further advancements in the fabrication of functional engineered tissues are partly dependent on developing new and improved technologies to monitor the properties of engineered tissues volumetrically, quantitatively, noninvasively, and nondestructively over time. Currently, engineered tissues are evaluated during fabrication using histology, biochemical assays, and direct mechanical tests. However, these techniques destroy tissue samples and, therefore, lack the capability for real-time, longitudinal monitoring. The research reported in this thesis developed nondestructive, noninvasive approaches to characterize the structural, biological, and mechanical properties of 3-D engineered tissues using high-frequency quantitative ultrasound and elastography technologies. A quantitative ultrasound technique, using a system-independent parameter known as the integrated backscatter coefficient (IBC), was employed to visualize and quantify structural properties of engineered tissues. Specifically, the IBC was demonstrated to estimate cell concentration and quantitatively detect differences in the microstructure of 3-D collagen hydrogels. Additionally, the feasibility of an ultrasound elastography technique called Single Tracking Location Acoustic Radiation Force Impulse (STL-ARFI) imaging was demonstrated for estimating the shear moduli of 3-D engineered tissues. High-frequency ultrasound techniques can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, these high-frequency quantitative ultrasound techniques can enable noninvasive, volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation.

  5. Lincoln Advanced Science & Engineering Reinforcement (LASER) Program.

    ERIC Educational Resources Information Center

    Williams, Willie

    The Lincoln Advanced Science and Engineering Reinforcement (LASER) Program at Lincoln University, which has recruited over 100 students for majors in technical fields, is described in this report. To date, over 70% have completed or will complete technical degrees in engineering, physics, chemistry, and computer science. Of those completing the…

  6. Advanced space engine preliminary design

    NASA Technical Reports Server (NTRS)

    Cuffe, J. P. B.; Bradie, R. E.

    1973-01-01

    A preliminary design was completed for an O2/H2, 89 kN (20,000 lb) thrust staged combustion rocket engine that has a single-bell nozzle with an overall expansion ratio of 400:1. The engine has a best estimate vacuum specific impulse of 4623.8 N-s/kg (471.5 sec) at full thrust and mixture ratio = 6.0. The engine employs gear-driven, low pressure pumps to provide low NPSH capability while individual turbine-driven, high-speed main pumps provide the system pressures required for high-chamber pressure operation. The engine design dry weight for the fixed-nozzle configuration is 206.9 kg (456.3 lb). Engine overall length is 234 cm (92.1 in.). The extendible nozzle version has a stowed length of 141.5 cm (55.7 in.). Critical technology items in the development of the engine were defined. Development program plans and their costs for development, production, operation, and flight support of the ASE were established for minimum cost and minimum time programs.

  7. Cell-Seeding Techniques in Vascular Tissue Engineering

    PubMed Central

    Villalona, Gustavo A.; Udelsman, Brooks; Duncan, Daniel R.; McGillicuddy, Edward; Sawh-Martinez, Rajendra F.; Hibino, Narutoshi; Painter, Christopher; Mirensky, Tamar; Erickson, Benjamin; Shinoka, Toshiharu

    2010-01-01

    Previous studies have demonstrated the benefits of cell seeding in the construction of tissue-engineered vascular grafts (TEVG). However, seeding methods are diverse and no method is clearly superior in either promoting seeding efficiency or improving long-term graft function. As we head into an era during which a variety of different TEVG are under investigation in clinical trials around the world, it is important to consider the regulatory issues surrounding the translation of these technologies. In this review, we summarize important advances in the field of vascular tissue engineering, with particular attention on cell-seeding techniques for TEVG development and special emphasis placed on regulatory issues concerning the clinical translation of these various methods. PMID:20085439

  8. Micro and nanotechnologies in heart valve tissue engineering.

    PubMed

    Hasan, Anwarul; Saliba, John; Pezeshgi Modarres, Hassan; Bakhaty, Ahmed; Nasajpour, Amir; Mofrad, Mohammad R K; Sanati-Nezhad, Amir

    2016-10-01

    Due to the increased morbidity and mortality resulting from heart valve diseases, there is a growing demand for off-the-shelf implantable tissue engineered heart valves (TEHVs). Despite the significant progress in recent years in improving the design and performance of TEHV constructs, viable and functional human implantable TEHV constructs have remained elusive. The recent advances in micro and nanoscale technologies including the microfabrication, nano-microfiber based scaffolds preparation, 3D cell encapsulated hydrogels preparation, microfluidic, micro-bioreactors, nano-microscale biosensors as well as the computational methods and models for simulation of biological tissues have increased the potential for realizing viable, functional and implantable TEHV constructs. In this review, we aim to present an overview of the importance and recent advances in micro and nano-scale technologies for the development of TEHV constructs. PMID:27414719

  9. Engine health monitoring: An advanced system

    NASA Technical Reports Server (NTRS)

    Dyson, R. J. E.

    1981-01-01

    The advanced propulsion monitoring system is described. The system was developed in order to fulfill a growing need for effective engine health monitoring. This need is generated by military requirements for increased performance and efficiency in more complex propulsion systems, while maintaining or improving the cost to operate. This program represents a vital technological step in the advancement of the state of the art for monitoring systems in terms of reliability, flexibility, accuracy, and provision of user oriented results. It draws heavily on the technology and control theory developed for modern, complex, electronically controlled engines and utilizes engine information which is a by-product of such a system.

  10. PROTEIN TEMPLATES IN HARD TISSUE ENGINEERING

    PubMed Central

    George, Anne; Ravindran, Sriram

    2010-01-01

    Biomineralization processes such as formation of bones and teeth require controlled mineral deposition and self-assembly into hierarchical biocomposites with unique mechanical properties. Ideal biomaterials for regeneration and repair of hard tissues must be biocompatible, possess micro and macroporosity for vascular invasion, provide surface chemistry and texture that facilitate cell attachment, proliferation, differentiation of lineage specific progenitor cells, and induce deposition of calcium phosphate mineral. To expect in-vivo like cellular response several investigators have used extracellular matrix proteins as templates to recreate in-vivo microenvironment for regeneration of hard tissues. Recently, several novel methods of designing tissue repair and restoration materials using bioinspired strategies are currently being formulated. Nanoscale structured materials can be fabricated via the spontaneous organization of self-assembling proteins to construct hierarchically organized nanomaterials. The advantage of such a method is that polypeptides can be specifically designed as building blocks incorporated with molecular recognition features and spatially distributed bioactive ligands that would provide a physiological environment for cells in-vitro and in-vivo. This is a rapidly evolving area and provides a promising platform for future development of nanostructured templates for hard tissue engineering. In this review we try to highlight the importance of proteins as templates for regeneration and repair of hard tissues as well as the potential of peptide based nanomaterials for regenerative therapies. PMID:20802848

  11. Biomaterial systems for orthopedic tissue engineering

    NASA Astrophysics Data System (ADS)

    Spoerke, Erik David

    2003-06-01

    The World Health Organization has estimated that one out of seven Americans suffers from a musculoskeletal impairment, annually incurring 28.6 million musculoskeletal injuries---more than half of all injuries. Bone tissue engineering has evolved rapidly to address this continued health concern. In the last decade, the focus of orthopedic biomaterials design has shifted from the use of common engineering metals and plastics to smart materials designed to mimic nature and elicit favorable bioresponse. Working within this new paradigm, this thesis explores unique chemical and materials systems for orthopedic tissue engineering. Improving on current titanium implant technologies, porous titanium scaffolds were utilized to better approximate the mechanical and structural properties of natural bone. These foam scaffolds were enhanced with bioactive coatings, designed to enhance osteoblastic implant colonization. The biopolymer poly(L-lysine) was incorporated into both hydroxypatite and octacalcium phosphate mineral phases to create modified organoapatite and pLys-CP coatings respectively. These coatings were synthesized and characterized on titanium surfaces, including porous structures such as titanium mesh and titanium foam. In addition, in vitro osteoblastic cell culture experiments probed the biological influences of these coatings. Organoapatite (OA) accelerated preosteoblastic colonization of titanium mesh and improved cellular ingrowth into titanium foam. Alternatively, the thin, uniform pLys-CP coating demonstrated significant potential as a substrate for chemically binding biological molecules and supramolecular assemblies. Biologically, pLys-CP demonstrated enhanced cellular attachment over titanium and inorganic calcium phosphate controls. Supramolecular self-assembled nanofiber assemblies were also explored both as stand-alone tissue engineering gels and as titanium coatings. Self-supporting nanofiber gels induced accelerated, biomimetic mineralization

  12. The Application of Tissue Engineering Procedures to Repair the Larynx

    ERIC Educational Resources Information Center

    Ringel, Robert L.; Kahane, Joel C.; Hillsamer, Peter J.; Lee, Annie S.; Badylak, Stephen F.

    2006-01-01

    The field of tissue engineering/regenerative medicine combines the quantitative principles of engineering with the principles of the life sciences toward the goal of reconstituting structurally and functionally normal tissues and organs. There has been relatively little application of tissue engineering efforts toward the organs of speech, voice,…

  13. Matrices and Scaffolds for DNA Delivery in Tissue Engineering

    PubMed Central

    De Laporte, Laura; Shea, Lonnie D.

    2007-01-01

    Regenerative medicine aims to create functional tissue replacements, typically through creating a controlled environment that promotes and directs the differentiation of stem or progenitor cells, either endogenous or transplanted. Scaffolds serve a central role in many strategies by providing the means to control the local environment. Gene delivery from the scaffold represents a versatile approach to manipulating the local environment for directing cell function. Research at the interface of biomaterials, gene therapy, and drug delivery has identified several design parameters for the vector and the biomaterial scaffold that must be satisfied. Progress has been made towards achieving gene delivery within a tissue engineering scaffold, though the design principles for the materials and vectors that produce efficient delivery require further development. Nevertheless, these advances in obtaining transgene expression with the scaffold have created opportunities to develop greater control of either delivery or expression and to identify the best practices for promoting tissue formation. Strategies to achieve controlled localized expression within the tissue engineering scaffold will have broad application to the regeneration of many tissues, with great promise for clinical therapies. PMID:17512630

  14. Latest advances in connective tissue disorders

    PubMed Central

    Rao, Vijay

    2013-01-01

    The connective tissue disorders comprise a number of related conditions that include systemic lupus erythematosus (SLE) and the antiphospholipid (Hughes) syndrome, scleroderma, myositis and Sjögren’s syndrome. They are characterized by autoantibody production and other immune-mediated dysfunction. There are common clinical and serological features with some patients having multiple overlapping connective tissue disorders. The latest advances include new approaches to therapy, including more focused utilization of existing therapies and the introduction of biological therapies in SLE, more precise protocols for assessment of severe disease manifestations such as in interstitial lung disease and pulmonary artery hypertension in scleroderma, new antibodies for disease characterization in myositis and new approaches to patient assessment in Sjögren’s syndrome. B cells have a critical role in most, if not all of these disorders such that B-cell depletion or suppression of B-cell activating cytokines improves disease in many patients. In particular, the introduction of rituximab, a monoclonal antibody targeting the CD20 molecule on B cells, into clinical practice for rheumatoid arthritis and B-cell lymphoma has been a key driver of experimental approaches to therapy in connective tissue disorders. Genetic studies also suggest a role for the innate immune system in disease pathogenesis, suggesting further future targets for biological therapies over the next few years. PMID:23904866

  15. Elastomeric PGS scaffolds in arterial tissue engineering.

    PubMed

    Lee, Kee-Won; Wang, Yadong

    2011-01-01

    Cardiovascular disease is one of the leading cause of mortality in the US and especially, coronary artery disease increases with an aging population and increasing obesity. Currently, bypass surgery using autologous vessels, allografts, and synthetic grafts are known as a commonly used for arterial substitutes. However, these grafts have limited applications when an inner diameter of arteries is less than 6 mm due to low availability, thrombotic complications, compliance mismatch, and late intimal hyperplasia. To overcome these limitations, tissue engineering has been successfully applied as a promising alternative to develop small-diameter arterial constructs that are nonthrombogenic, robust, and compliant. Several previous studies have developed small-diameter arterial constructs with tri-lamellar structure, excellent mechanical properties and burst pressure comparable to native arteries. While high tensile strength and burst pressure by increasing collagen production from a rigid material or cell sheet scaffold, these constructs still had low elastin production and compliance, which is a major problem to cause graft failure after implantation. Considering these issues, we hypothesized that an elastometric biomaterial combined with mechanical conditioning would provide elasticity and conduct mechanical signals more efficiently to vascular cells, which increase extracellular matrix production and support cellular orientation. The objective of this report is to introduce a fabrication technique of porous tubular scaffolds and a dynamic mechanical conditioning for applying them to arterial tissue engineering. We used a biodegradable elastomer, poly (glycerol sebacate) (PGS) for fabricating porous tubular scaffolds from the salt fusion method. Adult primary baboon smooth muscle cells (SMCs) were seeded on the lumen of scaffolds, which cultured in our designed pulsatile flow bioreactor for 3 weeks. PGS scaffolds had consistent thickness and randomly distributed macro

  16. Engineered Tissue Patch for Cardiac Cell Therapy

    PubMed Central

    Zhang, Jianyi

    2015-01-01

    Opinion statement Cell therapy can be administered via injections delivered directly into the myocardium or as engineered cardiac tissue patches, which are the subject of this review. Engineered cardiac patches can be created from sheets of interconnected cells or by suspending the cells in a scaffold of material that is designed to mimic the native extracellular matrix. The sheet-based approach produces patches with well-aligned and electronically coupled cardiomyocytes, but cell-containing scaffolds are more readily vascularized by the host's circulatory system and, consequently, are currently more suitable for applications that require a thicker patch. Cell patches can also be modified for the co-delivery of peptides that may promote cell survival and activate endogenous repair mechanisms; nevertheless, techniques for controlling inflammation, limiting apoptosis, and improving vascular growth need continue to be developed to make it a therapeutic modality for patients with myocardial infarction. PMID:26122908

  17. Tissue Engineering Organs for Space Biology Research

    NASA Technical Reports Server (NTRS)

    Vandenburgh, H. H.; Shansky, J.; DelTatto, M.; Lee, P.; Meir, J.

    1999-01-01

    Long-term manned space flight requires a better understanding of skeletal muscle atrophy resulting from microgravity. Atrophy most likely results from changes at both the systemic level (e.g. decreased circulating growth hormone, increased circulating glucocorticoids) and locally (e.g. decreased myofiber resting tension). Differentiated skeletal myofibers in tissue culture have provided a model system over the last decade for gaining a better understanding of the interactions of exogenous growth factors, endogenous growth factors, and muscle fiber tension in regulating protein turnover rates and muscle cell growth. Tissue engineering these cells into three dimensional bioartificial muscle (BAM) constructs has allowed us to extend their use to Space flight studies for the potential future development of countermeasures.

  18. Tissue Engineering Considerations in Dental Pulp Regeneration

    PubMed Central

    Nosrat, Ali; Kim, Jong Ryul; Verma, Prashant; S. Chand, Priya

    2014-01-01

    Regenerative endodontic procedure is introduced as a biologically based treatment for immature teeth with pulp necrosis. Successful clinical and radiographic outcomes following regenerative procedures have been reported in landmark case reports. Retrospective studies have shown that this conservative treatment allows for continued root development and increases success and survival rate of the treated teeth compared to other treatment options. Although the goal of treatment is regeneration of a functional pulp tissue, histological analyses show a different outcome. Developing predictable protocols would require the use of key elements for tissue engineering: stem cells, bioactive scaffolds, and growth factors. In this study we will review the evidence based steps and outcomes of regenerative endodontics. PMID:24396373

  19. Cryogenic 3D printing for tissue engineering.

    PubMed

    Adamkiewicz, Michal; Rubinsky, Boris

    2015-12-01

    We describe a new cryogenic 3D printing technology for freezing hydrogels, with a potential impact to tissue engineering. We show that complex frozen hydrogel structures can be generated when the 3D object is printed immersed in a liquid coolant (liquid nitrogen), whose upper surface is maintained at the same level as the highest deposited layer of the object. This novel approach ensures that the process of freezing is controlled precisely, and that already printed frozen layers remain at a constant temperature. We describe the device and present results which illustrate the potential of the new technology. PMID:26548335

  20. Myocardial tissue engineering using electrospun nanofiber composites

    PubMed Central

    Kim, Pyung-Hwan; Cho, Je-Yoel

    2016-01-01

    Emerging trends for cardiac tissue engineering are focused on increasing the biocompatibility and tissue regeneration ability of artificial heart tissue by incorporating various cell sources and bioactive molecules. Although primary cardiomyocytes can be successfully implanted, clinical applications are restricted due to their low survival rates and poor proliferation. To develop successful cardiovascular tissue regeneration systems, new technologies must be introduced to improve myocardial regeneration. Electrospinning is a simple, versatile technique for fabricating nanofibers. Here, we discuss various biodegradable polymers (natural, synthetic, and combinatorial polymers) that can be used for fiber fabrication. We also describe a series of fiber modification methods that can increase cell survival, proliferation, and migration and provide supporting mechanical properties by mimicking micro-environment structures, such as the extracellular matrix (ECM). In addition, the applications and types of nanofiber-based scaffolds for myocardial regeneration are described. Finally, fusion research methods combined with stem cells and scaffolds to improve biocompatibility are discussed. [BMB Reports 2016; 49(1): 26-36] PMID:26497579

  1. Piezoelectric polymers as biomaterials for tissue engineering applications.

    PubMed

    Ribeiro, Clarisse; Sencadas, Vítor; Correia, Daniela M; Lanceros-Méndez, Senentxu

    2015-12-01

    Tissue engineering often rely on scaffolds for supporting cell differentiation and growth. Novel paradigms for tissue engineering include the need of active or smart scaffolds in order to properly regenerate specific tissues. In particular, as electrical and electromechanical clues are among the most relevant ones in determining tissue functionality in tissues such as muscle and bone, among others, electroactive materials and, in particular, piezoelectric ones, show strong potential for novel tissue engineering strategies, in particular taking also into account the existence of these phenomena within some specific tissues, indicating their requirement also during tissue regeneration. This referee reports on piezoelectric materials used for tissue engineering applications. The most used materials for tissue engineering strategies are reported together with the main achievements, challenges and future needs for research and actual therapies. This review provides thus a compilation of the most relevant results and strategies and a start point for novel research pathways in the most relevant and challenging open questions. PMID:26355812

  2. Directed assembly of cell-laden hydrogels for engineering functional tissues

    PubMed Central

    Kachouie, Nezamoddin N; Du, Yanan; Bae, Hojae; Khabiry, Masoud; Ahari, Amirhossein F; Zamanian, Behnam; Fukuda, Junji

    2010-01-01

    Tissue engineering aims to develop functionalized tissues for organ replacement or restoration. Biodegradable scaffolds have been used in tissue engineering to support cell growth and maintain mechanical and biological properties of tissue constructs. Ideally cells on these scaffolds adhere, proliferate and deposit matrix at a rate that is consistent with scaffold degradation. However, the cellular rearrangement within these scaffolds often does not recapitulate the architecture of the native tissues. Directed assembly of tissue-like structures is an attractive alternative to scaffold-based approach for tissue engineering which potentially can build tissue constructs with biomimetic architecture and function. In directed assembly, shape-controlled microstructures are fabricated in which organized structures of different cell types can be used as tissue building blocks. To fabricate tissue building blocks, hydrogels are commonly used as biomaterials for cell encapsulation to mimic the matrix in vivo. The hydrogel-based tissue building blocks can be arranged in pre-defined architectures by various directed tissue assembly techniques. In this paper, recent advances in directed assembly-based tissue engineering are summarized as an emerging alternative to meet challenges associated with scaffold-based tissue engineering and future directions are addressed. PMID:21220962

  3. Remodeling of tissue-engineered bone structures in vivo.

    PubMed

    Hofmann, Sandra; Hilbe, Monika; Fajardo, Robert J; Hagenmüller, Henri; Nuss, Katja; Arras, Margarete; Müller, Ralph; von Rechenberg, Brigitte; Kaplan, David L; Merkle, Hans P; Meinel, Lorenz

    2013-09-01

    Implant design for bone regeneration is expected to be optimized when implant structures resemble the anatomical situation of the defect site. We tested the validity of this hypothesis by exploring the feasibility of generating different in vitro engineered bone-like structures originating from porous silk fibroin scaffolds decorated with RGD sequences (SF-RGD), seeded with human mesenchymal stem cells (hMSC). Scaffolds with small (106-212 μm), medium (212-300 μm), and large pore diameter ranges (300-425 μm) were seeded with hMSC and subsequently differentiated in vitro into bone-like tissue resembling initial scaffold geometries and featuring bone-like structures. Eight weeks after implantation into calvarial defects in mice, the in vitro engineered bone-like tissues had remodeled into bone featuring different proportions of woven/lamellar bone bridging the defects. Regardless of pore diameter, all implants integrated well, vascularization was advanced, and bone marrow ingrowth had started. Ultimately, in this defect model, the geometry of the in vitro generated tissue-engineered bone structure, trabecular- or plate-like, had no significant impact on the healing of the defect, owing to an efficient remodeling of its structure after implantation. PMID:23958323

  4. Remodeling of tissue-engineered bone structures in vivo

    PubMed Central

    Hofmann, Sandra; Hilbe, Monika; Fajardo, Robert J.; Hagenmüller, Henri; Nuss, Katja; Arras, Margarete; Müller, Ralph; von Rechenberg, Brigitte; Kaplan, David L.; Merkle, Hans P.; Meinel, Lorenz

    2013-01-01

    Implant design for bone regeneration is expected to be optimized when implant structures resemble the anatomical situation of the defect site. We tested the validity of this hypothesis by exploring the feasibility of generating different in vitro engineered bone-like structures originating from porous silk fibroin scaffolds decorated with RGD sequences (SF-RGD), seeded with human mesenchymal stem cells (hMSC). Scaffolds with small (106 – 212 μm), medium (212 – 300 μm) and large pore diameter ranges (300 – 425 μm) were seeded with hMSC and subsequently differentiated in vitro into bone-like tissue resembling initial scaffold geometries and featuring bone-like structures. Eight weeks after implantation into calvarial defects in mice, the in vitro engineered bone-like tissues had remodeled into bone featuring different proportions of woven/lamellar bone bridging the defects. Regardless of pore diameter all implants integrated well, vascularization was advanced and, bone marrow ingrowth had started. Ultimately, in this defect model, the geometry of the in vitro generated tissue-engineered bone structure, trabecular- or plate-like, had no significant impact on the healing of the defect, owing to an efficient remodeling of its structure after implantation. PMID:23958323

  5. Imaging Approaches in Functional Assessment of Implantable Myogenic Biomaterials and Engineered Muscle Tissue

    PubMed Central

    Gargiulo, Paolo

    2015-01-01

    The fields of tissue engineering and regenerative medicine utilize implantable biomaterials and engineered tissues to regenerate damaged cells or replace lost tissues. There are distinct challenges in all facets of this research, but functional assessments and monitoring of such complex environments as muscle tissues present the current strategic priority. Many extant methods for addressing these questions result in the destruction or alteration of tissues or cell populations under investigation. Modern advances in non-invasive imaging modalities present opportunities to rethink some of the anachronistic methods, however, their standard employment may not be optimal when considering advancements in myology. New image analysis protocols and/or combinations of established modalities need to be addressed. This review focuses on efficacies and limitations of available imaging modalities to the functional assessment of implantable myogenic biomaterials and engineered muscle tissues. PMID:26913149

  6. New perspectives for advanced automobile diesel engines

    NASA Technical Reports Server (NTRS)

    Tozzi, L.; Sekar, R.; Kamo, R.; Wood, J. C.

    1983-01-01

    Computer simulation results are presented for advanced automobile diesel engine performance. Four critical factors for performance enhancement were identified: (1) part load preheating and exhaust gas energy recovery, (2) fast heat release combustion process, (3) reduction in friction, and (4) air handling system efficiency. Four different technology levels were considered in the analysis. Simulation results are compared in terms of brake specific fuel consumption and vehicle fuel economy in km/liter (miles per gallon). Major critical performance sensitivity areas are: (1) combustion process, (2) expander and compressor efficiency, and (3) part load preheating and compound system. When compared to the state of the art direct injection, cooled, automobile diesel engine, the advanced adiabatic compound engine concept showed the unique potential of doubling the fuel economy. Other important performance criteria such as acceleration, emissions, reliability, durability and multifuel capability are comparable to or better than current passenger car diesel engines.

  7. Tissue Engineering Applications of Three-Dimensional Bioprinting.

    PubMed

    Zhang, Xiaoying; Zhang, Yangde

    2015-07-01

    Recent advances in tissue engineering have adapted the additive manufacturing technology, also known as three-dimensional printing, which is used in several industrial applications, for the fabrication of bioscaffolds and viable tissue and/or organs to overcome the limitations of other in vitro conventional methods. 3D bioprinting technology has gained enormous attention as it enabled 3D printing of a multitude of biocompatible materials, different types of cells and other supporting growth factors into complex functional living tissues in a 3D format. A major advantage of this technology is its ability for simultaneously 3D printing various cell types in defined spatial locations, which makes this technology applicable to regenerative medicine to meet the need for suitable for transplantation suitable organs and tissues. 3D bioprinting is yet to successfully overcome the many challenges related to building 3D structures that closely resemble native organs and tissues, which are complex structures with defined microarchitecture and a variety of cell types in a confined area. An integrated approach with a combination of technologies from the fields of engineering, biomaterials science, cell biology, physics, and medicine is required to address these complexities. Meeting this challenge is being made possible by directing the 3D bioprinting to manufacture biomimetic-shaped 3D structures, using organ/tissue images, obtained from magnetic resonance imaging and computerized tomography, and employing computer-aided design and manufacturing technologies. Applications of 3D bioprinting include the generation of multilayered skin, bone, vascular grafts, heart valves, etc. The current 3D bioprinting technologies need to be improved with respect to the mechanical strength and integrity in the manufactured constructs as the presently used biomaterials are not of optimal viscosity. A better understanding of the tissue/organ microenvironment, which consists of multiple types of

  8. Tissue Engineering a Biological Repair Strategy for Lumbar Disc Herniation

    PubMed Central

    O'Connell, Grace D.; Leach, J. Kent; Klineberg, Eric O.

    2015-01-01

    Abstract The intervertebral disc is a critical part of the intersegmental soft tissue of the spinal column, providing flexibility and mobility, while absorbing large complex loads. Spinal disease, including disc herniation and degeneration, may be a significant contributor to low back pain. Clinically, disc herniations are treated with both nonoperative and operative methods. Operative treatment for disc herniation includes removal of the herniated material when neural compression occurs. While this strategy may have short-term advantages over nonoperative methods, the remaining disc material is not addressed and surgery for mild degeneration may have limited long-term advantage over nonoperative methods. Furthermore, disc herniation and surgery significantly alter the mechanical function of the disc joint, which may contribute to progression of degeneration in surrounding tissues. We reviewed recent advances in tissue engineering and regenerative medicine strategies that may have a significant impact on disc herniation repair. Our review on tissue engineering strategies focuses on cell-based and inductive methods, each commonly combined with material-based approaches. An ideal clinically relevant biological repair strategy will significantly reduce pain and repair and restore flexibility and motion of the spine. PMID:26634189

  9. Potential for Imaging Engineered Tissues with X-Ray Phase Contrast

    PubMed Central

    Appel, Alyssa; Anastasio, Mark A.

    2011-01-01

    As the field of tissue engineering advances, it is crucial to develop imaging methods capable of providing detailed three-dimensional information on tissue structure. X-ray imaging techniques based on phase-contrast (PC) have great potential for a number of biomedical applications due to their ability to provide information about soft tissue structure without exogenous contrast agents. X-ray PC techniques retain the excellent spatial resolution, tissue penetration, and calcified tissue contrast of conventional X-ray techniques while providing drastically improved imaging of soft tissue and biomaterials. This suggests that X-ray PC techniques are very promising for evaluation of engineered tissues. In this review, four different implementations of X-ray PC imaging are described and applications to tissues of relevance to tissue engineering reviewed. In addition, recent applications of X-ray PC to the evaluation of biomaterial scaffolds and engineered tissues are presented and areas for further development and application of these techniques are discussed. Imaging techniques based on X-ray PC have significant potential for improving our ability to image and characterize engineered tissues, and their continued development and optimization could have significant impact on the field of tissue engineering. PMID:21682604

  10. An overview of recent patents on musculoskeletal interface tissue engineering.

    PubMed

    Rao, Rohit T; Browe, Daniel P; Lowe, Christopher J; Freeman, Joseph W

    2016-02-01

    Interface tissue engineering involves the development of engineered grafts that promote integration between multiple tissue types. Musculoskeletal tissue interfaces are critical to the safe and efficient transmission of mechanical forces between multiple musculoskeletal tissues, e.g., between ligament and bone tissue. However, these interfaces often do not physiologically regenerate upon injury, resulting in impaired tissue function. Therefore, interface tissue engineering approaches are considered to be particularly relevant for the structural restoration of musculoskeletal tissues interfaces. In this article, we provide an overview of the various strategies used for engineering musculoskeletal tissue interfaces with a specific focus on the recent important patents that have been issued for inventions that were specifically designed for engineering musculoskeletal interfaces as well as those that show promise to be adapted for this purpose. PMID:26577344

  11. Advanced aircraft engine materials trends

    NASA Technical Reports Server (NTRS)

    Dreshfield, R. L.; Gray, H. R.; Levine, S. R.; Signorelli, R.

    1981-01-01

    Recent activities of the Lewis Research Center are reviewed which are directed toward developing materials for rotating hot section components for aircraft gas turbines. Turbine blade materials activities are directed at increasing metal temperatures approximately 100 C compared to current directionally solidified alloys by use of oxide dispersion strengthening or tungsten alloy wire reinforcement of nickel or iron base superalloys. The application of thermal barrier coatings offers a promise of increasing gas temperatures an additional 100 C with current cooling technology. For turbine disk alloys, activities are directed toward reducing the cost of turbine disks by 50 percent through near net shape fabrication of prealloyed powders as well as towards improved performance. In addition, advanced alloy concepts and fabrication methods for dual alloy disks are being studied as having potential for improving the life of future high performance disks and reducing the amount of strategic materials required in these components.

  12. Tissue engineering skeletal muscle for orthopaedic applications

    NASA Technical Reports Server (NTRS)

    Payumo, Francis C.; Kim, Hyun D.; Sherling, Michael A.; Smith, Lee P.; Powell, Courtney; Wang, Xiao; Keeping, Hugh S.; Valentini, Robert F.; Vandenburgh, Herman H.

    2002-01-01

    With current technology, tissue-engineered skeletal muscle analogues (bioartificial muscles) generate too little active force to be clinically useful in orthopaedic applications. They have been engineered genetically with numerous transgenes (growth hormone, insulinlike growth factor-1, erythropoietin, vascular endothelial growth factor), and have been shown to deliver these therapeutic proteins either locally or systemically for months in vivo. Bone morphogenetic proteins belonging to the transforming growth factor-beta superfamily are osteoinductive molecules that drive the differentiation pathway of mesenchymal cells toward the chondroblastic or osteoblastic lineage, and stimulate bone formation in vivo. To determine whether skeletal muscle cells endogenously expressing bone morphogenetic proteins might serve as a vehicle for systemic bone morphogenetic protein delivery in vivo, proliferating skeletal myoblasts (C2C12) were transduced with a replication defective retrovirus containing the gene for recombinant human bone morphogenetic protein-6 (C2BMP-6). The C2BMP-6 cells constitutively expressed recombinant human bone morphogenetic protein-6 and synthesized bioactive recombinant human bone morphogenetic protein-6, based on increased alkaline phosphatase activity in coincubated mesenchymal cells. C2BMP-6 cells did not secrete soluble, bioactive recombinant human bone morphogenetic protein-6, but retained the bioactivity in the cell layer. Therefore, genetically-engineered skeletal muscle cells might serve as a platform for long-term delivery of osteoinductive bone morphogenetic proteins locally.

  13. Photocrosslinkable Gelatin Hydrogel for Epidermal Tissue Engineering.

    PubMed

    Zhao, Xin; Lang, Qi; Yildirimer, Lara; Lin, Zhi Yuan; Cui, Wenguo; Annabi, Nasim; Ng, Kee Woei; Dokmeci, Mehmet R; Ghaemmaghami, Amir M; Khademhosseini, Ali

    2016-01-01

    Natural hydrogels are promising scaffolds to engineer epidermis. Currently, natural hydrogels used to support epidermal regeneration are mainly collagen- or gelatin-based, which mimic the natural dermal extracellular matrix but often suffer from insufficient and uncontrollable mechanical and degradation properties. In this study, a photocrosslinkable gelatin (i.e., gelatin methacrylamide (GelMA)) with tunable mechanical, degradation, and biological properties is used to engineer the epidermis for skin tissue engineering applications. The results reveal that the mechanical and degradation properties of the developed hydrogels can be readily modified by varying the hydrogel concentration, with elastic and compressive moduli tuned from a few kPa to a few hundred kPa, and the degradation times varied from a few days to several months. Additionally, hydrogels of all concentrations displayed excellent cell viability (>90%) with increasing cell adhesion and proliferation corresponding to increases in hydrogel concentrations. Furthermore, the hydrogels are found to support keratinocyte growth, differentiation, and stratification into a reconstructed multilayered epidermis with adequate barrier functions. The robust and tunable properties of GelMA hydrogels suggest that the keratinocyte laden hydrogels can be used as epidermal substitutes, wound dressings, or substrates to construct various in vitro skin models. PMID:25880725

  14. Silk film biomaterials for cornea tissue engineering

    PubMed Central

    Lawrence, Brian D.; Marchant, Jeffrey K.; Pindrus, Mariya; Omenetto, Fiorenzo; Kaplan, David L.

    2009-01-01

    Biomaterials for corneal tissue engineering must demonstrate several critical features for potential utility in vivo, including transparency, mechanical integrity, biocompatibility and slow biodegradation. Silk film biomaterials were designed and characterized to meet these functional requirements. Silk protein films were used in a biomimetic approach to replicate corneal stromal tissue architecture. The films were 2 μm thick to emulate corneal collagen lamellae dimensions, and were surface patterned to guide cell alignment. To enhance trans-lamellar diffusion of nutrients and to promote cell-cell interaction, pores with 0.5 to 5.0 μm diameters were introduced into the silk films. Human and rabbit corneal fibroblast proliferation, alignment and corneal extracellular matrix expression on these films in both 2D and 3D cultures was demonstrated. The mechanical properties, optical clarity and surface patterned features of these films, combined with their ability to support corneal cell functions suggest this new biomaterial system offers important potential benefits for corneal tissue regeneration. PMID:19059642

  15. Adipose tissue extract promotes adipose tissue regeneration in an adipose tissue engineering chamber model.

    PubMed

    Lu, Zijing; Yuan, Yi; Gao, Jianhua; Lu, Feng

    2016-05-01

    An adipose tissue engineering chamber model of spontaneous adipose tissue generation from an existing fat flap has been described. However, the chamber does not completely fill with adipose tissue in this model. Here, the effect of adipose tissue extract (ATE) on adipose tissue regeneration was investigated. In vitro, the adipogenic and angiogenic capacities of ATE were evaluated using Oil Red O and tube formation assays on adipose-derived stem cells (ASCs) and rat aortic endothelial cells (RAECs), respectively. In vivo, saline or ATE was injected into the adipose tissue engineering chamber 1 week after its implantation. At different time points post-injection, the contents were morphometrically, histologically, and immunohistochemically evaluated, and the expression of growth factors and adipogenic genes was analyzed by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time PCR. With the exception of the baseline control group, in which fat flaps were not inserted into a chamber, the total volume of fat flap tissue increased significantly in all groups, especially in the ATE group. Better morphology and structure, a thinner capsule, and more vessels were observed in the ATE group than in the control group. Expression of angiogenic growth factors and adipogenic markers were significantly higher in the ATE group. ATE therefore significantly promoted adipose tissue regeneration and reduced capsule formation in an adipose tissue engineering chamber model. These data suggest that ATE provides a more angiogenic and adipogenic microenvironment for adipose tissue formation by releasing various cytokines and growth factors that also inhibit capsule formation. PMID:26678825

  16. Advancements in engineering turbulence modeling

    NASA Technical Reports Server (NTRS)

    Shih, T.-H.

    1991-01-01

    Some new developments in two-equation models and second order closure models are presented. Two-equation models (k-epsilon models) have been widely used in computational fluid dynamics (CFD) for engineering problems. Most of low-Reynolds number two-equation models contain some wall-distance damping functions to account for the effect of wall on turbulence. However, this often causes the confusion and difficulties in computing flows with complex geometry and also needs an ad hoc treatment near the separation and reattachment points. A set of modified two-equation models is proposed to remove the aforementioned shortcomings. The calculations using various two-equation models are compared with direct numerical simulations of channel flow and flat boundary layers. Development of a second order closure model is also discussed with emphasis on the modeling of pressure related correlation terms and dissipation rates in the second moment equations. All the existing models poorly predict the normal stresses near the wall and fail to predict the 3-D effect of mean flow on the turbulence (e.g. decrease in the shear stress caused by the cross flow in the boundary layer). The newly developed second order near-wall turbulence model is described and is capable of capturing the near-wall behavior of turbulence as well as the effect of 3-D mean flow on the turbulence.

  17. A modular approach to cardiac tissue engineering.

    PubMed

    Leung, Brendan M; Sefton, Michael V

    2010-10-01

    Functional cardiac tissue was prepared using a modular tissue engineering approach with the goal of creating vascularized tissue. Rat aortic endothelial cells (RAEC) were seeded onto submillimeter-sized modules made of type I bovine collagen supplemented with Matrigel™ (25% v/v) embedded with cardiomyocyte (CM)-enriched neonatal rat heart cells and assembled into a contractile, macroporous, sheet-like construct. Modules (without RAEC) cultured in 10% bovine serum (BS) were more contractile and responsive to external stimulus (lower excitation threshold, higher maximum capture rate, and greater en face fractional area changes) than modules cultured in 10% fetal BS. Incorporating 25% Matrigel in the matrix reduced the excitation threshold and increased the fractional area change relative to collagen only modules (without RAEC). A coculture medium, containing 10% BS, low Mg2+ (0.814mM), and normal glucose (5.5mM), was used to maintain RAEC junction morphology (VE-cadherin) and CM contractility, although the responsiveness of CM was attenuated with RAEC on the modules. Macroporous, sheet-like module constructs were assembled by partially immobilizing a layer of modules in alginate gel until day 8, with or without RAEC. RAEC/CM module sheets were electrically responsive; however, like modules with RAEC this responsiveness was attenuated relative to CM-only sheets. Muscle bundles coexpressing cardiac troponin I and connexin-43 were evident near the perimeter of modules and at intermodule junctions. These results suggest the potential of the modular approach as a platform for building vascularized cardiac tissue. PMID:20504074

  18. Growth factor-eluting technologies for bone tissue engineering.

    PubMed

    Nyberg, Ethan; Holmes, Christina; Witham, Timothy; Grayson, Warren L

    2016-04-01

    Growth factors are essential orchestrators of the normal bone fracture healing response. For non-union defects, delivery of exogenous growth factors to the injured site significantly improves healing outcomes. However, current clinical methods for scaffold-based growth factor delivery are fairly rudimentary, and there is a need for greater spatial and temporal regulation to increase their in vivo efficacy. Various approaches used to provide spatiotemporal control of growth factor delivery from bone tissue engineering scaffolds include physical entrapment, chemical binding, surface modifications, biomineralization, micro- and nanoparticle encapsulation, and genetically engineered cells. Here, we provide a brief review of these technologies, describing the fundamental mechanisms used to regulate release kinetics. Examples of their use in pre-clinical studies are discussed, and their capacities to provide tunable, growth factor delivery are compared. These advanced scaffold systems have the potential to provide safer, more effective therapies for bone regeneration than the systems currently employed in the clinic. PMID:25967594

  19. Natural and Genetically Engineered Proteins for Tissue Engineering

    PubMed Central

    Gomes, Sílvia; Leonor, Isabel B.; Mano, João F.; Reis, Rui L.

    2011-01-01

    To overcome the limitations of traditionally used autografts, allografts and, to a lesser extent, synthetic materials, there is the need to develop a new generation of scaffolds with adequate mechanical and structural support, control of cell attachment, migration, proliferation and differentiation and with bio-resorbable features. This suite of properties would allow the body to heal itself at the same rate as implant degradation. Genetic engineering offers a route to this level of control of biomaterial systems. The possibility of expressing biological components in nature and to modify or bioengineer them further, offers a path towards multifunctional biomaterial systems. This includes opportunities to generate new protein sequences, new self-assembling peptides or fusions of different bioactive domains or protein motifs. New protein sequences with tunable properties can be generated that can be used as new biomaterials. In this review we address some of the most frequently used proteins for tissue engineering and biomedical applications and describe the techniques most commonly used to functionalize protein-based biomaterials by combining them with bioactive molecules to enhance biological performance. We also highlight the use of genetic engineering, for protein heterologous expression and the synthesis of new protein-based biopolymers, focusing the advantages of these functionalized biopolymers when compared with their counterparts extracted directly from nature and modified by techniques such as physical adsorption or chemical modification. PMID:22058578

  20. Advanced oxygen-hydrocarbon rocket engine study

    NASA Technical Reports Server (NTRS)

    Obrien, C. J.

    1980-01-01

    Preliminary identification and evaluation of promising liquid oxygen/ hydrocarbon (LO2/HC) rocket engine cycles is reported. A consistent and reliable data base for vehicle optimization and design studies, to demonstrate the significance of propulsion system improvements, and to select the critical technology areas necessary to realize such advances is presented.

  1. A tissue-engineered jellyfish with biomimetic propulsion.

    PubMed

    Nawroth, Janna C; Lee, Hyungsuk; Feinberg, Adam W; Ripplinger, Crystal M; McCain, Megan L; Grosberg, Anna; Dabiri, John O; Parker, Kevin Kit

    2012-08-01

    Reverse engineering of biological form and function requires hierarchical design over several orders of space and time. Recent advances in the mechanistic understanding of biosynthetic compound materials, computer-aided design approaches in molecular synthetic biology 4,5 and traditional soft robotics, and increasing aptitude in generating structural and chemical micro environments that promote cellular self-organization have enhanced the ability to recapitulate such hierarchical architecture in engineered biological systems. Here we combined these capabilities in a systematic design strategy to reverse engineer a muscular pump. We report the construction of a freely swimming jellyfish from chemically dissociated rat tissue and silicone polymer as a proof of concept. The constructs, termed 'medusoids', were designed with computer simulations and experiments to match key determinants of jellyfish propulsion and feeding performance by quantitatively mimicking structural design, stroke kinematics and animal-fluid interactions. The combination of the engineering design algorithm with quantitative benchmarks of physiological performance suggests that our strategy is broadly applicable to reverse engineering of muscular organs or simple life forms that pump to survive. PMID:22820316

  2. A tissue-engineered jellyfish with biomimetic propulsion

    PubMed Central

    Nawroth, Janna C; Lee, Hyungsuk; Feinberg, Adam W; Ripplinger, Crystal M; McCain, Megan L; Grosberg, Anna; Dabiri, John O; Parker, Kevin Kit

    2014-01-01

    Reverse engineering of biological form and function requires hierarchical design over several orders of space and time. Recent advances in the mechanistic understanding of biosynthetic compound materials1–3, computer-aided design approaches in molecular synthetic biology4,5 and traditional soft robotics6,7, and increasing aptitude in generating structural and chemical microenvironments that promote cellular self-organization8–10 have enhanced the ability to recapitulate such hierarchical architecture in engineered biological systems. Here we combined these capabilities in a systematic design strategy to reverse engineer a muscular pump. We report the construction of a freely swimming jellyfish from chemically dissociated rat tissue and silicone polymer as a proof of concept. The constructs, termed ‘medusoids’, were designed with computer simulations and experiments to match key determinants of jellyfish propulsion and feeding performance by quantitatively mimicking structural design, stroke kinematics and animal-fluid interactions. The combination of the engineering design algorithm with quantitative benchmarks of physiological performance suggests that our strategy is broadly applicable to reverse engineering of muscular organs or simple life forms that pump to survive. PMID:22820316

  3. Perspectives on the Interface of Drug Delivery and Tissue Engineering

    PubMed Central

    Ekenseair, Adam K.; Kasper, F. Kurtis; Mikos, Antonios G.

    2012-01-01

    Controlled drug delivery of bioactive molecules continues to be an essential component of engineering strategies for tissue defect repair. This article surveys the current challenges associated with trying to regenerate complex tissues utilizing drug delivery and gives perspectives on the development of translational tissue engineering therapies which promote spatiotemporal cell-signaling cascades to maximize the rate and quality of repair. PMID:23000743

  4. Mesoporous silica nanoparticles in tissue engineering--a perspective.

    PubMed

    Rosenholm, Jessica Maria; Zhang, Jixi; Linden, Mika; Sahlgren, Cecilia

    2016-02-01

    In this review, we summarize the latest developments and give a perspective on future applications of mesoporous silica nanoparticles (MSNs) in regenerative medicine. MSNs constitute a flexible platform for controlled delivery of drugs and imaging agents in tissue engineering and stem cell therapy. We highlight the recent advances in applying MSNs for controlled drug delivery and stem cell tracking. We touch upon novel functions of MSNs in real time imaging of drug release and biological function, and as tools to control the chemical and mechanical environment of stem cells. We discuss the need for novel model systems for studying biofunctionality and biocompatibility of MSNs, and how the interdisciplinary activities within the field will advance biotechnology research. PMID:26784861

  5. Bridging the Divide between Neuroprosthetic Design, Tissue Engineering and Neurobiology

    PubMed Central

    Leach, Jennie B.; Achyuta, Anil Kumar H.; Murthy, Shashi K.

    2009-01-01

    Neuroprosthetic devices have made a major impact in the treatment of a variety of disorders such as paralysis and stroke. However, a major impediment in the advancement of this technology is the challenge of maintaining device performance during chronic implantation (months to years) due to complex intrinsic host responses such as gliosis or glial scarring. The objective of this review is to bring together research communities in neurobiology, tissue engineering, and neuroprosthetics to address the major obstacles encountered in the translation of neuroprosthetics technology into long-term clinical use. This article draws connections between specific challenges faced by current neuroprosthetics technology and recent advances in the areas of nerve tissue engineering and neurobiology. Within the context of the device–nervous system interface and central nervous system implants, areas of synergistic opportunity are discussed, including platforms to present cells with multiple cues, controlled delivery of bioactive factors, three-dimensional constructs and in vitro models of gliosis and brain injury, nerve regeneration strategies, and neural stem/progenitor cell biology. Finally, recent insights gained from the fields of developmental neurobiology and cancer biology are discussed as examples of exciting new biological knowledge that may provide fresh inspiration toward novel technologies to address the complexities associated with long-term neuroprosthetic device performance. PMID:20161810

  6. Tissue Engineering and Regenerative Medicine 2015: A Year in Review.

    PubMed

    Wobma, Holly; Vunjak-Novakovic, Gordana

    2016-04-01

    This may be the most exciting time ever for the field of tissue engineering and regenerative medicine (TERM). After decades of progress, it has matured, integrated, and diversified into entirely new areas, and it is starting to make the pivotal shift toward translation. The most exciting science and applications continue to emerge at the boundaries of disciplines, through increasingly effective interactions between stem cell biologists, bioengineers, clinicians, and the commercial sector. In this "Year in Review," we highlight some of the major advances reported over the last year (Summer 2014-Fall 2015). Using a methodology similar to that established in previous years, we identified four areas that generated major progress in the field: (i) pluripotent stem cells, (ii) microtissue platforms for drug testing and disease modeling, (iii) tissue models of cancer, and (iv) whole organ engineering. For each area, we used some of the most impactful articles to illustrate the important concepts and results that advanced the state of the art of TERM. We conclude with reflections on emerging areas and perspectives for future development in the field. PMID:26714410

  7. Bioprinted Scaffolds for Cartilage Tissue Engineering.

    PubMed

    Kang, Hyun-Wook; Yoo, James J; Atala, Anthony

    2015-01-01

    Researchers are focusing on bioprinting technology as a viable option to overcome current difficulties in cartilage tissue engineering. Bioprinting enables a three-dimensional (3-D), free-form, computer-designed structure using biomaterials, biomolecules, and/or cells. The inner and outer shape of a scaffold can be controlled by this technology with great precision. Here, we introduce a hybrid bioprinting technology that is a co-printing process of multiple materials including high-strength synthetic polymer and cell-laden hydrogel. The synthetic polymer provides mechanical support for shape maintenance and load bearing, while the hydrogel provides the biological environment for artificial cartilage regeneration. This chapter introduces the procedures for printing of a 3-D scaffold using our hybrid bioprinting technology and includes the source materials for preparation of 3-D printing. PMID:26445837

  8. Hype and expectations in tissue engineering.

    PubMed

    Oerlemans, Anke J M; van Hoek, Maria E C; van Leeuwen, Evert; Dekkers, Wim Jm M

    2014-01-01

    Scientific progress and the development of new technologies often incite enthusiasm, both in scientists and the public at large, and this is especially apparent in discussions of emerging medical technologies, such as tissue engineering (TE). Future-oriented narratives typically discuss potential applications with much hype and expectations. In this article, we analyze the discourse on TE, its history and the promises present in the discourse surrounding it. Subsequently, we regard discussions about implantable bioartificial kidneys, and consider the concepts of hype and expectations in TE in general. Finally, we discuss what ethically responsible choices should be made in discussing TE to adequately deal with the scientific reality and public expectations surrounding this technology. PMID:24351011

  9. Scaffolds for central nervous system tissue engineering

    NASA Astrophysics Data System (ADS)

    He, Jin; Wang, Xiu-Mei; Spector, Myron; Cui, Fu-Zhai

    2012-03-01

    Traumatic injuries to the brain and spinal cord of the central nervous system (CNS) lead to severe and permanent neurological deficits and to date there is no universally accepted treatment. Owing to the profound impact, extensive studies have been carried out aiming at reducing inflammatory responses and overcoming the inhibitory environment in the CNS after injury so as to enhance regeneration. Artificial scaffolds may provide a suitable environment for axonal regeneration and functional recovery, and are of particular importance in cases in which the injury has resulted in a cavitary defect. In this review we discuss development of scaffolds for CNS tissue engineering, focusing on mechanism of CNS injuries, various biomaterials that have been used in studies, and current strategies for designing and fabricating scaffolds.

  10. Advanced nozzle and engine components test facility

    NASA Technical Reports Server (NTRS)

    Beltran, Luis R.; Delroso, Richard L.; Delrosario, Ruben

    1992-01-01

    A test facility for conducting scaled advanced nozzle and engine component research is described. The CE-22 test facility, located in the Engine Research Building of the NASA Lewis Research Center, contains many systems for the economical testing of advanced scale-model nozzles and engine components. The combustion air and altitude exhaust systems are described. Combustion air can be supplied to a model up to 40 psig for primary air flow, and 40, 125, and 450 psig for secondary air flow. Altitude exhaust can be simulated up to 48,000 ft, or the exhaust can be atmospheric. Descriptions of the multiaxis thrust stand, a color schlieren flow visualization system used for qualitative flow analysis, a labyrinth flow measurement system, a data acquisition system, and auxiliary systems are discussed. Model recommended design information and temperature and pressure instrumentation recommendations are included.

  11. Engineered Polymers for Advanced Drug Delivery

    PubMed Central

    Kim, Sungwon; Kim, Jong-Ho; Jeon, Oju; Kwon, Ick Chan; Park, Kinam

    2009-01-01

    Engineered polymers have been utilized for developing advanced drug delivery systems. The development of such polymers has caused advances in polymer chemistry, which, in turn, has resulted in smart polymers that can respond to changes in environmental condition, such as temperature, pH, and biomolecules. The responses vary widely from swelling/deswelling to degradation. Drug-polymer conjugates and drug-containing nano/micro-particles have been used for drug targeting. Engineered polymers and polymeric systems have also been used in new areas, such as molecular imaging as well as in nanotechnology. This review examines the engineered polymers that have been used as traditional drug delivery and as more recent applications in nanotechnology. PMID:18977434

  12. Orbit transfer rocket engine technology program: Advanced engine study

    NASA Technical Reports Server (NTRS)

    Erickson, C. M.

    1992-01-01

    In Task D.6 of the Advanced Engine Study, three primary subtasks were accomplished: (1) design of parametric data; (2) engine requirement variation studies; and (3) vehicle study/engine study coordination. Parametric data were generated for vacuum thrusts ranging from 7500 lbf to 50,000 lbf, nozzle expansion ratios from 600 to 1200, and engine mixture ratios from 5:1 to 7:1. Failure Modes and Effects Analysis (FMEA) was used as a departure point for these parametric analyses. These data are intended to assist in definition and trade studies. In the Engine Requirements Variation Studies, the individual effects of increasing the throttling ratio from 10:1 to 20:1 and requiring the engine to operate at a maximum mixture ratio of 12:1 were determined. Off design engine balances were generated at these extreme conditions and individual component operating requirements analyzed in detail. Potential problems were identified and possible solutions generated. In the Vehicle Study/Engine Study coordination subtask, vehicle contractor support was provided as needed, addressing a variety of issues uncovered during vehicle trade studies. This support was primarily provided during Technical Interchange Meetings (TIM) in which Space Exploration Initiative (SEI) studies were addressed.

  13. Heart Regeneration with Embryonic Cardiac Progenitor Cells and Cardiac Tissue Engineering

    PubMed Central

    Tian, Shuo; Liu, Qihai; Gnatovskiy, Leonid; Ma, Peter X.; Wang, Zhong

    2015-01-01

    Myocardial infarction (MI) is the leading cause of death worldwide. Recent advances in stem cell research hold great potential for heart tissue regeneration through stem cell-based therapy. While multiple cell types have been transplanted into MI heart in preclinical studies or clinical trials, reduction of scar tissue and restoration of cardiac function have been modest. Several challenges hamper the development and application of stem cell-based therapy for heart regeneration. Application of cardiac progenitor cells (CPCs) and cardiac tissue engineering for cell therapy has shown great promise to repair damaged heart tissue. This review presents an overview of the current applications of embryonic CPCs and the development of cardiac tissue engineering in regeneration of functional cardiac tissue and reduction of side effects for heart regeneration. We aim to highlight the benefits of the cell therapy by application of CPCs and cardiac tissue engineering during heart regeneration. PMID:26744736

  14. Combining regenerative medicine strategies to provide durable reconstructive options: auricular cartilage tissue engineering.

    PubMed

    Jessop, Zita M; Javed, Muhammad; Otto, Iris A; Combellack, Emman J; Morgan, Siân; Breugem, Corstiaan C; Archer, Charles W; Khan, Ilyas M; Lineaweaver, William C; Kon, Moshe; Malda, Jos; Whitaker, Iain S

    2016-01-01

    Recent advances in regenerative medicine place us in a unique position to improve the quality of engineered tissue. We use auricular cartilage as an exemplar to illustrate how the use of tissue-specific adult stem cells, assembly through additive manufacturing and improved understanding of postnatal tissue maturation will allow us to more accurately replicate native tissue anisotropy. This review highlights the limitations of autologous auricular reconstruction, including donor site morbidity, technical considerations and long-term complications. Current tissue-engineered auricular constructs implanted into immune-competent animal models have been observed to undergo inflammation, fibrosis, foreign body reaction, calcification and degradation. Combining biomimetic regenerative medicine strategies will allow us to improve tissue-engineered auricular cartilage with respect to biochemical composition and functionality, as well as microstructural organization and overall shape. Creating functional and durable tissue has the potential to shift the paradigm in reconstructive surgery by obviating the need for donor sites. PMID:26822227

  15. Ceramic technology for Advanced Heat Engines Project

    SciTech Connect

    Johnson, D.R.

    1991-07-01

    Significant accomplishments in fabricating ceramic components for advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and database and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. An assessment of needs was completed, and a five year project plan was developed with extensive input from private industry. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities. This project is managed by ORNL for the Office of Transportation Technologies, Office of Transportation Materials, and is closely coordinated with complementary ceramics tasks funded by other DOE offices, NASA, DOD, and industry.

  16. Advanced component technologies for energy-efficient turbofan engines

    NASA Technical Reports Server (NTRS)

    Saunders, N. T.

    1980-01-01

    A cooperative government-industry effort, the Energy Efficient Engine Project, to develop the advanced technology base for future commercial development of a new generation of more fuel conservative turbofan engines for airline use is described. Engine configurations that are dependent upon technology advances in each major engine component are defined and current design and development of the advanced components are included.

  17. Tissue Engineered Constructs: Perspectives on Clinical Translation

    PubMed Central

    Lu, Lichun; Arbit, Harvey M.; Herrick, James L.; Segovis, Suzanne Glass; Maran, Avudaiappan; Yaszemski, Michael J.

    2015-01-01

    In this article, a “bedside to bench and back” approach for developing tissue engineered medical products (TEMPs) for clinical applications is reviewed. The driving force behind this approach is unmet clinical needs. Preclinical research, both in vitro and in vivo using small and large animal models, will help find solutions to key research questions. In clinical research, ethical issues regarding the use of cells and tissues, their sources, donor consent, as well as clinical trials are important considerations. Regulatory issues, at both institutional and government levels, must be addressed prior to the translation of TEMPs to clinical practice. TEMPs are regulated as drugs, biologics, devices, or combination products by the US Food and Drug Administration (FDA). Depending on the mode of regulation, applications for TEMP introduction must be filed with the FDA to demonstrate safety and effectiveness in premarket clinical studies, followed by 510(k) premarket clearance or premarket approval (for medical devices), biologics license application approval (for biologics), or New Drug Application approval (for drugs). A case study on nerve cuffs is presented to illustrate the regulatory process. Finally, perspectives on commercialization such as finding a company partner and funding issues, as well as physician culture change, are presented. PMID:25711151

  18. Tissue engineered constructs: perspectives on clinical translation.

    PubMed

    Lu, Lichun; Arbit, Harvey M; Herrick, James L; Segovis, Suzanne Glass; Maran, Avudaiappan; Yaszemski, Michael J

    2015-03-01

    In this article, a "bedside to bench and back" approach for developing tissue engineered medical products (TEMPs) for clinical applications is reviewed. The driving force behind this approach is unmet clinical needs. Preclinical research, both in vitro and in vivo using small and large animal models, will help find solutions to key research questions. In clinical research, ethical issues regarding the use of cells and tissues, their sources, donor consent, as well as clinical trials are important considerations. Regulatory issues, at both institutional and government levels, must be addressed prior to the translation of TEMPs to clinical practice. TEMPs are regulated as drugs, biologics, devices, or combination products by the U.S. Food and Drug Administration (FDA). Depending on the mode of regulation, applications for TEMP introduction must be filed with the FDA to demonstrate safety and effectiveness in premarket clinical studies, followed by 510(k) premarket clearance or premarket approval (for medical devices), biologics license application approval (for biologics), or new drug application approval (for drugs). A case study on nerve cuffs is presented to illustrate the regulatory process. Finally, perspectives on commercialization such as finding a company partner and funding issues, as well as physician culture change, are presented. PMID:25711151

  19. Optimization strategies for electrospun silk fibroin tissue engineering scaffolds

    PubMed Central

    Meinel, Anne J.; Kubow, Kristopher E.; Klotzsch, Enrico; Garcia-Fuentes, Marcos; Smith, Michael L.; Vogel, Viola; Merkle, Hans P.; Meinel, Lorenz

    2013-01-01

    As a contribution to the functionality of scaffolds in tissue engineering, here we report on advanced scaffold design through introduction and evaluation of topographical, mechanical and chemical cues. For scaffolding, we used silk fibroin (SF), a well established biomaterial. Biomimetic alignment of fibers was achieved as a function of the rotational speed of the cylindrical target during electrospinning of a SF solution blended with polyethylene oxide. Seeding fibrous SF scaffolds with human mesenchymal stem cells (hMSC) demonstrated that fiber alignment could guide hMSC morphology and orientation demonstrating the impact of scaffold topography on the engineering of oriented tissues. Beyond currently established methodologies to measure bulk properties, we assessed the mechanical properties of the fibers by conducting extension at breakage experiments on the level of single fibers. Chemical modification of the scaffolds was tested using donor/acceptor fluorophore labeled fibronectin. Fluorescence resonance energy transfer imaging allowed to assess the conformation of fibronectin when adsorbed on the SF scaffolds, and demonstrated an intermediate extension level of its subunits. Biological assays based on hMSC showed enhanced cellular adhesion and spreading as a result of fibronectin adsorbed on the scaffolds. Our studies demonstrate the versatility of SF as a biomaterial to engineer modified fibrous scaffolds and underscore the use of biofunctionally relevant analytical assays to optimize fibrous biomaterial scaffolds. PMID:19233463

  20. Parthenogenetic stem cells for tissue-engineered heart repair

    PubMed Central

    Didié, Michael; Christalla, Peter; Rubart, Michael; Muppala, Vijayakumar; Döker, Stephan; Unsöld, Bernhard; El-Armouche, Ali; Rau, Thomas; Eschenhagen, Thomas; Schwoerer, Alexander P.; Ehmke, Heimo; Schumacher, Udo; Fuchs, Sigrid; Lange, Claudia; Becker, Alexander; Tao, Wen; Scherschel, John A.; Soonpaa, Mark H.; Yang, Tao; Lin, Qiong; Zenke, Martin; Han, Dong-Wook; Schöler, Hans R.; Rudolph, Cornelia; Steinemann, Doris; Schlegelberger, Brigitte; Kattman, Steve; Witty, Alec; Keller, Gordon; Field, Loren J.; Zimmermann, Wolfram-Hubertus

    2013-01-01

    Uniparental parthenotes are considered an unwanted byproduct of in vitro fertilization. In utero parthenote development is severely compromised by defective organogenesis and in particular by defective cardiogenesis. Although developmentally compromised, apparently pluripotent stem cells can be derived from parthenogenetic blastocysts. Here we hypothesized that nonembryonic parthenogenetic stem cells (PSCs) can be directed toward the cardiac lineage and applied to tissue-engineered heart repair. We first confirmed similar fundamental properties in murine PSCs and embryonic stem cells (ESCs), despite notable differences in genetic (allelic variability) and epigenetic (differential imprinting) characteristics. Haploidentity of major histocompatibility complexes (MHCs) in PSCs is particularly attractive for allogeneic cell-based therapies. Accordingly, we confirmed acceptance of PSCs in MHC-matched allotransplantation. Cardiomyocyte derivation from PSCs and ESCs was equally effective. The use of cardiomyocyte-restricted GFP enabled cell sorting and documentation of advanced structural and functional maturation in vitro and in vivo. This included seamless electrical integration of PSC-derived cardiomyocytes into recipient myocardium. Finally, we enriched cardiomyocytes to facilitate engineering of force-generating myocardium and demonstrated the utility of this technique in enhancing regional myocardial function after myocardial infarction. Collectively, our data demonstrate pluripotency, with unrestricted cardiogenicity in PSCs, and introduce this unique cell type as an attractive source for tissue-engineered heart repair. PMID:23434590

  1. Tissue Engineering in the Gut: Developments in Neuromusculature

    PubMed Central

    Bitar, Khalil N.; Raghavan, Shreya; Zakhem, Elie

    2014-01-01

    The complexity of the gastrointestinal (GI) tract lies in its anatomy as well as in its physiology. Several different cell types populate the GI tract adding to the complexity of cell sourcing for regenerative medicine. Each cell layer has a specialized function in mediating digestion, absorption, secretion, motility and excretion. Tissue engineering and regenerative medicine aim to regenerate the specific layers mimicking architecture and recapitulating function. Gastrointestinal motility is the underlying program that mediates the diverse functions of the intestines, as an organ. Hence, the first logical step in GI regenerative medicine is the reconstruction of the tubular smooth musculature along with the drivers of their input, the enteric nervous system. Recent advances in the field of GI tissue engineering have focused on the use of scaffolding biomaterials in combination with cells and bioactive factors. The ability to innervate the bioengineered muscle is a critical step to ensure proper functionality. Finally, in vivo studies are essential to evaluate implant integration with host tissue, survival and functionality. In this review, we will focus on the tubular structure of the GI tract, tools for innervation and finally evaluation of in vivo strategies for GI replacements. PMID:24681129

  2. Biomimetic nanoclay scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Ambre, Avinash Harishchandra

    Tissue engineering offers a significant potential alternative to conventional methods for rectifying tissue defects by evoking natural regeneration process via interactions between cells and 3D porous scaffolds. Imparting adequate mechanical properties to biodegradable scaffolds for bone tissue engineering is an important challenge and extends from molecular to macroscale. This work focuses on the use of sodium montmorillonite (Na-MMT) to design polymer composite scaffolds having enhanced mechanical properties along with multiple interdependent properties. Materials design beginning at the molecular level was used in which Na-MMT clay was modified with three different unnatural amino acids and further characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). Based on improved bicompatibility with human osteoblasts (bone cells) and intermediate increase in d-spacing of MMT clay (shown by XRD), 5-aminovaleric acid modified clay was further used to prepare biopolymer (chitosan-polygalacturonic acid complex) scaffolds. Osteoblast proliferation in biopolymer scaffolds containing 5-aminovaleric acid modified clay was similar to biopolymer scaffolds containing hydroxyapatite (HAP). A novel process based on biomineralization in bone was designed to prepare 5-aminovaleric acid modified clay capable of imparting multiple properties to the scaffolds. Bone-like apatite was mineralized in modified clay and a novel nanoclay-HAP hybrid (in situ HAPclay) was obtained. FTIR spectroscopy indicated a molecular level organic-inorganic association between the intercalated 5-aminovaleric acid and mineralized HAP. Osteoblasts formed clusters on biopolymer composite films prepared with different weight percent compositions of in situ HAPclay. Human MSCs formed mineralized nodules on composite films and mineralized extracellular matrix (ECM) in composite scaffolds without the use of osteogenic supplements. Polycaprolactone (PCL), a synthetic polymer, was

  3. Advances in protease engineering for laundry detergents.

    PubMed

    Vojcic, Ljubica; Pitzler, Christian; Körfer, Georgette; Jakob, Felix; Ronny Martinez; Maurer, Karl-Heinz; Schwaneberg, Ulrich

    2015-12-25

    Proteases are essential ingredients in modern laundry detergents. Over the past 30 years, subtilisin proteases employed in the laundry detergent industry have been engineered by directed evolution and rational design to tailor their properties towards industrial demands. This comprehensive review discusses recent success stories in subtilisin protease engineering. Advances in protease engineering for laundry detergents comprise simultaneous improvement of thermal resistance and activity at low temperatures, a rational strategy to modulate pH profiles, and a general hypothesis for how to increase promiscuous activity towards the production of peroxycarboxylic acids as mild bleaching agents. The three protease engineering campaigns presented provide in-depth analysis of protease properties and have identified principles that can be applied to improve or generate enzyme variants for industrial applications beyond laundry detergents. PMID:25579194

  4. Advanced automotive diesel engine system study

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A conceptual study of an advanced automotive diesel engine is discussed. The engine concept selected for vehicle installation was a supercharged 1.4 liter, 4 cylinder spark assisted diesel of 14:1 compression ratio. A compounding unit consisting of a Lysholm compressor and expander is connected to the engine crankshaft by a belt drive. The inlet air charge is heated by the expander exhaust gas via a heat exchanger. Four levels of technology achievement on the selected engine concept were evaluated, from state-of-the-art to the ideal case. This resulted in the fuel economy increasing from 53.2 mpg to 81.7 mpg, and the 0-60 mph time decreasing from 17.6 seconds to 10.9 seconds.

  5. Tissue engineering: a 21st century solution to surgical reconstruction.

    PubMed

    Fuchs, J R; Nasseri, B A; Vacanti, J P

    2001-08-01

    Tissue engineering has emerged as a rapidly expanding approach to address the organ shortage problem. It is an "interdisciplinary field that applies the principles and methods of engineering and the life sciences toward the development of biological substitutes that can restore, maintain, or improve tissue function." Much progress has been made in the tissue engineering of structures relevant to cardiothoracic surgery, including heart valves, blood vessels, myocardium, esophagus, and trachea. PMID:11515900

  6. Advanced nuclear rocket engine mission analysis

    SciTech Connect

    Ramsthaler, J.; Farbman, G.; Sulmeisters, T.; Buden, D.; Harris, P.

    1987-12-01

    The use of a derivative of the NERVA engine developed from 1955 to 1973 was evluated for potential application to Air Force orbital transfer and maneuvering missions in the time period 1995 to 2020. The NERVA stge was found to have lower life cycle costs (LCC) than an advanced chemical stage for performing low earth orbit (LEO) to geosynchronous orbit (GEO0 missions at any level of activity greater than three missions per year. It had lower life cycle costs than a high performance nuclear electric engine at any level of LEO to GEO mission activity. An examination of all unmanned orbital transfer and maneuvering missions from the Space Transportation Architecture study (STAS 111-3) indicated a LCC advantage for the NERVA stage over the advanced chemical stage of fifteen million dollars. The cost advanced accured from both the orbital transfer and maneuvering missions. Parametric analyses showed that the specific impulse of the NERVA stage and the cost of delivering material to low earth orbit were the most significant factors in the LCC advantage over the chemical stage. Lower development costs and a higher thrust gave the NERVA engine an LCC advantage over the nuclear electric stage. An examination of technical data from the Rover/NERVA program indicated that development of the NERVA stage has a low technical risk, and the potential for high reliability and safe operation. The data indicated the NERVA engine had a great flexibility which would permit a single stage to perform all Air Force missions.

  7. Advanced Engineering Environments: Implications for Aerospace Manufacturing

    NASA Technical Reports Server (NTRS)

    Thomas, D.

    2001-01-01

    There are significant challenges facing today's aerospace industry. Global competition, more complex products, geographically-distributed design teams, demands for lower cost, higher reliability and safer vehicles, and the need to incorporate the latest technologies quicker all face the developer of aerospace systems. New information technologies offer promising opportunities to develop advanced engineering environments (AEEs) to meet these challenges. Significant advances in the state-of-the-art of aerospace engineering practice are envisioned in the areas of engineering design and analytical tools, cost and risk tools, collaborative engineering, and high-fidelity simulations early in the development cycle. These advances will enable modeling and simulation of manufacturing methods, which will in turn allow manufacturing considerations to be included much earlier in the system development cycle. Significant cost savings, increased quality, and decreased manufacturing cycle time are expected to result. This paper will give an overview of the NASA's Intelligent Synthesis Environment, the agency initiative to develop an AEE, with a focus on the anticipated benefits in aerospace manufacturing.

  8. Ultrasound Technologies for the Spatial Patterning of Cells and Extracellular Matrix Proteins and the Vascularization of Engineered Tissue

    NASA Astrophysics Data System (ADS)

    Garvin, Kelley A.

    Technological advancements in the field of tissue engineering could save the lives of thousands of organ transplant patients who die each year while waiting for donor organs. Currently, two of the primary challenges preventing tissue engineers from developing functional replacement tissues and organs are the need to recreate complex cell and extracellular microenvironments and to vascularize the tissue to maintain cell viability and function. Ultrasound is a form of mechanical energy that can noninvasively and nondestructively interact with tissues at the cell and protein level. In this thesis, novel ultrasound-based technologies were developed for the spatial patterning of cells and extracellular matrix proteins and the vascularization of three-dimensional engineered tissue constructs. Acoustic radiation forces associated with ultrasound standing wave fields were utilized to noninvasively control the spatial organization of cells and cell-bound extracellular matrix proteins within collagen-based engineered tissue. Additionally, ultrasound induced thermal mechanisms were exploited to site-specifically pattern various extracellular matrix collagen microstructures within a single engineered tissue construct. Finally, ultrasound standing wave field technology was used to promote the rapid and extensive vascularization of three-dimensional tissue constructs. As such, the ultrasound technologies developed in these studies have the potential to provide the field of tissue engineering with novel strategies to spatially pattern cells and extracellular matrix components and to vascularize engineered tissue, and thus, could advance the fabrication of functional replacement tissues and organs in the field of tissue engineering.

  9. A Perspective on the Clinical Translation of Scaffolds for Tissue Engineering

    PubMed Central

    Webber, Matthew J.; Khan, Omar F.; Sydlik, Stefanie A.; Tang, Benjamin C.; Langer, Robert

    2016-01-01

    Scaffolds have been broadly applied within tissue engineering and regenerative medicine to regenerate, replace, or augment diseased or damaged tissue. For a scaffold to perform optimally, several design considerations must be addressed, with an eye toward the eventual form, function, and tissue site. The chemical and mechanical properties of the scaffold must be tuned to optimize the interaction with cells and surrounding tissues. For complex tissue engineering, mass transport limitations, vascularization, and host tissue integration are important considerations. As the tissue architecture to be replaced becomes more complex and hierarchical, scaffold design must also match this complexity to recapitulate a functioning tissue. We outline these design constraints and highlight creative and emerging strategies to overcome limitations and modulate scaffold properties for optimal regeneration. We also highlight some of the most advanced strategies that have seen clinical application and discuss the hurdles that must be overcome for clinical use and commercialization of tissue engineering technologies. Finally, we provide a perspective on the future of scaffolds as a functional contributor to advancing tissue engineering and regenerative medicine. PMID:25201605

  10. Tissue engineering in urethral reconstruction—an update

    PubMed Central

    Mangera, Altaf; Chapple, Christopher R

    2013-01-01

    The field of tissue engineering is rapidly progressing. Much work has gone into developing a tissue engineered urethral graft. Current grafts, when long, can create initial donor site morbidity. In this article, we evaluate the progress made in finding a tissue engineered substitute for the human urethra. Researchers have investigated cell-free and cell-seeded grafts. We discuss different approaches to developing these grafts and review their reported successes in human studies. With further work, tissue engineered grafts may facilitate the management of lengthy urethral strictures requiring oral mucosa substitution urethroplasty. PMID:23042444

  11. Advanced oxygen-hydrocarbon rocket engine study

    NASA Technical Reports Server (NTRS)

    Obrien, C. J.; Ewen, R. L.

    1981-01-01

    This study identifies and evaluates promising LO2/HC rocket engine cycles, produces a consistent and reliable data base for vehicle optimization and design studies, demonstrates the significance of propulsion system improvements, and selects the critical technology areas necessary to realize an improved surface to orbit transportation system. Parametric LO2/HC engine data were generated over a range of thrust levels from 890 to 6672 kN (200K to 1.5M 1bF) and chamber pressures from 6890 to 34500 kN (1000 to 5000 psia). Engine coolants included RP-1, refined RP-1, LCH4, LC3H8, LO2, and LH2. LO2/RP-1 G.G. cycles were found to be not acceptable for advanced engines. The highest performing LO2/RP-1 staged combustion engine cycle utilizes LO2 as the coolant and incorporates an oxidizer rich preburner. The highest performing cycle for LO2/LCH4 and LO2/LC3H8 utilizes fuel cooling and incorporates both fuel and oxidizer rich preburners. LO2/HC engine cycles permitting the use of a third fluid LH2 coolant and an LH2 rich gas generator provide higher performance at significantly lower pump discharge pressures. The LO2/HC dual throat engine, because of its high altitude performance, delivers the highest payload for the vehicle configuration that was investigated.

  12. Solid Free-form Fabrication Technology and Its Application to Bone Tissue Engineering

    PubMed Central

    Lee, Jin Woo; Kim, Jong Young; Cho, Dong-Woo

    2010-01-01

    The development of scaffolds for use in cell-based therapies to repair damaged bone tissue has become a critical component in the field of bone tissue engineering. However, design of scaffolds using conventional fabrication techniques has limited further advancement, due to a lack of the required precision and reproducibility. To overcome these constraints, bone tissue engineers have focused on solid free-form fabrication (SFF) techniques to generate porous, fully interconnected scaffolds for bone tissue engineering applications. This paper reviews the potential application of SFF fabrication technologies for bone tissue engineering with respect to scaffold fabrication. In the near future, bone scaffolds made using SFF apparatus should become effective therapies for bone defects. PMID:24855546

  13. The potential of optical coherence tomography in the engineering of living tissue.

    PubMed

    Mason, C; Markusen, J F; Town, M A; Dunnill, P; Wang, R K

    2004-04-01

    The better repair of human tissue is an urgent medical goal and in order to achieve a safe outcome there is a parallel need for sensitive, non-invasive methods of assessing the quality of the engineered tissues and organs prior to surgical implantation. Optical coherence tomography (OCT) can potentially fulfil this role. The current status of OCT as an advanced imaging tool in clinical medicine, developmental biology and material science is reviewed and the parallels to the engineering of living tissue and organs are discussed. Preliminary data are also presented for a tissue engineering bioreactor with in situ OCT imaging. The data suggest that OCT can be utilized as a real time, non-destructive, non-invasive tool to critically monitor the morphology of tissue-engineered constructs during their fabrication and growth. PMID:15128192

  14. Development of Advanced Small Hydrogen Engines

    SciTech Connect

    Sapru, Krishna; Tan, Zhaosheng; Chao, Ben

    2010-09-30

    The main objective of the project is to develop advanced, low cost conversions of small (< 25 hp) gasoline internal combustion engines (ICEs) to run on hydrogen fuel while maintaining the same performance and durability. This final technical report summarizes the results of i) the details of the conversion of several small gasoline ICEs to run on hydrogen, ii) the durability test of a converted hydrogen engine and iii) the demonstration of a prototype bundled canister solid hydrogen storage system. Peak power of the hydrogen engine achieves 60% of the power output of the gasoline counterpart. The efforts to boost the engine power with various options including installing the over-sized turbocharger, retrofit of custom-made pistons with high compression ratio, an advanced ignition system, and various types of fuel injection systems are not realized. A converted Honda GC160 engine with ACS system to run with hydrogen fuel is successful. Total accumulative runtime is 785 hours. A prototype bundled canister solid hydrogen storage system having nominal capacity of 1.2 kg is designed, constructed and demonstrated. It is capable of supporting a wide range of output load of a hydrogen generator.

  15. Library of Advanced Materials for Engineering : LAME.

    SciTech Connect

    Hammerand, Daniel Carl; Scherzinger, William Mark

    2007-08-01

    Constitutive modeling is an important aspect of computational solid mechanics. Sandia National Laboratories has always had a considerable effort in the development of constitutive models for complex material behavior. However, for this development to be of use the models need to be implemented in our solid mechanics application codes. In support of this important role, the Library of Advanced Materials for Engineering (LAME) has been developed in Engineering Sciences. The library allows for simple implementation of constitutive models by model developers and access to these models by application codes. The library is written in C++ and has a very simple object oriented programming structure. This report summarizes the current status of LAME.

  16. Orbital transfer rocket engine technology: Advanced engine study

    NASA Technical Reports Server (NTRS)

    Hayden, Warren R.

    1992-01-01

    An advanced LOX/LH2 engine study for the use of NASA and vehicle prime contractors in developing concepts for manned missions to the Moon, Mars, and Phobos is documented. Parametric design data was obtained at five engine thrusts from 7.5K lbf to 50K lbf. Also, a separate task evaluated engine throttling over a 20:1 range and operation at a mixture ratio of 12 plus or minus 1 versus the 6 plus or minus 1 nominal. Cost data was also generated for DDT&E, first unit production, and factors in other life cycle costs. The major limitation of the study was lack of contact with vehicle prime contractors to resolve the issues in vehicle/engine interfaces. The baseline Aerojet dual propellant expander cycle was shown capable of meeting all performance requirements with an expected long operational life due to the high thermal margins. The basic engine design readily accommodated the 20:1 throttling requirement and operation up to a mixture ratio of 10 without change. By using platinum for baffled injector construction the increased thermal margin allowed operation up to mixture ratio 13. An initial engine modeling with an Aerojet transient simulation code (named MLETS) indicates stable engine operation with the baseline control system. A throttle ratio of 4 to 5 seconds from 10 percent to 100 percent thrust is also predicted. Performance predictions are 483.1 sec at 7.5K lbf, 487.3 sec at 20K lbf, and 485.2 sec at 50K lbf with a mixture ratio of 6 and an area ratio of 1200. Engine envelopes varied from 120 in. length/53 in. exit diameter at 7.5K lbf to 305 in. length/136 in. exit diameter at 50 K lbf. Packaging will be an important consideration. Continued work is recommended to include more vehicle prime contractor/engine contractor joint assessment of the interface issues.

  17. Ignition angle advancer for internal combustion engine

    SciTech Connect

    Yamazaki, T.

    1986-08-19

    This patent describes a throttle and spark advance control system for an internal combustion engine having a spark advance mechanism and a throttle valve comprising an operator controlled element, a throttle control lever supported for pivotal movement about an axis and directly connected to the operator controlled element for rotation under operator control. It also includes means for positively connecting the throttle control lever to the throttle valve for positioning the throttle valve in response to movement of the throttle control lever. A spark advance control lever supported for pivotal movement about an axis is included as well as motion transmitting means for operatively connecting the spark advance control lever to the throttle control lever for pivotal movement of the spark advance control lever about its axis in response to pivotal movement of the throttle control lever about its axis and the spark control lever to the spark advance mechanism for controlling the position of the spark advance mechanism in response to the position of the throttle control lever.

  18. Computational model-informed design and bioprinting of cell-patterned constructs for bone tissue engineering.

    PubMed

    Carlier, Aurélie; Skvortsov, Gözde Akdeniz; Hafezi, Forough; Ferraris, Eleonora; Patterson, Jennifer; Koç, Bahattin; Van Oosterwyck, Hans

    2016-01-01

    Three-dimensional (3D) bioprinting is a rapidly advancing tissue engineering technology that holds great promise for the regeneration of several tissues, including bone. However, to generate a successful 3D bone tissue engineering construct, additional complexities should be taken into account such as nutrient and oxygen delivery, which is often insufficient after implantation in large bone defects. We propose that a well-designed tissue engineering construct, that is, an implant with a specific spatial pattern of cells in a matrix, will improve the healing outcome. By using a computational model of bone regeneration we show that particular cell patterns in tissue engineering constructs are able to enhance bone regeneration compared to uniform ones. We successfully bioprinted one of the most promising cell-gradient patterns by using cell-laden hydrogels with varying cell densities and observed a high cell viability for three days following the bioprinting process. In summary, we present a novel strategy for the biofabrication of bone tissue engineering constructs by designing cell-gradient patterns based on a computational model of bone regeneration, and successfully bioprinting the chosen design. This integrated approach may increase the success rate of implanted tissue engineering constructs for critical size bone defects and also can find a wider application in the biofabrication of other types of tissue engineering constructs. PMID:27187017

  19. Genome engineering in cattle: recent technological advancements.

    PubMed

    Wang, Zhongde

    2015-02-01

    Great strides in technological advancements have been made in the past decade in cattle genome engineering. First, the success of cloning cattle by somatic cell nuclear transfer (SCNT) or chromatin transfer (CT) is a significant advancement that has made obsolete the need for using embryonic stem (ES) cells to conduct cell-mediated genome engineering, whereby site-specific genetic modifications can be conducted in bovine somatic cells via DNA homologous recombination (HR) and whereby genetically engineered cattle can subsequently be produced by animal cloning from the genetically modified cells. With this approach, a chosen bovine genomic locus can be precisely modified in somatic cells, such as to knock out (KO) or knock in (KI) a gene via HR, a gene-targeting strategy that had almost exclusively been used in mouse ES cells. Furthermore, by the creative application of embryonic cloning to rejuvenate somatic cells, cattle genome can be sequentially modified in the same line of somatic cells and complex genetic modifications have been achieved in cattle. Very recently, the development of designer nucleases-such as zinc finger nucleases (ZFNs) and transcription activator-like effector nuclease (TALENs), and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-has enabled highly efficient and more facile genome engineering in cattle. Most notably, by employing such designer nucleases, genomes can be engineered at single-nucleotide precision; this process is now often referred to as genome or gene editing. The above achievements are a drastic departure from the traditional methods of creating genetically modified cattle, where foreign DNAs are randomly integrated into the animal genome, most often along with the integrations of bacterial or viral DNAs. Here, I review the most recent technological developments in cattle genome engineering by highlighting some of the major achievements in creating genetically engineered

  20. Scaffolding in tissue engineering: general approaches and tissue-specific considerations

    PubMed Central

    Leong, K. W.

    2008-01-01

    Scaffolds represent important components for tissue engineering. However, researchers often encounter an enormous variety of choices when selecting scaffolds for tissue engineering. This paper aims to review the functions of scaffolds and the major scaffolding approaches as important guidelines for selecting scaffolds and discuss the tissue-specific considerations for scaffolding, using intervertebral disc as an example. PMID:19005702

  1. Optimization of nanoparticles for cardiovascular tissue engineering.

    PubMed

    Izadifar, Mohammad; Kelly, Michael E; Haddadi, Azita; Chen, Xiongbiao

    2015-06-12

    Nano-particulate delivery systems have increasingly been playing important roles in cardiovascular tissue engineering. Properties of nanoparticles (e.g. size, polydispersity, loading capacity, zeta potential, morphology) are essential to system functions. Notably, these characteristics are regulated by fabrication variables, but in a complicated manner. This raises a great need to optimize fabrication process variables to ensure the desired nanoparticle characteristics. This paper presents a comprehensive experimental study on this matter, along with a novel method, the so-called Geno-Neural approach, to analyze, predict and optimize fabrication variables for desired nanoparticle characteristics. Specifically, ovalbumin was used as a protein model of growth factors used in cardiovascular tissue regeneration, and six fabrication variables were examined with regard to their influence on the characteristics of nanoparticles made from high molecular weight poly(lactide-co-glycolide). The six-factor five-level central composite rotatable design was applied to the conduction of experiments, and based on the experimental results, a geno-neural model was developed to determine the optimum fabrication conditions. For desired particle sizes of 150, 200, 250 and 300 nm, respectively, the optimum conditions to achieve the low polydispersity index, higher negative zeta potential and higher loading capacity were identified based on the developed geno-neural model and then evaluated experimentally. The experimental results revealed that the polymer and the external aqueous phase concentrations and their interactions with other fabrication variables were the most significant variables to affect the size, polydispersity index, zeta potential, loading capacity and initial burst release of the nanoparticles, while the electron microscopy images of the nanoparticles showed their spherical geometries with no sign of large pores or cracks on their surfaces. The release study revealed

  2. Optimization of nanoparticles for cardiovascular tissue engineering

    NASA Astrophysics Data System (ADS)

    Izadifar, Mohammad; Kelly, Michael E.; Haddadi, Azita; Chen, Xiongbiao

    2015-06-01

    Nano-particulate delivery systems have increasingly been playing important roles in cardiovascular tissue engineering. Properties of nanoparticles (e.g. size, polydispersity, loading capacity, zeta potential, morphology) are essential to system functions. Notably, these characteristics are regulated by fabrication variables, but in a complicated manner. This raises a great need to optimize fabrication process variables to ensure the desired nanoparticle characteristics. This paper presents a comprehensive experimental study on this matter, along with a novel method, the so-called Geno-Neural approach, to analyze, predict and optimize fabrication variables for desired nanoparticle characteristics. Specifically, ovalbumin was used as a protein model of growth factors used in cardiovascular tissue regeneration, and six fabrication variables were examined with regard to their influence on the characteristics of nanoparticles made from high molecular weight poly(lactide-co-glycolide). The six-factor five-level central composite rotatable design was applied to the conduction of experiments, and based on the experimental results, a geno-neural model was developed to determine the optimum fabrication conditions. For desired particle sizes of 150, 200, 250 and 300 nm, respectively, the optimum conditions to achieve the low polydispersity index, higher negative zeta potential and higher loading capacity were identified based on the developed geno-neural model and then evaluated experimentally. The experimental results revealed that the polymer and the external aqueous phase concentrations and their interactions with other fabrication variables were the most significant variables to affect the size, polydispersity index, zeta potential, loading capacity and initial burst release of the nanoparticles, while the electron microscopy images of the nanoparticles showed their spherical geometries with no sign of large pores or cracks on their surfaces. The release study revealed

  3. Hydrogel scaffolds for tissue engineering: Progress and challenges

    PubMed Central

    El-Sherbiny, Ibrahim M.; Yacoub, Magdi H.

    2013-01-01

    Designing of biologically active scaffolds with optimal characteristics is one of the key factors for successful tissue engineering. Recently, hydrogels have received a considerable interest as leading candidates for engineered tissue scaffolds due to their unique compositional and structural similarities to the natural extracellular matrix, in addition to their desirable framework for cellular proliferation and survival. More recently, the ability to control the shape, porosity, surface morphology, and size of hydrogel scaffolds has created new opportunities to overcome various challenges in tissue engineering such as vascularization, tissue architecture and simultaneous seeding of multiple cells. This review provides an overview of the different types of hydrogels, the approaches that can be used to fabricate hydrogel matrices with specific features and the recent applications of hydrogels in tissue engineering. Special attention was given to the various design considerations for an efficient hydrogel scaffold in tissue engineering. Also, the challenges associated with the use of hydrogel scaffolds were described. PMID:24689032

  4. Expediting the transition from replacement medicine to tissue engineering.

    PubMed

    Coury, Arthur J

    2016-06-01

    In this article, an expansive interpretation of "Tissue Engineering" is proposed which is in congruence with classical and recent published definitions. I further simplify the definition of tissue engineering as: "Exerting systematic control of the body's cells, matrices and fluids." As a consequence, many medical therapies not commonly considered tissue engineering are placed in this category because of their effect on the body's responses. While the progress of tissue engineering strategies is inexorable and generally positive, it has been subject to setbacks as have many important medical therapies. Medical practice is currently undergoing a transition on several fronts (academics, start-up companies, going concerns) from the era of "replacement medicine" where body parts and functions are replaced by mechanical, electrical or chemical therapies to the era of tissue engineering where health is restored by regeneration generation or limitation of the body's tissues and functions by exploiting our expanding knowledge of the body's biological processes to produce natural, healthy outcomes. PMID:27047677

  5. Technology readiness for advanced ducted engines

    SciTech Connect

    Eckardt, D.; Brines, G.L.

    1989-01-01

    The Advanced Ducted Engines (ADEs) currently undergoing development for next-generation passenger aircraft typically possess bypass ratios of the order of 12-25 and specific fuel consumption figures 12-17 percent lower than current advanced turbofans. An extensive technology-readiness program has been mounted on behalf of ADE design definition over the last two years, encompassing among its concerns aircraft/engine-installation interference, low pressure-ratio fan aerodynamics, fan/nacelle interactions (including windmilling and thrust-reversal), acoustic characteristics, transonic-drive turbines, and slender nacelle aerodynamic and mechanical design. Both turbine-driven and geared ADE fans, which may be of single-rotating or contrarotating type, are discussed. 5 refs.

  6. Systems Engineering Building Advances Power Grid Research

    SciTech Connect

    Virden, Jud; Huang, Henry; Skare, Paul; Dagle, Jeff; Imhoff, Carl; Stoustrup, Jakob; Melton, Ron; Stiles, Dennis; Pratt, Rob

    2015-08-19

    Researchers and industry are now better equipped to tackle the nation’s most pressing energy challenges through PNNL’s new Systems Engineering Building – including challenges in grid modernization, buildings efficiency and renewable energy integration. This lab links real-time grid data, software platforms, specialized laboratories and advanced computing resources for the design and demonstration of new tools to modernize the grid and increase buildings energy efficiency.

  7. Plasma Diagnostics Development for Advanced Rocket Engines

    NASA Astrophysics Data System (ADS)

    Glover, Timothy; Kittrell, Carter; Chan, Anthony; Chang-Diaz, Franklin

    2000-10-01

    The VASIMR (Variable Specific Impulse Magnetoplasma Rocket) engine is a next-generation rocket engine under development at the Johnson Space Center's Advanced Space Propulsion Laboratory. With an exhaust velocity up to 50 times that of chemical rocket engines such as the Space Shuttle Main Engine, the VASIMR concept promises fast, efficient interplanetary flight. Rice University has participated in VASIMR research since 1996 and at present is developing two new diagnostic probes: a retarding potential analyzer to measure the velocity of ions in the rocket's exhaust, and a moveable optical probe to examine the spectrum of the rocket's helicon plasma source. In support of the probe development, a test facility is under construction at Rice, consisting of a small electric rocket engine firing into a 2-m vacuum chamber. This engine, the MPD (magnetoplasmadynamic) thruster, dates from the 1960's and provides a well-characterized source plasma for testing of the probes under development. We present details of the ion energy analyzer and the facility under construction at Rice.

  8. [Strategies to choose scaffold materials for tissue engineering].

    PubMed

    Gao, Qingdong; Zhu, Xulong; Xiang, Junxi; Lü, Yi; Li, Jianhui

    2016-02-01

    Current therapies of organ failure or a wide range of tissue defect are often not ideal. Transplantation is the only effective way for long time survival. But it is hard to meet huge patients demands because of donor shortage, immune rejection and other problems. Tissue engineering could be a potential option. Choosing a suitable scaffold material is an essential part of it. According to different sources, tissue engineering scaffold materials could be divided into three types which are natural and its modified materials, artificial and composite ones. The purpose of tissue engineering scaffold is to repair the tissues or organs damage, so could reach the ideal recovery in its function and structure aspect. Therefore, tissue engineering scaffold should even be as close as much to the original tissue or organs in function and structure. We call it "organic scaffold" and this strategy might be the drastic perfect substitute for the tissues or organs in concern. Optimized organization with each kind scaffold materials could make up for biomimetic structure and function of the tissue or organs. Scaffold material surface modification, optimized preparation procedure and cytosine sustained-release microsphere addition should be considered together. This strategy is expected to open new perspectives for tissue engineering. Multidisciplinary approach including material science, molecular biology, and engineering might find the most ideal tissue engineering scaffold. Using the strategy of drawing on each other strength and optimized organization with each kind scaffold material to prepare a multifunctional biomimetic tissue engineering scaffold might be a good method for choosing tissue engineering scaffold materials. Our research group had differentiated bone marrow mesenchymal stem cells into bile canaliculi like cells. We prepared poly(L-lactic acid)/poly(ε-caprolactone) biliary stent. The scaffold's internal played a part in the long-term release of cytokines which

  9. Imaging tissue engineered blood vessel mimics with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bonnema, Garret Thomas

    suggest that OCT endoscopic systems may be a valuable tool for assessing and optimizing the development of tissue engineered constructs. Conversely, the BVMs modeled the arterial response to deployed stents allowing the development of automated OCT analysis software. These results suggest that blood vessel mimics may be used to advance OCT technology and techniques.

  10. Liquid lubricants for advanced aircraft engines

    NASA Technical Reports Server (NTRS)

    Loomis, William R.; Fusaro, Robert L.

    1993-01-01

    An overview of liquid lubricants for use in current and projected high performance turbojet engines is discussed. Chemical and physical properties are reviewed with special emphasis placed on the oxidation and thermal stability requirements imposed upon the lubrication system. A brief history is given of the development of turbine engine lubricants which led to the present day synthetic oils with their inherent modification advantages. The status and state of development of some eleven candidate classes of fluids for use in advanced turbine engines are discussed. Published examples of fundamental studies to obtain a better understanding of the chemistry involved in fluid degradation are reviewed. Alternatives to high temperature fluid development are described. The importance of continuing work on improving current high temperature lubricant candidates and encouraging development of new and improved fluid base stocks are discussed.

  11. Liquid lubricants for advanced aircraft engines

    NASA Technical Reports Server (NTRS)

    Loomis, William R.; Fusaro, Robert L.

    1992-01-01

    An overview of liquid lubricants for use in current and projected high performance turbojet engines is discussed. Chemical and physical properties are reviewed with special emphasis placed on the oxidation and thermal stability requirements imposed upon the lubrication system. A brief history is given of the development of turbine engine lubricants which led to the present day synthetic oils with their inherent modification advantages. The status and state of development of some eleven candidate classes of fluids for use in advanced turbine engines are discussed. Published examples of fundamental studies to obtain a better understanding of the chemistry involved in fluid degradation are reviewed. Alternatives to high temperature fluid development are described. The importance of continuing work on improving current high temperature lubricant candidates and encouraging development of new and improved fluid base stocks are discussed.

  12. Acellular organ scaffolds for tumor tissue engineering

    NASA Astrophysics Data System (ADS)

    Guller, Anna; Trusova, Inna; Petersen, Elena; Shekhter, Anatoly; Kurkov, Alexander; Qian, Yi; Zvyagin, Andrei

    2015-12-01

    Rationale: Tissue engineering (TE) is an emerging alternative approach to create models of human malignant tumors for experimental oncology, personalized medicine and drug discovery studies. Being the bottom-up strategy, TE provides an opportunity to control and explore the role of every component of the model system, including cellular populations, supportive scaffolds and signalling molecules. Objectives: As an initial step to create a new ex vivo TE model of cancer, we optimized protocols to obtain organ-specific acellular matrices and evaluated their potential as TE scaffolds for culture of normal and tumor cells. Methods and results: Effective decellularization of animals' kidneys, ureter, lungs, heart, and liver has been achieved by detergent-based processing. The obtained scaffolds demonstrated biocompatibility and growthsupporting potential in combination with normal (Vero, MDCK) and tumor cell lines (C26, B16). Acellular scaffolds and TE constructs have been characterized and compared with morphological methods. Conclusions: The proposed methodology allows creation of sustainable 3D tumor TE constructs to explore the role of organ-specific cell-matrix interaction in tumorigenesis.

  13. Tissue engineering red blood cells: a therapeutic.

    PubMed

    van Veen, Theun; Hunt, John A

    2015-07-01

    The use of red blood cells (RBCs) in transfusion is widespread in modern medicine. Limitations in blood transfusion have made an urgent argument for the focus on alternatives, as particular medical treatments heavily rely on the supply of donated blood. Stem cells have been successfully used in vitro to produce RBCs and researchers are currently challenged with developing larger-scale culture methods to meet the requirements for clinically relevant cell numbers. The ultimate conditions that will be beneficial for this type of research are trivial. A successful human clinical trial has shown that tremendous progress has already been made in this field. Other alternatives are based on the oxygen carrier protein that RBCs contain, i.e. haemoglobin (Hb). Chemically defined molecules and crosslinked proteins, which are able to bind and transport oxygen, have been found to be functional in vivo. Major progress has been achieved, but developing highly suitable products for the transfusion market still remains an enormous challenge for these acellular blood substitutes. We provide a review about developing alternatives for blood transfusion, with the emphasis on tissue-engineering approaches. PMID:24753354

  14. Advanced general aviation engine/airframe integration study

    NASA Technical Reports Server (NTRS)

    Zmroczek, L. A.

    1982-01-01

    A comparison of the in-airframe performance and efficiency of the advanced engine concepts is presented. The results indicate that the proposed advanced engines can significantly improve the performance and economy of general aviation airplanes. The engine found to be most promising is the highly advanced version of a rotary combustion (Wankel) engine. The low weight and fuel consumption of this engine, as well as its small size, make it suited for aircraft use.

  15. Hydroxyapatite-titanium bulk composites for bone tissue engineering applications.

    PubMed

    Kumar, Alok; Biswas, Krishanu; Basu, Bikramjit

    2015-02-01

    The research work on bulk hydroxyapatite (HA)-based composites are driven by the need to develop biomaterials with better mechanical properties without compromising its bioactivity and biocompatibility properties. Despite several years of research, the mechanical properties of the HA-based composites still need to be enhanced to match the properties of natural cortical bone. In this regard, the scope of this review on the HA-based bulk biomaterials is limited to the processing and the mechanical as well as biocompatibility properties for bone tissue engineering applications of a model system that is hydroxyapatite-titanium (HA-Ti) bulk composites. It will be discussed in this review how HA-Ti based bulk composites can be processed to have better fracture toughness and strength without compromising biocompatibility. The advantages of the functionally gradient materials to integrate the mechanical and biocompatibility properties is a promising approach in hard tissue engineering and has been emphasized here in reference to the limited literature reports. On the biomaterials fabrication aspect, the recent results are discussed to demonstrate that advanced manufacturing techniques, like spark plasma sintering can be adopted as a processing route to restrict the sintering reactions, while enhancing the mechanical properties. Various toughening mechanisms related to careful tailoring of microstructure are discussed. The in vitro cytocompatibilty, cell fate processes as well as in vivo biocompatibility results are also reviewed and the use of flow cytometry to quantify in vitro cell fate processes is being emphasized. PMID:24737723

  16. Recent progress in interfacial tissue engineering approaches for osteochondral defects.

    PubMed

    Castro, Nathan J; Hacking, S Adam; Zhang, Lijie Grace

    2012-08-01

    This review provides a brief synopsis of the anatomy and physiology of the osteochondral interface, scaffold-based and non-scaffold based approaches for engineering both tissues independently as well as recent developments in the manufacture of gradient constructs. Novel manufacturing techniques and nanotechnology will be discussed with potential application in osteochondral interfacial tissue engineering. PMID:22677924

  17. Construction Strategy and Progress of Whole Intervertebral Disc Tissue Engineering.

    PubMed

    Yang, Qiang; Xu, Hai-Wei; Hurday, Sookesh; Xu, Bao-Shan

    2016-02-01

    Degenerative disc disease (DDD) is the major cause of low back pain, which usually leads to work absenteeism, medical visits and hospitalization. Because the current conservative procedures and surgical approaches to treatment of DDD only aim to relieve the symptoms of disease but not to regenerate the diseased disc, their long-term efficiency is limited. With the rapid developments in medical science, tissue engineering techniques have progressed markedly in recent years, providing a novel regenerative strategy for managing intervertebral disc disease. However, there are as yet no ideal methods for constructing tissue-engineered intervertebral discs. This paper reviews published reports pertaining to intervertebral disc tissue engineering and summarizes data concerning the seed cells and scaffold materials for tissue-engineered intervertebral discs, construction of tissue-engineered whole intervertebral discs, relevant animal experiments and effects of mechanics on the construction of tissue-engineered intervertebral disc and outlines the existing problems and future directions. Although the perfect regenerative strategy for treating DDD has not yet been developed, great progress has been achieved in the construction of tissue-engineered intervertebral discs. It is believed that ongoing research on intervertebral disc tissue engineering will result in revolutionary progress in the treatment of DDD. PMID:27028376

  18. Tissue engineering in periodontal regeneration: A brief review

    PubMed Central

    Dabra, Sarita; Chhina, Kamalpreet; Soni, Nitin; Bhatnagar, Rakhi

    2012-01-01

    Periodontal disease is a major public health issue and the development of effective therapies to treat the disease and regenerate periodontal tissue is an important goal of today's medicine. Regeneration of periodontal tissue is perhaps one of the most complex process to occur in the body. Langer and colleagues proposed tissue engineering as a possible technique for regenerating the lost periodontal tissues. Tissue engineering is a multidisciplinary field, which involves the application of the principles and methods of engineering and life sciences to help in the development of biological substitutes to restore, maintain or improve the function of damaged tissues and organs. A Google/Medline search was conducted and relevant literature evaluating the potential role of the tissue engineering in periodontal regeneration, which included histological studies and controlled clinical trials, was reviewed. A comprehensive search was designed. The articles were independently screened for eligibility. Articles with authentic controls and proper randomization and pertaining specifically to their role in periodontal regeneration were included. The available literature was analyzed and compiled. The analysis indicate tissue engineering to be a promising, as well as an effective novel approach to reconstruct and engineer the periodontal apparatus. Here, we represent several articles, as well as recent texts that make up a special and an in-depth review on the subject. The purpose behind writing this brief review has been to integrate the evidence of research related to tissue engineering so as to implement them in our daily practice. PMID:23559940

  19. Bio-inspired 3D microenvironments: a new dimension in tissue engineering.

    PubMed

    Magin, Chelsea M; Alge, Daniel L; Anseth, Kristi S

    2016-04-01

    Biomaterial scaffolds have been a foundational element of the tissue engineering paradigm since the inception of the field. Over the years there has been a progressive move toward the rational design and fabrication of bio-inspired materials that mimic the composition as well as the architecture and 3D structure of tissues. In this review, we chronicle advances in the field that address key challenges in tissue engineering as well as some emerging applications. Specifically, a summary of the materials and chemistries used to engineer bio-inspired 3D matrices that mimic numerous aspects of the extracellular matrix is provided, along with an overview of bioprinting, an additive manufacturing approach, for the fabrication of engineered tissues with precisely controlled 3D structures and architectures. To emphasize the potential clinical impact of the bio-inspired paradigm in biomaterials engineering, some applications of bio-inspired matrices are discussed in the context of translational tissue engineering. However, focus is also given to recent advances in the use of engineered 3D cellular microenvironments for fundamental studies in cell biology, including photoresponsive systems that are shedding new light on how matrix properties influence cell phenotype and function. In an outlook for future work, the need for high-throughput methods both for screening and fabrication is highlighted. Finally, microscale organ-on-a-chip technologies are highlighted as a promising area for future investment in the application of bio-inspired microenvironments. PMID:26942469

  20. [Tissue engineering applied to the trachea as a graft].

    PubMed

    Barrera-Ramírez, Elisa; Rico-Escobar, Edna; Garrido-Cardona, Rubén E

    2016-01-01

    Tissue engineering offers, through new technologies, an ex vivo generation of organs and functional tissues as grafts for transplants, for the improvement and substitution of biological functions, with an absence of immunological response. The treatment of extended tracheal lesions is a substitution of the affected segment; nevertheless, the allogeneic transplant has failed and the use of synthetic materials has not had good results. New tissue engineering technology is being developed to offer a tracheal graft for a posterior implantation. The purpose of this article is to review all the methods and components used by the engineering of tissue for tracheal grafts. PMID:26927653

  1. Powder-based 3D printing for bone tissue engineering.

    PubMed

    Brunello, G; Sivolella, S; Meneghello, R; Ferroni, L; Gardin, C; Piattelli, A; Zavan, B; Bressan, E

    2016-01-01

    Bone tissue engineered 3-D constructs customized to patient-specific needs are emerging as attractive biomimetic scaffolds to enhance bone cell and tissue growth and differentiation. The article outlines the features of the most common additive manufacturing technologies (3D printing, stereolithography, fused deposition modeling, and selective laser sintering) used to fabricate bone tissue engineering scaffolds. It concentrates, in particular, on the current state of knowledge concerning powder-based 3D printing, including a description of the properties of powders and binder solutions, the critical phases of scaffold manufacturing, and its applications in bone tissue engineering. Clinical aspects and future applications are also discussed. PMID:27086202

  2. Barriers to the Clinical Translation of Orthopedic Tissue Engineering

    PubMed Central

    2011-01-01

    Tissue engineering and regenerative medicine have been the subject of increasingly intensive research for over 20 years, and there is concern in some quarters over the lack of clinically useful products despite the large sums of money invested. This review provides one perspective on orthopedic applications from a biologist working in academia. It is suggested that the delay in clinical application is not atypical of new, biologically based technologies. Some barriers to progress are acknowledged and discussed, but it is also noted that preclinical studies have identified several promising types of cells, scaffolds, and morphogenetic signals, which, although not optimal, are worth advancing toward human trials to establish a bridgehead in the clinic. Although this transitional technology will be replaced by more sophisticated, subsequent systems, it will perform valuable pioneering functions and facilitate the clinical development of the field. Some strategies for achieving this are suggested. PMID:21682607

  3. Barriers to the clinical translation of orthopedic tissue engineering.

    PubMed

    Evans, Christopher H

    2011-12-01

    Tissue engineering and regenerative medicine have been the subject of increasingly intensive research for over 20 years, and there is concern in some quarters over the lack of clinically useful products despite the large sums of money invested. This review provides one perspective on orthopedic applications from a biologist working in academia. It is suggested that the delay in clinical application is not atypical of new, biologically based technologies. Some barriers to progress are acknowledged and discussed, but it is also noted that preclinical studies have identified several promising types of cells, scaffolds, and morphogenetic signals, which, although not optimal, are worth advancing toward human trials to establish a bridgehead in the clinic. Although this transitional technology will be replaced by more sophisticated, subsequent systems, it will perform valuable pioneering functions and facilitate the clinical development of the field. Some strategies for achieving this are suggested. PMID:21682607

  4. Cardiac tissue engineering and regeneration using cell-based therapy

    PubMed Central

    Alrefai, Mohammad T; Murali, Divya; Paul, Arghya; Ridwan, Khalid M; Connell, John M; Shum-Tim, Dominique

    2015-01-01

    Stem cell therapy and tissue engineering represent a forefront of current research in the treatment of heart disease. With these technologies, advancements are being made into therapies for acute ischemic myocardial injury and chronic, otherwise nonreversible, myocardial failure. The current clinical management of cardiac ischemia deals with reestablishing perfusion to the heart but not dealing with the irreversible damage caused by the occlusion or stenosis of the supplying vessels. The applications of these new technologies are not yet fully established as part of the management of cardiac diseases but will become so in the near future. The discussion presented here reviews some of the pioneering works at this new frontier. Key results of allogeneic and autologous stem cell trials are presented, including the use of embryonic, bone marrow-derived, adipose-derived, and resident cardiac stem cells. PMID:25999743

  5. 3D-printed fluidic networks as vasculature for engineered tissue.

    PubMed

    Kinstlinger, Ian S; Miller, Jordan S

    2016-05-24

    Fabrication of vascular networks within engineered tissue remains one of the greatest challenges facing the fields of biomaterials and tissue engineering. Historically, the structural complexity of vascular networks has limited their fabrication in tissues engineered in vitro. Recently, however, key advances have been made in constructing fluidic networks within biomaterials, suggesting a strategy for fabricating the architecture of the vasculature. These techniques build on emerging technologies within the microfluidics community as well as on 3D printing. The freeform fabrication capabilities of 3D printing are allowing investigators to fabricate fluidic networks with complex architecture inside biomaterial matrices. In this review, we examine the most exciting 3D printing-based techniques in this area. We also discuss opportunities for using these techniques to address open questions in vascular biology and biophysics, as well as for engineering therapeutic tissue substitutes in vitro. PMID:27173478

  6. Tissue Engineering Stem Cells – An e-Governance Strategy

    PubMed Central

    Grange, Simon

    2011-01-01

    The rules of governance are changing. They are necessarily becoming more stringent as interventions offered to treat conditions carry unpredictable side effects, often associated with novel therapeutic vectors. The clinical relevance of this relates to the obligations of those involved in research, to ensure the best protection for subjects whilst encouraging the development of the field. Existing evidence supports the concept of e-Governance both in operational health research and more broadly in the strategic domain of policy formation. Building on the impact of the UK Comprehensive Research Network and recent EU Directives, it is now possible to focus on the issues of regulation for cell therapies in musculoskeletal science through the development of the Advanced Therapeutic Medicinal Products (ATMP) category of research products. This article reviews the framework that has borne this and the need for more detailed Virtual Research Integration and Collaboration (VRIC) systems to ensure regulatory compliance. Technology research and development plans must develop in close association between tissue engineering and treating clinicians. The scope of this strategy relates to the handling of human tissues the transport and storage of specimens in accordance with current EU directives and the Human Tissue Authority (HTA) regulations. PMID:21886693

  7. Tissue Engineering Stem Cells - An e-Governance Strategy.

    PubMed

    Grange, Simon

    2011-01-01

    The rules of governance are changing. They are necessarily becoming more stringent as interventions offered to treat conditions carry unpredictable side effects, often associated with novel therapeutic vectors. The clinical relevance of this relates to the obligations of those involved in research, to ensure the best protection for subjects whilst encouraging the development of the field. Existing evidence supports the concept of e-Governance both in operational health research and more broadly in the strategic domain of policy formation. Building on the impact of the UK Comprehensive Research Network and recent EU Directives, it is now possible to focus on the issues of regulation for cell therapies in musculoskeletal science through the development of the Advanced Therapeutic Medicinal Products (ATMP) category of research products. This article reviews the framework that has borne this and the need for more detailed Virtual Research Integration and Collaboration (VRIC) systems to ensure regulatory compliance. Technology research and development plans must develop in close association between tissue engineering and treating clinicians. The scope of this strategy relates to the handling of human tissues the transport and storage of specimens in accordance with current EU directives and the Human Tissue Authority (HTA) regulations. PMID:21886693

  8. Neural tissue engineering options for peripheral nerve regeneration.

    PubMed

    Gu, Xiaosong; Ding, Fei; Williams, David F

    2014-08-01

    Tissue engineered nerve grafts (TENGs) have emerged as a potential alternative to autologous nerve grafts, the gold standard for peripheral nerve repair. Typically, TENGs are composed of a biomaterial-based template that incorporates biochemical cues. A number of TENGs have been used experimentally to bridge long peripheral nerve gaps in various animal models, where the desired outcome is nerve tissue regeneration and functional recovery. So far, the translation of TENGs to the clinic for use in humans has met with a certain degree of success. In order to optimize the TENG design and further approach the matching of TENGs with autologous nerve grafts, many new cues, beyond the traditional ones, will have to be integrated into TENGs. Furthermore, there is a strong requirement for monitoring the real-time dynamic information related to the construction of TENGs. The aim of this opinion paper is to specifically and critically describe the latest advances in the field of neural tissue engineering for peripheral nerve regeneration. Here we delineate new attempts in the design of template (or scaffold) materials, especially in the context of biocompatibility, the choice and handling of support cells, and growth factor release systems. We further discuss the significance of RNAi for peripheral nerve regeneration, anticipate the potential application of RNAi reagents for TENGs, and speculate on the possible contributions of additional elements, including angiogenesis, electrical stimulation, molecular inflammatory mediators, bioactive peptides, antioxidant reagents, and cultured biological constructs, to TENGs. Finally, we consider that a diverse array of physicochemical and biological cues must be orchestrated within a TENG to create a self-consistent coordinated system with a close proximity to the regenerative microenvironment of the peripheral nervous system. PMID:24818883

  9. Stem cell-derived vasculature: A potent and multidimensional technology for basic research, disease modeling, and tissue engineering.

    PubMed

    Lowenthal, Justin; Gerecht, Sharon

    2016-05-01

    Proper blood vessel networks are necessary for constructing and re-constructing tissues, promoting wound healing, and delivering metabolic necessities throughout the body. Conversely, an understanding of vascular dysfunction has provided insight into the pathogenesis and progression of diseases both common and rare. Recent advances in stem cell-based regenerative medicine - including advances in stem cell technologies and related progress in bioscaffold design and complex tissue engineering - have allowed rapid advances in the field of vascular biology, leading in turn to more advanced modeling of vascular pathophysiology and improved engineering of vascularized tissue constructs. In this review we examine recent advances in the field of stem cell-derived vasculature, providing an overview of stem cell technologies as a source for vascular cell types and then focusing on their use in three primary areas: studies of vascular development and angiogenesis, improved disease modeling, and the engineering of vascularized constructs for tissue-level modeling and cell-based therapies. PMID:26427871

  10. Tendon Reconstruction with Tissue Engineering Approach--A Review.

    PubMed

    Verdiyeva, Gunay; Koshy, Kiron; Glibbery, Natalia; Mann, Haroon; Seifalian, Alexander M

    2015-09-01

    Tendon injuries are a common and rising occurrence, associated with significant impairment to quality of life and financial burden to the healthcare system. Clinically, they represent an unresolved problem, due to poor natural tendon healing and the inability of current treatment strategies to restore the tendon to its native state. Tissue engineering offers a promising alternative, with the incorporation of scaffolds, cells and growth factors to support the complete regeneration of the tendon. The materials used in tendon engineering to date have provided significant advances in structural integrity and biological compatibility and in many cases the results obtained are superior to those observed in natural healing. However, grafts fail to reproduce the qualities of the pre-injured tendon and each has weaknesses subject to its constituent parts. Furthermore, many materials and cell types are being investigated concurrently, with seemingly little association or comparison between research results. In this review the properties of the most-investigated and effective components have been appraised in light of the surrounding literature, with research from early in-vitro experiments to clinical trials being discussed. Extensive comparisons have been made between scaffolds, cell types and growth factors used, listing strengths and weaknesses to provide a stable platform for future research. Promising future endeavours are also described in the field of nanocomposite material science, stem cell sources and growth factors, which may bypass weaknesses found in individual elements. The future of tendon engineering looks bright, with growing understanding in material technology, cell and growth factor application and encouraging recent advances bringing us ever closer to regenerating the native tendon. PMID:26485923

  11. Biological and biophysical principles in extracorporal bone tissue engineering. Part I.

    PubMed

    Meyer, U; Joos, U; Wiesmann, H P

    2004-06-01

    Advances in the field of bone tissue engineering have encouraged physicians to introduce these techniques into clinical practice. Bone tissue engineering is the construction, repair or replacement of damaged or missing bone in humans or animals. Engineering of bone can take place within the animal body or extracorporal in a bioreactor for later grafting into the body. Appropriate cell types and non-living substrata are minimal requirements for an extracorporal tissue engineering approach. This review discusses the biological and biophysical background of in vitro bone tissue engineering. Biochemical and biophysical stimuli of cell growth and differentiation are regarded as potent tools to improve bone formation in vitro. The paper focuses on basic principles in extracorporal engineering of bone-like tissues, intended to be implanted in animal experiments and clinical studies. Particular attention is given in this part to the contributions of cell and material science to the development of bone-like tissues. Several approaches are at the level of clinical applicability and it can be expected that widespread use of engineered bone constructs will change the surgeon's work in the near future. PMID:15145032

  12. Recent Advances in Engineering Polyvalent Biological Interactions

    PubMed Central

    2015-01-01

    Polyvalent interactions, where multiple ligands and receptors interact simultaneously, are ubiquitous in nature. Synthetic polyvalent molecules, therefore, have the ability to affect biological processes ranging from protein–ligand binding to cellular signaling. In this review, we discuss recent advances in polyvalent scaffold design and applications. First, we will describe recent developments in the engineering of polyvalent scaffolds based on biomolecules and novel materials. Then, we will illustrate how polyvalent molecules are finding applications as toxin and pathogen inhibitors, targeting molecules, immune response modulators, and cellular effectors. PMID:25426695

  13. Advanced concurrent-engineering environment. Final report

    SciTech Connect

    Jortner, J.N.; Friesen, J.A.

    1997-07-01

    Sandia demonstrated large-scale visualization in a conference room environment. Project focused in the installation of hardware for visualization and display, and the integration of software tools for design and animation of 3-dimensional parts. Using a high-end visualization server, 3-dimensional modeling and animation software, and leading edge World Wide Web technology, an advanced concurrent engineering environment was simulated where a design team was able to work collectively, rather than as solely disjoint individual efforts. Finally, a successful animation of a Sandia part was demonstrated, and a computer video generated. This video is now accessible on a Sandia internal web server.

  14. Advanced concurrent engineering environment final report

    SciTech Connect

    Jortner, J.N.; Friesen, J.A.; Schwegel, J.

    1997-08-01

    Sandia demonstrated large-scale visualization in a conference room environment. Project focused on the installation of hardware for visualization and display, and the integration of software tools for design and animation of 3-dimensional parts. Using a high-end visualization server, 3-dimensional modeling and animation software, and leading edge World Wide Web technology, and advanced concurrent engineering environment was simulated where a design team was able to work collectively, rather than as solely disjoint individual efforts. Finally, a successful animation of a Sandia part was demonstrated, and a computer video generated. This video is now accessible on a Sandia internal web server.

  15. Cell-based tissue engineering strategies used in the clinical repair of articular cartilage.

    PubMed

    Huang, Brian J; Hu, Jerry C; Athanasiou, Kyriacos A

    2016-08-01

    One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products. PMID:27177218

  16. Systems engineering and integration: Advanced avionics laboratories

    NASA Technical Reports Server (NTRS)

    1990-01-01

    In order to develop the new generation of avionics which will be necessary for upcoming programs such as the Lunar/Mars Initiative, Advanced Launch System, and the National Aerospace Plane, new Advanced Avionics Laboratories are required. To minimize costs and maximize benefits, these laboratories should be capable of supporting multiple avionics development efforts at a single location, and should be of a common design to support and encourage data sharing. Recent technological advances provide the capability of letting the designer or analyst perform simulations and testing in an environment similar to his engineering environment and these features should be incorporated into the new laboratories. Existing and emerging hardware and software standards must be incorporated wherever possible to provide additional cost savings and compatibility. Special care must be taken to design the laboratories such that real-time hardware-in-the-loop performance is not sacrificed in the pursuit of these goals. A special program-independent funding source should be identified for the development of Advanced Avionics Laboratories as resources supporting a wide range of upcoming NASA programs.

  17. Tissue Contraction Force Microscopy for Optimization of Engineered Cardiac Tissue.

    PubMed

    Schaefer, Jeremy A; Tranquillo, Robert T

    2016-01-01

    We developed a high-throughput screening assay that allows for relative comparison of the twitch force of millimeter-scale gel-based cardiac tissues. This assay is based on principles taken from traction force microscopy and uses fluorescent microspheres embedded in a soft polydimethylsiloxane (PDMS) substrate. A gel-forming cell suspension is simply pipetted onto the PDMS to form hemispherical cardiac tissue samples. Recordings of the fluorescent bead movement during tissue pacing are used to determine the maximum distance that the tissue can displace the elastic PDMS substrate. In this study, fibrin gel hemispheres containing human induced pluripotent stem cell-derived cardiomyocytes were formed on the PDMS and allowed to culture for 9 days. Bead displacement values were measured and compared to direct force measurements to validate the utility of the system. The amplitude of bead displacement correlated with direct force measurements, and the twitch force generated by the tissues was the same in 2 and 4 mg/mL fibrin gels, even though the 2 mg/mL samples visually appear more contractile if the assessment were made on free-floating samples. These results demonstrate the usefulness of this assay as a screening tool that allows for rapid sample preparation, data collection, and analysis in a simple and cost-effective platform. PMID:26538167

  18. The role of perfusion bioreactors in bone tissue engineering

    PubMed Central

    Gaspar, Diana Alves; Gomide, Viviane; Monteiro, Fernando Jorge

    2012-01-01

    Tissue engineering has emerged as a possible alternative to current treatments for bone injuries and defects. However, the common tissue engineering approach presents some obstacles to the development of functional tissues, such as insufficient nutrient and metabolite transport and non-homogenous cell distribution. Culture of bone cells in three-dimensional constructs in bioreactor systems is a solution for those problems as it improves mass transport in the culture system. For bone tissue engineering spinner flasks, rotating wall vessels and perfusion systems have been investigated, and based on these, variations that support cell seeding and mechanical stimulation have also been researched. This review aims at providing an overview of the concepts, advantages and future applications of bioreactor systems for bone tissue engineering with emphasis on the design of different perfusion systems and parameters that can be optimized. PMID:23507883

  19. Tissue Engineering of Articular Cartilage with Biomimetic Zones

    PubMed Central

    Klein, Travis J.; Malda, Jos; Sah, Robert L.

    2009-01-01

    Articular cartilage damage is a persistent and increasing problem with the aging population, and treatments to achieve biological repair or restoration remain a challenge. Cartilage tissue engineering approaches have been investigated for over 20 years, but have yet to achieve the consistency and effectiveness for widespread clinical use. One of the potential reasons for this is that the engineered tissues do not have or establish the normal zonal organization of cells and extracellular matrix that appears critical for normal tissue function. A number of approaches are being taken currently to engineer tissue that more closely mimics the organization of native articular cartilage. This review focuses on the zonal organization of native articular cartilage, strategies being used to develop such organization, the reorganization that occurs after culture or implantation, and future prospects for the tissue engineering of articular cartilage with biomimetic zones. PMID:19203206

  20. Fibrin Gel as an Injectable Biodegradable Scaffold and Cell Carrier for Tissue Engineering

    PubMed Central

    Li, Yuting; Meng, Hao; Liu, Yuan

    2015-01-01

    Due to the increasing needs for organ transplantation and a universal shortage of donated tissues, tissue engineering emerges as a useful approach to engineer functional tissues. Although different synthetic materials have been used to fabricate tissue engineering scaffolds, they have many limitations such as the biocompatibility concerns, the inability to support cell attachment, and undesirable degradation rate. Fibrin gel, a biopolymeric material, provides numerous advantages over synthetic materials in functioning as a tissue engineering scaffold and a cell carrier. Fibrin gel exhibits excellent biocompatibility, promotes cell attachment, and can degrade in a controllable manner. Additionally, fibrin gel mimics the natural blood-clotting process and self-assembles into a polymer network. The ability for fibrin to cure in situ has been exploited to develop injectable scaffolds for the repair of damaged cardiac and cartilage tissues. Additionally, fibrin gel has been utilized as a cell carrier to protect cells from the forces during the application and cell delivery processes while enhancing the cell viability and tissue regeneration. Here, we review the recent advancement in developing fibrin-based biomaterials for the development of injectable tissue engineering scaffold and cell carriers. PMID:25853146

  1. [Ocular surface reconstruction by tissue engineering].

    PubMed

    Kinoshita, Shigeru

    2002-12-01

    Ocular surface reconstruction by tissue engineering using somatic stem cells is a second-generation modality. In order to treat bilaterally affected, severe ocular surface disorders, we investigated the transplantation of two types of cultivated mucosal epithelia: allogenic corneal epithelial stem cells, and autologous oral mucosal epithelial cells. For this, first, we summarized the clinical results of allogenic keratoepithelioplasty and limbal transplantation. In addition, we showed that the immunological shift from Th1 to Th2 by using keyhole limpet hemocyanin was effective in suppressing the incidence of immunological rejection. Second, we investigated the transplantation of cultivated human corneal epithelial stem cells onto amniotic membrane. The cultivated sheet was created by co-culture with 3T3 fibroblasts, using the air-lift method, in cultivating the corneal epithelial stem cell on the amniotic membrane. These cultivated cells demonstrated positive keratin 3 and 12 specific to in vivo corneal epithelium, tight junction related proteins, and telomerase activity. The transplanted allogenic human corneal epithelial sheet survived on the corneal surface in all cases, and was quite effective for achieving ocular surface stability in the acute phase of Stevens-Johnson syndrome, ocular cicatricial pemphigoid, or chemical injury. However, a few cases developed immunological rejection or opportunistic infection. Third, to establish the transplantation of the autologous cultivated oral mucosal epithelial sheet, we performed animal experiments using rabbits. In vitro oral mucosal epithelial sheet showed histology similar to that of in vivo corneal epithelial sheet. It expressed positive keratin 3 as well. Since the autologous transplantation of this sheet survived on the ocular surface with the recovery of corneal transparency, a cultivated oral mucosal epithelium may become a substitute for corneal epithelium. Fourth, we created a cultivated human corneal

  2. Development of Hydrogels and Biomimetic Regulators as Tissue Engineering Scaffolds

    PubMed Central

    Shi, Junbin; Xing, Malcolm M. Q.; Zhong, Wen

    2012-01-01

    This paper reviews major research and development issues relating to hydrogels as scaffolds for tissue engineering, the article starts with a brief introduction of tissue engineering and hydrogels as extracellular matrix mimics, followed by a description of the various types of hydrogels and preparation methods, before a discussion of the physical and chemical properties that are important to their application. There follows a short comment on the trends of future research and development. Throughout the discussion there is an emphasis on the genetic understanding of bone tissue engineering application. PMID:24957963

  3. Vascularization and Angiogenesis in Tissue Engineering: Beyond Creating Static Networks.

    PubMed

    Rouwkema, Jeroen; Khademhosseini, Ali

    2016-09-01

    Engineered tissues need a vascular network to supply cells with nutrients and oxygen after implantation. A network that can connect to the vasculature of the patient after implantation can be included during in vitro culture. For optimal integration, this network needs to be highly organized, including venules, capillaries, and arterioles, to supply all of the cells with sufficient nutrients. Owing to the importance of vascularization for the clinical applicability of tissue engineering, many approaches have been investigated to include an organized vascular network in tissue constructs. This review will give an overview of recent efforts, and will propose future perspectives to engineer the optimal, functional vascular network. PMID:27032730

  4. Progress and opportunities for tissue-engineered skin

    NASA Astrophysics Data System (ADS)

    MacNeil, Sheila

    2007-02-01

    Tissue-engineered skin is now a reality. For patients with extensive full-thickness burns, laboratory expansion of skin cells to achieve barrier function can make the difference between life and death, and it was this acute need that drove the initiation of tissue engineering in the 1980s. A much larger group of patients have ulcers resistant to conventional healing, and treatments using cultured skin cells have been devised to restart the wound-healing process. In the laboratory, the use of tissue-engineered skin provides insight into the behaviour of skin cells in healthy skin and in diseases such as vitiligo, melanoma, psoriasis and blistering disorders.

  5. Structural and functional imaging of engineered tissue development using an integrated OCT and multiphoton microscope

    NASA Astrophysics Data System (ADS)

    Fahrner, Lester J., IV; Tan, Wei; Vinegoni, Claudio; Eurell, Thomas E.; Boppart, Stephen A.

    2004-07-01

    Recent advances in the field of tissue engineering have led to the development of complex three-dimensional tissue constructs. It has become clear, however, that the traditional tools used for studying standard cell cultures are not always adequate for diagnostically studying thick, highly-scattering cultured tissues. Furthermore, many techniques used for studying three-dimensional constructs are invasive or require exogenous fluorophores, which damage the tissue and prevent time-course studies of tissue development. An integrated optical coherence tomography (OCT) and multi-photon microscope (MPM) has been constructed for visualizing 3-D engineered tissues. OCT was used for imaging structure and cell organization, while MPM was used for assessing functional properties of cells. We demonstrate technical developments involved in the construction of this instrument and its use in the non-destructive investigation of cell movement and tissue organization in engineered tissues. Cells labeled with GFP and exogenous fluorescent probes have also been imaged with OCT and confocal microscopy. Studies indicate that an integrated microscope has the potential to be an enabling diagnostic tool for future studies in the growth and organization of engineering tissues and in cell-cell and cell-matrix interactions.

  6. Improved silicon carbide for advanced heat engines

    NASA Technical Reports Server (NTRS)

    Whalen, Thomas J.

    1988-01-01

    This is the third annual technical report for the program entitled, Improved Silicon Carbide for Advanced Heat Engines, for the period February 16, 1987 to February 15, 1988. The objective of the original program was the development of high strength, high reliability silicon carbide parts with complex shapes suitable for use in advanced heat engines. Injection molding is the forming method selected for the program because it is capable of forming complex parts adaptable for mass production on an economically sound basis. The goals of the revised program are to reach a Weibull characteristic strength of 550 MPa (80 ksi) and a Weibull modulus of 16 for bars tested in 4-point loading. Two tasks are discussed: Task 1 which involves materials and process improvements, and Task 2 which is a MOR bar matrix to improve strength and reliability. Many statistically designed experiments were completed under task 1 which improved the composition of the batches, the mixing of the powders, the sinter and anneal cycles. The best results were obtained by an attritor mixing process which yielded strengths in excess of 550 MPa (80 ksi) and an individual Weibull modulus of 16.8 for a 9-sample group. Strengths measured at 1200 and 1400 C were equal to the room temperature strength. Annealing of machined test bars significantly improved the strength. Molding yields were measured and flaw distributions were observed to follow a Poisson process. The second iteration of the Task 2 matrix experiment is described.

  7. Improved silicon carbide for advanced heat engines

    NASA Technical Reports Server (NTRS)

    Whalen, Thomas J.

    1987-01-01

    This is the second annual technical report entitled, Improved Silicon Carbide for Advanced Heat Engines, and includes work performed during the period February 16, 1986 to February 15, 1987. The program is conducted for NASA under contract NAS3-24384. The objective is the development of high strength, high reliability silicon carbide parts with complex shapes suitable for use in advanced heat engines. The fabrication methods used are to be adaptable for mass production of such parts on an economically sound basis. Injection molding is the forming method selected. This objective is to be accomplished in a two-phase program: (1) to achieve a 20 percent improvement in strength and a 100 percent increase in Weibull modulus of the baseline material; and (2) to produce a complex shaped part, a gas turbine rotor, for example, with the improved mechanical properties attained in the first phase. Eight tasks are included in the first phase covering the characterization of the properties of a baseline material, the improvement of those properties and the fabrication of complex shaped parts. Activities during the first contract year concentrated on two of these areas: fabrication and characterization of the baseline material (Task 1) and improvement of material and processes (Task 7). Activities during the second contract year included an MOR bar matrix study to improve mechanical properties (Task 2), materials and process improvements (Task 7), and a Ford-funded task to mold a turbocharger rotor with an improved material (Task 8).

  8. Multiscale assembly for tissue engineering and regenerative medicine

    PubMed Central

    Inci, Fatih; Tasoglu, Savas; Erkmen, Burcu; Demirci, Utkan

    2015-01-01

    Our understanding of cell biology and its integration with materials science has led to technological innovations in the bioengineering of tissue-mimicking grafts that can be utilized in clinical and pharmaceutical applications. Bio-engineering of native-like multiscale building blocks provides refined control over the cellular microenvironment, thus enabling functional tissues. In this review, we focus on assembling building blocks from the biomolecular level to the millimeter scale. We also provide an overview of techniques for assembling molecules, cells, spheroids, and microgels and achieving bottom-up tissue engineering. Additionally, we discuss driving mechanisms for self- and guided assembly to create micro-to-macro scale tissue structures. PMID:25796488

  9. [The biologic functional surfaces and their applications in tissue engineering].

    PubMed

    Yao, Fanglian; Chen, Man; Zhang, Hong; Zhang, Haiyue; An, Xiaoyan; Yao, Kangde

    2007-10-01

    The construction of biologic functional surfaces of materials, from the visual angle of material science, is aimed to make the biomaterials adapted by tissues, and to endow them with dynamic conformity; moreover, from the view-point of clinical applications, it is the functional surface to join the environmental tissues with the implanted material, playing the role of artificial extracellular matrix (ECM). The architecture of biologic functional surface is very important in tissue engineering science. Here the primary concepts of biological surface science and the construction and application of biofunctional surfaces in tissue engineering are reviewed. PMID:18027721

  10. Advanced bristle seals for gas turbine engines

    NASA Astrophysics Data System (ADS)

    Cabe, Jerry L.

    1993-01-01

    A seven month proof-of-concept program was conducted for an advanced bristle seal, called a bush seal, for use in gas turbine engines. This program was performed as a Small Business Innovation Research (SBIR) Phase 1 project. Bush seal specimen and a full ring bush seal were designed, evaluated, and manufactured for testing. An analytical study of the potential of the bush seal relative to a labyrinth seal was conducted. Static and dynamic testing of the bush seal was performed to determine the behavior of the bristles under pressurization and during contact with a rotating labyrinth tooth. Stable behavior of the bristle elements was observed during static pressurization of a full ring bush seal. The dynamic testing of various configurations of bush seal against a rotating labyrinth tooth showed minimal wear of the bristles relative to a conventional labyrinth seal. The development and application of the bush seal concept to gas turbine engines has the potential of improving the engine's performance while decreasing the degradation of the seal performance over time.

  11. Recent insights on applications of pullulan in tissue engineering.

    PubMed

    Singh, Ram Sarup; Kaur, Navpreet; Rana, Vikas; Kennedy, John F

    2016-11-20

    Tissue engineering is a recently emerging line of act which assists the regeneration of damaged tissues, unable to self-repair themselves and in turn, enhances the natural healing potential of patients. The repair of injured tissue can be induced with the help of some artificially created polymer scaffolds for successful tissue regeneration. The pullulan composite scaffolds can be used to enhance the proliferation and differentiation of cells for tissue regeneration. The unique pattern of pullulan with α-(1→4) and α-(1→6) linkages along with the presence of nine hydroxyl groups on its surface, endows the polymer with distinctive physical features required for tissue engineering. Pullulan can be used for vascular engineering, bone repair and skin tissue engineering. Pullulan composite scaffolds can also be used for treatment of injured femoral condyle bone, skull bone and full thickness skin wound of murine models, transversal mandibular and tibial osteotomy in goat, etc. This review article highlights the latest developments on applications of pullulan and its derivatives in tissue engineering. PMID:27561517

  12. Stem cell origin differently affects bone tissue engineering strategies

    PubMed Central

    Mattioli-Belmonte, Monica; Teti, Gabriella; Salvatore, Viviana; Focaroli, Stefano; Orciani, Monia; Dicarlo, Manuela; Fini, Milena; Orsini, Giovanna; Di Primio, Roberto; Falconi, Mirella

    2015-01-01

    Bone tissue engineering approaches are encouraging for the improvement of conventional bone grafting technique drawbacks. Thanks to their self-renewal and multi-lineage differentiation ability, stem cells are one of the major actors in tissue engineering approaches, and among these adult mesenchymal stem cells (MSCs) hold a great promise for regenerative medicine strategies. Bone marrow MSCs (BM-MSCs) are the first- identified and well-recognized stem cell population used in bone tissue engineering. Nevertheless, several factors hamper BM-MSC clinical application and subsequently, new stem cell sources have been investigated for these purposes. The fruitful selection and combination of tissue engineered scaffold, progenitor cells, and physiologic signaling molecules allowed the surgeon to reconstruct the missing natural tissue. On the basis of these considerations, we analyzed the capability of two different scaffolds, planned for osteochondral tissue regeneration, to modulate differentiation of adult stem cells of dissimilar local sources (i.e., periodontal ligament, maxillary periosteum) as well as adipose-derived stem cells (ASCs), in view of possible craniofacial tissue engineering strategies. We demonstrated that cells are differently committed toward the osteoblastic phenotype and therefore, taking into account their specific features, they could be intriguing cell sources in different stem cell-based bone/periodontal tissue regeneration approaches. PMID:26441682

  13. Repair and tissue engineering techniques for articular cartilage

    PubMed Central

    Makris, Eleftherios A.; Gomoll, Andreas H.; Malizos, Konstantinos N.; Hu, Jerry C.; Athanasiou, Kyriacos A.

    2015-01-01

    Chondral and osteochondral lesions due to injury or other pathology commonly result in the development of osteoarthritis, eventually leading to progressive total joint destruction. Although current progress suggests that biologic agents can delay the advancement of deterioration, such drugs are incapable of promoting tissue restoration. The limited ability of articular cartilage to regenerate renders joint arthroplasty an unavoidable surgical intervention. This Review describes current, widely used clinical repair techniques for resurfacing articular cartilage defects; short-term and long-term clinical outcomes of these techniques are discussed. Also reviewed is a developmental pipeline of regenerative biological products that over the next decade could revolutionize joint care by functionally healing articular cartilage. These products include cell-based and cell-free materials such as autologous and allogeneic cell-based approaches and multipotent and pluripotent stem-cell-based techniques. Central to these efforts is the prominent role that tissue engineering has in translating biological technology into clinical products; therefore, concomitant regulatory processes are also discussed. PMID:25247412

  14. Multiscale fabrication of biomimetic scaffolds for tympanic membrane tissue engineering.

    PubMed

    Mota, Carlos; Danti, Serena; D'Alessandro, Delfo; Trombi, Luisa; Ricci, Claudio; Puppi, Dario; Dinucci, Dinuccio; Milazzo, Mario; Stefanini, Cesare; Chiellini, Federica; Moroni, Lorenzo; Berrettini, Stefano

    2015-06-01

    The tympanic membrane (TM) is a thin tissue able to efficiently collect and transmit sound vibrations across the middle ear thanks to the particular orientation of its collagen fibers, radiate on one side and circular on the opposite side. Through the combination of advanced scaffolds and autologous cells, tissue engineering (TE) could offer valuable alternatives to autografting in major TM lesions. In this study, a multiscale approach based on electrospinning (ES) and additive manufacturing (AM) was investigated to fabricate scaffolds, based on FDA approved copolymers, resembling the anatomic features and collagen fiber arrangement of the human TM. A single scale TM scaffold was manufactured using a custom-made collector designed to confer a radial macro-arrangement to poly(lactic-co-glycolic acid) electrospun fibers during their deposition. Dual and triple scale scaffolds were fabricated combining conventional ES with AM to produce poly(ethylene oxide terephthalate)/poly(butylene terephthalate) block copolymer scaffolds with anatomic-like architecture. The processing parameters were optimized for each manufacturing method and copolymer. TM scaffolds were cultured in vitro with human mesenchymal stromal cells, which were viable, metabolically active and organized following the anisotropic character of the scaffolds. The highest viability, cell density and protein content were detected in dual and triple scale scaffolds. Our findings showed that these biomimetic micro-patterned substrates enabled cell disposal along architectural directions, thus appearing as promising substrates for developing functional TM replacements via TE. PMID:25947357

  15. Angiogenesis in tissue engineering: from concept to the vascularization of scaffold construct

    NASA Astrophysics Data System (ADS)

    Amirah Ishak, Siti; Pangestu Djuansjah, J. R.; Kadir, M. R. Abdul; Sukmana, Irza

    2014-06-01

    Angiogenesis, the formation of micro-vascular network from the preexisting vascular vessels, has been studied in the connection to the normal developmental process as well as numerous diseases. In tissue engineering research, angiogenesis is also essential to promote micro-vascular network inside engineered tissue constructs, mimicking a functional blood vessel in vivo. Micro-vascular network can be used to maintain adequate tissue oxygenation, nutrient transfer and waste removal. One of the problems faced by angiogenesis researchers is to find suitable in vitro assays and methods for assessing the effect of regulators on angiogenesis and micro-vessel formation. The assay would be reliable and repeatable with easily quantifiable with physiologically relevant. This review aims to highlights recent advanced and future challenges in developing and using an in vitro angiogenesis assay for the application on biomedical and tissue engineering research.

  16. Tissue engineering, stem cells, cloning, and parthenogenesis: new paradigms for therapy

    PubMed Central

    Hipp, Jason; Atala, Anthony

    2004-01-01

    Patients suffering from diseased and injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs which is worsening yearly due to the aging population. Scientists in the field of tissue engineering apply the principles of cell transplantation, materials science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Both therapeutic cloning (nucleus from a donor cell is transferred into an enucleated oocyte), and parthenogenesis (oocyte is activated and stimulated to divide), permit extraction of pluripotent embryonic stem cells, and offer a potentially limitless source of cells for tissue engineering applications. The stem cell field is also advancing rapidly, opening new options for therapy. The present article reviews recent progress in tissue engineering and describes applications of these new technologies that may offer novel therapies for patients with end-stage organ failure. PMID:15588286

  17. Environmental regulation of valvulogenesis: implications for tissue engineering.

    PubMed

    Riem Vis, Paul W; Kluin, Jolanda; Sluijter, Joost P G; van Herwerden, Lex A; Bouten, Carlijn V C

    2011-01-01

    Ongoing research efforts aim at improving the creation of tissue-engineered heart valves for in vivo systemic application. Hence, in vitro studies concentrate on optimising culture protocols incorporating biological as well as biophysical stimuli for tissue development. Important lessons can be drawn from valvulogenesis to mimic natural valve development in vitro. Here, we review the up-to-date status of valvulogenesis, focussing on the biomolecular and biophysical regulation of semilunar valve development. In addition, we discuss potential benefits of incorporating concepts derived from valvulogenesis, as well as alternative approaches, in tissue-engineering protocols, to improve in vitro valve development. The combined efforts from clinicians, cell biologists and engineers are required to implement and evaluate these approaches to achieve optimised protocols for heart-valve tissue engineering. PMID:20637649

  18. Engineering extracellular matrix structure in 3D multiphase tissues

    PubMed Central

    Gillette, Brian M.; Rossen, Ninna S.; Das, Nikkan; Leong, Debra; Wang, Meixin; Dugar, Arushi; Sia, Samuel K.

    2011-01-01

    In native tissues, microscale variations in the extracellular matrix (ECM) structure can drive different cellular behaviors. Although control over ECM structure could prove useful in tissue engineering and in studies of cellular behavior, isotropic 3D matrices poorly replicate variations in local microenvironments. In this paper, we demonstrate a method to engineer local variations in the density and size of collagen fibers throughout 3D tissues. The results showed that, in engineered multiphase tissues, the structures of collagen fibers in both the bulk ECM phases (as measured by mesh size and width of fibers) as well as at tissue interfaces (as measured by density of fibers and thickness of tissue interfaces) could be modulated by varying the collagen concentrations and gelling temperatures. As the method makes use of a previously published technique for tissue bonding, we also confirmed that significant adhesion strength at tissue interfaces was achieved under all conditions tested. Hence, this study demonstrates how collagen fiber structures can be engineered within all regions of a tightly integrated multiphase tissue scaffold by exploiting knowledge of collagen assembly. PMID:21840047

  19. Intestinal Tissue Engineering: Current Concepts and Future Vision of Regenerative Medicine in the Gut

    PubMed Central

    Bitar, Khalil N.; Raghavan, Shreya

    2011-01-01

    Background and Purpose Functional tissue engineering of the gastrointestinal (GI) tract is a complex process aiming to aid the regeneration of structural layers of smooth muscle, intrinsic enteric neuronal plexuses, specialized mucosa and epithelial cells as well as interstitial cells. The final tissue engineered construct is intended to mimic the native GI tract anatomically and physiologically. Physiological functionality of tissue engineered constructs is of utmost importance while considering clinical translation. The construct comprises of cellular components as well as biomaterial scaffolding components. Together, these determine the immune-response a tissue engineered construct would elicit from a host upon implantation. Over the last decade, significant advances have been made to mitigate adverse host reactions. These include a quest for identifying autologous cell sources like embryonic and adult stem cells, bone marrow-derived cells, neural crest-derived cells and muscle-derived stem cells. Scaffolding biomaterials have been fabricated with increasing biocompatibility and biodegradability. Manufacturing processes have advanced to allow for precise spatial architecture of scaffolds in order to mimic in vivo milieu closely and achieve neovascularization. This review will focus on the current concepts and the future vision of functional tissue engineering of the diverse neuromuscular structures of the GI tract from the esophagus to the internal anal sphincter. PMID:22188325

  20. Low-intensity pulsed ultrasound in dentofacial tissue engineering.

    PubMed

    Tanaka, Eiji; Kuroda, Shingo; Horiuchi, Shinya; Tabata, Akira; El-Bialy, Tarek

    2015-04-01

    Oral and maxillofacial diseases affect millions of people worldwide and hence tissue engineering can be considered an interesting and clinically relevant approach to regenerate orofacial tissues after being affected by different diseases. Among several innovations for tissue regeneration, low-intensity pulsed ultrasound (LIPUS) has been used extensively in medicine as a therapeutic, operative, and diagnostic tool. LIPUS is accepted to promote bone fracture repair and regeneration. Furthermore, the effect of LIPUS on soft tissues regeneration has been paid much attention, and many studies have performed to evaluate the potential use of LIPUS to tissue engineering soft tissues. The present article provides an overview about the status of LIPUS stimulation as a tool to be used to enhance regeneration/tissue engineering. This review consists of five parts. Part 1 is a brief introduction of the acoustic description of LIPUS and mechanical action. In Part 2, biological problems in dentofacial tissue engineering are proposed. Part 3 explores biologic mechanisms of LIPUS to cells and tissues in living body. In Part 4, the effectiveness of LIPUS on cell metabolism and tissue regeneration in dentistry are summarized. Finally, Part 5 relates the possibility of clinical application of LIPUS in orthodontics. The present review brings out better understanding of the bioeffect of LIPUS therapy on orofacial tissues which is essential to the successful integration of management remedies for tissue regeneration/engineering. To develop an evidence-based approach to clinical management and treatment of orofacial degenerative diseases using LIPUS, we would like to be in full pursuit of LIPUS biotherapy. Still, there are many challenges for this relatively new strategy, but the up to date achievements using it promises to go far beyond the present possibilities. PMID:25672801

  1. Fiber-Based Tissue Engineering: Progress, Challenges, and Opportunities

    PubMed Central

    Tamayol, Ali; Akbari, Mohsen; Annabi, Nasim; Paul, Arghya; Khademhosseini, Ali; Juncker, David

    2013-01-01

    Tissue engineering aims to improve the function of diseased or damaged organs by creating biological substitutes. To fabricate a functional tissue, the engineered construct should mimic the physiological environment including its structural, topographical, and mechanical properties. Moreover, the construct should facilitate nutrients and oxygen diffusion as well as removal of metabolic waste during tissue regeneration. In the last decade, fiber-based techniques such as weaving, knitting, braiding, as well as electrospinning, and direct writing have emerged as promising platforms for making 3D tissue constructs that can address the above mentioned challenges. Here, we critically review the techniques used to form cell-free and cell-laden fibers and to assemble them into scaffolds. We compare their mechanical properties, morphological features and biological activity. We discuss current challenges and future opportunities of fiber-based tissue engineering (FBTE) for use in research and clinical practice. PMID:23195284

  2. The role of tissue engineering and biomaterials in cardiac regenerative medicine.

    PubMed

    Zhao, Yimu; Feric, Nicole T; Thavandiran, Nimalan; Nunes, Sara S; Radisic, Milica

    2014-11-01

    In recent years, the development of 3-dimensional engineered heart tissue (EHT) has made large strides forward because of advances in stem cell biology, materials science, prevascularization strategies, and nanotechnology. As a result, the role of tissue engineering in cardiac regenerative medicine has become multifaceted as new applications become feasible. Cardiac tissue engineering has long been established to have the potential to partially or fully restore cardiac function after cardiac injury. However, EHTs may also serve as surrogate human cardiac tissue for drug-related toxicity screening. Cardiotoxicity remains a major cause of drug withdrawal in the pharmaceutical industry. Unsafe drugs reach the market because preclinical evaluation is insufficient to weed out cardiotoxic drugs in all their forms. Bioengineering methods could provide functional and mature human myocardial tissues, ie, physiologically relevant platforms, for screening the cardiotoxic effects of pharmaceutical agents and facilitate the discovery of new therapeutic agents. Finally, advances in induced pluripotent stem cells have made patient-specific EHTs possible, which opens up the possibility of personalized medicine. Herein, we give an overview of the present state of the art in cardiac tissue engineering, the challenges to the field, and future perspectives. PMID:25442432

  3. An Update to Space Biomedical Research: Tissue Engineering in Microgravity Bioreactors

    PubMed Central

    Barzegari, Abolfazl; Saei, Amir Ata

    2012-01-01

    Introduction The severe need for constructing replacement tissues in organ transplanta-tion has necessitated the development of tissue engineering approaches and bioreactors that can bring these approaches to reality. The inherent limitations of conventional bioreactors in generating realistic tissue constructs led to the devise of the microgravity tissue engineering that uses Rotating Wall Vessel (RWV) bioreactors initially developed by NASA. Methods In this review article, we intend to highlight some major advances and accomplishments in the rapidly-growing field of tissue engineering that could not be achieved without using microgravity. Results Research is now focused on assembly of 3 dimensional (3D) tissue fragments from various cell types in human body such as chon-drocytes, osteoblasts, embryonic and mesenchymal stem cells, hepatocytes and pancreas islet cells. Hepatocytes cultured under microgravity are now being used in extracorporeal bioartificial liver devices. Tissue constructs can be used not only in organ replacement therapy, but also in pharmaco-toxicology and food safety assessment. 3D models of vari-ous cancers may be used in studying cancer development and biology or in high-throughput screening of anticancer drug candidates. Finally, 3D heterogeneous assemblies from cancer/immune cells provide models for immunotherapy of cancer. Conclusion Tissue engineering in (simulated) microgravity has been one of the stunning impacts of space research on biomedical sciences and their applications on earth. PMID:23678438

  4. Stratified scaffold design for engineering composite tissues.

    PubMed

    Mosher, Christopher Z; Spalazzi, Jeffrey P; Lu, Helen H

    2015-08-01

    A significant challenge to orthopaedic soft tissue repair is the biological fixation of autologous or allogeneic grafts with bone, whereby the lack of functional integration between such grafts and host bone has limited the clinical success of anterior cruciate ligament (ACL) and other common soft tissue-based reconstructive grafts. The inability of current surgical reconstruction to restore the native fibrocartilaginous insertion between the ACL and the femur or tibia, which minimizes stress concentration and facilitates load transfer between the soft and hard tissues, compromises the long-term clinical functionality of these grafts. To enable integration, a stratified scaffold design that mimics the multiple tissue regions of the ACL interface (ligament-fibrocartilage-bone) represents a promising strategy for composite tissue formation. Moreover, distinct cellular organization and phase-specific matrix heterogeneity achieved through co- or tri-culture within the scaffold system can promote biomimetic multi-tissue regeneration. Here, we describe the methods for fabricating a tri-phasic scaffold intended for ligament-bone integration, as well as the tri-culture of fibroblasts, chondrocytes, and osteoblasts on the stratified scaffold for the formation of structurally contiguous and compositionally distinct regions of ligament, fibrocartilage and bone. The primary advantage of the tri-phasic scaffold is the recapitulation of the multi-tissue organization across the native interface through the layered design. Moreover, in addition to ease of fabrication, each scaffold phase is similar in polymer composition and therefore can be joined together by sintering, enabling the seamless integration of each region and avoiding delamination between scaffold layers. PMID:25846397

  5. Stem cell sources for vascular tissue engineering and regeneration.

    PubMed

    Bajpai, Vivek K; Andreadis, Stelios T

    2012-10-01

    This review focuses on the stem cell sources with the potential to be used in vascular tissue engineering and to promote vascular regeneration. The first clinical studies using tissue-engineered vascular grafts are already under way, supporting the potential of this technology in the treatment of cardiovascular and other diseases. Despite progress in engineering biomaterials with the appropriate mechanical properties and biological cues as well as bioreactors for generating the correct tissue microenvironment, the source of cells that make up the vascular tissues remains a major challenge for tissue engineers and physicians. Mature cells from the tissue of origin may be difficult to obtain and suffer from limited proliferative capacity, which may further decline as a function of donor age. On the other hand, multipotent and pluripotent stem cells have great potential to provide large numbers of autologous cells with a great differentiation capacity. Here, we discuss the adult multipotent as well as embryonic and induced pluripotent stem cells, their differentiation potential toward vascular lineages, and their use in engineering functional and implantable vascular tissues. We also discuss the associated challenges that need to be addressed in order to facilitate the transition of this technology from the bench to the bedside. PMID:22571595

  6. Stem Cell Sources for Vascular Tissue Engineering and Regeneration

    PubMed Central

    Bajpai, Vivek K.

    2012-01-01

    This review focuses on the stem cell sources with the potential to be used in vascular tissue engineering and to promote vascular regeneration. The first clinical studies using tissue-engineered vascular grafts are already under way, supporting the potential of this technology in the treatment of cardiovascular and other diseases. Despite progress in engineering biomaterials with the appropriate mechanical properties and biological cues as well as bioreactors for generating the correct tissue microenvironment, the source of cells that make up the vascular tissues remains a major challenge for tissue engineers and physicians. Mature cells from the tissue of origin may be difficult to obtain and suffer from limited proliferative capacity, which may further decline as a function of donor age. On the other hand, multipotent and pluripotent stem cells have great potential to provide large numbers of autologous cells with a great differentiation capacity. Here, we discuss the adult multipotent as well as embryonic and induced pluripotent stem cells, their differentiation potential toward vascular lineages, and their use in engineering functional and implantable vascular tissues. We also discuss the associated challenges that need to be addressed in order to facilitate the transition of this technology from the bench to the bedside. PMID:22571595

  7. Application of the cell sheet technique in tissue engineering

    PubMed Central

    CHEN, GUANGNAN; QI, YIYING; NIU, LIE; DI, TUOYU; ZHONG, JINWEI; FANG, TINGTING; YAN, WEIQI

    2015-01-01

    The development and application of the tissue engineering technique has shown a significant potential in regenerative medicine. However, the limitations of conventional tissue engineering methods (cell suspensions, scaffolds and/or growth factors) restrict its application in certain fields. The novel cell sheet technique can overcome such disadvantages. Cultured cells can be harvested as intact sheets without the use of proteolytic enzymes, such as trypsin or dispase, which can result in cell damage and loss of differentiated phenotypes. The cell sheet is a complete layer, which contains extracellular matrix, ion channel, growth factor receptors, nexin and other important cell surface proteins. Mesenchymal stem cells (MSCs), which have the potential for multiple differentiation, are promising candidate seed cells for tissue engineering. The MSC sheet technique may have potential in the fields of regenerative medicine and tissue engineering in general. Additionally, induced pluripotent stem cell and embryonic stem cell-derived cell sheets have been proposed for tissue regeneration. Currently, the application of cell sheet for tissue reconstruction includes: Direct recipient sites implantation, superposition of cell sheets to construct three-dimensional structure for implantation, or cell sheet combined with scaffolds. The present review discusses the progress in cell sheet techniques, particularly stem cell sheet techniques, in tissue engineering. PMID:26623011

  8. Adipose-Derived Stem Cell Delivery for Adipose Tissue Engineering: Current Status and Potential Applications in a Tissue Engineering Chamber Model.

    PubMed

    Zhan, Weiqing; Tan, Shaun S; Lu, Feng

    2016-08-01

    In reconstructive surgery, there is a clinical need for adequate implants to repair soft tissue defects caused by traumatic injury, tumor resection, or congenital abnormalities. Adipose tissue engineering may provide answers to this increasing demand. This study comprehensively reviews current approaches to adipose tissue engineering, detailing different cell carriers under investigation, with a special focus on the application of adipose-derived stem cells (ASCs). ASCs act as building blocks for new tissue growth and as modulators of the host response. Recent studies have also demonstrated that the implantation of a hollow protected chamber, combined with a vascular pedicle within the fat flaps provides blood supply and enables the growth of large-volume of engineered soft tissue. Conceptually, it would be of value to co-regulate this unique chamber model with adipose-derived stem cells to obtain a greater volume of soft tissue constructs for clinical use. Our review provides a cogent update on these advances and details the generation of possible fat substitutes. PMID:27075632

  9. Applications of fiber optic sensors in advanced engine controls

    NASA Astrophysics Data System (ADS)

    Nitka, Edward F., II

    1989-06-01

    Measured parameters, operating ranges, accuracy requirements, environmental constraints, and speed of response of fiber optic sensors are identified for three categories of engines. The three engine categories are: (1) current turbojet, turbofan, and turboprop engines; (2) next generation and turbofan engines to be built in the 1990s; and (3) advanced supersonic/hypersonic engines represented by ramjet, scramjet, and air-turbo-ramjet concepts. The key development and test efforts in engine control applications of fiber optic sensors are discussed.

  10. Strategies for improving the physiological relevance of human engineered tissues

    PubMed Central

    Abbott, Rosalyn D; Kaplan, David L

    2015-01-01

    This review examines important robust methods for sustained, steady state, in vitro culture. To achieve ‘physiologically relevant’ tissues in vitro additional complexity must be introduced to provide suitable transport, cell signaling, and matrix support for cells in 3D environments to achieve stable readouts of tissue function. Most tissue engineering systems draw conclusions on tissue functions such as responses to toxins, nutrition or drugs based on short term outcomes with in vitro cultures (2–14 days). However, short term cultures limit insight with physiological relevance, as the cells and tissues have not reached a steady state. PMID:25937289

  11. Ceramic technology for advanced heat engines project

    SciTech Connect

    Not Available

    1990-09-01

    The Ceramic Technology for Advanced Heat Engines Project was developed by the Department of Energy's Office of Transportation Systems in Conservation and Renewable Energy. This project was developed to meet the ceramic technology requirements of the OTT's automotive technology programs. This project is managed by ORNL and is closely coordinated with complementary ceramics tasks funded by other DOE offices, NASA, DoD, and industry. Research is discussed under the following topics; Turbomilling of SiC Whiskers; microwave sintering of silicon nitride; and milling characterization; processing of monolithics; silicon nitride matrix; oxide matrix; silicate matrix; thermal and wear coatings; joining; design; contact interfaces; time-dependent behavior; environmental effects; fracture mechanics; nondestructive evaluation; and technology transfer. References, figures, and tables are included with each topic.

  12. Various advanced design projects promoting engineering education

    NASA Astrophysics Data System (ADS)

    The Universities Space Research Association (USRA) Advanced Design Program (ADP) program promotes engineering education in the field of design by presenting students with challenging design projects drawn from actual NASA interests. In doing so, the program yields two very positive results. Firstly, the students gain a valuable experience that will prepare them for design problems with which they will be faced in their professional careers. Secondly, NASA is able to use the work done by students as an additional resource in meeting its own design objectives. The 1994 projects include: Universal Test Facility; Automated Protein Crystal Growth Facility; Stiffening of the ACES Deployable Space Boom; Launch System Design for Access to Space; LH2 Fuel Tank Design for SSTO Vehicle; and Feed System Design for a Reduced Pressure Tank.

  13. Various advanced design projects promoting engineering education

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Universities Space Research Association (USRA) Advanced Design Program (ADP) program promotes engineering education in the field of design by presenting students with challenging design projects drawn from actual NASA interests. In doing so, the program yields two very positive results. Firstly, the students gain a valuable experience that will prepare them for design problems with which they will be faced in their professional careers. Secondly, NASA is able to use the work done by students as an additional resource in meeting its own design objectives. The 1994 projects include: Universal Test Facility; Automated Protein Crystal Growth Facility; Stiffening of the ACES Deployable Space Boom; Launch System Design for Access to Space; LH2 Fuel Tank Design for SSTO Vehicle; and Feed System Design for a Reduced Pressure Tank.

  14. [Tissue engineering and construction of human skin in vitro].

    PubMed

    Arvelo, Francisco

    2007-09-01

    Tissue engineering is the new science that has come to make possible the growth of new organ tissue from small fragments of healthy tissue, thus partially or totally restoring the lost functions of ill tissues or organs, as shown by the achievements made with the culture of skin, cornea or cartilage. Thus far, this new science is able to ensure the recovery of lost functions and, doubtlessly, in a near future will be capable of developing tissues and organs not unlike natural ones. In our laboratory we have began the development of tissue engineering techniques for the successful construction of in vitro skin with the aim at mid term of producing cornea and cartilage. In a first clinical trial, these techniques were applied in the treatment of chronic skin lesions and the advantages and reach of these new tools were demonstrated for the effective solution of problems with would otherwise not be easily solved through the use of conventional treatments. PMID:17853796

  15. Using Simulated Debates to Teach History of Engineering Advances

    ERIC Educational Resources Information Center

    Reynolds, Terry S.

    1976-01-01

    Described is a technique for utilizing debates of past engineering controversies in the classroom as a means of teaching the history of engineering advances. Included is a bibliography for three debate topics relating to important controversies. (SL)

  16. Modular Assembly Approach to Engineer Geometrically Precise Cardiovascular Tissue.

    PubMed

    Lee, Benjamin W; Liu, Bohao; Pluchinsky, Adam; Kim, Nathan; Eng, George; Vunjak-Novakovic, Gordana

    2016-04-01

    This modular assembly approach to microfabricate functional cardiovascular tissue composites enables quantitative assessment of the effects of microarchitecture on cellular function. Cardiac and endothelial modules are micromolded separately, designed to direct cardiomyocyte alignment and anisotropic contraction or vascular network formation. Assembled cardiovascular tissue composites contract synchronously, facilitating the use of this tissue-engineering platform to study structure-function relationships in the heart. PMID:26865105

  17. Recent Developments in Vascular Imaging Techniques in Tissue Engineering and Regenerative Medicine

    PubMed Central

    Upputuri, Paul Kumar; Sivasubramanian, Kathyayini; Mark, Chong Seow Khoon; Pramanik, Manojit

    2015-01-01

    Adequate vascularisation is key in determining the clinical outcome of stem cells and engineered tissue in regenerative medicine. Numerous imaging modalities have been developed and used for the visualization of vascularisation in tissue engineering. In this review, we briefly discuss the very recent advances aiming at high performance imaging of vasculature. We classify the vascular imaging modalities into three major groups: nonoptical methods (X-ray, magnetic resonance, ultrasound, and positron emission imaging), optical methods (optical coherence, fluorescence, multiphoton, and laser speckle imaging), and hybrid methods (photoacoustic imaging). We then summarize the strengths and challenges of these methods for preclinical and clinical applications. PMID:25821821

  18. Recent developments in vascular imaging techniques in tissue engineering and regenerative medicine.

    PubMed

    Upputuri, Paul Kumar; Sivasubramanian, Kathyayini; Mark, Chong Seow Khoon; Pramanik, Manojit

    2015-01-01

    Adequate vascularisation is key in determining the clinical outcome of stem cells and engineered tissue in regenerative medicine. Numerous imaging modalities have been developed and used for the visualization of vascularisation in tissue engineering. In this review, we briefly discuss the very recent advances aiming at high performance imaging of vasculature. We classify the vascular imaging modalities into three major groups: nonoptical methods (X-ray, magnetic resonance, ultrasound, and positron emission imaging), optical methods (optical coherence, fluorescence, multiphoton, and laser speckle imaging), and hybrid methods (photoacoustic imaging). We then summarize the strengths and challenges of these methods for preclinical and clinical applications. PMID:25821821

  19. Introduction to Advanced Engine Control Concepts

    NASA Technical Reports Server (NTRS)

    Sanjay, Garg

    2007-01-01

    With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet these challenges through the concept of Intelligent Propulsion Systems. The key enabling technologies for an Intelligent Propulsion System are the increased efficiencies of components through active control, advanced diagnostics and prognostics integrated with intelligent engine control to enhance operational reliability and component life, and distributed control with smart sensors and actuators in an adaptive fault tolerant architecture. This presentation describes the current activities of the Controls and Dynamics Branch in the areas of active component control and propulsion system intelligent control, and presents some recent analytical and experimental results in these areas.

  20. SAPLE: Sandia Advanced Personnel Locator Engine.

    SciTech Connect

    Procopio, Michael J.

    2010-04-01

    We present the Sandia Advanced Personnel Locator Engine (SAPLE) web application, a directory search application for use by Sandia National Laboratories personnel. SAPLE's purpose is to return Sandia personnel 'results' as a function of user search queries, with its mission to make it easier and faster to find people at Sandia. To accomplish this, SAPLE breaks from more traditional directory application approaches by aiming to return the correct set of results while placing minimal constraints on the user's query. Two key features form the core of SAPLE: advanced search query interpretation and inexact string matching. SAPLE's query interpretation permits the user to perform compound queries when typing into a single search field; where able, SAPLE infers the type of field that the user intends to search on based on the value of the search term. SAPLE's inexact string matching feature yields a high-quality ranking of personnel search results even when there are no exact matches to the user's query. This paper explores these two key features, describing in detail the architecture and operation of SAPLE. Finally, an extensive analysis on logged search query data taken from an 11-week sample period is presented.

  1. Photo Cleavable Polymers for Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Apostol, Monica

    We have found that P4VP and PMMA thin films can be etched with UVA radiation. Furthermore, we also found that dermal fibroblasts could be cultured successfully on the P4VP polymer, with a doubling time comparable to tissue culture Petri dish standards. Consequently we were able to grow tissue on P4VP substrates which could easily be lifted using UVA radiation. The cells that were removed were then re-plated at a lower density and a series of assays was performed at 3 and 6 days. While only a small amount of damage was discernable at day 3 nearly complete recovery was observed at day 6. The technique was also used to pattern areas within the tissue, where other types of cells could be inserted. In order to demonstrate the technique, a hybrid tissue layer was produced, where the dermal fibroblasts in a circular area at the center of the sample were removed via exposure through a mask. A keratinocyte layer was inserted which adhere to the fibroblast layer forming a tissue with integrated layers of two distinct cell types. We also investigated the effects of coated TiO2 particles on cells exposed to UVC. We found that as expected, cells were adversely affected by exposure to UVC and died even after exposure to as little as 3.5 J/cm 2. Addition of 0.4mg/ml TiO2 particles that were uncoated did not provide protection, and the cells died at the same rate. Addition of 4mg/ml of coated TiO2 on the other hand, did not affect cell viability in the absence of UV light and increased the viability after exposure to UVC radiation. In fact the cells containing the coated particles were indistinguishable for the unexposed control samples even after exposure to as much as 7.1J/cm 2 of UVC.

  2. Multifaceted signaling regulators of chondrogenesis: Implications in cartilage regeneration and tissue engineering

    PubMed Central

    Green, Jordan D.; Tollemar, Viktor; Dougherty, Mark; Yan, Zhengjian; Yin, Liangjun; Ye, Jixing; Collier, Zachary; Mohammed, Maryam K.; Haydon, Rex C.; Luu, Hue H.; Kang, Richard; Lee, Michael J.; Ho, Sherwin H.; He, Tong-Chuan; Shi, Lewis L.; Athiviraham, Aravind

    2015-01-01

    Defects of articular cartilage present a unique clinical challenge due to its poor self-healing capacity and avascular nature. Current surgical treatment options do not ensure consistent regeneration of hyaline cartilage in favor of fibrous tissue. Here, we review the current understanding of the most important biological regulators of chondrogenesis and their interactions, to provide insight into potential applications for cartilage tissue engineering. These include various signaling pathways, including: fibroblast growth factors (FGFs), transforming growth factor β (TGF-β)/bone morphogenic proteins (BMPs), Wnt/β-catenin, Hedgehog, Notch, hypoxia, and angiogenic signaling pathways. Transcriptional and epigenetic regulation of chondrogenesis will also be discussed. Advances in our understanding of these signaling pathways have led to promising advances in cartilage regeneration and tissue engineering. PMID:26835506

  3. Biomaterial based cardiac tissue engineering and its applications

    PubMed Central

    Huyer, Locke Davenport; Montgomery, Miles; Zhao, Yimu; Xiao, Yun; Conant, Genevieve; Korolj, Anastasia; Radisic, Milica

    2015-01-01

    Cardiovascular disease is a leading cause of death worldwide, necessitating the development of effective treatment strategies. A myocardial infarction involves the blockage of a coronary artery leading to depletion of nutrient and oxygen supply to cardiomyocytes and massive cell death in a region of the myocardium. Cardiac tissue engineering is the growth of functional cardiac tissue in vitro on biomaterial scaffolds for regenerative medicine application. This strategy relies on the optimization of the complex relationship between cell networks and biomaterial properties. In this review, we discuss important biomaterial properties for cardiac tissue engineering applications, such as elasticity, degradation, and induced host response, and their relationship to engineered cardiac cell environments. With these properties in mind, we also emphasize in vitro use of cardiac tissues for high-throughput drug screening and disease modelling. PMID:25989939

  4. Biomaterial based cardiac tissue engineering and its applications.

    PubMed

    Huyer, Locke Davenport; Montgomery, Miles; Zhao, Yimu; Xiao, Yun; Conant, Genevieve; Korolj, Anastasia; Radisic, Milica

    2015-06-01

    Cardiovascular disease is a leading cause of death worldwide, necessitating the development of effective treatment strategies. A myocardial infarction involves the blockage of a coronary artery leading to depletion of nutrient and oxygen supply to cardiomyocytes and massive cell death in a region of the myocardium. Cardiac tissue engineering is the growth of functional cardiac tissue in vitro on biomaterial scaffolds for regenerative medicine application. This strategy relies on the optimization of the complex relationship between cell networks and biomaterial properties. In this review, we discuss important biomaterial properties for cardiac tissue engineering applications, such as elasticity, degradation, and induced host response, and their relationship to engineered cardiac cell environments. With these properties in mind, we also emphasize in vitro use of cardiac tissues for high-throughput drug screening and disease modelling. PMID:25989939

  5. Stem cells for tissue engineering of articular cartilage.

    PubMed

    Gao, J; Yao, J Q; Caplan, A I

    2007-07-01

    Articular cartilage injuries are one of the most common disorders in the musculo-skeletal system. Injured cartilage tissue cannot spontaneously heal and, if not treated, can lead to osteoarthritis of the affected joints. Although a variety of procedures are being employed to repair cartilage damage, methods that result in consistent durable repair tissue are not yet available. Tissue engineering is a recently developed science that merges the fields of cell biology, engineering, material science, and surgery to regenerate new functional tissue. Three critical components in tissue engineering of cartilage are as follows: first, sufficient cell numbers within the defect, such as chondrocytes or multipotent stem cells capable of differentiating into chondrocytes; second, access to growth and differentiation factors that modulate these cells to differentiate through the chondrogenic lineage; third, a cell carrier or matrix that fills the defect, delivers the appropriate cells, and supports cell proliferation and differentiation. Stem cells that exist in the embyro or in adult somatic tissues are able to renew themselves through cell division without changing their phenotype and are able to differentiate into multiple lineages including the chondrogenic lineage under certain physiological or experimental conditions. Here the application of stem cells as a cell source for cartilage tissue engineering is reviewed. PMID:17822146

  6. Smooth Muscle Strips for Intestinal Tissue Engineering

    PubMed Central

    Walthers, Christopher M.; Lee, Min; Wu, Benjamin M.; Dunn, James C. Y.

    2014-01-01

    Functionally contracting smooth muscle is an essential part of the engineered intestine that has not been replicated in vitro. The purpose of this study is to produce contracting smooth muscle in culture by maintaining the native smooth muscle organization. We employed intact smooth muscle strips and compared them to dissociated smooth muscle cells in culture for 14 days. Cells isolated by enzymatic digestion quickly lost maturity markers for smooth muscle cells and contained few enteric neural and glial cells. Cultured smooth muscle strips exhibited periodic contraction and maintained neural and glial markers. Smooth muscle strips cultured for 14 days also exhibited regular fluctuation of intracellular calcium, whereas cultured smooth muscle cells did not. After implantation in omentum for 14 days on polycaprolactone scaffolds, smooth muscle strip constructs expressed high levels of smooth muscle maturity markers as well as enteric neural and glial cells. Intact smooth muscle strips may be a useful component for engineered intestinal smooth muscle. PMID:25486279

  7. Superior Tissue Evolution in Slow-Degrading Scaffolds for Valvular Tissue Engineering.

    PubMed

    Brugmans, Marieke M C P; Soekhradj-Soechit, R Sarita; van Geemen, Daphne; Cox, Martijn; Bouten, Carlijn V C; Baaijens, Frank P T; Driessen-Mol, Anita

    2016-01-01

    Synthetic polymers are widely used to fabricate porous scaffolds for the regeneration of cardiovascular tissues. To ensure mechanical integrity, a balance between the rate of scaffold absorption and tissue formation is of high importance. A higher rate of tissue formation is expected in fast-degrading materials than in slow-degrading materials. This could be a result of synthetic cells, which aim to compensate for the fast loss of mechanical integrity of the scaffold by deposition of collagen fibers. Here, we studied the effect of fast-degrading polyglycolic acid scaffolds coated with poly-4-hydroxybutyrate (PGA-P4HB) and slow-degrading poly-ɛ-caprolactone (PCL) scaffolds on amount of tissue, composition, and mechanical characteristics in time, and compared these engineered values with values for native human heart valves. Electrospun PGA-P4HB and PCL scaffolds were either kept unseeded in culture or were seeded with human vascular-derived cells. Tissue formation, extracellular matrix (ECM) composition, remaining scaffold weight, tissue-to-scaffold weight ratio, and mechanical properties were analyzed every week up to 6 weeks. Mass of unseeded PCL scaffolds remained stable during culture, whereas PGA-P4HB scaffolds degraded rapidly. When seeded with cells, both scaffold types demonstrated increasing amounts of tissue with time, which was more pronounced for PGA-P4HB-based tissues during the first 2 weeks; however, PCL-based tissues resulted in the highest amount of tissue after 6 weeks. This study is the first to provide insight into the tissue-to-scaffold weight ratio, therewith allowing for a fair comparison between engineered tissues cultured on scaffolds as well as between native heart valve tissues. Although the absolute amount of ECM components differed between the engineered tissues, the ratio between ECM components was similar after 6 weeks. PCL-based tissues maintained their shape, whereas the PGA-P4HB-based tissues deformed during culture. After 6 weeks

  8. Ceramic applications in the advanced Stirling automotive engine

    NASA Technical Reports Server (NTRS)

    Tomazic, W. A.; Cairelli, J. E.

    1977-01-01

    The ideal cycle, its application to a practical machine, and the specific advantages of high efficiency, low emissions, multi-fuel capability, and low noise of the stirling engine are discussed. Certain portions of the Stirling engine must operate continuously at high temperature. Ceramics offer the potential of cost reduction and efficiency improvement for advanced engine applications. Potential applications for ceramics in Stirling engines, and some of the special problems pertinent to using ceramics in the Stirling engine are described. The research and technology program in ceramics which is planned to support the development of advanced Stirling engines is outlined.

  9. Regeneration of the anterior cruciate ligament: Current strategies in tissue engineering

    PubMed Central

    Nau, Thomas; Teuschl, Andreas

    2015-01-01

    Recent advancements in the field of musculoskeletal tissue engineering have raised an increasing interest in the regeneration of the anterior cruciate ligament (ACL). It is the aim of this article to review the current research efforts and highlight promising tissue engineering strategies. The four main components of tissue engineering also apply in several ACL regeneration research efforts. Scaffolds from biological materials, biodegradable polymers and composite materials are used. The main cell sources are mesenchymal stem cells and ACL fibroblasts. In addition, growth factors and mechanical stimuli are applied. So far, the regenerated ACL constructs have been tested in a few animal studies and the results are encouraging. The different strategies, from in vitro ACL regeneration in bioreactor systems to bio-enhanced repair and regeneration, are under constant development. We expect considerable progress in the near future that will result in a realistic option for ACL surgery soon. PMID:25621217

  10. Microfabrication of Cell-Laden Hydrogels for Engineering Mineralized and Load Bearing Tissues.

    PubMed

    Li, Chia-Cheng; Kharaziha, Mahshid; Min, Christine; Maas, Richard; Nikkhah, Mehdi

    2015-01-01

    Microengineering technologies and advanced biomaterials have extensive applications in the field of regenerative medicine. In this chapter, we review the integration of microfabrication techniques and hydrogel-based biomaterials in the field of dental, bone, and cartilage tissue engineering. We primarily discuss the major features that make hydrogels attractive candidates to mimic extracellular matrix (ECM), and we consider the benefits of three-dimensional (3D) culture systems for tissue engineering applications. We then focus on the fundamental principles of microfabrication techniques including photolithography, soft lithography and bioprinting approaches. Lastly, we summarize recent research on microengineering cell-laden hydrogel constructs for dental, bone and cartilage regeneration, and discuss future applications of microfabrication techniques for load-bearing tissue engineering. PMID:26545742

  11. Advanced oxygen-hydrocarbon rocket engine study

    NASA Technical Reports Server (NTRS)

    Obrien, C. J.; Salkeld, R.

    1980-01-01

    The advantages and disadvantages, system performance and operating limits, engine parametric data, and technology requirements for candidate high pressure LO2/Hydrocarbon engine systems are summarized. These summaries of parametric analysis and design provide a consistent engine system data base. Power balance data were generated for the eleven engine cycles. Engine cycle rating parameters were established and the desired condition and the effect of the parameter on the engine and/or vehicle are described.

  12. Living electrodes: tissue engineering the neural interface.

    PubMed

    Green, Rylie A; Lim, Khoon S; Henderson, William C; Hassarati, Rachelle T; Martens, Penny J; Lovell, Nigel H; Poole-Warren, Laura A

    2013-01-01

    Soft, cell integrated electrode coatings are proposed to address the problem of scar tissue encapsulation of stimulating neuroprosthetics. The aim of these studies was to prove the concept and feasibility of integrating a cell loaded hydrogel with existing electrode coating technologies. Layered conductive hydrogel constructs are embedded with neural cells and shown to both support cell growth and maintain electro activity. The safe charge injection limit of these electrodes was 8 times higher than conventional platinum (Pt) electrodes and the stiffness was four orders of magnitude lower than Pt. Future studies will determine the biological cues required to support stem cell differentiation from the electrode surface. PMID:24111345

  13. Advanced stratified charge rotary aircraft engine design study

    NASA Technical Reports Server (NTRS)

    Badgley, P.; Berkowitz, M.; Jones, C.; Myers, D.; Norwood, E.; Pratt, W. B.; Ellis, D. R.; Huggins, G.; Mueller, A.; Hembrey, J. H.

    1982-01-01

    A technology base of new developments which offered potential benefits to a general aviation engine was compiled and ranked. Using design approaches selected from the ranked list, conceptual design studies were performed of an advanced and a highly advanced engine sized to provide 186/250 shaft Kw/HP under cruise conditions at 7620/25,000 m/ft altitude. These are turbocharged, direct-injected stratified charge engines intended for commercial introduction in the early 1990's. The engine descriptive data includes tables, curves, and drawings depicting configuration, performance, weights and sizes, heat rejection, ignition and fuel injection system descriptions, maintenance requirements, and scaling data for varying power. An engine-airframe integration study of the resulting engines in advanced airframes was performed on a comparative basis with current production type engines. The results show airplane performance, costs, noise & installation factors. The rotary-engined airplanes display substantial improvements over the baseline, including 30 to 35% lower fuel usage.

  14. Biocompatible magnetic core-shell nanocomposites for engineered magnetic tissues

    NASA Astrophysics Data System (ADS)

    Rodriguez-Arco, Laura; Rodriguez, Ismael A.; Carriel, Victor; Bonhome-Espinosa, Ana B.; Campos, Fernando; Kuzhir, Pavel; Duran, Juan D. G.; Lopez-Lopez, Modesto T.

    2016-04-01

    The inclusion of magnetic nanoparticles into biopolymer matrixes enables the preparation of magnetic field-responsive engineered tissues. Here we describe a synthetic route to prepare biocompatible core-shell nanostructures consisting of a polymeric core and a magnetic shell, which are used for this purpose. We show that using a core-shell architecture is doubly advantageous. First, gravitational settling for core-shell nanocomposites is slower because of the reduction of the composite average density connected to the light polymer core. Second, the magnetic response of core-shell nanocomposites can be tuned by changing the thickness of the magnetic layer. The incorporation of the composites into biopolymer hydrogels containing cells results in magnetic field-responsive engineered tissues whose mechanical properties can be controlled by external magnetic forces. Indeed, we obtain a significant increase of the viscoelastic moduli of the engineered tissues when exposed to an external magnetic field. Because the composites are functionalized with polyethylene glycol, the prepared bio-artificial tissue-like constructs also display excellent ex vivo cell viability and proliferation. When implanted in vivo, the engineered tissues show good biocompatibility and outstanding interaction with the host tissue. Actually, they only cause a localized transitory inflammatory reaction at the implantation site, without any effect on other organs. Altogether, our results suggest that the inclusion of magnetic core-shell nanocomposites into biomaterials would enable tissue engineering of artificial substitutes whose mechanical properties could be tuned to match those of the potential target tissue. In a wider perspective, the good biocompatibility and magnetic behavior of the composites could be beneficial for many other applications.The inclusion of magnetic nanoparticles into biopolymer matrixes enables the preparation of magnetic field-responsive engineered tissues. Here we

  15. Skeletal muscle tissue engineering: strategies for volumetric constructs

    PubMed Central

    Cittadella Vigodarzere, Giorgio; Mantero, Sara

    2014-01-01

    Skeletal muscle tissue is characterized by high metabolic requirements, defined structure and high regenerative potential. As such, it constitutes an appealing platform for tissue engineering to address volumetric defects, as proven by recent works in this field. Several issues common to all engineered constructs constrain the variety of tissues that can be realized in vitro, principal among them the lack of a vascular system and the absence of reliable cell sources; as it is, the only successful tissue engineering constructs are not characterized by active function, present limited cellular survival at implantation and possess low metabolic requirements. Recently, functionally competent constructs have been engineered, with vascular structures supporting their metabolic requirements. In addition to the use of biochemical cues, physical means, mechanical stimulation and the application of electric tension have proven effective in stimulating the differentiation of cells and the maturation of the constructs; while the use of co-cultures provided fine control of cellular developments through paracrine activity. This review will provide a brief analysis of some of the most promising improvements in the field, with particular attention to the techniques that could prove easily transferable to other branches of tissue engineering. PMID:25295011

  16. Tissue engineering a surrogate niche for metastatic cancer cells.

    PubMed

    Seib, F Philipp; Berry, Janice E; Shiozawa, Yusuke; Taichman, Russell S; Kaplan, David L

    2015-05-01

    In breast and prostate cancer patients, the bone marrow is a preferred site of metastasis. We hypothesized that we could use tissue-engineering strategies to lure metastasizing cancer cells to tissue-engineered bone marrow. First, we generated highly porous 3D silk scaffolds that were biocompatible and amenable to bone morphogenetic protein 2 functionalization. Control and functionalized silk scaffolds were subcutaneously implanted in mice and bone marrow development was followed. Only functionalized scaffolds developed cancellous bone and red bone marrow, which appeared as early as two weeks post-implantation and further developed over the 16-week study period. This tissue-engineered bone marrow microenvironment could be readily manipulated in situ to understand the biology of bone metastasis. To test the ability of functionalized scaffolds to serve as a surrogate niche for metastasis, human breast cancer cells were injected into the mammary fat pads of mice. The treatment of animals with scaffolds had no significant effect on primary tumor growth. However, extensive metastasis was observed in functionalized scaffolds, and the highest levels for scaffolds that were in situ manipulated with receptor activator of nuclear factor kappa-B ligand (RANKL). We also applied this tissue-engineered bone marrow model in a prostate cancer and experimental metastasis setting. In summary, we were able to use tissue-engineered bone marrow to serve as a target or "trap" for metastasizing cancer cells. PMID:25771021

  17. Tissue engineering a surrogate niche for metastatic cancer cells

    PubMed Central

    Seib, F. Philipp; Berry, Janice E.; Shiozawa, Yusuke; Taichman, Russell S.; Kaplan, David L.

    2015-01-01

    In breast and prostate cancer patients, the bone marrow is a preferred site of metastasis. We hypothesized that we could use tissue-engineering strategies to lure metastasizing cancer cells to tissue-engineered bone marrow. First, we generated highly porous 3D silk scaffolds that were biocompatible and amenable to bone morphogenetic protein 2 functionalization. Control and functionalized silk scaffolds were subcutaneously implanted in mice and bone marrow development was followed. Only functionalized scaffolds developed cancellous bone and red bone marrow, which appeared as early as two weeks post-implantation and further developed over the 16-week study period. This tissue-engineered bone marrow microenvironment could be readily manipulated in situ to understand the biology of bone metastasis. To test the ability of functionalized scaffolds to serve as a surrogate niche for metastasis, human breast cancer cells were injected into the mammary fat pads of mice. The treatment of animals with scaffolds had no significant effect on primary tumor growth. However, extensive metastasis was observed in functionalized scaffolds, and the highest levels for scaffolds that were in situ manipulated with receptor activator of nuclear factor kappa-B ligand (RANKL). We also applied this tissue-engineered bone marrow model in a prostate cancer and experimental metastasis setting. In summary, we were able to use tissue-engineered bone marrow to serve as a target for metastasizing cancer cells. PMID:25771021

  18. Bioactive scaffold for bone tissue engineering: An in vivo study

    NASA Astrophysics Data System (ADS)

    Livingston, Treena Lynne

    Massive bone loss of the proximal femur is a common problem in revision cases of total hip implants. Allograft is typically used to reconstruct the site for insertion of the new prosthesis. However, for long term fixation and function, it is desirable that the allograft becomes fully replaced by bone tissue and aids in the regeneration of bone to that site. However, allograft use is typically associated with delayed incorporation and poor remodeling. Due to these profound limitations, alternative approaches are needed. Tissue engineering is an attractive approach to designing improved graft materials. By combining osteogenic activity with a resorbable scaffold, bone formation can be stimulated while providing structure and stability to the limb during incorporation and remodeling of the scaffold. Porous, surface modified bioactive ceramic scaffolds (pSMC) have been developed which stimulate the expression of the osteoblastic phenotype and production of bone-like tissue in vitro. The scaffold and two tissue-engineered constructs, osteoprogenitor cells seeded onto scaffolds or cells expanded in culture to form bone tissue on the scaffolds prior to implantation, were investigated in a long bone defect model. The rate of incorporation was assessed. Both tissue-engineered constructs stimulated bone formation and comparable repair at 2 weeks. In a rat femoral window defect model, bone formation increased over time for all groups in concert with scaffold resorption, leading to a 40% increase in bone and 40% reduction of the scaffold in the defect by 12 weeks. Both tissue-engineered constructs enhanced the rate of mechanical repair of long bones due to better bony union with the host cortex. Long bones treated with tissue engineered constructs demonstrated a return in normal torsional properties by 4 weeks as compared to 12 weeks for long bones treated with pSMC. Culture expansion of cells to produce bone tissue in vitro did not accelerate incorporation over the treatment

  19. Coaxial electrospun fibers: applications in drug delivery and tissue engineering.

    PubMed

    Lu, Yang; Huang, Jiangnan; Yu, Guoqiang; Cardenas, Romel; Wei, Suying; Wujcik, Evan K; Guo, Zhanhu

    2016-09-01

    Coelectrospinning and emulsion electrospinning are two main methods for preparing core-sheath electrospun nanofibers in a cost-effective and efficient manner. Here, physical phenomena and the effects of solution and processing parameters on the coaxial fibers are introduced. Coaxial fibers with specific drugs encapsulated in the core can exhibit a sustained and controlled release. Their exhibited high surface area and three-dimensional nanofibrous network allows the electrospun fibers to resemble native extracellular matrices. These features of the nanofibers show that they have great potential in drug delivery and tissue engineering applications. Proteins, growth factors, antibiotics, and many other agents have been successfully encapsulated into coaxial fibers for drug delivery. A main advantage of the core-sheath design is that after the process of electrospinning and release, these drugs remain bioactive due to the protection of the sheath. Applications of coaxial fibers as scaffolds for tissue engineering include bone, cartilage, cardiac tissue, skin, blood vessels and nervous tissue, among others. A synopsis of novel coaxial electrospun fibers, discussing their applications in drug delivery and tissue engineering, is covered pertaining to proteins, growth factors, antibiotics, and other drugs and applications in the fields of bone, cartilage, cardiac, skin, blood vessel, and nervous tissue engineering, respectively. WIREs Nanomed Nanobiotechnol 2016, 8:654-677. doi: 10.1002/wnan.1391 For further resources related to this article, please visit the WIREs website. PMID:26848106

  20. Expediting the transition from replacement medicine to tissue engineering

    PubMed Central

    Coury, Arthur J.

    2016-01-01

    In this article, an expansive interpretation of “Tissue Engineering” is proposed which is in congruence with classical and recent published definitions. I further simplify the definition of tissue engineering as: “Exerting systematic control of the body’s cells, matrices and fluids.” As a consequence, many medical therapies not commonly considered tissue engineering are placed in this category because of their effect on the body’s responses. While the progress of tissue engineering strategies is inexorable and generally positive, it has been subject to setbacks as have many important medical therapies. Medical practice is currently undergoing a transition on several fronts (academics, start-up companies, going concerns) from the era of “replacement medicine” where body parts and functions are replaced by mechanical, electrical or chemical therapies to the era of tissue engineering where health is restored by regeneration generation or limitation of the body’s tissues and functions by exploiting our expanding knowledge of the body’s biological processes to produce natural, healthy outcomes. PMID:27047677

  1. Patterning vascular networks in vivo for tissue engineering applications.

    PubMed

    Chaturvedi, Ritika R; Stevens, Kelly R; Solorzano, Ricardo D; Schwartz, Robert E; Eyckmans, Jeroen; Baranski, Jan D; Stapleton, Sarah Chase; Bhatia, Sangeeta N; Chen, Christopher S

    2015-05-01

    The ultimate design of functionally therapeutic engineered tissues and organs will rely on our ability to engineer vasculature that can meet tissue-specific metabolic needs. We recently introduced an approach for patterning the formation of functional spatially organized vascular architectures within engineered tissues in vivo. Here, we now explore the design parameters of this approach and how they impact the vascularization of an engineered tissue construct after implantation. We used micropatterning techniques to organize endothelial cells (ECs) into geometrically defined "cords," which in turn acted as a template after implantation for the guided formation of patterned capillaries integrated with the host tissue. We demonstrated that the diameter of the cords before implantation impacts the location and density of the resultant capillary network. Inclusion of mural cells to the vascularization response appears primarily to impact the dynamics of vascularization. We established that clinically relevant endothelial sources such as induced pluripotent stem cell-derived ECs and human microvascular endothelial cells can drive vascularization within this system. Finally, we demonstrated the ability to control the juxtaposition of parenchyma with perfused vasculature by implanting cords containing a mixture of both a parenchymal cell type (hepatocytes) and ECs. These findings define important characteristics that will ultimately impact the design of vasculature structures that meet tissue-specific needs. PMID:25390971

  2. Role of morphogenetic proteins in skeletal tissue engineering and regeneration.

    PubMed

    Reddi, A H

    1998-03-01

    Morphogenesis is the developmental cascade of pattern formation and body plan establishment, culminating in the adult form. It has formed the basis for the emerging discipline of tissue engineering, which uses principles of molecular developmental biology and morphogenesis gleaned through studies on inductive signals, responding stem cells, and the extracellular matrix to design and construct spare parts that restore function to the human body. Among the many organs in the body, bone has considerable powers for regeneration and is a prototype model for tissue engineering. Implantation of demineralized bone matrix into subcutaneous sites results in local bone induction. This model mimics sequential limb morphogenesis and has permitted the isolation of bone morphogens, such as bone morphogenetic proteins (BMPs), from demineralized adult bone matrix. BMPs initiate, promote, and maintain chondrogenesis and osteogenesis, but are also involved in the morphogenesis of organs other than bone. The symbiosis of the mechanisms underlying bone induction and differentiation is critical for tissue engineering and is governed by both biomechanics (physical forces) and context (microenvironment/extracellular matrix), which can be duplicated by biomimetic biomaterials such as collagens, hydroxyapatite, proteoglycans, and cell adhesion glycoproteins, including fibronectins and laminin. Rules of tissue architecture elucidated in bone morphogenesis may provide insights into tissue engineering and be universally applicable for all organs/tissues, including bones and joints. PMID:9528003

  3. Manufacturing Road Map for Tissue Engineering and Regenerative Medicine Technologies

    PubMed Central

    Hunsberger, Joshua; Harrysson, Ola; Shirwaiker, Rohan; Starly, Binil; Wysk, Richard; Cohen, Paul; Allickson, Julie; Yoo, James

    2015-01-01

    Summary The Regenerative Medicine Foundation Annual Conference held on May 6 and 7, 2014, had a vision of assisting with translating tissue engineering and regenerative medicine (TERM)-based technologies closer to the clinic. This vision was achieved by assembling leaders in the field to cover critical areas. Some of these critical areas included regulatory pathways for regenerative medicine therapies, strategic partnerships, coordination of resources, developing standards for the field, government support, priorities for industry, biobanking, and new technologies. The final day of this conference featured focused sessions on manufacturing, during which expert speakers were invited from industry, government, and academia. The speakers identified and accessed roadblocks plaguing the field where improvements in advanced manufacturing offered many solutions. The manufacturing sessions included (a) product development toward commercialization in regenerative medicine, (b) process challenges to scale up manufacturing in regenerative medicine, and (c) infrastructure needs for manufacturing in regenerative medicine. Subsequent to this, industry was invited to participate in a survey to further elucidate the challenges to translation and scale-up. This perspective article will cover the lessons learned from these manufacturing sessions and early results from the survey. We also outline a road map for developing the manufacturing infrastructure, resources, standards, capabilities, education, training, and workforce development to realize the promise of TERM. PMID:25575525

  4. Perspectives on the Role of Nanotechnology in Bone Tissue Engineering

    PubMed Central

    Saiz, Eduardo; Zimmermann, Elizabeth A.; Lee, Janice S.; Wegst, Ulrike G.K.; Tomsia, Antoni P.

    2013-01-01

    Objective This review surveys new developments in bone tissue engineering, specifically focusing on the promising role of nanotechnology and describes future avenues of research. Methods The review first reinforces the need to fabricate scaffolds with multi-dimensional hierarchies for improved mechanical integrity. Next, new advances to promote bioactivity by manipulating the nano-level internal surfaces of scaffolds are examined followed by an evaluation of techniques to using scaffolds as a vehicle for local drug delivery to promote bone regeneration/integration and methods of seeding cells into the scaffold. Results Through a review of the state of the field, critical questions are posed to guide future research towards producing materials and therapies to bring state-of-the-art technology to clinical settings. Significance The development of scaffolds for bone regeneration requires a material able to promote rapid bone formation while possessing sufficient strength to prevent fracture under physiological loads. Success in simultaneously achieving mechanical integrity and sufficient bioactivity with a single material has been limited. However, the use of new tools to manipulate and characterize matter down to the nano-scale may enable a new generation of bone scaffolds that will surpass the performance of autologous bone implants. PMID:22901861

  5. Application of Hydrogels in Heart Valve Tissue Engineering

    PubMed Central

    Zhang, Xing; Xu, Bin; Puperi, Daniel S.; Wu, Yan; West, Jennifer L.; Grande-Allen, K. Jane

    2015-01-01

    With an increasing number of patients requiring valve replacement, there is heightened interest in advancing heart valve tissue engineering (HVTE) to provide solutions to the many limitations of current surgical treatments. A variety of materials have been developed as scaffolds for HVTE including natural polymers, synthetic polymers, and decellularized valvular matrices. Among them, biocompatible hydrogels are generating growing interest. Natural hydrogels, such as collagen and fibrin, generally show good bioactivity, but poor mechanical durability. Synthetic hydrogels, on the other hand, have tunable mechanical properties; however, appropriate cell-matrix interactions are difficult to obtain. Moreover, hydrogels can be used as cell carriers when the cellular component is seeded into the polymer meshes or decellularized valve scaffolds. In this review, we discuss current research strategies for HVTE with an emphasis on hydrogel applications. The physicochemical properties and fabrication methods of these hydrogels, as well as their mechanical properties and bioactivities are described. Performance of some hydrogels including in vitro evaluation using bioreactors and in vivo tests in different animal models are also discussed. For future HVTE, it will be compelling to examine how hydrogels can be constructed from composite materials to replicate mechanical properties and mimic biological functions of the native heart valve. PMID:25955010

  6. Poly(3-hydroxybutyrate) multifunctional composite scaffolds for tissue engineering applications.

    PubMed

    Misra, Superb K; Ansari, Tahera I; Valappil, Sabeel P; Mohn, Dirk; Philip, Sheryl E; Stark, Wendelin J; Roy, Ipsita; Knowles, Jonathan C; Salih, Vehid; Boccaccini, Aldo R

    2010-04-01

    Poly(3-hydroxybutyrate) (P(3HB)) foams exhibiting highly interconnected porosity (85% porosity) were prepared using a unique combination of solvent casting and particulate leaching techniques by employing commercially available sugar cubes as porogen. Bioactive glass (BG) particles of 45S5 Bioglass grade were introduced in the scaffold microstructure, both in micrometer ((m-BG), <5 microm) and nanometer ((n-BG), 30 nm) sizes. The in vitro bioactivity of the P(3HB)/BG foams was confirmed within 10 days of immersion in simulated body fluid and the foams showed high level of protein adsorption. The foams interconnected porous microstructure proved to be suitable for MG-63 osteoblast cell attachment and proliferation. The foams implanted in rats as subcutaneous implants resulted in a non-toxic and foreign body response after one week of implantation. In addition to showing bioactivity and biocompatibility, the P(3HB)/BG composite foams also exhibited bactericidal properties, which was tested on the growth of Staphylococcus aureus. An attempt was made at developing multifunctional scaffolds by incorporating, in addition to BG, selected concentrations of Vitamin E or/and carbon nanotubes. P(3HB) scaffolds with multifunctionalities (viz. bactericidal, bioactive, electrically conductive, antioxidative behaviour) were thus produced, which paves the way for next generation of advanced scaffolds for bone tissue engineering. PMID:20045554

  7. Manufacturing road map for tissue engineering and regenerative medicine technologies.

    PubMed

    Hunsberger, Joshua; Harrysson, Ola; Shirwaiker, Rohan; Starly, Binil; Wysk, Richard; Cohen, Paul; Allickson, Julie; Yoo, James; Atala, Anthony

    2015-02-01

    The Regenerative Medicine Foundation Annual Conference held on May 6 and 7, 2014, had a vision of assisting with translating tissue engineering and regenerative medicine (TERM)-based technologies closer to the clinic. This vision was achieved by assembling leaders in the field to cover critical areas. Some of these critical areas included regulatory pathways for regenerative medicine therapies, strategic partnerships, coordination of resources, developing standards for the field, government support, priorities for industry, biobanking, and new technologies. The final day of this conference featured focused sessions on manufacturing, during which expert speakers were invited from industry, government, and academia. The speakers identified and accessed roadblocks plaguing the field where improvements in advanced manufacturing offered many solutions. The manufacturing sessions included (a) product development toward commercialization in regenerative medicine, (b) process challenges to scale up manufacturing in regenerative medicine, and (c) infrastructure needs for manufacturing in regenerative medicine. Subsequent to this, industry was invited to participate in a survey to further elucidate the challenges to translation and scale-up. This perspective article will cover the lessons learned from these manufacturing sessions and early results from the survey. We also outline a road map for developing the manufacturing infrastructure, resources, standards, capabilities, education, training, and workforce development to realize the promise of TERM. PMID:25575525

  8. Biocompatible magnetic core-shell nanocomposites for engineered magnetic tissues.

    PubMed

    Rodriguez-Arco, Laura; Rodriguez, Ismael A; Carriel, Victor; Bonhome-Espinosa, Ana B; Campos, Fernando; Kuzhir, Pavel; Duran, Juan D G; Lopez-Lopez, Modesto T

    2016-04-14

    The inclusion of magnetic nanoparticles into biopolymer matrixes enables the preparation of magnetic field-responsive engineered tissues. Here we describe a synthetic route to prepare biocompatible core-shell nanostructures consisting of a polymeric core and a magnetic shell, which are used for this purpose. We show that using a core-shell architecture is doubly advantageous. First, gravitational settling for core-shell nanocomposites is slower because of the reduction of the composite average density connected to the light polymer core. Second, the magnetic response of core-shell nanocomposites can be tuned by changing the thickness of the magnetic layer. The incorporation of the composites into biopolymer hydrogels containing cells results in magnetic field-responsive engineered tissues whose mechanical properties can be controlled by external magnetic forces. Indeed, we obtain a significant increase of the viscoelastic moduli of the engineered tissues when exposed to an external magnetic field. Because the composites are functionalized with polyethylene glycol, the prepared bio-artificial tissue-like constructs also display excellent ex vivo cell viability and proliferation. When implanted in vivo, the engineered tissues show good biocompatibility and outstanding interaction with the host tissue. Actually, they only cause a localized transitory inflammatory reaction at the implantation site, without any effect on other organs. Altogether, our results suggest that the inclusion of magnetic core-shell nanocomposites into biomaterials would enable tissue engineering of artificial substitutes whose mechanical properties could be tuned to match those of the potential target tissue. In a wider perspective, the good biocompatibility and magnetic behavior of the composites could be beneficial for many other applications. PMID:27029891

  9. Engineering smooth muscle tissue with a predefined structure.

    PubMed

    Kim, B S; Mooney, D J

    1998-08-01

    Nonwoven meshes of polyglycolic acid (PGA) fibers are attractive synthetic extracellular matrices (ECMs) for tissue engineering and have been used to engineer many types of tissues. However, these synthetic ECMs lack structural stability and often cannot maintain their original structure during tissue development. This makes it difficult to design an engineered tissue with a predefined configuration and dimensions. In this study, we investigated the ability of PGA fiber-based matrices bonded at their fiber crosspoints with a secondary polymer, poly-L-lactic acid (PLLA), to resist cellular contractile forces and maintain their predefined structure during the process of smooth muscle (SM) tissue development in vitro. Physically bonded PGA matrices exhibited a 10- to 35-fold increase in the compressive modulus over unbonded PGA matrices, depending on the mass of PLLA utilized to bond the PGA matrices. In addition, the bonded PGA matrices degraded much more slowly than the unbonded matrices. The PLLA bonding of PGA matrices had no effect on the ability of cells to adhere to the matrices. After 7 weeks in culture, the bonded matrices maintained 101 +/- 4% of their initial volume and an approximate original shape while the unbonded matrices contracted to 5 +/- 1% of their initial volume with an extreme change in their shape. At this time the bonded PGA matrices had a high cellularity, with smooth muscle cells (SMCs) and ECM proteins produced by these cells (e.g., elastin) filling the pores between PGA fibers. This study demonstrated that physically bonded PGA fiber-based matrices allow the maintenance of the configuration and dimensions of the original matrices and the development of a new tissue in a predefined three-dimensional structure. This approach may be useful for engineering a variety of tissues of various structures and shapes, and our study demonstrates the importance of matching both the initial mechanical properties and the degradation rate of a matrix to

  10. FY2014 Advanced Combustion Engine Annual Progress Report

    SciTech Connect

    2015-03-01

    The Advanced Combustion Engine research and development (R&D) subprogram within the DOE Vehicle Technologies Office (VTO) provides support and guidance for many cutting-edge automotive technologies under development. Research focuses on addressing critical barriers to commercializing higher efficiency, very low emissions advanced internal combustion engines for passenger and commercial vehicles.

  11. Nanofiber Scaffold-Based Tissue-Engineered Retinal Pigment Epithelium to Treat Degenerative Eye Diseases.

    PubMed

    Hotaling, Nathan A; Khristov, Vladimir; Wan, Qin; Sharma, Ruchi; Jha, Balendu Shekhar; Lotfi, Mostafa; Maminishkis, Arvydas; Simon, Carl G; Bharti, Kapil

    2016-06-01

    Clinical-grade manufacturing of a functional retinal pigment epithelium (RPE) monolayer requires reproducing, as closely as possible, the natural environment in which RPE grows. In vitro, this can be achieved by a tissue engineering approach, in which the RPE is grown on a nanofibrous biological or synthetic scaffold. Recent research has shown that nanofiber scaffolds perform better for cell growth and transplantability compared with their membrane counterparts and that the success of the scaffold in promoting cell growth/function is not heavily material dependent. With these strides, the field has advanced enough to begin to consider implementation of one, or a combination, of the tissue engineering strategies discussed herein. In this study, we review the current state of tissue engineering research for in vitro culture of RPE/scaffolds and the parameters for optimal scaffold design that have been uncovered during this research. Next, we discuss production methods and manufacturers that are capable of producing the nanofiber scaffolds in such a way that would be biologically, regulatory, clinically, and commercially viable. Then, a discussion of how the scaffolds could be characterized, both morphologically and mechanically, to develop a testing process that is viable for regulatory screening is performed. Finally, an example of a tissue-engineered RPE/scaffold construct is given to provide the reader a framework for understanding how these pieces could fit together to develop a tissue-engineered RPE/scaffold construct that could pass regulatory scrutiny and can be commercially successful. PMID:27110730

  12. The General Electric Advanced Course in Engineering.

    ERIC Educational Resources Information Center

    Mack, Donald R.

    A three-year, in-house engineering course offered to selected General Electric Company engineers is discussed. It is designed to develop the ability to identify and solve real engineering problems. The course may be taken concurrently with college courses in a cooperative program that can result in a graduate degree in engineering. (MLH)

  13. Tissue engineering and its potential impact on surgery.

    PubMed

    Lalan, S; Pomerantseva, I; Vacanti, J P

    2001-11-01

    The loss or failure of an organ or tissue is one of the most frequent, devastating, and costly problems in healthcare. Current treatment modalities include transplantation of organs, surgical reconstruction, use of mechanical devices, or supplementation of metabolic products. A new field, tissue engineering, applies the principles and methods of engineering, material science, and cell and molecular biology toward the development of viable substitutes which restore, maintain, or improve the function of human tissues. In this review, we outline the opportunities and challenges of this emerging interdisciplinary field and its attempts to provide solutions to tissue creation and repair. Within this context, we present our experience using the basic tools of tissue engineering to guide regeneration of diverse tissues that include the liver, small intestine, cardiovascular structures, nerve, and cartilage. And in addition, we discuss the necessity of finding new strategies to achieve vascularization of complex tissues for transplant and present our approaches utilizing MicroElectroMechanical Systems (MEMS) technology and three-dimensional printing. PMID:11760750

  14. Nanostructured materials for applications in drug delivery and tissue engineering*

    PubMed Central

    GOLDBERG, MICHAEL; LANGER, ROBERT; JIA, XINQIAO

    2010-01-01

    Research in the areas of drug delivery and tissue engineering has witnessed tremendous progress in recent years due to their unlimited potential to improve human health. Meanwhile, the development of nanotechnology provides opportunities to characterize, manipulate and organize matter systematically at the nanometer scale. Biomaterials with nano-scale organizations have been used as controlled release reservoirs for drug delivery and artificial matrices for tissue engineering. Drug-delivery systems can be synthesized with controlled composition, shape, size and morphology. Their surface properties can be manipulated to increase solubility, immunocompatibility and cellular uptake. The limitations of current drug delivery systems include suboptimal bioavailability, limited effective targeting and potential cytotoxicity. Promising and versatile nano-scale drug-delivery systems include nanoparticles, nanocapsules, nanotubes, nanogels and dendrimers. They can be used to deliver both small-molecule drugs and various classes of biomacromolecules, such as peptides, proteins, plasmid DNA and synthetic oligodeoxynucleotides. Whereas traditional tissue-engineering scaffolds were based on hydrolytically degradable macroporous materials, current approaches emphasize the control over cell behaviors and tissue formation by nano-scale topography that closely mimics the natural extracellular matrix (ECM). The understanding that the natural ECM is a multifunctional nanocomposite motivated researchers to develop nanofibrous scaffolds through electrospinning or self-assembly. Nanocomposites containing nanocrystals have been shown to elicit active bone growth. Drug delivery and tissue engineering are closely related fields. In fact, tissue engineering can be viewed as a special case of drug delivery where the goal is to accomplish controlled delivery of mammalian cells. Controlled release of therapeutic factors in turn will enhance the efficacy of tissue engineering. From a materials

  15. Bone Regeneration Based on Tissue Engineering Conceptions — A 21st Century Perspective

    PubMed Central

    Henkel, Jan; Woodruff, Maria A.; Epari, Devakara R.; Steck, Roland; Glatt, Vaida; Dickinson, Ian C.; Choong, Peter F. M.; Schuetz, Michael A.; Hutmacher, Dietmar W.

    2013-01-01

    The role of Bone Tissue Engineering in the field of Regenerative Medicine has been the topic of substantial research over the past two decades. Technological advances have improved orthopaedic implants and surgical techniques for bone reconstruction. However, improvements in surgical techniques to reconstruct bone have been limited by the paucity of autologous materials available and donor site morbidity. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding the surgical options for restoring the form and function of injured bone. Specifically, novel bioactive (second generation) biomaterials have been developed that are characterised by controlled action and reaction to the host tissue environment, whilst exhibiting controlled chemical breakdown and resorption with an ultimate replacement by regenerating tissue. Future generations of biomaterials (third generation) are designed to be not only osteoconductive but also osteoinductive, i.e. to stimulate regeneration of host tissues by combining tissue engineering and in situ tissue regeneration methods with a focus on novel applications. These techniques will lead to novel possibilities for tissue regeneration and repair. At present, tissue engineered constructs that may find future use as bone grafts for complex skeletal defects, whether from post-traumatic, degenerative, neoplastic or congenital/developmental “origin” require osseous reconstruction to ensure structural and functional integrity. Engineering functional bone using combinations of cells, scaffolds and bioactive factors is a promising strategy and a particular feature for future development in the area of hybrid materials which are able to exhibit suitable biomimetic and mechanical properties. This review will discuss the state of the art in this field and what we can expect from future generations of bone regeneration concepts. PMID:26273505

  16. Improved silicon carbide for advanced heat engines

    NASA Technical Reports Server (NTRS)

    Whalen, Thomas J.

    1989-01-01

    The development of high strength, high reliability silicon carbide parts with complex shapes suitable for use in advanced heat engines is studied. Injection molding was the forming method selected for the program because it is capable of forming complex parts adaptable for mass production on an economically sound basis. The goals were to reach a Weibull characteristic strength of 550 MPa (80 ksi) and a Weibull modulus of 16 for bars tested in four-point loading. Statistically designed experiments were performed throughout the program and a fluid mixing process employing an attritor mixer was developed. Compositional improvements in the amounts and sources of boron and carbon used and a pressureless sintering cycle were developed which provided samples of about 99 percent of theoretical density. Strengths were found to improve significantly by annealing in air. Strengths in excess of 550 MPa (80 ksi) with Weibull modulus of about 9 were obtained. Further improvements in Weibull modulus to about 16 were realized by proof testing. This is an increase of 86 percent in strength and 100 percent in Weibull modulus over the baseline data generated at the beginning of the program. Molding yields were improved and flaw distributions were observed to follow a Poisson process. Magic angle spinning nuclear magnetic resonance spectra were found to be useful in characterizing the SiC powder and the sintered samples. Turbocharger rotors were molded and examined as an indication of the moldability of the mixes which were developed in this program.

  17. Improved silicon nitride for advanced heat engines

    NASA Technical Reports Server (NTRS)

    Yeh, Hun C.; Fang, Ho T.

    1987-01-01

    The technology base required to fabricate silicon nitride components with the strength, reliability, and reproducibility necessary for actual heat engine applications is presented. Task 2 was set up to develop test bars with high Weibull slope and greater high temperature strength, and to conduct an initial net shape component fabrication evaluation. Screening experiments were performed in Task 7 on advanced materials and processing for input to Task 2. The technical efforts performed in the second year of a 5-yr program are covered. The first iteration of Task 2 was completed as planned. Two half-replicated, fractional factorial (2 sup 5), statistically designed matrix experiments were conducted. These experiments have identified Denka 9FW Si3N4 as an alternate raw material to GTE SN502 Si3N4 for subsequent process evaluation. A detailed statistical analysis was conducted to correlate processing conditions with as-processed test bar properties. One processing condition produced a material with a 97 ksi average room temperature MOR (100 percent of goal) with 13.2 Weibull slope (83 percent of goal); another condition produced 86 ksi (6 percent over baseline) room temperature strength with a Weibull slope of 20 (125 percent of goal).

  18. Pericyte-targeting drug delivery and tissue engineering

    PubMed Central

    Kang, Eunah; Shin, Jong Wook

    2016-01-01

    Pericytes are contractile mural cells that wrap around the endothelial cells of capillaries and venules. Depending on the triggers by cellular signals, pericytes have specific functionality in tumor microenvironments, properties of potent stem cells, and plasticity in cellular pathology. These features of pericytes can be activated for the promotion or reduction of angiogenesis. Frontier studies have exploited pericyte-targeting drug delivery, using pericyte-specific peptides, small molecules, and DNA in tumor therapy. Moreover, the communication between pericytes and endothelial cells has been applied to the induction of vessel neoformation in tissue engineering. Pericytes may prove to be a novel target for tumor therapy and tissue engineering. The present paper specifically reviews pericyte-specific drug delivery and tissue engineering, allowing insight into the emerging research targeting pericytes. PMID:27313454

  19. Tissue engineering and peripheral nerve reconstruction: an overview.

    PubMed

    Geuna, Stefano; Gnavi, Sara; Perroteau, Isabelle; Tos, Pierluigi; Battiston, Bruno

    2013-01-01

    Nerve repair is no more regarded as merely a matter of microsurgical reconstruction. To define this evolving reconstructive/regenerative approach, the term tissue engineering is being increasingly used since it reflects the search for interdisciplinary and integrated treatment strategies. However, the drawback of this new approach is its intrinsic complexity, which is the result of the variety of scientific disciplines involved. This chapter presents a synthetic overview of the state of the art in peripheral nerve tissue engineering with a look forward at the most promising innovations emerging from basic science investigation. This review is intended to set the stage for the collection of papers in the thematic issue of the International Review of Neurobiology that is focused on the various interdisciplinary approaches in peripheral nerve tissue engineering. PMID:24083430

  20. Synthetic biodegradable functional polymers for tissue engineering: a brief review

    PubMed Central

    BaoLin, GUO; MA, Peter X.

    2015-01-01

    Scaffolds play a crucial role in tissue engineering. Biodegradable polymers with great processing flexibility are the predominant scaffolding materials. Synthetic biodegradable polymers with well-defined structure and without immunological concerns associated with naturally derived polymers are widely used in tissue engineering. The synthetic biodegradable polymers that are widely used in tissue engineering, including polyesters, polyanhydrides, polyphosphazenes, polyurethane, and poly (glycerol sebacate) are summarized in this article. New developments in conducting polymers, photoresponsive polymers, amino-acid-based polymers, enzymatically degradable polymers, and peptide-activated polymers are also discussed. In addition to chemical functionalization, the scaffold designs that mimic the nano and micro features of the extracellular matrix (ECM) are presented as well, and composite and nanocomposite scaffolds are also reviewed. PMID:25729390

  1. Pericyte-targeting drug delivery and tissue engineering.

    PubMed

    Kang, Eunah; Shin, Jong Wook

    2016-01-01

    Pericytes are contractile mural cells that wrap around the endothelial cells of capillaries and venules. Depending on the triggers by cellular signals, pericytes have specific functionality in tumor microenvironments, properties of potent stem cells, and plasticity in cellular pathology. These features of pericytes can be activated for the promotion or reduction of angiogenesis. Frontier studies have exploited pericyte-targeting drug delivery, using pericyte-specific peptides, small molecules, and DNA in tumor therapy. Moreover, the communication between pericytes and endothelial cells has been applied to the induction of vessel neoformation in tissue engineering. Pericytes may prove to be a novel target for tumor therapy and tissue engineering. The present paper specifically reviews pericyte-specific drug delivery and tissue engineering, allowing insight into the emerging research targeting pericytes. PMID:27313454

  2. An airline study of advanced technology requirements for advanced high speed commercial transport engines. 1: Engine design study assessment

    NASA Technical Reports Server (NTRS)

    Sallee, G. P.

    1973-01-01

    The advanced technology requirements for an advanced high speed commercial tranport engine are presented. The results of the phase 1 study effort cover the following areas: (1) statement of an airline's major objectives for future transport engines, (2) airline's method of evaluating engine proposals, (3) description of an optimum engine for a long range subsonic commercial transport including installation and critical design features, (4) discussion of engine performance problems and experience with performance degradation, (5) trends in engine and pod prices with increasing technology and objectives for the future, (6) discussion of the research objectives for composites, reversers, advanced components, engine control systems, and devices to reduce the impact of engine stall, and (7) discussion of the airline objectives for noise and pollution reduction.

  3. Protein turnover during in vitro tissue engineering.

    PubMed

    Li, Qiyao; Chang, Zhen; Oliveira, Gisele; Xiong, Maiyer; Smith, Lloyd M; Frey, Brian L; Welham, Nathan V

    2016-03-01

    Repopulating acellular biological scaffolds with phenotypically appropriate cells is a promising approach for regenerating functional tissues and organs. Under this tissue engineering paradigm, reseeded cells are expected to remodel the scaffold by active protein synthesis and degradation; however, the rate and extent of this remodeling remain largely unknown. Here, we present a technique to measure dynamic proteome changes during in vitro remodeling of decellularized tissue by reseeded cells, using vocal fold mucosa as the model system. Decellularization and recellularization were optimized, and a stable isotope labeling strategy was developed to differentiate remnant proteins constituting the original scaffold from proteins newly synthesized by reseeded cells. Turnover of matrix and cellular proteins and the effects of cell-scaffold interaction were elucidated. This technique sheds new light on in vitro tissue remodeling and the process of tissue regeneration, and is readily applicable to other tissue and organ systems. PMID:26724458

  4. Methods of Monitoring Cell Fate and Tissue Growth in Three-Dimensional Scaffold-Based Strategies for In Vitro Tissue Engineering.

    PubMed

    Leferink, Anne M; van Blitterswijk, Clemens A; Moroni, Lorenzo

    2016-08-01

    In the field of tissue engineering, there is a need for methods that allow assessing the performance of tissue-engineered constructs noninvasively in vitro and in vivo. To date, histological analysis is the golden standard to retrieve information on tissue growth, cellular distribution, and cell fate on tissue-engineered constructs after in vitro cell culture or on explanted specimens after in vivo applications. Yet, many advances have been made to optimize imaging techniques for monitoring tissue-engineered constructs with a sub-mm or μm resolution. Many imaging modalities have first been developed for clinical applications, in which a high penetration depth has been often more important than lateral resolution. In this study, we have reviewed the current state of the art in several imaging approaches that have shown to be promising in monitoring cell fate and tissue growth upon in vitro culture. Depending on the aimed tissue type and scaffold properties, some imaging methods are more applicable than others. Optical methods are mostly suited for transparent materials such as hydrogels, whereas magnetic resonance-based methods are mostly applied to obtain contrast between hard and soft tissues regardless of their transparency. Overall, this review shows that the field of imaging in scaffold-based tissue engineering is developing at a fast pace and has the potential to overcome the limitations of destructive endpoint analysis. PMID:26825610

  5. Advanced component technologies for energy-efficient turbofan engines

    NASA Technical Reports Server (NTRS)

    Saunders, N. T.

    1980-01-01

    The paper reviews NASA's Energy Efficient Engine Project which was initiated to provide the advanced technology base for a new generation of fuel-conservative engines for introduction into airline service by the late 1980s. Efforts in this project are directed at advancing engine component and systems technologies to a point of demonstrating technology-readiness by 1984. Early results indicate high promise in achieving most of the goals established in the project.

  6. [Advanced online search techniques and dedicated search engines for physicians].

    PubMed

    Nahum, Yoav

    2008-02-01

    In recent years search engines have become an essential tool in the work of physicians. This article will review advanced search techniques from the world of information specialists, as well as some advanced search engine operators that may help physicians improve their online search capabilities, and maximize the yield of their searches. This article also reviews popular dedicated scientific and biomedical literature search engines. PMID:18357673

  7. Physiology and metabolism of tissue-engineered skeletal muscle.

    PubMed

    Cheng, Cindy S; Davis, Brittany N J; Madden, Lauran; Bursac, Nenad; Truskey, George A

    2014-09-01

    Skeletal muscle is a major target for tissue engineering, given its relative size in the body, fraction of cardiac output that passes through muscle beds, as well as its key role in energy metabolism and diabetes, and the need for therapies for muscle diseases such as muscular dystrophy and sarcopenia. To date, most studies with tissue-engineered skeletal muscle have utilized murine and rat cell sources. On the other hand, successful engineering of functional human muscle would enable different applications including improved methods for preclinical testing of drugs and therapies. Some of the requirements for engineering functional skeletal muscle include expression of adult forms of muscle proteins, comparable contractile forces to those produced by native muscle, and physiological force-length and force-frequency relations. This review discusses the various strategies and challenges associated with these requirements, specific applications with cultured human myoblasts, and future directions. PMID:24912506

  8. Physiology and Metabolism of Tissue Engineered Skeletal Muscle

    PubMed Central

    Cheng, Cindy S.; Davis, Brittany N.J.; Madden, Lauran; Bursac, Nenad; Truskey, George A.

    2014-01-01

    Skeletal muscle is a major target for tissue engineering, given its relative size in the body, fraction of cardiac output that passes through muscle beds, as well as its key role in energy metabolism and diabetes, and the need for therapies for muscle diseases such as muscular dystrophy and sarcopenia. To date, most studies with tissue-engineered skeletal muscle have utilized murine and rat cell sources. On the other hand, successful engineering of functional human muscle would enable different applications including improved methods for preclinical testing of drugs and therapies. Some of the requirements for engineering functional skeletal muscle include expression of adult forms of muscle proteins, comparable contractile forces to those produced by native muscle, and physiological force-length and force-frequency relations. This review discusses the various strategies and challenges associated with these requirements, specific applications with cultured human myoblasts, and future directions. PMID:24912506

  9. The influence of topography on tissue engineering perspective.

    PubMed

    Mansouri, Negar; SamiraBagheri

    2016-04-01

    The actual in vivo tissue scaffold offers a three-dimensional (3D) structural support along with a nano-textured surfaces consist of a fibrous network in order to deliver cell adhesion and signaling. A scaffold is required, until the tissue is entirely regenerated or restored, to act as a temporary ingrowth template for cell proliferation and extracellular matrix (ECM) deposition. This review depicts some of the most significant three dimensional structure materials used as scaffolds in various tissue engineering application fields currently being employed to mimic in vivo features. Accordingly, some of the researchers' attempts have envisioned utilizing graphene for the fabrication of porous and flexible 3D scaffolds. The main focus of this paper is to evaluate the topographical and topological optimization of scaffolds for tissue engineering applications in order to improve scaffolds' mechanical performances. PMID:26838922

  10. Electrospun nanofibrous 3D scaffold for bone tissue engineering.

    PubMed

    Eap, Sandy; Ferrand, Alice; Palomares, Carlos Mendoza; Hébraud, Anne; Stoltz, Jean-François; Mainard, Didier; Schlatter, Guy; Benkirane-Jessel, Nadia

    2012-01-01

    Tissue engineering aims at developing functional substitutes for damaged tissues by mimicking natural tissues. In particular, tissue engineering for bone regeneration enables healing of some bone diseases. Thus, several methods have been developed in order to produce implantable biomaterial structures that imitate the constitution of bone. Electrospinning is one of these methods. This technique produces nonwoven scaffolds made of nanofibers which size and organization match those of the extracellular matrix. Until now, seldom electrospun scaffolds were produced with thickness exceeding one millimeter. This article introduces a new kind of electrospun membrane called 3D scaffold of thickness easily exceeding one centimeter. The manufacturing involves a solution of poly(ε-caprolactone) in DMF/DCM system. The aim is to establish parameters for electrospinning in order to characterize these 3D scaffolds and, establish whether such scaffolds are potentially interesting for bone regeneration. PMID:22766712

  11. Colorectal tissue engineering: prerequisites, current status and perspectives.

    PubMed

    Denost, Quentin; Adam, Jean-Philippe; Rullier, Eric; Bareille, Reine; Montembault, Alexandra; David, Laurent; Bordenave, Laurence

    2013-07-01

    Gastrointestinal tissue engineering has emerged over the past 20 years and was often focused on esophagus, stomach or small intestine, whereas bioengineering researches of colorectal tissue are scarce. However, some promising results have been obtained in animal models. Refinements should be performed in scaffold and cell source selection to allow smooth muscle layer regeneration. Indeed, synthetic and natural polymers such as small intestinal submucosa and collagen sponge seeded with organoid units or smooth muscle cells did not allow smooth muscle regeneration. Mesenchymal stem cells derived from adipose tissue seeded on composite scaffold could represent an interesting way to achieve this goal. This article reviews potential indications, current status and perspectives of tissue engineering in the area of colorectal surgery. PMID:23895077

  12. Vascular assembly in natural and engineered tissues.

    PubMed

    Hirschi, Karen K; Skalak, Thomas C; Peirce, Shayn M; Little, Charles D

    2002-06-01

    With the advent of molecular embryology and exploitation of genetic models systems, many genes necessary for normal blood vessel formation during early development have been identified. These genes include soluble effectors and their receptors, as well as components of cell-cell junctions and mediators of cell-matrix interactions. In vitro model systems (2-D and 3-D) to study paracrine and autocrine interactions of vascular cells and their progenitors have also been created. These systems are being combined to study the behavior of genetically altered cells to dissect and define the cellular role(s) of specific genes and gene families in directing the migration, proliferation, and differentiation needed for blood vessel assembly. It is clear that a complex spatial and temporal interplay of signals, including both genetic and environmental, modulates the assembly process. The development of real-time imaging and image analysis will enable us to gain further insights into this process. Collaborative efforts among vascular biologists, biomedical engineers, mathematicians, and physicists will allow us to bridge the gap between understanding vessel assembly in vivo and assembling vessels ex vivo. PMID:12081906

  13. Biomimetic Polymers for Cardiac Tissue Engineering

    PubMed Central

    2016-01-01

    Heart failure is a morbid disorder characterized by progressive cardiomyocyte (CM) dysfunction and death. Interest in cell-based therapies is growing, but sustainability of injected CMs remains a challenge. To mitigate this, we developed an injectable biomimetic Reverse Thermal Gel (RTG) specifically engineered to support long-term CM survival. This RTG biopolymer provided a solution-based delivery vehicle of CMs, which transitioned to a gel-based matrix shortly after reaching body temperature. In this study we tested the suitability of this biopolymer to sustain CM viability. The RTG was biomolecule-functionalized with poly-l-lysine or laminin. Neonatal rat ventricular myocytes (NRVM) and adult rat ventricular myocytes (ARVM) were cultured in plain-RTG and biomolecule-functionalized-RTG both under 3-dimensional (3D) conditions. Traditional 2D biomolecule-coated dishes were used as controls. We found that the RTG-lysine stimulated NRVM to spread and form heart-like functional syncytia. Regarding cell contraction, in both RTG and RTG-lysine, beating cells were recorded after 21 days. Additionally, more than 50% (p value < 0.05; n = 5) viable ARVMs, characterized by a well-defined cardiac phenotype represented by sarcomeric cross-striations, were found in the RTG-laminin after 8 days. These results exhibit the tremendous potential of a minimally invasive CM transplantation through our designed RTG-cell therapy platform. PMID:27073119

  14. Decellularized matrices for cardiovascular tissue engineering

    PubMed Central

    Moroni, Francesco; Mirabella, Teodelinda

    2014-01-01

    Cardiovascular disease (CVD) is one of the leading causes of death in the Western world. The replacement of damaged vessels and valves has been practiced since the 1950’s. Synthetic grafts, usually made of bio-inert materials, are long-lasting and mechanically relevant, but fail when it comes to “biointegration”. Decellularized matrices, instead, can be considered biological grafts capable of stimulating in vivo migration and proliferation of endothelial cells (ECs), recruitment and differentiation of mural cells, finally, culminating in the formation of a biointegrated tissue. Decellularization protocols employ osmotic shock, ionic and non-ionic detergents, proteolitic digestions and DNase/RNase treatments; most of them effectively eliminate the cellular component, but show limitations in preserving the native structure of the extracellular matrix (ECM). In this review, we examine the current state of the art relative to decellularization techniques and biological performance of decellularized heart, valves and big vessels. Furthermore, we focus on the relevance of ECM components, native and resulting from decellularization, in mediating in vivo host response and determining repair and regeneration, as opposed to graft corruption. PMID:24660110

  15. Biomolecular localization: Applications in tissue engineering

    NASA Astrophysics Data System (ADS)

    Znidarsic, William John

    A carrier material designed for in vivo implantation of cells can be chemically modified to present ligands that interact with cell surface receptors and guide new tissue formation. This study presents a versatile technique for modification of alginate matrices that relies upon molecular coating of nanoparticle surfaces, using a layer-by-layer deposition technique, followed by dispersion of these particles with the alginate gel matrix. The deposition technique results in nanoparticle coatings that present a variety of biological information including organic molecules (e.g. amines, polyacrylic acid (PAA), phosphoproteins, collagen, albumin, and growth factors) and inorganic calcium phosphate (e.g. hydroxyapatite). Results show that incorporation of coated nanoparticles can stimulate cell proliferation when compared with incorporation of un-coated particles and/or free molecules. Because cells incorporated within the volume of the alginate matrix present cell surface receptors that are spatially distributed on the nano-scale, the observed stimulation in proliferation may be a result of changes in local concentration of molecules that are coated on the nanoparticles rather than added in "free form". In the repair of maxillofacial defects, alginate gels are used clinically for the delivery and localization of stem cells. Similar techniques for three-dimensional localization of biomolecules within these constructs may possibly prove beneficial in stimulating positive biological outcomes in vivo.

  16. Materials and surface modification for tissue engineered vascular scaffolds.

    PubMed

    Li, Zhong-Kui; Wu, Zhong-Shi; Lu, Ting; Yuan, Hao-Yong; Tang, Hao; Tang, Zhen-Jie; Tan, Ling; Wang, Bin; Yan, Si-Ming

    2016-10-01

    Although vascular implantation has been used as an effective treatment for cardiovascular disease for many years, off-the-shelf and regenerable vascular scaffolds are still not available. Tissue engineers have tested various materials and methods of surface modification in the attempt to develop a scaffold that is more suitable for implantation. Extracellular matrix-based natural materials and biodegradable polymers, which are the focus of this review, are considered to be suitable materials for production of tissue-engineered vascular grafts. Various methods of surface modification that have been developed will also be introduced, their impacts will be summarized and assessed, and challenges for further research will briefly be discussed. PMID:27484610

  17. Tissue-Engineered Skeletal Muscle Organoids for Reversible Gene Therapy

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman; DelTatto, Michael; Shansky, Janet; Lemaire, Julie; Chang, Albert; Payumo, Francis; Lee, Peter; Goodyear, Amy; Raven, Latasha

    1996-01-01

    Genetically modified murine skeletal myoblasts were tissue engineered in vitro into organ-like structures (organoids) containing only postmitotic myoribers secreting pharmacological levels of recombinant human growth hormone (rhGH). Subcutaneous organoid implantation under tension led to the rapid and stable appearance of physiological sera levels of rhGH for up to 12 weeks, whereas surgical removal led to its rapid disappearance. Reversible delivery of bioactive compounds from postmitotic cells in tissue engineered organs has several advantages over other forms of muscle gene therapy.

  18. Tissue-Engineered Skeletal Muscle Organoids for Reversible Gene Therapy

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman; DelTatto, Michael; Shansky, Janet; Lemaire, Julie; Chang, Albert; Payumo, Francis; Lee, Peter; Goodyear, Amy; Raven, Latasha

    1996-01-01

    Genetically modified murine skeletal myoblasts were tissue engineered in vitro into organ-like structures (organoids) containing only postmitotic myofibers secreting pharmacological levels of recombinant human growth hormone (rhGH). Subcutaneous organoid Implantation under tension led to the rapid and stable appearance of physiological sera levels of rhGH for up to 12 weeks, whereas surgical removal led to its rapid disappearance. Reversible delivery of bioactive compounds from postimtotic cells in tissue engineered organs has several advantages over other forms of muscle gene therapy.

  19. Electrospinning of silk fibroin and collagen for vascular tissue engineering.

    PubMed

    Zhou, Juan; Cao, Chuanbao; Ma, Xilan; Lin, Jing

    2010-11-01

    Tubular scaffolds of silk fibroin (SF)/collagen (Col) were prepared by electrospinning with the aim to develop a new scaffold for vascular tissue engineering. The effects of the solvent, solution concentration and collagen content on the morphology of the scaffolds were investigated by SEM. FTIR and XRD were used to investigate their structural changes. Although there were morphological and structural differences, the water uptake and the tensile strength of the scaffolds with different collagen content showed no significant difference. This study confirmed the feasibility of the fabrication of SF/Col tubular scaffold by electrospinning from aqueous solution and provided promising tubular scaffold for vascular tissue engineering. PMID:20688101

  20. Plant-Derived Human Collagen Scaffolds for Skin Tissue Engineering

    PubMed Central

    Willard, James J.; Drexler, Jason W.; Das, Amitava; Roy, Sashwati; Shilo, Shani; Shoseyov, Oded

    2013-01-01

    Tissue engineering scaffolds are commonly formed using proteins extracted from animal tissues, such as bovine hide. Risks associated with the use of these materials include hypersensitivity and pathogenic contamination. Human-derived proteins lower the risk of hypersensitivity, but possess the risk of disease transmission. Methods engineering recombinant human proteins using plant material provide an alternate source of these materials without the risk of disease transmission or concerns regarding variability. To investigate the utility of plant-derived human collagen (PDHC) in the development of engineered skin (ES), PDHC and bovine hide collagen were formed into tissue engineering scaffolds using electrospinning or freeze-drying. Both raw materials were easily formed into two common scaffold types, electrospun nonwoven scaffolds and lyophilized sponges, with similar architectures. The processing time, however, was significantly lower with PDHC. PDHC scaffolds supported primary human cell attachment and proliferation at an equivalent or higher level than the bovine material. Interleukin-1 beta production was significantly lower when activated THP-1 macrophages where exposed to PDHC electrospun scaffolds compared to bovine collagen. Both materials promoted proper maturation and differentiation of ES. These data suggest that PDHC may provide a novel source of raw material for tissue engineering with low risk of allergic response or disease transmission. PMID:23298216

  1. Plant-derived human collagen scaffolds for skin tissue engineering.

    PubMed

    Willard, James J; Drexler, Jason W; Das, Amitava; Roy, Sashwati; Shilo, Shani; Shoseyov, Oded; Powell, Heather M

    2013-07-01

    Tissue engineering scaffolds are commonly formed using proteins extracted from animal tissues, such as bovine hide. Risks associated with the use of these materials include hypersensitivity and pathogenic contamination. Human-derived proteins lower the risk of hypersensitivity, but possess the risk of disease transmission. Methods engineering recombinant human proteins using plant material provide an alternate source of these materials without the risk of disease transmission or concerns regarding variability. To investigate the utility of plant-derived human collagen (PDHC) in the development of engineered skin (ES), PDHC and bovine hide collagen were formed into tissue engineering scaffolds using electrospinning or freeze-drying. Both raw materials were easily formed into two common scaffold types, electrospun nonwoven scaffolds and lyophilized sponges, with similar architectures. The processing time, however, was significantly lower with PDHC. PDHC scaffolds supported primary human cell attachment and proliferation at an equivalent or higher level than the bovine material. Interleukin-1 beta production was significantly lower when activated THP-1 macrophages where exposed to PDHC electrospun scaffolds compared to bovine collagen. Both materials promoted proper maturation and differentiation of ES. These data suggest that PDHC may provide a novel source of raw material for tissue engineering with low risk of allergic response or disease transmission. PMID:23298216

  2. X-ray phase contrast imaging of calcified tissue and biomaterial structure in bioreactor engineered tissues.

    PubMed

    Appel, Alyssa A; Larson, Jeffery C; Garson, Alfred B; Guan, Huifeng; Zhong, Zhong; Nguyen, Bao-Ngoc B; Fisher, John P; Anastasio, Mark A; Brey, Eric M

    2015-03-01

    Tissues engineered in bioreactor systems have been used clinically to replace damaged tissues and organs. In addition, these systems are under continued development for many tissue engineering applications. The ability to quantitatively assess material structure and tissue formation is critical for evaluating bioreactor efficacy and for preimplantation assessment of tissue quality. Techniques that allow for the nondestructive and longitudinal monitoring of large engineered tissues within the bioreactor systems will be essential for the translation of these strategies to viable clinical therapies. X-ray Phase Contrast (XPC) imaging techniques have shown tremendous promise for a number of biomedical applications owing to their ability to provide image contrast based on multiple X-ray properties, including absorption, refraction, and scatter. In this research, mesenchymal stem cell-seeded alginate hydrogels were prepared and cultured under osteogenic conditions in a perfusion bioreactor. The constructs were imaged at various time points using XPC microcomputed tomography (µCT). Imaging was performed with systems using both synchrotron- and tube-based X-ray sources. XPC µCT allowed for simultaneous three-dimensional (3D) quantification of hydrogel size and mineralization, as well as spatial information on hydrogel structure and mineralization. Samples were processed for histological evaluation and XPC showed similar features to histology and quantitative analysis consistent with the histomorphometry. These results provide evidence of the significant potential of techniques based on XPC for noninvasive 3D imaging engineered tissues grown in bioreactors. PMID:25257802

  3. X-ray Phase Contrast Imaging of Calcified Tissue and Biomaterial Structure in Bioreactor Engineered Tissues

    SciTech Connect

    Appel, Alyssa A.; Larson, Jeffery C.; Garson, III, Alfred B.; Guan, Huifeng; Zhong, Zhong; Nguyen, Bao-Ngoc; Fisher, John P.; Anastasio, Mark A.; Brey, Eric M.

    2014-11-04

    Tissues engineered in bioreactor systems have been used clinically to replace damaged tissues and organs. In addition, these systems are under continued development for many tissue engineering applications. The ability to quantitatively assess material structure and tissue formation is critical for evaluating bioreactor efficacy and for preimplantation assessment of tissue quality. These techniques allow for the nondestructive and longitudinal monitoring of large engineered tissues within the bioreactor systems and will be essential for the translation of these strategies to viable clinical therapies. X-ray Phase Contrast (XPC) imaging techniques have shown tremendous promise for a number of biomedical applications owing to their ability to provide image contrast based on multiple X-ray properties, including absorption, refraction, and scatter. In this research, mesenchymal stem cell-seeded alginate hydrogels were prepared and cultured under osteogenic conditions in a perfusion bioreactor. The constructs were imaged at various time points using XPC microcomputed tomography (µCT). Imaging was performed with systems using both synchrotron- and tube-based X-ray sources. XPC µCT allowed for simultaneous three-dimensional (3D) quantification of hydrogel size and mineralization, as well as spatial information on hydrogel structure and mineralization. Samples were processed for histological evaluation and XPC showed similar features to histology and quantitative analysis consistent with the histomorphometry. Furthermore, these results provide evidence of the significant potential of techniques based on XPC for noninvasive 3D imaging engineered tissues grown in bioreactors.

  4. Stem cell-based tissue engineering with silk biomaterials.

    PubMed

    Wang, Yongzhong; Kim, Hyeon-Joo; Vunjak-Novakovic, Gordana; Kaplan, David L

    2006-12-01

    Silks are naturally occurring polymers that have been used clinically as sutures for centuries. When naturally extruded from insects or worms, silk is composed of a filament core protein, termed fibroin, and a glue-like coating consisting of sericin proteins. In recent years, silk fibroin has been increasingly studied for new biomedical applications due to the biocompatibility, slow degradability and remarkable mechanical properties of the material. In addition, the ability to now control molecular structure and morphology through versatile processability and surface modification options have expanded the utility for this protein in a range of biomaterial and tissue-engineering applications. Silk fibroin in various formats (films, fibers, nets, meshes, membranes, yarns, and sponges) has been shown to support stem cell adhesion, proliferation, and differentiation in vitro and promote tissue repair in vivo. In particular, stem cell-based tissue engineering using 3D silk fibroin scaffolds has expanded the use of silk-based biomaterials as promising scaffolds for engineering a range of skeletal tissues like bone, ligament, and cartilage, as well as connective tissues like skin. To date fibroin from Bombyx mori silkworm has been the dominant source for silk-based biomaterials studied. However, silk fibroins from spiders and those formed via genetic engineering or the modification of native silk fibroin sequence chemistries are beginning to provide new options to further expand the utility of silk fibroin-based materials for medical applications. PMID:16890988

  5. Tissue-engineered lymphatic graft for the treatment of lymphedema

    PubMed Central

    Kanapathy, Muholan; Patel, Nikhil M.; Kalaskar, Deepak M.; Mosahebi, Afshin; Mehrara, Babak J.; Seifalian, Alexander M.

    2015-01-01

    Background Lymphedema is a chronic debilitating condition and curative treatment is yet to be found. Tissue engineering approach, which combines cellular components, scaffold, and molecular signals hold great potential in the treatment of secondary lymphedema with the advent of lymphatic graft to reconstruct damaged collecting lymphatic vessel. This review highlights the ideal characteristics of lymphatic graft, the limitation and challenges faced, and the approaches in developing tissue-engineered lymphatic graft. Methods Literature on tissue engineering of lymphatic system and lymphatic tissue biology was reviewed. Results The prime challenge in the design and manufacturing of this graft is producing endothelialized conduit with intraluminal valves. Suitable scaffold material is needed to ensure stability and functionality of the construct. Endothelialization of the construct can be enhanced via biofunctionalization and nanotopography, which mimics extracellular matrix. Nanocomposite polymers with improved performance over existing biomaterials are likely to benefit the development of lymphatic graft. Conclusions With the in-depth understanding of tissue engineering, nanotechnology, and improved knowledge on the biology of lymphatic regeneration, the aspiration to develop successful lymphatic graft is well achievable. PMID:25248852

  6. Controlling the Structural and Functional Anisotropy of Engineered Cardiac Tissues

    PubMed Central

    Bursac, N

    2014-01-01

    The ability to control the degree of structural and functional anisotropy in 3D engineered cardiac tissues would have high utility for both in vitro studies of cardiac muscle physiology and pathology as well as potential tissue engineering therapies for myocardial infarction. Here, we applied a high aspect ratio soft lithography technique to generate network-like tissue patches seeded with neonatal rat cardiomyocytes. Fabricating longer elliptical pores within the patch networks increased the overall cardiomyocyte and extracellular matrix (ECM) alignment within the patch. Improved uniformity of cell and matrix alignment yielded an increase in anisotropy of action potential propagation and faster longitudinal conduction velocity (LCV). Cardiac tissue patches with a higher degree of cardiomyocyte alignment and electrical anisotropy also demonstrated greater isometric twitch forces. After two weeks of culture, specific measures of electrical and contractile function (LCV = 26.8 ± 0.8 cm/s, specific twitch force = 8.9 ± 1.1 mN/mm2 for the longest pores studied) were comparable to those of neonatal rat myocardium. We have thus described methodology for engineering of highly functional 3D engineered cardiac tissues with controllable degree of anisotropy. PMID:24717534

  7. Musculoskeletal tissue engineering with human umbilical cord mesenchymal stromal cells

    PubMed Central

    Wang, Limin; Ott, Lindsey; Seshareddy, Kiran; Weiss, Mark L; Detamore, Michael S

    2011-01-01

    Multipotent mesenchymal stromal cells (MSCs) hold tremendous promise for tissue engineering and regenerative medicine, yet with so many sources of MSCs, what are the primary criteria for selecting leading candidates? Ideally, the cells will be multipotent, inexpensive, lack donor site morbidity, donor materials should be readily available in large numbers, immunocompatible, politically benign and expandable in vitro for several passages. Bone marrow MSCs do not meet all of these criteria and neither do embryonic stem cells. However, a promising new cell source is emerging in tissue engineering that appears to meet these criteria: MSCs derived from Wharton’s jelly of umbilical cord MSCs. Exposed to appropriate conditions, umbilical cord MSCs can differentiate in vitro along several cell lineages such as the chondrocyte, osteoblast, adipocyte, myocyte, neuronal, pancreatic or hepatocyte lineages. In animal models, umbilical cord MSCs have demonstrated in vivo differentiation ability and promising immunocompatibility with host organs/tissues, even in xenotransplantation. In this article, we address their cellular characteristics, multipotent differentiation ability and potential for tissue engineering with an emphasis on musculoskeletal tissue engineering. PMID:21175290

  8. Cryopreservation of Cell/Scaffold Tissue-Engineered Constructs

    PubMed Central

    Costa, Pedro F.; Dias, Ana F.; Reis, Rui L.

    2012-01-01

    The aim of this work was to study the effect of cryopreservation over the functionality of tissue-engineered constructs, analyzing the survival and viability of cells seeded, cultured, and cryopreserved onto 3D scaffolds. Further, it also evaluated the effect of cryopreservation over the properties of the scaffold material itself since these are critical for the engineering of most tissues and in particular, tissues such as bone. For this purpose, porous scaffolds, namely fiber meshes based on a starch and poly(caprolactone) blend were seeded with goat bone marrow stem cells (GBMSCs) and cryopreserved for 7 days. Discs of the same material seeded with GBMSCs were also used as controls. After this period, these samples were analyzed and compared to samples collected before the cryopreservation process. The obtained results demonstrate that it is possible to maintain cell viability and scaffolds properties upon cryopreservation of tissue-engineered constructs based on starch scaffolds and goat bone marrow mesenchymal cells using standard cryopreservation methods. In addition, the outcomes of this study suggest that the greater porosity and interconnectivity of scaffolds favor the retention of cellular content and cellular viability during cryopreservation processes, when compared with nonporous discs. These findings indicate that it might be possible to prepare off-the-shelf engineered tissue substitutes and preserve them to be immediately available upon request for patients' needs. PMID:22676448

  9. A Novel Albumin-Based Tissue Scaffold for Autogenic Tissue Engineering Applications

    PubMed Central

    Li, Pei-Shan; -Liang Lee, I.; Yu, Wei-Lin; Sun, Jui-Sheng; Jane, Wann-Neng; Shen, Hsin-Hsin

    2014-01-01

    Tissue scaffolds provide a framework for living tissue regeneration. However, traditional tissue scaffolds are exogenous, composed of metals, ceramics, polymers, and animal tissues, and have a defined biocompatibility and application. This study presents a new method for obtaining a tissue scaffold from blood albumin, the major protein in mammalian blood. Human, bovine, and porcine albumin was polymerised into albumin polymers by microbial transglutaminase and was then cast by freeze-drying-based moulding to form albumin tissue scaffolds. Scanning electron microscopy and material testing analyses revealed that the albumin tissue scaffold possesses an extremely porous structure, moderate mechanical strength, and resilience. Using a culture of human mesenchymal stem cells (MSCs) as a model, we showed that MSCs can be seeded and grown in the albumin tissue scaffold. Furthermore, the albumin tissue scaffold can support the long-term osteogenic differentiation of MSCs. These results show that the albumin tissue scaffold exhibits favourable material properties and good compatibility with cells. We propose that this novel tissue scaffold can satisfy essential needs in tissue engineering as a general-purpose substrate. The use of this scaffold could lead to the development of new methods of artificial fabrication of autogenic tissue substitutes. PMID:25034369

  10. A Novel Albumin-Based Tissue Scaffold for Autogenic Tissue Engineering Applications

    NASA Astrophysics Data System (ADS)

    Li, Pei-Shan; -Liang Lee, I.; Yu, Wei-Lin; Sun, Jui-Sheng; Jane, Wann-Neng; Shen, Hsin-Hsin

    2014-07-01

    Tissue scaffolds provide a framework for living tissue regeneration. However, traditional tissue scaffolds are exogenous, composed of metals, ceramics, polymers, and animal tissues, and have a defined biocompatibility and application. This study presents a new method for obtaining a tissue scaffold from blood albumin, the major protein in mammalian blood. Human, bovine, and porcine albumin was polymerised into albumin polymers by microbial transglutaminase and was then cast by freeze-drying-based moulding to form albumin tissue scaffolds. Scanning electron microscopy and material testing analyses revealed that the albumin tissue scaffold possesses an extremely porous structure, moderate mechanical strength, and resilience. Using a culture of human mesenchymal stem cells (MSCs) as a model, we showed that MSCs can be seeded and grown in the albumin tissue scaffold. Furthermore, the albumin tissue scaffold can support the long-term osteogenic differentiation of MSCs. These results show that the albumin tissue scaffold exhibits favourable material properties and good compatibility with cells. We propose that this novel tissue scaffold can satisfy essential needs in tissue engineering as a general-purpose substrate. The use of this scaffold could lead to the development of new methods of artificial fabrication of autogenic tissue substitutes.

  11. Hydrogel bioprinted microchannel networks for vascularization of tissue engineering constructs.

    PubMed

    Bertassoni, Luiz E; Cecconi, Martina; Manoharan, Vijayan; Nikkhah, Mehdi; Hjortnaes, Jesper; Cristino, Ana Luiza; Barabaschi, Giada; Demarchi, Danilo; Dokmeci, Mehmet R; Yang, Yunzhi; Khademhosseini, Ali

    2014-07-01

    Vascularization remains a critical challenge in tissue engineering. The development of vascular networks within densely populated and metabolically functional tissues facilitate transport of nutrients and removal of waste products, thus preserving cellular viability over a long period of time. Despite tremendous progress in fabricating complex tissue constructs in the past few years, approaches for controlled vascularization within hydrogel based engineered tissue constructs have remained limited. Here, we report a three dimensional (3D) micromolding technique utilizing bioprinted agarose template fibers to fabricate microchannel networks with various architectural features within photocrosslinkable hydrogel constructs. Using the proposed approach, we were able to successfully embed functional and perfusable microchannels inside methacrylated gelatin (GelMA), star poly(ethylene glycol-co-lactide) acrylate (SPELA), poly(ethylene glycol) dimethacrylate (PEGDMA) and poly(ethylene glycol) diacrylate (PEGDA) hydrogels at different concentrations. In particular, GelMA hydrogels were used as a model to demonstrate the functionality of the fabricated vascular networks in improving mass transport, cellular viability and differentiation within the cell-laden tissue constructs. In addition, successful formation of endothelial monolayers within the fabricated channels was confirmed. Overall, our proposed strategy represents an effective technique for vascularization of hydrogel constructs with useful applications in tissue engineering and organs on a chip. PMID:24860845

  12. New pulsatile bioreactor for fabrication of tissue-engineered patches.

    PubMed

    Sodian, R; Lemke, T; Loebe, M; Hoerstrup, S P; Potapov, E V; Hausmann, H; Meyer, R; Hetzer, R

    2001-01-01

    To date, one approach to tissue engineering has been to develop in vitro conditions to ultimately fabricate functional cardiovascular structures prior to final implantation. In our current experiment, we developed a new pulsatile flow system that provides biochemical and biomechanical signals to regulate autologous patch-tissue development in vitro. The newly developed patch bioreactor is made of Plexiglas and is completely transparent (Mediport Kardiotechnik, Berlin). The bioreactor is connected to an air-driven respirator pump, and the cell culture medium continuously circulates through a closed-loop system. We thus developed a closed-loop, perfused bioreactor for long-term patch-tissue conditioning, which combines continuous, pulsatile perfusion and mechanical stimulation by periodically stretching the tissue-engineered patch constructs. By adjusting the stroke volume, the stroke rate, and the inspiration/expiration time of the ventilator, it allows various pulsatile flows and different levels of pressure. The whole system is a highly isolated cell culture setting, which provides a high level of sterility, gas supply, and fits into a standard humidified incubator. The bioreactor can be sterilized by ethylene oxide and assembled with a standard screwdriver. Our newly developed bioreactor provides optimal biomechanical and biodynamical stimuli for controlled tissue development and in vitro conditioning of an autologous tissue-engineered patch. PMID:11410898

  13. Hydrogel Bioprinted Microchannel Networks for Vascularization of Tissue Engineering Constructs

    PubMed Central

    Bertassoni, Luiz E.; Cecconi, Martina; Manoharan, Vijayan; Nikkhah, Mehdi; Hjortnaes, Jesper; Cristino, Ana Luiza; Barabaschi, Giada; Demarchi, Danilo; Dokmeci, Mehmet R.; Yang, Yunzhi; Khademhosseini, Ali

    2014-01-01

    Vascularization remains a critical challenge in tissue engineering. The development of vascular networks within densely populated and metabolically functional tissues facilitate transport of nutrients and removal of waste products, thus preserving cellular viability over a long period of time. Despite tremendous progress in fabricating complex tissue constructs in the past few years, approaches for controlled vascularization within hydrogel based engineered tissue constructs have remained limited. Here, we report a three dimensional (3D) micromolding technique utilizing bioprinted agarose template fibers to fabricate microchannel networks with various architectural features within photo cross linkable hydrogel constructs. Using the proposed approach, we were able to successfully embed functional and perfusable microchannels inside methacrylated gelatin (GelMA), star poly (ethylene glycol-co-lactide) acrylate (SPELA), poly (ethylene glycol) dimethacrylate (PEGDMA) and poly (ethylene glycol) diacrylate (PEGDA) hydrogels at different concentrations. In particular, GelMA hydrogels were used as a model to demonstrate the functionality of the fabricated vascular networks in improving mass transport, cellular viability and differentiation within the cell-laden tissue constructs. In addition, successful formation of endothelial monolayers within the fabricated channels was confirmed. Overall, our proposed strategy represents an effective technique for vascularization of hydrogel constructs with useful applications in tissue engineering and organs on a chip. PMID:24860845

  14. Extraction and assembly of tissue-derived gels for cell culture and tissue engineering.

    PubMed

    Uriel, Shiri; Labay, Edwardine; Francis-Sedlak, Megan; Moya, Monica L; Weichselbaum, Ralph R; Ervin, Natalia; Cankova, Zdravka; Brey, Eric M

    2009-09-01

    Interactions with the extracellular matrix (ECM) play an important role in regulating cell function. Cells cultured in, or on, three-dimensional ECM recapitulate similar features to those found in vivo that are not present in traditional two-dimensional culture. In addition, both natural and synthetic materials containing ECM components have shown promise in a number of tissue engineering applications. Current materials available for cell culture and tissue engineering do not adequately reflect the diversity of ECM composition between tissues. In this paper, a method is presented for extracting solutions of proteins and glycoproteins from soft tissues and inducing assembly of these proteins into gels. The extracts contain ECM proteins specific to the tissue source with low levels of intracellular molecules. Gels formed from the tissue-derived extracts have nanostructure similar to ECM in vivo and can be used to culture cells as both a thin substrate coating and a thick gel. This technique could be used to assemble hydrogels with varying composition depending upon the tissue source, hydrogels for three-dimensional culture, as scaffolds for tissue engineering therapies, and to study cell-matrix interactions. PMID:19115821

  15. Extraction and Assembly of Tissue-Derived Gels for Cell Culture and Tissue Engineering

    PubMed Central

    Uriel, Shiri; Labay, Edwardine; Francis-Sedlak, Megan; Moya, Monica L.; Weichselbaum, Ralph R.; Ervin, Natalia; Cankova, Zdravka

    2009-01-01

    Interactions with the extracellular matrix (ECM) play an important role in regulating cell function. Cells cultured in, or on, three-dimensional ECM recapitulate similar features to those found in vivo that are not present in traditional two-dimensional culture. In addition, both natural and synthetic materials containing ECM components have shown promise in a number of tissue engineering applications. Current materials available for cell culture and tissue engineering do not adequately reflect the diversity of ECM composition between tissues. In this paper, a method is presented for extracting solutions of proteins and glycoproteins from soft tissues and inducing assembly of these proteins into gels. The extracts contain ECM proteins specific to the tissue source with low levels of intracellular molecules. Gels formed from the tissue-derived extracts have nanostructure similar to ECM in vivo and can be used to culture cells as both a thin substrate coating and a thick gel. This technique could be used to assemble hydrogels with varying composition depending upon the tissue source, hydrogels for three-dimensional culture, as scaffolds for tissue engineering therapies, and to study cell–matrix interactions. PMID:19115821

  16. Advanced General Aviation Turbine Engine (GATE) concepts

    NASA Technical Reports Server (NTRS)

    Lays, E. J.; Murray, G. L.

    1979-01-01

    Concepts are discussed that project turbine engine cost savings through use of geometrically constrained components designed for low rotational speeds and low stress to permit manufacturing economies. Aerodynamic development of geometrically constrained components is recommended to maximize component efficiency. Conceptual engines, airplane applications, airplane performance, engine cost, and engine-related life cycle costs are presented. The powerplants proposed offer encouragement with respect to fuel efficiency and life cycle costs, and make possible remarkable airplane performance gains.

  17. Biodegradable electroactive materials for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Guimard, Nathalie Kathryn

    polymerization can be achieved at the surface of these functionalized films and that the extent of polymer immobilization appears to be affected by the presence of immobilized thiophene. The results reported in this dissertation lead the author to suggest that it is possible to generate biodegradable electroactive materials. Further, she believes that with additional optimization these materials may prove beneficial for the regeneration of peripheral nerves and possibly other tissues that respond favorably to electrical stimulation.

  18. Smart Engines Via Advanced Model Based Controls

    SciTech Connect

    Allain, Marc

    2000-08-20

    A ''new'' process for developing control systems - Less engine testing - More robust control system - Shorter development cycle time - ''Smarter'' approach to engine control - On-board models describe engine behavior - Shorter, systematic calibration process - Customer and legislative requirements designed-in.

  19. The engineered Salmonella typhimurium inhibits tumorigenesis in advanced glioma

    PubMed Central

    Chen, Jian-qiang; Zhan, Yue-fu; Wang, Wei; Jiang, Sheng-nan; Li, Xiang-ying

    2015-01-01

    Objective To explore the antitumor role of the attenuated Salmonella typhimurium ΔppGpp with inducible cytolysin A (ClyA) in advanced stage of glioma. Materials and methods The C6 rat glioma cells were orthotopically implanted by surgery into the caudate nucleus of rat brains. The rats were then randomly divide