The Experts below are selected from a list of 21816 Experts worldwide ranked by ideXlab platform

Thomas Schmitz-rode - One of the best experts on this subject based on the ideXlab platform.

  • VascuTrainer: A Mobile and Disposable Bioreactor System for the Conditioning of Tissue-Engineered Vascular Grafts
    Annals of Biomedical Engineering, 2018
    Co-Authors: Frederic Wolf, Diana M. Rojas González, Ulrich Steinseifer, Markus Obdenbusch, Werner Herfs, Christian Brecher, Stefan Jockenhoevel, Petra Mela, Thomas Schmitz-rode
    Abstract:

    In vitro tissue engineering of vascular grafts requires dynamic conditioning in a Bioreactor System for in vitro tissue maturation and remodeling to receive a mechanically adequate and hemocompatible implant. The goal of the current work was to develop a Bioreactor System for the conditioning of vascular grafts which is (i) able to create a wide range of flow, pressure and frequency conditions, including physiological ones; (ii) compact and easy to assemble; (iii) transportable; (iv) disposable. The System is driven by a small centrifugal pump controlled via a custom-made control unit, which can also be operated on batteries to allow for autonomous transportation. To show the potential of the newly developed Bioreactor System small-caliber vascular composite grafts ( n  = 5, internal diameter = 3 mm, length = 12.5 cm) were fabricated using a fibrin scaffold embedding human umbilical artery smooth muscle cells and a polyvinylidene fluoride warp-knitted macroporous mesh. Subsequently, the vascular grafts were endothelialized and mounted in the Bioreactor System for conditioning. The conditioning parameters remained within the predefined range over the complete conditioning period and during operation on batteries as tested for up to 25 h. Fabrication and pre-conditioning under arterial pressure and shear stress conditions resulted in robust and hemocompatible tissue-engineered vascular grafts. Analysis of immunohistochemical stainings against extracellular matrix and cell-specific proteins revealed collagen I and collagen III deposition. The luminal surface was confluently covered with endothelial cells. The developed Bioreactor System showed cytocompatibility and pH, pO_2, pCO_2, glucose and lactate stayed constant. Sterility was maintained during the complete fabrication process of the vascular grafts. The potential of a versatile and mobile System and its functionality by conditioning tissue-engineered vascular grafts under physiological pressure and flow conditions could be demonstrated.

  • Novel Dynamic Bioreactor System for Heart Valve Cultivation under Echocardiographic Control
    IFMBE Proceedings, 2009
    Co-Authors: Sebastian Kreitz, Thomas Schmitz-rode, Guido Dohmen, S. Diamantouros, J. Frese, Thomas C. Flanagan, Ruediger Autschbach, Stefan Jockenhoevel
    Abstract:

    Dynamic Bioreactor Systems are widely used in heart valve tissue engineering as the means to apply defined mechanical stimuli on seeded myofibroblasts, thus promoting the development of sturdy yet elastic autologous tissue. Allowing for the delicate character of newly seeded cells as for the constant change of their mechanical properties over cultivation time, it is desirable to have a highly flexible dynamic Bioreactor System adjustable to the changing demands. For this task a pulsatile Bioreactor has been designed and built. This Bioreactor renders possible the application of highly configurable pressure profiles on a heart valve and hence the simulation of the changing physiological environment of a growing heart valve. It consists of a pressure chamber where a PC-controlled linear actuator applies pulsatile pressure on the valve through a silicone membrane, and a reservoir chamber where several monitoring devices can be attached. Through the use of pressure sensors direct feedback to the actuator is possible and the development of the heart valve can be closely supervised. The System has been successfully tested on newly acquired porcine aortic and pulmonary valves.

Jochen Buchs - One of the best experts on this subject based on the ideXlab platform.

  • Application of an improved continuous parallel shaken Bioreactor System for three microbial model Systems
    Bioprocess and Biosystems Engineering, 2008
    Co-Authors: Ali Akgün, Carsten Müller, Ramona Engmann, Jochen Buchs
    Abstract:

    A continuous parallel shaken Bioreactor System, combining the advantages of shaken Bioreactors with the advantages of continuous fermentation, was specifically manufactured from quartz glass and provides a geometric accuracy of

  • a novel parallel shaken Bioreactor System for continuous operation
    Biotechnology Progress, 2004
    Co-Authors: Ali Akgün, Bernd Maier, Diana Preis, Birthe Roth, Renata Klingelhofer, Jochen Buchs
    Abstract:

    A novel continuous Bioreactor System was developed as a shaken culture vessel for the investigation of the growth kinetics and product formation of microorganisms in milliscale. The novel Bioreactor System mainly consists of a specially designed 250-mL shake flask with two inlets, one for gas supply and one for medium supply, and one combined outlet on the side of flask for exhaust gas and culture liquid. As a result of the circulating motion of the fermentation broth in the shake flask, the maximum liquid height reaches the edge of the outlet and the fermentation broth is accelerated into the outlet by centrifugal force. Additionally, the excess fermentation broth leaving the culture vessel is continuously driven by the exhaust gas. Because of the small scale and the simple handling it is possible to operate many of these shaken Bioreactor vessels simultaneously. By using parallel vessels operated at different dilution rates on the same shaker, the data for a complete biomass over dilution rate (X-D) diagram of a biological culture can be evaluated in an efficient manner, thus saving money, materials, and time. Continuous fermentations of the yeast Saccharomyces cerevisiae H1022 (ATCC 32167) in the shaken Bioreactor System and in a conventional stirred tank fermentor showed very similar results.

Hiroshi Motai - One of the best experts on this subject based on the ideXlab platform.

  • Application of a Bioreactor System to Soy Sauce Production
    Developments in Food Engineering, 1994
    Co-Authors: Takashi Hamada, Yaichi Fukushima, Hiroshi Motai
    Abstract:

    Continuous fermentation of soy sauce with immobilized glutaminase and immobilized cells of Pediococcus halophilus, Zygosaccharomyces rouxii and Candida versatilis was investigated. Glutamic acid production and both lactic acid and alcohol fermentation continued for over 100 days without any problems. The total time required for the production of soy sauce by the Bioreactor System was much less than that of the conventional method (about 1/10). The soy sauce made by this System was similar to a conventional one in regard to chemical components and the quality of flavor.

  • Continuous production of soy sauce by a Bioreactor System
    Process Biochemistry, 1991
    Co-Authors: Takashi Hamada, Misao Sugishita, Yaichi Fukushima, Tetsuro Fukase, Hiroshi Motai
    Abstract:

    Abstract Continuous fermentation of soy sauce with immobilized glutaminase and immobilized cells of Pediococcus halophilus, Zygosaccharomyces rouxii , and Candida versatilis was investigated. Glutamic acid production and both lactic acid and alcohol fermentation continued constantly for over 100 days without any problems. The total time required for the production of soy sauce by the Bioreactor System was much less than of the conventional method (about 1/10). The soy sauce made by this System was similar to a conventional one in regard to chemical components and the quality of flavour.

Frederic Wolf - One of the best experts on this subject based on the ideXlab platform.

  • VascuTrainer: A Mobile and Disposable Bioreactor System for the Conditioning of Tissue-Engineered Vascular Grafts
    Annals of Biomedical Engineering, 2018
    Co-Authors: Frederic Wolf, Diana M. Rojas González, Ulrich Steinseifer, Markus Obdenbusch, Werner Herfs, Christian Brecher, Stefan Jockenhoevel, Petra Mela, Thomas Schmitz-rode
    Abstract:

    In vitro tissue engineering of vascular grafts requires dynamic conditioning in a Bioreactor System for in vitro tissue maturation and remodeling to receive a mechanically adequate and hemocompatible implant. The goal of the current work was to develop a Bioreactor System for the conditioning of vascular grafts which is (i) able to create a wide range of flow, pressure and frequency conditions, including physiological ones; (ii) compact and easy to assemble; (iii) transportable; (iv) disposable. The System is driven by a small centrifugal pump controlled via a custom-made control unit, which can also be operated on batteries to allow for autonomous transportation. To show the potential of the newly developed Bioreactor System small-caliber vascular composite grafts ( n  = 5, internal diameter = 3 mm, length = 12.5 cm) were fabricated using a fibrin scaffold embedding human umbilical artery smooth muscle cells and a polyvinylidene fluoride warp-knitted macroporous mesh. Subsequently, the vascular grafts were endothelialized and mounted in the Bioreactor System for conditioning. The conditioning parameters remained within the predefined range over the complete conditioning period and during operation on batteries as tested for up to 25 h. Fabrication and pre-conditioning under arterial pressure and shear stress conditions resulted in robust and hemocompatible tissue-engineered vascular grafts. Analysis of immunohistochemical stainings against extracellular matrix and cell-specific proteins revealed collagen I and collagen III deposition. The luminal surface was confluently covered with endothelial cells. The developed Bioreactor System showed cytocompatibility and pH, pO_2, pCO_2, glucose and lactate stayed constant. Sterility was maintained during the complete fabrication process of the vascular grafts. The potential of a versatile and mobile System and its functionality by conditioning tissue-engineered vascular grafts under physiological pressure and flow conditions could be demonstrated.

Ali Akgün - One of the best experts on this subject based on the ideXlab platform.

  • Application of an improved continuous parallel shaken Bioreactor System for three microbial model Systems
    Bioprocess and Biosystems Engineering, 2008
    Co-Authors: Ali Akgün, Carsten Müller, Ramona Engmann, Jochen Buchs
    Abstract:

    A continuous parallel shaken Bioreactor System, combining the advantages of shaken Bioreactors with the advantages of continuous fermentation, was specifically manufactured from quartz glass and provides a geometric accuracy of

  • a novel parallel shaken Bioreactor System for continuous operation
    Biotechnology Progress, 2004
    Co-Authors: Ali Akgün, Bernd Maier, Diana Preis, Birthe Roth, Renata Klingelhofer, Jochen Buchs
    Abstract:

    A novel continuous Bioreactor System was developed as a shaken culture vessel for the investigation of the growth kinetics and product formation of microorganisms in milliscale. The novel Bioreactor System mainly consists of a specially designed 250-mL shake flask with two inlets, one for gas supply and one for medium supply, and one combined outlet on the side of flask for exhaust gas and culture liquid. As a result of the circulating motion of the fermentation broth in the shake flask, the maximum liquid height reaches the edge of the outlet and the fermentation broth is accelerated into the outlet by centrifugal force. Additionally, the excess fermentation broth leaving the culture vessel is continuously driven by the exhaust gas. Because of the small scale and the simple handling it is possible to operate many of these shaken Bioreactor vessels simultaneously. By using parallel vessels operated at different dilution rates on the same shaker, the data for a complete biomass over dilution rate (X-D) diagram of a biological culture can be evaluated in an efficient manner, thus saving money, materials, and time. Continuous fermentations of the yeast Saccharomyces cerevisiae H1022 (ATCC 32167) in the shaken Bioreactor System and in a conventional stirred tank fermentor showed very similar results.