Bioreactors in tissue engineering

Bioreactors in tissue engineering

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  Presentation On Bioreactors in TissueEngineering Cell & Tissue Engineering (BME-7507) MOHAMMAD MOZAMMAL HOQUE BME- MENGG DEPARTMENT OF BIOMEDICAL ENGINEERING MILITARY INSTITUTE OF SCIENCE AND TECHNOLOGY (MIST) MIRPUR CANTONMENT, DHAKA-1216 PRESENTATION DATE:27-07-2019
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  Introduction  The term“bioreactor” refers to a system in which conditions are closely controlled to permit or induce certain behavior in living cells or tissues. The concept of bioreactors is neither new nor restricted to tissue engineering. Microbiologists use bioreactors (chemostats) to grow cultures of microorganisms under defined conditions. Bioreactors are also used in the brewing, food, pharmaceutical and biotechnology industries.  Bioreactor technologies intended for tissue engineering can be used to grow functional cells and tissues for transplantation, and for controlled in vitro studies on the regulation effect of biochemical and biomechanical factors on cell and tissue development.
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  Bioreactors in tissueengineering  Bioreactor is a device used to carry out all biological or any biochemical process under controlled environment like controlled pH, temperature, pressure and also nutrient supply with the waste removal.  As an important component of tissue engineering, bioreactor system plays a significant role in providing an optimized environment for functional 3D tissue development. In this regard, variety of culture systems have been developed for supporting engineered tissue constructs. These culture systems can be fundamentally divided in to two main categories.  I. Static culture systems  II. Dynamic culture systems
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  Static Culture Systems In tissue engineering the most common and simplest culturing strategy is to cultivate a cell seeded construct in static media. This static culture method is very conventional way of Culturing cells by using sterile polypropylene petri-dish or well plates.  In static cultures approximately 2X106 , Cells were seeded over tissue engineering Scaffolds with the seeding efficiency of 50 to 55% and grown in a humidified CO2 incubator under static conditions. After seeding, scaffolds were allowed Top lunge in culture medium forum form supply of nutrients and media has to change every third day until we get consistent cell growth over the scaffold surface. This traditional approach does not fulfill all the requirements for regeneration of every functional organ.
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  Dynamic culture systems Despite burgeoning advancement in tissue engineering, mass transfer limitation remains a prevalent predicament. Dynamic culture systems using various engineered bioreactors can be an alternative for enhancing mass transfer and reinstating the in vivo physiological fluidics in vitro. Tissue culture reactors those engage dynamic media flow for developing 3D tissues as fallows;  (A) Rotating-wall vessel bioreactors  (B) Spinner flask bioreactor  (C) Concentric cylinder bioreactor  (D) Flow perfusion bioreactor
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  Rotating-wall vessel bioreactors The RWV bioreactor is a suspension culture system that allows for the growth of epithelial cells under low physiological fluid shear conditions. The bioreactors come in two different formats, a high-aspect rotating vessel (HARV) or a slow-turning lateral vessel (STLV), in which they differ by their aeration source.  Figure 3: Tissue engineered ovine lung produced in the Rotating Wall Vessel
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  Spinner flask bioreactor Spinner-flask bioreactor is one such device that has been designed to better control the re-differentiation of de-differentiated cartilage tissues in vitro.  Spinner-flask bioreactor is the most common mechanically stirred bioreactors that can be used for the seeding of cells on 3Dpolymer scaffolds and for subsequent culture of the constructs. A spinner flask bioreactor uses a magnetic stirrer to mix the cell suspension around a static scaffold, aiding in the cell allocation through out the scaffold. Polymer scaffolds such as biodegradable PGA are threaded onto needles, separated by spacers. These provide attachment sites for chondrocytes and promote cell migration and differentiation. In this bioreactor cells are aimed into the scaffold by convection.
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  Concentric cylinder bioreactor It’s a homogeneous bioreactor system also familiar As modified air-lift bioreactor. Concentric bioreactors are the object of much attention owing to their simple construction and low energy consumption, together with High mass and heat transfer rates. These bioreactors are very useful for primary studies of construct growth and to assess the importance of cell density, nutrients, and hydrodynamic loading on cartilage development. Simple concentric bioreactor geometry will ensure low shear stress environment, uniform nutrient transport and dynamic seeding of scaffold.
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  Flow perfusion bioreactor The last decade has seen several efforts at improving mass transfer limitations for 3D scaffolds. For example, cell-seeded porous scaffolds have been set up on orbital shakers, spinner flasks and rotating bioreactors, etc. These methods increase media flow across the surface of the scaffold, offering an improvement over traditional static culture techniques. While these technologies satisfy the external requirement for medium flow, convection of medium at the external surface does not guarantee the media distribution within thick porous scaffold interiors.
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  Conclusion  we discussedtissue engineering bioreactors for the cultivation of engineered tissues over 3D biodegradable scaffolds. When we monitor the construction of various reactors in detail we realize that specific design requirements depend on the dimensions, complexity and application of the tissue to be engineered. Since, physical and mechanical forces play crucial role in tissue development, designing of novel reactor to impart more sophisticated environment to cells and tissues in vitro offers significant options to improve functional tissue engineering constructs.
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  Thank You