ويتم تمويل هذا العمل من قبل المعاهد الوطنية للصحة المنحة R01 EB - 008836 وHL083895 R01 (على حد سواء لLEN). يمكننا أن يشكر داريل سميث ، جامعة نافخي الزجاج ، لجعل المفاعلات الحيوية لأبحاثنا.

<ol>
	<li>Risau, W., Flamme, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vasculogenesis.">Vasculogenesis.</a> Annu. Rev. Cell Dev. Biol. 11, 73-91 (1995).</li><li>Fankhauser, F., Bebie, H., Kwasniewska, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Influcence+of+mechanical+Forices+and+Flow+Mechanisms+on+Vessel+Occlusion.">The Influcence of mechanical Forices and Flow Mechanisms on Vessel Occlusion.</a> Lasers in Surgery and Medicine. 6, 530-532 (1987).</li><li>Niklason, L. E., Gao, J., Abbott, W. M., Hirschi, K. K., Houser, S., Marini, R., Langer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+arteries+grown+in+vitro.">Functional arteries grown in vitro.</a> Science. 284, 489-493 (1999).</li><li>Prabhakar, V., Grinstaff, M. W., Alarcon, J., Knors, C., Solan, A. K., Niklason, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+porcine+arteries:+Effects+of+scaffold+modification.">Engineering porcine arteries: Effects of scaffold modification.</a> Journal of Biomedical Materials Research Part A. 67A, 303-311 (2003).</li><li>Mitchell, S. L., Niklason, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Requirements+for+growing+tissue-engineered+vascular+grafts.">Requirements for growing tissue-engineered vascular grafts.</a> Cardiovascular Pathology. 12, 59-64 (2003).</li><li>Dahl, S. L. M., Rhim, C., Song, Y. C., Niklason, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+properties+and+compositions+of+tissue+engineered+and+native+arteries.">Mechanical properties and compositions of tissue engineered and native arteries.</a> Annals of Biomedical Engineering. 35, 348-355 (2007).</li><li>Quint, C., Kondo, Y., Manson, R. J., Lawson, J. H., Dardik, A., Niklason, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decellularized+tissue-engineered+blood+vessel+as+an+arterial+conduit.">Decellularized tissue-engineered blood vessel as an arterial conduit.</a> Proc Natl Acad Sci U S A. 108, 9214-9219 (2011).</li><li>Niklason, L. E., Yeh, A. T., Calle, E. A., Bai, Y., Valent&#237;n, A., Humphrey, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enabling+Tools+for+Engineering+Collagenous+Tissues+Integrating+Bioreactors,+Intravital+Imaging,+and+Biomechanical+Modeling.">Enabling Tools for Engineering Collagenous Tissues Integrating Bioreactors, Intravital Imaging, and Biomechanical Modeling.</a> Proceedings of the National Academy of Sciences of the United States of America. 107, 3335-3339 (2010).</li><li>Gong, Z., Calkins, G., Cheng, E. -. c., Krause, D., Niklason, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+Culture+Medium+on+Smooth+Muscle+Cell+Differentiation+from+Human+Bone+Marrow-Derived+Mesenchymal+Stem+Cells.">Influence of Culture Medium on Smooth Muscle Cell Differentiation from Human Bone Marrow-Derived Mesenchymal Stem Cells.</a> Tissue Engineering Part A. 15, 319-330 (2009).</li><li>Gong, Z. D., Niklason, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small-diameter+human+vessel+wall+engineered+from+bone+marrow-derived+mesenchymal+stem+cells+(hMSCs.">Small-diameter human vessel wall engineered from bone marrow-derived mesenchymal stem cells (hMSCs.</a> Faseb Journal. 22, 1635-1648 (2008).</li><li>Poh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+vessels+engineered+from+human+cells.">Blood vessels engineered from human cells.</a> Lancet. 365, 2122-2124 (2005).</li><li>American Heart Association. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Biostatistical fact sheet: cardiovascular procedures. , (2002).</li></ol>

الإعلان عن أي تضارب في المصالح.

نوعية السفن هندسيا هو في جزء كبير منه تمليه نوعية SMCs المستخدمة في زراعة الأنسجة. الجوانب الحاسمة في النمط الظاهري SMC تشمل مورفولوجيا مقلص ، وانخفاض عدد الممر ، والقدرة على التكاثر داخل مفاعل حيوي. نوصي بأن يكون أكبر عدد ممر لا يتجاوز P3 في وقت البذر الخلية على السقالة ا...

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><th> اسم الكاشف / مواد </th><th> المزود </th><th> رقم كتالوج </th></tr><tr><td> FBS (الجنين المصل البقري) الحرارة المعطل </td><td> HyClone </td><td> SH30071 </td></tr><tr><td> DMEM </td><td> GIBCO </td><td> 11885 </td></tr><tr><td> rhFGF - الأساسية </td><td> R &amp; B </td><td> 234 - FSE </td></tr><tr><td> rrPDGF - BB </td><td> R &amp; B </td><td> 520 - BB </td></tr><tr><td> Penicilin G </td><td> سيغما </td><td> بينا </td></tr><tr><td> النحاس (II) سلفات </td><td> سيغما </td><td> C8027 </td></tr><tr><td> Gylcine </td><td> سيغما </td><td> C8790 </td></tr><tr><td> L - ألانين </td><td> سيغما </td><td> A7469 - 25G </td></tr><tr><td> L - برولين </td><td> سيغما </td><td> P5607 - 25G </td></tr><tr><td> حمض الأسكوربيك </td><td> سيغما </td><td> A4544 - 25G </td></tr><tr><td> HEPES </td><td> سيغما </td><td> H3375 - 100G </td></tr><tr><td> سيليكون سدادة </td><td> كول - Parmer </td><td> 06298-24 </td></tr><tr><td> Masterflex أنابيب L / S </td><td> كول - Parmer </td><td> 06508-16 ، 06508-18 </td></tr><tr><td> Masterflex مضخة </td><td> كول - Parmer </td><td> 7553-80 </td></tr><tr><td> الداكرون الكفة </td><td> ماكيه </td><td> 174406 </td></tr><tr><td> ورأى PGA </td><td> كونكورديا </td><td> MO000877 - 01 </td></tr><tr><td> 1.5 متري 4-0 Surgipro الثاني خياطة </td><td> Syneture </td><td> VP - 557 - X </td></tr><tr><td> 6-0 0.7 خياطة Dexon متري </td><td> Syneture </td><td> 7538-11 </td></tr><tr><td> 0.22μm PTFE مرشحات </td><td> Whatman </td><td> 6780-2502 </td></tr><tr><td> ثلاثة الطريق وقف الديك </td><td> ادواردز Lifesciences </td><td> 593WSC </td></tr><tr><td> محول الضغط </td><td> ادواردز Lifesciences </td><td> PX212 </td></tr><tr><td> أكياس الرابع </td><td> باكستر </td><td> R4R2110 </td></tr><tr><td> تخفيف المالحة تعيين </td><td> سهم </td><td> W20030 </td></tr><tr><td> سيليكون أنابيب </td><td> سان جوبان </td><td> F05027 </td></tr></tbody></table>

engineering biological-based vascular grafts using a pulsatile bioreactor

وقد كرس الكثير من الجهد لتطوير وتعزيز منهجية لتجديد وظيفية صغيرة قطرها يتجاوز الشرايين. في البيئة الفسيولوجية ، وكلاهما مطلوب تحفيز الميكانيكية والكيميائية للحفاظ على التنمية السليمة وظيفة 1،2 الأوعية الشريانية. تم تصميم أنظمة الثقافة مفاعل حيوي وضعتها مجموعتنا لدعم تجديد السفينة ضمن بيئة الكيماوي والميكانيكية التي تسيطر على وجه التحديد تحاكي السفن الأم. جمعيتنا مفاعل حيوي وإجراءات الصيانة بسيطة نوعا ما ومتكررة للغاية 3،4. هي المصنفة خلايا العضلات الملساء (SMCs) على حمض polyglycolic أنبوبي (PGA) أن شبكة مترابطة عبر أنابيب من السيليكون ومتوافقة مع مثقف في مفاعل حيوي مع أو بدون تحفيز نابض لمدة تصل إلى 12 أسبوعا. هناك أربع سمات رئيسية تميز مفاعل حيوي لدينا من بعض أسلافه. 1) خلافا للأنظمة التي تحاكي ثقافة أخرى فقط البيوكيميائية المحيطة الأوعية الدموية الأصلية ، مفاعل حيوي لدينا أيضا بإنشاء البيئة الفسيولوجية نابض عن طريق تطبيق سلالة شعاعي دوري للسفن في مجال الثقافة. 2) ويمكن تربيتها السفن المهندسة متعددة في وقت واحد في ظل ظروف الميكانيكية المختلفة داخل بيئة الكيميائية الخاضعة للرقابة. 3) ومفاعل حيوي يسمح طبقة أحادية من الخلايا البطانية (EC) لتكون مغلفة بسهولة على الجانب اللمعية السفن هندسيا لزرع النماذج الحيوانية. 4) يمكن للمفاعل حيوي لدينا تراوحت أيضا السفن الثقافة هندسيا مع حجم قطرها مختلفة من 1 مم إلى 3 مم ، وتوفير الجهد لتكييف كل فرد مفاعل حيوي لتتناسب مع حجم قطرها محددة. هندسة السفن مثقف في مفاعل حيوي لدينا تشبه الأوعية الدموية الأصلي تشريحيا إلى حد ما. الخلايا الموجودة في جدران الأوعية التعبير عن علامات النضج SMC مقلص مثل العضلات الملساء ميوسين الثقيلة سلسلة (SMMHC) 3. وتودع وكمية كبيرة من الكولاجين داخل المصفوفة خارج الخلية ، والتي هي المسؤولة عن القوة الميكانيكية النهائي للهندسة السفن 5. تحليل البيوكيميائية يشير أيضا إلى أن محتوى الكولاجين السفن هندسيا هو مماثلة لتلك الشرايين الأصلية 6. الأهم من ذلك ، وإعادة إنشاء مفاعل حيوي نابض باستمرار السفن التي يحمل الخواص الميكانيكية التي تسمح التجارب الناجحة في غرس 3،7 النماذج الحيوانية. بالإضافة إلى ذلك ، يمكن تعديل هذه مفاعل حيوي للسماح للمزيد من الوقت الحقيقي وتقييم ومتابعة إعادة عرض الكولاجين مع مرور الوقت ، غير جراحية ، وذلك باستخدام المجهر الضوئي غير الخطي (NLOM) 8. وختاما ، ينبغي لهذه مفاعل حيوي بمثابة منصة مثالية لدراسة الآليات الأساسية التي تنظم تجديد الطعوم الصغيرة القطر وظيفية في الأوعية الدموية.

Watch this Scientific Journal Video about Engineering Biological-Based Vascular Grafts Using a Pulsatile Bioreactor at JoVE.com

Engineering Biological-Based Vascular Grafts Using a Pulsatile Bioreactor

وقد وضعت مجموعتنا نظام الثقافة مفاعل حيوي الذي يحاكي تؤكد نابض الفسيولوجية للنظام القلب والأوعية الدموية لتجديد زرع صغيرة قطرها ترقيع الأوعية الدموية.

الطعوم الوعائية الهندسة البيولوجية ، عن طريق بناء مفاعل حيوي نابض

Much effort has been devoted to develop and advance the methodology to regenerate functional small-diameter arterial bypasses. In the physiological ...

engineering-biological-based-vascular-grafts-using-pulsatile

Research

JoVE Journal

Bioengineering

16.9K Views.  Yale University. وقد وضعت مجموعتنا نظام الثقافة مفاعل حيوي الذي يحاكي تؤكد نابض الفسيولوجية للنظام القلب والأوعية الدموية لتجديد زرع صغيرة قطرها ترقيع الأوعية الدموية.

Video: Engineering Biological-Based Vascular Grafts Using a Pulsatile Bioreactor

Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering

We designed a loading device that is capable of applying uniaxial or biaxial mechanical strain to a tissue engineered biocomposites fabricated for transplantation. While the device primarily functions as a bioreactor that mimics the native mechanical strains, it is also outfitted with a load cell for providing force feedback or mechanical testing of the constructs. The device subjects engineered cartilage constructs to biaxial mechanical loading with great precision of loading dose (amplitude and frequency) and is compact enough to fit inside a standard tissue culture incubator. It loads samples directly in a tissue culture plate, and multiple plate sizes are compatible with the system. The device has been designed using components manufactured for precision-guided laser applications. Bi-axial loading is accomplished by two orthogonal stages. The stages have a 50 mm travel range and are driven independently by stepper motor actuators, controlled by a closed-loop stepper motor driver that features micro-stepping capabilities, enabling step sizes of less than 50 nm. A polysulfone loading platen is coupled to the bi-axial moving platform. Movements of the stages are controlled by Thor-labs Advanced Positioning Technology (APT) software. The stepper motor driver is used with the software to adjust load parameters of frequency and amplitude of both shear and compression independently and simultaneously. Positional feedback is provided by linear optical encoders that have a bidirectional repeatability of 0.1 &mu;m and a resolution of 20 nm, translating to a positional accuracy of less than 3 &mu;m over the full 50 mm of travel. These encoders provide the necessary position feedback to the drive electronics to ensure true nanopositioning capabilities. In order to provide the force feedback to detect contact and evaluate loading responses, a precision miniature load cell is positioned between the loading platen and the moving platform. The load cell has high accuracies of 0.15% to 0.25% full scale.

We designed a novel mechanical loading bioreactor that can apply uniaxial or biaxial mechanical strain to a cartilage biocomposite prior to transplantation into an articular cartilage defect.

تصميم مفاعل حيوي ذو محورين الميكانيكية جار للهندسة الأنسجة

We  designed a loading device that is capable of applying uniaxial or biaxial  mechanical strain to a tissue engineered biocomposites fabricated for  ...

Operation of a Benchtop Bioreactor

Fermentation systems are used to provide an optimal growth environment for many different types of cell cultures. The ability afforded by fermentors to carefully control temperature, pH, and dissolved oxygen concentrations in particular makes them essential to efficient large scale growth and expression of fermentation products. This video will briefly describe the advantages of the fermentor over the shake flask. It will also identify key components of a typical benchtop fermentation system and give basic instruction on setup of the vessel and calibration of its probes. The viewer will be familiarized with the sterilization process and shown how to inoculate the growth medium in the vessel with culture. Basic concepts of operation, sampling, and harvesting will also be demonstrated. Simple data analysis and system cleanup will also be discussed.

Fermentors are used to increase culture yield and productivity of bioengineered cells. After screening multiple microbial or animal cell culture candidates in shake flasks, the next logical step is to increase the selected culture&#x2019;s biomass with the fermentor. This video demonstrates the setup and operation of a typical benchtop bioreactor system.

تشغيل الفوق تفاعلات الاحيائية

Fermentation systems are used to provide an optimal growth environment for many different types of cell cultures. The ability afforded by fermentors to ...

Nonhuman Primate Lung Decellularization and Recellularization Using a Specialized Large-organ Bioreactor

There are an insufficient number of lungs available to meet current and future organ transplantation needs. Bioartificial tissue regeneration is an attractive alternative to classic organ transplantation. This technology utilizes an organ&#39;s natural biological extracellular matrix (ECM) as a scaffold onto which autologous or stem/progenitor cells may be seeded and cultured in such a way that facilitates regeneration of the original tissue. The natural ECM is isolated by a process called decellularization. Decellularization is accomplished by treating tissues with a series of detergents, salts, and enzymes to achieve effective removal of cellular material while leaving the ECM intact. Studies conducted utilizing decellularization and subsequent recellularization of rodent lungs demonstrated marginal success in generating pulmonary-like tissue which is capable of gas exchange in vivo. While offering essential proof-of-concept, rodent models are not directly translatable to human use. Nonhuman primates (NHP) offer a more suitable model in which to investigate the use of bioartificial organ production for eventual clinical use.
The protocols for achieving complete decellularization of lungs acquired from the NHP rhesus macaque are presented. The resulting acellular lungs can be seeded with a variety of cells including mesenchymal stem cells and endothelial cells. The manuscript also describes the development of a bioreactor system in which cell-seeded macaque lungs can be cultured under conditions of mechanical stretch and strain provided by negative pressure ventilation as well as pulsatile perfusion through the vasculature; these forces are known to direct differentiation along pulmonary and endothelial lineages, respectively. Representative results of decellularization and cell seeding are provided.

Whole-organ decellularization produces natural biological scaffolds that may be used for regenerative medicine. The description of a nonhuman primate model of lung regeneration in which whole lungs are decellularized and then seeded with adult stem cells and endothelial cells in a bioreactor that facilitates vascular circulation and liquid media ventilation is presented.

There are an insufficient number of lungs available to meet current and future organ transplantation needs. Bioartificial tissue regeneration is an ...

Construction and Characterization of a Novel Vocal Fold Bioreactor

In vitro engineering of mechanically active tissues requires the presentation of physiologically relevant mechanical conditions to cultured cells. To emulate the dynamic environment of vocal folds, a novel vocal fold bioreactor capable of producing vibratory stimulations at fundamental phonation frequencies is constructed and characterized. The device is composed of a function generator, a power amplifier, a speaker selector and parallel vibration chambers. Individual vibration chambers are created by sandwiching a custom-made silicone membrane between a pair of acrylic blocks. The silicone membrane not only serves as the bottom of the chamber but also provides a mechanism for securing the cell-laden scaffold. Vibration signals, generated by a speaker mounted underneath the bottom acrylic block, are transmitted to the membrane aerodynamically by the oscillating air. Eight identical vibration modules, fixed on two stationary metal bars, are housed in an anti-humidity chamber for long-term operation in a cell culture incubator. The vibration characteristics of the vocal fold bioreactor are analyzed non-destructively using a Laser Doppler Vibrometer (LDV). The utility of the dynamic culture device is demonstrated by culturing cellular constructs in the presence of 200-Hz sinusoidal vibrations with a mid-membrane displacement of 40 &#181;m. Mesenchymal stem cells cultured in the bioreactor respond to the vibratory signals by altering the synthesis and degradation of vocal fold-relevant, extracellular matrix components. The novel bioreactor system presented herein offers an excellent in vitro platform for studying vibration-induced mechanotransduction and for the engineering of functional vocal fold tissues.

A novel vocal fold bioreactor capable of delivering physiologically relevant, vibratory stimulation to cultured cells is constructed and characterized. This dynamic culture device, when combined with a fibrous poly(&#949;-caprolactone) scaffold, creates a vocal fold-mimetic environment that modulates the behaviors of mesenchymal stem cells.

البناء وتوصيف من طية تفاعلات الاحيائية الرواية الصوتية

In vitro engineering of mechanically active tissues requires the presentation of physiologically relevant mechanical conditions to cultured cells. To ...

Cultivation of Mammalian Cells Using a Single-use Pneumatic Bioreactor System

Recent advances in mammalian, insect, and stem cell cultivation and scale-up have created tremendous opportunities for new therapeutics and personalized medicine innovations. However, translating these advances into therapeutic applications will require in vitro systems that allow for robust, flexible, and cost effective bioreactor systems. There are several bioreactor systems currently utilized in research and commercial settings; however, many of these systems are not optimal for establishing, expanding, and monitoring the growth of different cell types. The culture parameters most challenging to control in these systems include, minimizing hydrodynamic shear, preventing nutrient gradient formation, establishing uniform culture medium aeration, preventing microbial contamination, and monitoring and adjusting culture conditions in real-time. Using a pneumatic single-use bioreactor system, we demonstrate the assembly and operation of this novel bioreactor for mammalian cells grown on micro-carriers. This bioreactor system eliminates many of the challenges associated with currently available systems by minimizing hydrodynamic shear and nutrient gradient formation, and allowing for uniform culture medium aeration. Moreover, the bioreactor&#8217;s software allows for remote real-time monitoring and adjusting of the bioreactor run parameters. This bioreactor system also has tremendous potential for scale-up of adherent and suspension mammalian cells for production of a variety therapeutic proteins, monoclonal antibodies, stem cells, biosimilars, and vaccines.

Using a pneumatic bioreactor, we demonstrate the assembly, operation, and performance of this single-use bioreactor system for the growth of mammalian cells.

زراعة خلايا الثدييات عن طريق استخدام المفرد نظام هوائي تفاعلات الاحيائية

Recent advances in mammalian, insect, and stem cell cultivation and scale-up have created tremendous opportunities for new therapeutics and personalized ...

Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring

The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large animal model. A step by-step protocol for inter-positional placement of the TEV and real-time digital assessment of the TEV and native carotid arteries is described here. In vivo monitoring is made possible by the implantation of flow probes, catheters and ultrasonic crystals (capable of recording dynamic diameter changes of implanted TEVs and native carotid arteries) at the time of surgery. Once implanted, researchers can calculate arterial blood flow patterns, invasive blood pressure and artery diameter yielding parameters such as pulse wave velocity, augmentation index, pulse pressures and compliance. Data acquisition is accomplished using a single computer program for analysis throughout the duration of the experiment. Such invaluable data provides insight into TEV matrix remodeling, its resemblance to native/sham controls and overall TEV performance in vivo.

Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring

A step-by-step protocol for the inter-positional placement of Tissue Engineered Vessels (TEVs) into the carotid artery of a sheep using end-to-end anastomosis and real-time digital assessment in vivo until animal sacrifice.

تقنية جراحية لزرع الأنسجة المهندسة الأوعية الدموية الطعوم واللاحقة<em&gt; في فيفو</em&gt; الرصد

The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large ...

Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled.
The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The &#8220;static bioreactor&#8221; provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues.

In this work, we present a technique for the rapid fabrication of living vascular tissues by direct culturing of collagen, smooth muscle cells and endothelial cells. In addition, a new protocol for the mechanical characterization of engineered vascular tissues is described.

الهندسة 3D Cellularized الهلام الكولاجين لتجديد الأنسجة الوعائية

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. ...

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities

A novel reactor design, coined a high density bioreactor (HDBR), is presented for the cultivation and study of high density microbial communities. Past studies have evaluated the performance of the reactor for the removal of COD1 and nitrogen species2-4 by heterotrophic and chemoautotrophic bacteria, respectively. The HDBR design eliminates the requirement for external flocculation/sedimentation processes while still yielding effluent containing low suspended solids. In this study, the HDBR is applied as a photobioreactor (PBR) in order to characterize the nitrogen removal characteristics of an algae-based photosynthetic microbial community. As previously reported for this HDBR design, a stable biomass zone was established with a clear delineation between the biologically active portion of the reactor and the recycling reactor fluid, which resulted in a low suspended solid effluent. The algal community in the HDBR was observed to remove 18.4% of total nitrogen species in the influent. Varying NH4+ and NO3- concentrations in the feed did not have an effect on NH4+ removal (n=44, p=0.993 and n=44, p=0.610 respectively) while NH4+ feed concentration was found to be negatively related with NO3- removal (n=44, p=0.000) and NO3- feed concentration was found to be positively correlated with NO3- removal (n=44, p=0.000). Consistent removal of NH4+, combined with the accumulation of oxidized nitrogen species at high NH4+ fluxes indicates the presence of ammonia- and nitrite-oxidizing bacteria within the microbial community.

A novel reactor design, coined a high density bioreactor (HDBR), is presented for the cultivation and study of high density microbial communities. Here, the HDBR is successfully applied in a photobioreactor (PBR) configuration for the study of nitrogen metabolism by a mixed high density algal community.

مفاعل حيوي رواية لزراعة ارتفاع كثافة المجتمعات الميكروبية متنوعة

A novel reactor design, coined a high density bioreactor (HDBR), is presented for the cultivation and study of high density microbial communities. Past ...

Image-guided, Laser-based Fabrication of Vascular-derived Microfluidic Networks

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic networks embedded in PEGDA hydrogels. Here, we describe the creation of virtual masks that allow for image-guided laser control; the photopolymerization of a micromolded PEGDA hydrogel, suitable for microfluidic network fabrication and pressure head-driven flow; the setup and use of a commercially available laser scanning confocal microscope paired with a femtosecond pulsed Ti:S laser to induce hydrogel degradation; and the imaging of fabricated microfluidic networks using fluorescent species and confocal microscopy. Much of the protocol is focused on the proper setup and implementation of the microscope software and microscope macro, as these are crucial steps in using a commercial microscope for microfluidic fabrication purposes that contain a number of intricacies. The image-guided component of this technique allows for the implementation of 3D image stacks or user-generated 3D models, thereby allowing for creative microfluidic design and for the fabrication of complex microfluidic systems of virtually any configuration. With an expected impact in tissue engineering, the methods outlined in this protocol could aid in the fabrication of advanced biomimetic microtissue constructs for organ- and human-on-a-chip devices. By mimicking the complex architecture, tortuosity, size, and density of in vivo vasculature, essential biological transport processes can be replicated in these constructs, leading to more accurate in vitro modeling of drug pharmacokinetics and disease.

This protocol outlines the implementation of image-guided, laser-based hydrogel degradation to fabricate vascular-derived, biomimetic microfluidic networks embedded in poly(ethylene glycol) diacrylate (PEGDA) hydrogels. These biomimetic microfluidic systems may be useful for tissue engineering applications, generation of in vitro disease models, and fabrication of advanced "on-a-chip" devices.

صورة موجهة، التصنيع القائم على الليزر من شبكات ميكروفلويديك المستمدة الأوعية الدموية.

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic ...

Scaling of Engineered Vascular Grafts Using 3D Printed Guides and the Ring Stacking Method

Coronary artery disease remains a leading cause of death, affecting millions of Americans. With the lack of autologous vascular grafts available, engineered grafts offer great potential for patient treatment. However, engineered vascular grafts are generally not easily scalable, requiring manufacture of custom molds or polymer tubes in order to customize to different sizes, constituting a time-consuming and costly practice. Human arteries range in lumen diameter from about 2.0-38 mm and in wall thickness from about 0.5-2.5 mm. We have created a method, termed the "Ring Stacking Method," in which variable size rings of tissue of the desired cell type, demonstrated here with vascular smooth muscle cells (SMCs), can be created using guides of center posts to control lumen diameter and outer shells to dictate vessel wall thickness. These tissue rings are then stacked to create a tubular construct, mimicking the natural form of a blood vessel. The vessel length can be tailored by simply stacking the number of rings required to constitute the length needed. With our technique, tissues of tubular forms, similar to a blood vessel, can be readily manufactured in a variety of dimensions and lengths to meet the needs of the clinic and patient.

Scalable engineered blood vessels would improve clinical applicability. Using easily sizable 3D-printed guides, rings of vascular smooth muscle were created and stacked into a tubular form, forming a vascular graft. Grafts can be sized to meet the range of human coronary artery dimensions by simply changing the 3D-printed guide size.