وأيد هذا العمل من قبل مكتب البحوث والتنمية، RR &amp; D خدمة، وزارة شؤون المحاربين القدامى، المعاهد الوطنية للصحة كوبر 1P20RR024484، NIH K24 AR02128 وزارة الدفاع W81XWH-10-1-0643.

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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increasing+extracellular+matrix+production+in+regenerating+cartilage+with+intermittent+physiological+pressure.">Increasing extracellular matrix production in regenerating cartilage with intermittent physiological pressure.</a> Biotechnology and Bioengineering. 62, 166-174 (1999).</li><li>Frank, E. H., Jin, M., Loening, A. M., Levenston, M. E., Grodzinsky, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+versatile+shear+and+compression+apparatus+for+mechanical+stimulation+of+tissue+culture+explants.">A versatile shear and compression apparatus for mechanical stimulation of tissue culture explants.</a> J. Biomech. 33, 1523-1527 (2000).</li><li>Wagner, D. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrostatic+pressure+enhances+chondrogenic+differentiation+of+human+bone+marrow+stromal+cells+in+osteochondrogenic+medium.">Hydrostatic pressure enhances chondrogenic differentiation of human bone marrow stromal cells in osteochondrogenic medium.</a> Ann. Biomed. Eng. 36, 813-820 (2008).</li><li>Butler, D. L., Goldstein, S. A., Guilak, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+Tissue+Engineering:+The+Role+of+Biomechanics.">Functional Tissue Engineering: The Role of Biomechanics.</a> J. Biomech. Eng. 122, 570-575 (2000).</li><li>Guilak, F., Butler, D. L., Goldstein, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+Tissue+Engineering.+The+role+of+biomechanics+in+articular+cartilage+repair.">Functional Tissue Engineering. The role of biomechanics in articular cartilage repair.</a> Clin. Orthop. 391S, S295-S305 (2001).</li><li>Mauck, R. L., Byers, B. A., Yuan, X., Tuan, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+cartilaginous+ECM+gene+transcription+by+chondrocytes+and+MSCs+in+3D+culture+in+response+to+dynamic+loading.">Regulation of cartilaginous ECM gene transcription by chondrocytes and MSCs in 3D culture in response to dynamic loading.</a> Biomech. Model Mechanobiol. 6, 113-125 (2007).</li><li>Rubin, C., Xu, G., Judex, 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+anabolic+activity+of+bone+tissue,+suppressed+by+disuse,+is+normalized+by+brief+exposure+to+extremely+low-magnitude+mechanical+stimuli.">The anabolic activity of bone tissue, suppressed by disuse, is normalized by brief exposure to extremely low-magnitude mechanical stimuli.</a> FASEB J. 15, 2225-2229 (2001).</li><li>Wimmer, M. 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يعلن الكتاب أنه ليس لديهم مصالح مالية المتنافسة.

لقد قمنا بتصميم جهاز التحميل التي هي قادرة على تطبيق أحادي المحور أو ذو محورين سلالة الميكانيكية للأنسجة بنيات هندسيا ملفقة لزرع. الجهاز يمكن أن تستخدم مفاعل حيوي لزراعة في المختبر من biocomposites هندسيا أو كجهاز اختبار لوصف الخصائص الميكانيكية للأنسجة الأم أو بعد ا...

لقد قمنا بتصميم مفاعل حيوي التحميل التي هي قادرة على تطبيق أحادي المحور أو ذو محورين سلالة الميكانيكية للأنسجة وbiocomposites هندسيا ملفقة لزرع. تم تصميم هذا الجهاز في المقام الأول باعتباره مفاعل حيوي لاستبدال هندسيا للغضروف مفصلي، ويمكن أن تستخدم أيضا لغيرها من الأنسجة الحاملة في جسم الإنسان. الدافع لدينا في هذا التصميم مفاعل حيوي ينبع من Drachman وسوكولوف 1، الذي قدم الملاحظة المنوية من تشكيل غير طبيعي للغضروف مفصلي في افراخ الدجاج مشلولة بسبب غياب الحركة. وبالمثل، ممارسة الرياضة البدنية أمر ضروري لتطوير العضلات العادية والعظام. وتمشيا مع هذا المفهوم، حققت العديد من المجموعات البحثية كيف سائط مختلفة من المحفزات المادية خلال زراعة في المختبر ينظم الخصائص الكيميائية الحيوية والميكانيكية للbiocomposites خلية بيولوجية وإإكسبلنتس الأنسجة 2-7. مفهوم هندسة الأنسجة وظيفيةينطوي على استخدام المختبر في من المحفزات الميكانيكية لتحسين الخواص الوظيفية للأنسجة، أي الخواص الميكانيكية التي تمكن من الأنسجة لتحمل الإجهاد المتوقع في الجسم الحي، ويجهد 8،9. الإبلاغ عن العديد من الدراسات التحميل الميكانيكية استخدام من حيث القص وضغط لتحفيز يبني الغضروف المفصلي هندسيا للمفاصل. Mauck وآخرون. 10 تشير إلى أن التحميل الميكانيكية وحدها يمكن أن تحفز تكون الغضروف الخلايا الجذعية الوسيطة حتى في غياب عوامل النمو التي تعتبر حيوية. وقد تبين تطبيق جار الميكانيكية متقطعة مثل الضغط أو القص أثناء زراعة الأنسجة لتعديل الغضروف وتكوين العظام، ولكن قياس الجرعات المثلى من جار يختلف مع الخلية وخصائص الأنسجة 11. أهم وظيفة من الغضروف المفصلي هو القدرة على الصمود أمام قوات الضغط والقص داخلالمفصل، وبالتالي فإنه لا بد أن يكون الضغط العالي ومعاملات الرجوعية القص. وقد أدى عدم وجود القوة الميكانيكية وظيفية والتركيب الدقيق الفسيولوجية في الغضروف هندسيا في انهيار الجدد على الغضروف في الجسم الحي وفشل استراتيجيات استبدال الغضروف في المفاصل. على الرغم من الضغط والقص أثبتت عادة لتعديل وتحسين القوة الميكانيكية من biocomposites الغضروف المفصلي، وهو نهج مزيج نادر 6،12-15. Wartella وواين 16 تصميم مفاعل حيوي أن يطبق التوتر وضغط لإنتاج بدائل الغضروف الهلالي. والدمان وآخرون. 15 تصميم جهاز لتطبيق الضغط والقص إلى غضروفية تربيتها في مسامية الكالسيوم الركيزة متعدد الفوسفات. بيان وآخرون. أظهرت 17 الخواص الميكانيكية مطابقة الغضروف الأصلي مع زراعة في المختبر من غضروفية الكلاب الكبار في المواد الهلامية وتطبيق ذو محورين الميكانيكيةanical التحميل (الضغط التشوهي التحميل وانزلاق جار الاتصال). تم تصميم مفاعل حيوي ذو محورين جار الميكانيكية الأصلية كتبت بواسطة دانيال تشو في مختبرنا مع الهدف العام للحث على التكيفات المورفولوجية في أنسجة الغضروف المهندسة يبني مما أدى إلى معاملات الرجوعية الضغط والقص أعلى من المتاحة حاليا 18. ونحن نعتقد أن هذا البحث زيادة كبيرة في فهم أوسع لكيفية mechanotransduction يمكن التضمين لهندسة الأنسجة سريريا ذات الصلة.

<table border="1">
		<tbody>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>REAGENTS</td>
		 </tr>
		 <tr>
			<td>DMEM, High glucose, pyruvate</td>
			<td>Invitrogen</td>
			<td>11995</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Agarose Type II</td>
			<td>Sigma</td>
			<td>CAS 39346-81-1 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>Penicillin Streptomycin Glutamine 100X</td>
			<td>Invitrogen</td>
			<td>10378-016</td>
			<td></td>
		 </tr>
		 <tr>
			<td>ITS+ Premix</td>
			<td>BD Biosciences</td>
			<td>354352</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Pen Strep Glutamine</td>
			<td>Invitrogen</td>
			<td>10378-016</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Amphotericin B</td>
			<td>Invitrogen</td>
			<td>041-95780</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Ascorbic Acid</td>
			<td>Sigma</td>
			<td>A-2218</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Nonessential Amino Acid Solution 100x</td>
			<td>Sigma</td>
			<td>M-7145</td>
			<td></td>
		 </tr>
		 <tr>
			<td>L-proline</td>
			<td>Sigma</td>
			<td>P-5607</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Dexamethasone</td>
			<td>Sigma</td>
			<td>D-2915</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Recombinant Human Transforming Growth Factor &beta;1</td>
			<td>R&amp;D Systems</td>
			<td>240-B-010</td>
			<td></td>
		 </tr>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>EQUIPMENT</td>
		 </tr>
		 <tr>
			<td>Model 31 Load Cell (1000 g)</td>
			<td>Honeywell</td>
			<td>AL311</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Single Channel Display</td>
			<td>Honeywell</td>
			<td>SC500</td>
			<td></td>
		 </tr>
		 <tr>
			<td>50 mm Linear Encoded Travelmax Stage with Stepper Actuator</td>
			<td>Thorlabs</td>
			<td>LNR50SE/M</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Two Channel Stepper Motor Controller</td>
			<td>Thorlabs</td>
			<td>BSC102</td>
			<td></td>
		 </tr>
		 <tr>
			<td>50 mm Trapezoidal Stepper Motor Drive (2)</td>
			<td>Thorlabs</td>
			<td>DRV014</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Adjustable Kinematic Locator (4)</td>
			<td>Thorlabs</td>
			<td>KL02</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Precision Right Angle Plate</td>
			<td>Thorlabs</td>
			<td>AP90/M</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Vertical Mounting Bracket</td>
			<td>Thorlabs</td>
			<td>LNR50P2/M</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Solid Aluminum Breadboard</td>
			<td>Thorlabs</td>
			<td>MB3030/M</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Gel Casting System with 1.5 mm and 0.75 mm spacer plates </td>
			<td>BioRad</td>
			<td>#1653312 and #1653310 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>Disposable Biopsy Punch, 5 mm</td>
			<td>Miltex, Inc.</td>
			<td>33-35</td>
			<td></td>
		 </tr>
		 <tr>
			<td>16 mm hollow punch</td>
			<td>Neiko Tools</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Non-Tissue Culture Treated Plates, 24 Well, Flat Bottom</td>
			<td>BD Biosciences</td>
			<td>351147</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Ultra-Moisture-Resistant Polysulfone sheet for loading platens</td>
			<td>McMaster-Carr</td>
			<td>86735k19</td>
			<td>Custom-machined</td>
		 </tr>
		</tbody>
 </table>

design of a biaxial mechanical loading bioreactor for tissue engineering

قمنا بتصميم جهاز التحميل التي هي قادرة على تطبيق أحادي المحور أو ذو محورين سلالة الميكانيكية للأنسجة وbiocomposites هندسيا ملفقة لزرع. في حين أن الجهاز يعمل في المقام الأول باعتباره مفاعل حيوي الذي يحاكي سلالات الميكانيكية الأم، يتم تجهيزه أيضا مع خلية الحمل لتوفير التغذية المرتدة للقوة أو الاختبارات الميكانيكية للبنيات. الموضوعات جهاز هندسيا يبني الغضروف لتحميل الميكانيكي ذو محورين بقدر كبير من الدقة من جرعة التحميل (السعة والتردد) ومضغوط بما يكفي لتناسب داخل نسيج الثقافة الحاضنة القياسية. فإنه يحمل العينات مباشرة في لوحة زراعة الأنسجة، والأحجام لوحة متعددة متوافقة مع النظام. وقد تم تصميم الجهاز باستخدام المكونات المصنعة لتطبيقات الليزر الموجهة بدقة. ويتم إنجاز التحميل ثنائية المحوري بواسطة مرحلتين متعامد. المراحل لديها مجموعة والسفر 50 ملم وتكون مدفوعة بشكل مستقل من قبل السائر المحركات المحركات، التي تسيطر عليهاسائق حلقة مغلقة السائر المحركات التي تتميز قدرات الجزئي خطوة، خطوة تمكين أحجام أقل من 50 نانومتر. ويقترن A polysulfone التحميل الصوانى إلى منصة متحركة ثنائية المحوري. يتم التحكم في الحركات من المراحل من قبل ثور-مختبرات متطورة تكنولوجيا تحديد المواقع (APT) والبرمجيات. ويستخدم السائق السائر المحركات مع البرنامج لضبط المعلمات حمولة من التردد والسعة من كلا القص وضغط بشكل مستقل في وقت واحد. يتم توفير ردود الفعل الموضعية عن طريق الترميز الخطي البصرية التي تحتوي على التكرار ثنائية الاتجاه من 0.1 ميكرون وقرار من 20 نانومتر، وترجمة لدقة الموضعية أقل من 3 ميكرون على كامل 50 ملم من السفر. هذه الترميز وتوفير التغذية المرتدة الموقف اللازم للإلكترونيات حملة لضمان قدرات nanopositioning صحيح. من أجل توفير التغذية المرتدة للقوة للكشف عن الاتصال وتقييم الاستجابات التحميل، يتم وضع الدقة تحميل خلية مصغرة بين الصوانى التحميل وموفنز منصة. الخلية الحمل لديها دقة عالية من 0.15٪ إلى 0.25٪ نطاق كامل.

تم اختبار الجهاز باستخدام الاغاروز المواد الهلامية المصنف مع 20 مليون خلية / مل غضروفية وزراعتها في وجود أحادي المحور (ضغط) أو ذو محورين (الضغط والقص) تحميل الميكانيكية. تم عزل غضروفية الخنازير الأساسي من الغضروف المفصلي من 2-4 الخنازير القديمة الشهر. ومثقف 5 مم وقطرها 1.5...

Watch this Scientific Journal Video about Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering at JoVE.com

Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering

قمنا بتصميم رواية مفاعل حيوي جار الميكانيكية التي يمكن أن تنطبق ذو محورين أو ذو محورين سلالة الميكانيكية إلى biocomposite الغضروف قبل الزرع إلى خلل الغضروف المفصلي.

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  ...

design-biaxial-mechanical-loading-bioreactor-for-tissue

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14.2K Views.  The Warren Alpert Brown Medical School of Brown University and the Rhode Island Hospital. قمنا بتصميم رواية مفاعل حيوي جار الميكانيكية التي يمكن أن تنطبق ذو محورين أو ذو محورين سلالة الميكانيكية إلى biocomposite الغضروف قبل الزرع إلى خلل الغضروف المفصلي.

Video: Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering

Engineering Biological-Based Vascular Grafts Using a Pulsatile Bioreactor

Much effort has been devoted to develop and advance the methodology to regenerate functional small-diameter arterial bypasses. In the physiological environment, both mechanical and chemical stimulation are required to maintain the proper development and functionality of arterial vessels1,2.
Bioreactor culture systems developed by our group are designed to support vessel regeneration within a precisely controlled chemo-mechanical environment mimicking that of native vessels. Our bioreactor assembly and maintenance procedures are fairly simple and highly repeatable3,4. Smooth muscle cells (SMCs) are seeded onto a tubular polyglycolic acid (PGA) mesh that is threaded over compliant silicone tubing and cultured in the bioreactor with or without pulsatile stimulation for up to 12 weeks. There are four main attributes that distinguish our bioreactor from some predecessors. 1) Unlike other culture systems that simulate only the biochemical surrounding of native blood vessels, our bioreactor also creates a physiological pulsatile environment by applying cyclic radial strain to the vessels in culture. 2) Multiple engineered vessels can be cultured simultaneously under different mechanical conditions within a controlled chemical environment. 3) The bioreactor allows a mono layer of endothelial cells (EC) to be easily coated onto the luminal side of engineered vessels for animal implantation models. 4) Our bioreactor can also culture engineered vessels with different diameter size ranged from 1 mm to 3 mm, saving the effort to tailor each individual bioreactor to fit a specific diameter size. 
The engineered vessels cultured in our bioreactor resemble native blood vessels histologically to some degree. Cells in the vessel walls express mature SMC contractile markers such as smooth muscle myosin heavy chain (SMMHC)3. A substantial amount of collagen is deposited within the extracellular matrix, which is responsible for ultimate mechanical strength of the engineered vessels5. Biochemical analysis also indicates that collagen content of engineered vessels is comparable to that of native arteries6. Importantly, the pulsatile bioreactor has consistently regenerated vessels that exhibit mechanical properties that permit successful implantation experiments in animal models3,7. Additionally, this bioreactor can be further modified to allow real-time assessment and tracking of collagen remodeling over time, non-invasively, using a non-linear optical microscopy (NLOM)8. To conclude, this bioreactor should serve as an excellent platform to study the fundamental mechanisms that regulate the regeneration of functional small-diameter vascular grafts.

Our group has developed a bioreactor culture system that mimics the physiological pulsatile stresses of the cardiovascular system to regenerate implantable small-diameter vascular grafts.

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 ...

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, tension, and compression. Research has shown calcific lesions in diseased valves occur in areas of high mechanical stress as a result of endothelial disruption or interstitial matrix damage1-3. Hence, it is not surprising that epidemiological studies have shown high blood pressure to be a leading risk factor in the onset of aortic valve disease4. 
The only treatment option currently available for valve disease is surgical replacement of the diseased valve with a bioprosthetic or mechanical valve5. Improved understanding of valve biology in response to physical stresses would help elucidate the mechanisms of valve pathogenesis. In turn, this could help in the development of non-invasive therapies such as pharmaceutical intervention or prevention. Several bioreactors have been previously developed to study the mechanobiology of native or engineered heart valves6-9. Pulsatile bioreactors have also been developed to study a range of tissues including cartilage10, bone11 and bladder12. The aim of this work was to develop a cyclic pressure system that could be used to elucidate the biological response of aortic valve leaflets to increased pressure loads. 
The system consisted of an acrylic chamber in which to place samples and produce cyclic pressure, viton diaphragm solenoid valves to control the timing of the pressure cycle, and a computer to control electrical devices. The pressure was monitored using a pressure transducer, and the signal was conditioned using a load cell conditioner. A LabVIEW program regulated the pressure using an analog device to pump compressed air into the system at the appropriate rate. The system mimicked the dynamic transvalvular pressure levels associated with the aortic valve; a saw tooth wave produced a gradual increase in pressure, typical of the transvalvular pressure gradient that is present across the valve during diastole, followed by a sharp pressure drop depicting valve opening in systole. The LabVIEW program allowed users to control the magnitude and frequency of cyclic pressure. The system was able to subject tissue samples to physiological and pathological pressure conditions. This device can be used to increase our understanding of how heart valves respond to changes in the local mechanical environment.

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

A cyclic pressure bioreactor capable of subjecting heart valve tissue to physiological and pathological pressure conditions has been designed. A LabVIEW program allows users to control pressure magnitude, amplitude and frequency. This device can be used to study the mechanobiology of heart valve tissue or isolated cells.

تصميم مفاعل حيوي لضغط الدوري السابقين فيفو دراسة صمامات القلب الأورطي

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

Postproduction Processing of Electrospun Fibres for Tissue Engineering

Electrospinning is a commonly used and versatile method to produce scaffolds (often biodegradable) for 3D tissue engineering.1, 2, 3 Many tissues in vivo undergo biaxial distension to varying extents such as skin, bladder, pelvic floor and even the hard palate as children grow. In producing scaffolds for these purposes there is a need to develop scaffolds of appropriate biomechanical properties (whether achieved without or with cells) and which are sterile for clinical use. The focus of this paper is not how to establish basic electrospinning parameters (as there is extensive literature on electrospinning) but on how to modify spun scaffolds post production to make them fit for tissue engineering purposes - here thickness, mechanical properties and sterilisation (required for clinical use) are considered and we also describe how cells can be cultured on scaffolds and subjected to biaxial strain to condition them for specific applications.
Electrospinning tends to produce thin sheets; as the electrospinning collector becomes coated with insulating fibres it becomes a poor conductor such that fibres no longer deposit on it. Hence we describe approaches to produce thicker structures by heat or vapour annealing increasing the strength of scaffolds but not necessarily the elasticity. Sequential spinning of scaffolds of different polymers to achieve complex scaffolds is also described. Sterilisation methodologies can adversely affect strength and elasticity of scaffolds. We compare three methods for their effects on the biomechanical properties on electrospun scaffolds of poly lactic-co-glycolic acid (PLGA).
Imaging of cells on scaffolds and assessment of production of extracellular matrix (ECM) proteins by cells on scaffolds is described. Culturing cells on scaffolds in vitro can improve scaffold strength and elasticity but the tissue engineering literature shows that cells often fail to produce appropriate ECM when cultured under static conditions. There are few commercial systems available that allow one to culture cells on scaffolds under dynamic conditioning regimes - one example is the Bose Electroforce 3100 which can be used to exert a conditioning programme on cells in scaffolds held using mechanical grips within a media filled chamber.4 An approach to a budget cell culture bioreactor for controlled distortion in 2 dimensions is described. We show that cells can be induced to produce elastin under these conditions. Finally assessment of the biomechanical properties of processed scaffolds cultured with or without cells is described.

Electrospun scaffolds can be processed post production for tissue engineering applications. Here we describe methods for spinning complex scaffolds (by consecutive spinning), for making thicker scaffolds (by multi-layering using heat or vapour annealing), for achieving sterility (aseptic production or sterilisation post production) and for achieving appropriate biomechanical properties.

المعالجة بعد الإنتاج من الألياف Electrospun للهندسة الأنسجة

Electrospinning is a commonly used and versatile method to produce  scaffolds (often biodegradable) for 3D tissue engineering.1, 2, 3 Many tissues in vivo ...

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 ...

Design and Construction of Artificial Extracellular Matrix (aECM) Proteins from Escherichia coli for Skin Tissue Engineering

Recombinant technology is a versatile platform to create novel artificial proteins with tunable properties. For the last decade, many artificial proteins that have incorporated functional domains derived from nature (or created de novo) have been reported. In particular, artificial extracellular matrix (aECM) proteins have been developed; these aECM proteins consist of biological domains taken from fibronectin, laminins and collagens and are combined with structural domains including elastin-like repeats, silk and collagen repeats. To date, aECM proteins have been widely investigated for applications in tissue engineering and wound repair. Recently, Tjin and coworkers developed integrin-specific aECM proteins designed for promoting human skin keratinocyte attachment and propagation. In their work, the aECM proteins incorporate cell binding domains taken from fibronectin, laminin-5 and collagen IV, as well as flanking elastin-like repeats. They demonstrated that the aECM proteins developed in their work were promising candidates for use as substrates in artificial skin. Here, we outline the design and construction of such aECM proteins as well as their purification process using the thermo-responsive characteristics of elastin.

Design and Construction of Artificial Extracellular Matrix aECM Proteins from Escherichia coli for Skin Tissue Engineering

Recombinant technologies have enabled material designers to create novel artificial proteins with customized functionalities for tissue engineering applications. For example, artificial extracellular matrix proteins can be designed to incorporate structural and biological domains derived from native ECMs. Here, we describe the construction and purification of aECM proteins containing elastin-like repeats.

تصميم وبناء الاصطناعي خارج الخلية مصفوفة (aECM) والبروتينات من<em&gt; الإشريكية القولونية</em&gt; للبشرة هندسة الأنسجة

Recombinant technology is a versatile platform to create novel artificial proteins with tunable properties. For the last decade, many artificial proteins ...

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

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.

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

This is a guideline for constructing in vivo vascularized tissue using a microsurgical arteriovenous loop or a flow-through pedicle configuration inside a tissue engineering chamber. The vascularized tissues generated can be employed for organ regeneration and replacement of tissue defects, as well as for drug testing and disease modeling.

هندسة الأنسجة عن طريق الجوهرية الأوعية الدموية في<em&gt; في فيفو</em&gt; غرفة هندسة الأنسجة

In reconstructive surgery, there is a clinical need for an alternative to the current methods of autologous reconstruction which are complex, costly and ...

Recombinant Collagen I Peptide Microcarriers for Cell Expansion and Their Potential Use As Cell Delivery System in a Bioreactor Model

Tissue engineering is a promising field, focused on developing solutions for the increasing demand on tissues and organs regarding transplantation purposes. The process to generate such tissues is complex, and includes an appropriate combination of specific cell types, scaffolds, and physical or biochemical stimuli to guide cell growth and differentiation. Microcarriers represent an appealing tool to expand cells in a three-dimensional (3D) microenvironment, since they provide higher surface-to volume ratios and mimic more closely the in vivo situation compared to traditional two-dimensional methods. The vascular system, supplying oxygen and nutrients to the cells and ensuring waste removal, constitutes an important building block when generating engineered tissues. In fact, most constructs fail after being implanted due to lacking vascular support. In this study, we present a protocol for endothelial cell expansion on recombinant collagen-based microcarriers under dynamic conditions in spinner flask and bioreactors, and we explain how to determine in this setting cell viability and functionality. In addition, we propose a method for cell delivery for vascularization purposes without additional detachment steps necessary. Furthermore, we provide a strategy to evaluate the cell vascularization potential in a perfusion bioreactor on a decellularized&#160;biological matrix. We believe that the use of the presented methods could lead to the development of new cell-based therapies for a large range of tissue engineering applications in the clinical practice.

We propose a cell expansion protocol on macroporous microcarriers and their use as delivery system in a perfusion bioreactor to seed a decellularized tissue matrix. We also include different techniques to determine cell proliferation and viability of cells cultured on microcarriers. Furthermore, we demonstrate functionality of cells after bioreactor cultures.

المؤتلف الكولاجين أنا ميكروكاريرس الببتيد لتوسيع الخلية وإمكانية استخدامها كنظام إيصال خلية في مفاعل حيوي نموذج

Tissue engineering is a promising field, focused on developing solutions for the increasing demand on tissues and organs regarding transplantation ...

Agarose-based Tissue Mimicking Optical Phantoms for Diffuse Reflectance Spectroscopy

This protocol describes how to make agarose-based tissue-mimicking phantoms and demonstrates how to determine their optical properties using a conventional optical system with an integrating sphere. Measuring systems for the acquisition of the diffuse reflectance and total transmittance spectra are constructed with a broadband white light source, a light guide, an achromatic lens, an integrating sphere, a sample holder, an optical fiber probe, and a multi-channel spectrometer. An acrylic mold consisting of two rectangular acrylic pieces and a U-shaped acrylic piece is constructed to create an epidermal phantom and a dermal phantom with whole blood. The application of a sodium dithionite (Na2S2O4) solution to the dermal phantom enables the researcher to deoxygenate hemoglobin in red blood cells distributed in the dermal phantom. The inverse Monte Carlo simulation with the diffuse reflectance and total transmittance spectra measured by a spectrometer with an integrating sphere is performed to determine the absorption coefficient spectrum &#181;a(&#955;) and the reduced scattering coefficient spectrum &#181;s&#39;(&#955;) of each layer phantom. A two-layered phantom mimicking the diffuse reflectance of human skin tissue is also demonstrated by piling up the epidermal phantom on the dermal phantom.

Here, we demonstrate how agarose-based tissue-mimicking optical phantoms are made and how their optical properties are determined using a conventional optical system with an integrating sphere.

النسيج المستندة إلى [اغروس] محاكاة أشباح البصري للتحليل الطيفي الانعكاس منتشر

This protocol describes how to make agarose-based tissue-mimicking phantoms and demonstrates how to determine their optical properties using a ...

Biaxial Mechanical Characterizations of Atrioventricular Heart Valves

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive models, which provide a mathematical representation of the mechanical function of those structures. This presented biaxial mechanical testing protocol involves (i) tissue acquisition, (ii) the preparation of tissue specimens, (iii) biaxial mechanical testing, and (iv) postprocessing of the acquired data. First, tissue acquisition requires obtaining porcine or ovine hearts from a local Food and Drug Administration-approved abattoir for later dissection to retrieve the valve leaflets. Second, tissue preparation requires using tissue specimen cutters on the leaflet tissue to extract a clear zone for testing. Third, biaxial mechanical testing of the leaflet specimen requires the use of a commercial biaxial mechanical tester, which consists of force-controlled, displacement-controlled, and stress-relaxation testing protocols to characterize the leaflet tissue&#39;s mechanical properties. Finally, post-processing requires the use of data image correlation techniques and force and displacement readings to summarize the tissue&#39;s mechanical behaviors in response to external loading. In general, results from biaxial testing demonstrate that the leaflet tissues yield a nonlinear, anisotropic mechanical response. The presented biaxial testing procedure is advantageous to other methods since the method presented here allows for a more comprehensive characterization of the valve leaflet tissue under one unified testing scheme, as opposed to separate testing protocols on different tissue specimens. The proposed testing method has its limitations in that shear stress is potentially present in the tissue sample. However, any potential shear is presumed negligible.

This protocol involves characterizations of atrioventricular valve leaflets with force-controlled, displacement-controlled, and stress-relaxation biaxial mechanical testing procedures. Results acquired with this protocol can be used for constitutive model development to simulate the mechanical behavior of functioning valves under a finite element simulation framework.

بياكسيال الخصائص الميكانيكية لصمامات القلب بي

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive ...

3D Bioprinting of Murine Cortical Astrocytes for Engineering Neural-Like Tissue

Astrocytes are glial cells with an essential role in the central nervous system (CNS), including neuronal support and functionality. These cells also respond to neural injuries and act to protect the tissue from degenerative events. In vitro studies of astrocytes&#39; functionality are important to elucidate the mechanisms involved in such events and contribute to developing therapies to treat neurological disorders. This protocol describes a method to biofabricate a neural-like tissue structure rich in astrocytes by 3D bioprinting astrocytes-laden bioink. An extrusion-based 3D bioprinter was used in this work, and astrocytes were extracted from C57Bl/6 mice pups&#39; brain cortices. The bioink was prepared by mixing cortical astrocytes from up to passage 3 to a biomaterial solution composed of gelatin, gelatin-methacryloyl (GelMA), and fibrinogen, supplemented with laminin, which presented optimal bioprinting conditions. The 3D bioprinting conditions minimized cell stress, contributing to the high viability of the astrocytes during the process, in which 74.08% &#177; 1.33% of cells were viable right after bioprinting. After 1 week of incubation, the viability of astrocytes significantly increased to 83.54% &#177; 3.00%, indicating that the 3D construct represents a suitable microenvironment for cell growth. The biomaterial composition allowed cell attachment and stimulated astrocytic behavior, with cells expressing the specific astrocytes marker glial fibrillary acidic protein (GFAP) and possessing typical astrocytic morphology. This&#160;reproducible protocol provides a valuable method to biofabricate 3D neural-like tissue rich in astrocytes that resembles cells&#39; native microenvironment, useful to researchers that aim to understand astrocytes&#39; functionality and their relation to the mechanisms involved in neurological diseases.

Here we report a method of 3D bioprinting murine cortical astrocytes for biofabricating neural-like tissues to study the functionality of astrocytes in the central nervous system and the mechanisms involving glial cells in neurological diseases and treatments.

الطباعة الحيوية ثلاثية الأبعاد للخلايا الفلكية القشرية لمورين للأنسجة الهندسية الشبيهة بالعصبية

Astrocytes are glial cells with an essential role in the central nervous system (CNS), including neuronal support and functionality. These cells also ...