ऊतक के मूल्यांकन के लिए चुंबकीय अनुनाद Elastography पद्धति इंजीनियर निर्माण विकास
Summary
प्रक्रिया वसा और यांत्रिक सूक्ष्म चुंबकीय अनुनाद elastography (μMRE) का उपयोग गुण की noninvasive स्थानीय मूल्यांकन के माध्यम osteogenic ऊतक इंजीनियर constructs के इंजीनियर परिणाम की निगरानी के लिए चुंबकीय अनुनाद elastography की कार्यप्रणाली को दर्शाता है.
Abstract
Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use of destructive assessment is not acceptable. A proposed alternative is the use of an imaging process called magnetic resonance elastography. Elastography is a nondestructive method for determining the engineered outcome by measuring local mechanical property values (i.e., complex shear modulus), which are essential markers for identifying the structure and functionality of a tissue. As a noninvasive means for evaluation, the monitoring of engineered constructs with imaging modalities such as magnetic resonance imaging (MRI) has seen increasing interest in the past decade1. For example, the magnetic resonance (MR) techniques of diffusion and relaxometry have been able to characterize the changes in chemical and physical properties during engineered tissue development2. The method proposed in the following protocol uses microscopic magnetic resonance elastography (μMRE) as a noninvasive MR based technique for measuring the mechanical properties of small soft tissues3. MRE is achieved by coupling a sonic mechanical actuator with the tissue of interest and recording the shear wave propagation with an MR scanner4. Recently, μMRE has been applied in tissue engineering to acquire essential growth information that is traditionally measured using destructive mechanical macroscopic techniques5. In the following procedure, elastography is achieved through the imaging of engineered constructs with a modified Hahn spin-echo sequence coupled with a mechanical actuator. As shown in Figure 1, the modified sequence synchronizes image acquisition with the transmission of external shear waves; subsequently, the motion is sensitized through the use of oscillating bipolar pairs. Following collection of images with positive and negative motion sensitization, complex division of the data produce a shear wave image. Then, the image is assessed using an inversion algorithm to generate a shear stiffness map6. The resulting measurements at each voxel have been shown to strongly correlate (R2>0.9914) with data collected using dynamic mechanical analysis7. In this study, elastography is integrated into the tissue development process for monitoring human mesenchymal stem cell (hMSC) differentiation into adipogenic and osteogenic constructs as shown in Figure 2.
Protocol
Discussion
इस प्रक्रिया में, ऊतक इंजीनियर constructs के लिए MRE की प्रक्रिया सेल तैयारी से एक elastogram की पीढ़ी के लिए प्रदर्शन किया है. ऊतक इंजीनियरिंग पाइपलाइन के nondestructive यांत्रिक मूल्यांकन पद्धति लागू करके, यह अब संभव है है के…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
इस शोध में भाग RO3-02-EB007299 NIH और NSF EPSCoR प्रथम पुरस्कार द्वारा समर्थित किया गया था.
Materials
| Material Name | Tipo | Company | Catalogue number | Comments |
| MSCGM-Bullet Kit | Reagent | Lonza | PT-3001 | Store at 4°C |
| 1X DPBS | Reagent | Invitrogen | 21600-010 | |
| 0.05% Trypsin-EDTA | Reagent | Gibco, Invitrogen | 25300-054 | Store at -20°C |
| Dexamethasone | Reagent | Sigma-Aldrich | D2915 | |
| 3-Isobutyl-1-methylxanthine | Reagent | Sigma-Aldrich | I5879 | Store at -20°C |
| Insulin-bovine pancreas | Reagent | Sigma-Aldrich | I6634 | Store at -20°C |
| Indomethacin | Reagent | Sigma-Aldrich | I7378 | |
| Β-Glycerophosphate | Reagent | Sigma-Aldrich | G9891 | |
| L-Ascorbic Acid 2-phosphate | Reagent | Sigma-Aldrich | A8960 | |
| Gelfoam | Scaffold | Pharmacia & Upjohn Co. | 09-0315-08 | |
| Human mesenchymal stem cells | Cell Line | Lonza | PT-2501 | |
| 9.4T MR Scanner | Equipment | Agilent | 400MHz WB | |
| 10mm Litz Coil | Equipment | Doty Scientific | ||
| Laser Doppler Vibrometer | Equipment | Polytec | PDV-100 | |
| Vibrosoft (20) | Software | Polytec | ||
| Function generator | Equipment | Agilent | AFG 3022B | |
| Amplifier | Equipment | Piezo inc | EPA-104-115 | |
| Piezo Bending motor | Equipment | Piezo inc. | T234-A4Cl-203X | |
| Computer-Linux | Equipment | Processor: Intel Core 2 Duo E8400 Memory: 2G |
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| Computer-Windows | Equipment | Processor: Intel Core 2 Duo E8400 Memory: 2G |
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| MATLAB | Software | Mathworks, inc | 2009b |
Riferimenti
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