Author + information
- Charles Hu,
- Cyrus W. Beh,
- Shashank Hegde,
- James Park,
- Cliff R. Weiss,
- Peter Johnston,
- Jeff TH Wang,
- Hai–Quan Mao and
- Dara Kraitchman
Microencapsulation offers a mean to enhance stem cell engraftment. However, the delivery of relatively large capsules (~300 μm) fabricated by conventional methods is challenging. The purpose of this study was to evaluate the feasibility of imaging–visible, single cell microencapsulation technique as a safer, more effective treatment for ischemic heart disease.
Custom microfluidic devices fabricated using soft lithography were used to create highly uniform, barium sulfate or iron oxide impregnated alginate microcapsules containing single human mesenchymal stem cells. Spherical water–in–oil emulsion droplets containing cells and contrast agent were stabilized by cationic crosslinking. Size uniformity was determined by scanning electron microscopy analysis. Permeability was examined by incubation with fluorescent lectins. X–ray radiopacity was determined in phantoms and in vivo after direct renal and intramyocardial injection by X–ray and MRI, respectively.
Single cells were successfully encapsulated into stable, uniform hydrogel microspheres. Microspheres encapsulated with barium sulfate without cells had a mean diameter of 54 ± 8.1 μm. Microcapsules were permeable to <75 kDa and impermeable to 120 kDa molecules. Phantom radiopacity was comparable to that of 10% iohexal in digital radiographs and computed tomography (microspheres: 2809 ± 1208 HU, 10% iohexal: 1482 ± 354 HU). Real–time visualization of intrarenal and intramyocardial injections were possible, but follow–up intracardiac tracking was unsuccessful.
Highly uniform microcapsules for individual stem cells that provide immunoprotection yet allow the free flow of nutrients, cytokines, and waste products were created. This new microfluidic method is highly scalable for rapid production and thus offers promise for improved engraftment in ischemic cardiovascular diseases. It is also amenable to co–encapsulation of water–soluble drugs, multiple cell types and various contrast agents. Delivery confirmation and tracking of stem cells using a radiopaque microcapsule was possible, but the current MR–visible formulation was not sufficiently sensitive for serial imaging.
Moderated Poster Contributions
Poster Sessions, Expo North
Sunday, March 10, 2013, 3:45 p.m.–4:30 p.m.
Session Title: Cell Therapy and Angiogenesis
Abstract Category: 42. TCT@ACC–i2: Cell Therapy & Angiogenesis
Presentation Number: 2110M–228
- 2013 American College of Cardiology Foundation