About this item:

72 Views | 29 Downloads

Author Notes:

Corresponding author. Tel.: +1 404 385 4108; fax: +1 404 894 2291. barbara.boyan@bme.gatech.edu (B.D. Boyan).

The authors would like to thank Sha’Aqua Ashbury for her assistance with histology.

Subject:

Research Funding:

This study was funded in part by the National Science Foundation Graduate Research Program (Lee), the Department of Defense, and Children’s Healthcare of Atlanta.

This research was also supported in part by NIH grant DE04141 (Boskey).

Keywords:

  • Science & Technology
  • Technology
  • Engineering, Biomedical
  • Materials Science, Biomaterials
  • Engineering
  • Materials Science
  • Calcification
  • Alginate
  • Microencapsulation
  • Adipose stem cell microbeads
  • Bone tissue engineering
  • MOLECULAR-WEIGHT DISTRIBUTION
  • STEM-CELLS
  • BONE-FORMATION
  • TISSUE
  • HYDROGELS
  • CARTILAGE
  • BEADS
  • MINERALIZATION
  • MICROCAPSULES
  • DEGRADATION

Regulating in vivo calcification of alginate microbeads

Tools:

Journal Title:

Biomaterials

Volume:

Volume 31, Number 18

Publisher:

, Pages 4926-4934

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Alginate calcification has been previously reported clinically and during animal implantation; however no study has investigated the mechanism, extensively characterized the mineral, or evaluated multiple methods to regulate or eliminate mineralization. In the present study, alginate calcification was first studied in vitro: calcium-crosslinked alginate beads sequestered surrounding phosphate while forming traces of hydroxyapatite. Calcification in vivo was then examined in nude mice using alginate microbeads with and without adipose stem cells (ASCs). Variables included the delivery method, site of delivery, sex of the animal, time in vivo, crosslinking solution, and method of storage prior to delivery. Calcium-crosslinked alginate microbeads mineralized when injected subcutaneously or implanted intramuscularly after 1-6 months. More extensive analysis with histology, microCT, FTIR, XRD, and EDS showed calcium phosphate deposits throughout the microbeads with surface mineralization that closely matched hydroxyapatite found in bone. Incorporating 25 m. m bisphosphonate reduced alginate calcification whereas using barium chloride eliminated mineralization. Buffering the crosslinking solution with HEPES at pH 7.3 while washing and storing samples in basal media prior to implantation also eliminated calcification in vivo. This study shows that alginate processing prior to implantation can significantly influence bulk hydroxyapatite formation and presents a method to regulate alginate calcification.

Copyright information:

© 2010 Elsevier Ltd.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Creative Commons License

Export to EndNote