1331 Gas-foaming Macroporous CPC Scaffold Encapsulating Human Umbilical-Cord Mesenchymal Stem Cells

Saturday, March 24, 2012: 9:45 a.m. - 11 a.m.
Presentation Type: Poster Session
W. CHEN1, H. ZHOU1, M. TANG1, M.D. WEIR1, C. BAO2, and H.H. XU1, 1Endodontics, Operative Dentistry and Prosthodontics Department, University of Maryland Dental School, Baltimore, MD, 2State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China
Tissue engineering approaches are promising to meet the increasing need for bone regeneration. Calcium phosphate cement (CPC) can be injected and self-set to form a scaffold with excellent osteoconductivity. Objectives: To develop macroporous CPC-chitosan-fiber constructs containing alginate-fibrin microbeads encapsulating human umbilical-cord mesenchymal stem cells (hUCMSCs), and investigate hUCMSC release from the degrading microbeads and proliferation inside porous CPC. Methods: The hUCMSC-encapsulating alginate-fibrin microbeads were completely wrapped inside CPC paste, with gas-foaming porogen (0%, 5%, 10%, 15%, 20%, 25%, and 30% mass fractions) creating macropores in CPC to provide access for culture media. The viability and proliferation of hUCMSCs, microbead degradation, and porosity and mechanical properties of gas-foaming CPC were measured. Results: Increasing porogen content in CPC significantly increased cell viability, from 49% of live cells in CPC without porogen, to 86% of live cells in CPC with 15% porogen (P<0.05). The alginate-fibrin microbeads started to degrade and release cells inside CPC at 7 d. The released cells proliferated inside macroporous CPC. The live cell number inside CPC with 15% porogen significantly increased from 272±24 cells/cm2 (n=5) at 1d to 337±27 cells/mm2 at 21d (P<0.05). The pore volume fraction of CPC increased from 46.8% to 78.4% via gas-foaming method, with macropore sizes of about 100-400µm. The strength of the CPC-chitosan-fiber scaffold with 15% porogen was 3.8±0.5 MPa, which approximated the reported 3.5 MPa for cancellous bone. Conclusions: A novel gas-foaming macroporous CPC construct containing degradable alginate-fibrin microbeads was developed which encapsulated hUCMSCs. The cells had good viability inside the porous CPC construct. The degradable microbeads in CPC quickly released the cells which proliferated over time inside the porous CPC. The self-setting and strong CPC with alginate-fibrin microbeads for stem cell delivery is promising for bone tissue engineering applications.
This abstract is based on research that was funded entirely or partially by an outside source: NIH/NIDCR R01DE14190 and DE17974 (HX)

Keywords: Bone repair, Cements, Delivery systems, Fiber-reinforced composites and Tissue engineering