AVS 59th Annual International Symposium and Exhibition
    Biomaterial Interfaces Monday Sessions
       Session BI-MoM

Paper BI-MoM5
Chemically Defined Synthetic Surfaces for Mesenchymal Stem Cell Expansion

Monday, October 29, 2012, 9:40 am, Room 23

Session: Surfaces to Control Cell Response
Presenter: L. Meagher, CSIRO Materials Science and Engineering, Australia
Authors: L. Meagher, CSIRO Materials Science and Engineering, Australia
H. Thissen, CSIRO Materials Science and Engineering, Australia
P. Pasic, CSIRO Materials Science and Engineering, Australia
R.A. Evans, CSIRO Materials Science and Engineering, Australia
S. Pereira, CSIRO Materials Science and Engineering, Australia
K. Tsang, CSIRO Materials Science and Engineering, Australia
V. Glattauer, CSIRO Materials Science and Engineering, Australia
K. Styan, CSIRO Materials Science and Engineering, Australia
C.L. Be, CSIRO Materials Science and Engineering, Australia
D. Haylock, CSIRO Materials Science and Engineering, Australia
Correspondent: Click to Email
Interest in surface initiated polymerisation (SIP) for biomedical applications has increased rapidly recently, particularly the use of “living” free radical polymerisation mechanisms1 as highly defined coating properties/architectures can be achieved. Here we demonstrate that advanced coatings can be produced using a surface immobilised macro-chain transfer agent approach2 and that such coatings can be used for the effective control of cell-surface interactions, an essential requirement in a broad range of applications in biomaterials and regenerative medicine. In the expansion of stem cells for therapeutic applications, fully synthetic, chemically defined materials are a requirement. Polymeric coatings which contain synthetic cell signalling molecules are key to ongoing progress in the generation of cells as therapies. Coating characterization was carried out using X-ray photoelectron spectroscopy (XPS) and colloid probe atomic force microscope (AFM). Cell culture studies were carried out using bone marrow derived human mesenchymal stem cells (hMSCs) using standard techniques. Differentiation of hMSCs was carried out using standard protocols in induction medias and the presence of characteristic cell surface markers was determined using flow cytometry. Substrate materials were silicon wafers or tissue culture polystyrene (TCPS).

In this study, we focus on a surface initiated Radical Addition-Fragmentation chain Transfer (RAFT) approach and present data demonstrating that dense polymer brushes can be prepared via surface immobilized macro-RAFT agents. The brush nature of the coatings was confirmed using a combination of XPS analysis and direct interaction force measurements with the AFM colloid probe technique. The properties of the coatings could be fine tuned using a variety of parameters such as the RAFT agent surface density, the polymerisation conditions, the monomer feed composition and the conjugation of cell attachment motifs such as cyclic peptides which interact with cell surface integrins. For example, the combination of a low cell adherent, low protein adsorbing polymer brush coating containing a conjugated peptide which interacted with alphavbeta3 integrins resulted in a surface which supported the expansion of hMSCs in a xeno-free, chemically defined, serum replacement media. In addition the expanded cells expressed cell surface markers typical of undifferentiated hMSCs and the expanded cells were able to differentiate along adipogenic, osteogenic and chondrogenic pathways.

1 Edmond, S., Osborne, V.L. and Huck, W.T.S., Chem. Soc. Rev. 2004, 33, 14.2 Meagher, L., Thissen, H., Pasic, P., Evans, R.A. and Johnson, G., WO2008/019450.