Chemical aspects of cell adhesion and -growth for vascular grafts
-
1
École Polytechnique de Montréal, Institute of Biomedical Engineering, Canada
-
2
École Polytechnique de Montréal, Department of Engineering Physics, Canada
-
3
Centre de recherche du CHUM (CRCHUM), Laboratory of Endovascular Materials (LBeV), Canada
-
4
École de technologie supérieure, Department of Mechanical Engineering, Canada
-
5
École Polytechnique de Montréal, Department of Chemical Engineering, Canada
Introduction: Various routes enable one to functionalize polymer surfaces for enhanced cell adhesion and -growth. For example, commercial products [1] like tissue-culture poly(styrene) (TCP) have oxygen (O)-containing groups (e.g. OH, C=O, COOR) that originate from plasma-based surface modification, while Primaria™ in addition contains N-bearing functionalities like primary amines, NH2; Parylene diX-AM [2] is a commercial coating with only NH2. Such polar surfaces also enable covalent immobilization of bioactive molecules, to foster specific cell response to implants such as vascular grafts. This study compares various functionalization processes in their ability to create high densities of functional groups, and compares the efficacies of O- and N-rich polymer surfaces, along with “hybrid” (O+N) ones, for culture of hMSCs (human mesenchymal stem cells) and HUVECs (human umbilical vein endothelial cells).
Materials and Methods: Low-pressure plasma-polymerized (“L-PP”) coatings were prepared on polyethylene terephthalate (PET) films from mixtures of C2H4 with NH3 (“L-PPE:N”), N2O (“L-PPE:O,N”), or O2 (diluted in Ar, “L-PPE:O”); and simple surface modification of PET with NH3 plasma (“PETf”). Commercial Primaria™ and Parylene diX-AM were used for comparison. PET films were also treated with polyallylamine (PAAm) by aminolysis in an alkaline (pH=12.5) PAAm solution. Compositions and bond types of these surfaces were obtained by X-ray photoelectron spectroscopy (XPS); prior derivatization by TFBA (4-trifluoromethybenzaldehyde) allowed us to determine amine concentrations, [NH2]. A bioactive molecule, chondroitin sulfate (CS), was grafted onto [NH2]-rich surfaces by EDC/NHS chemistry. Finally, hMSCs and HUVECs were seeded onto the surfaces, the Alamar Blue test being used to evaluate cell adhesion and -growth at three time-points (24h, 4d, 6d).
Results:
Table 1 shows compositions and [NH2] values; L-PPE:N, PETf, PAAm and Parylene diX AM manifest a wide [NH2] range, up to 6.4 at.%. For PAAm, [NH2] could be varied by controlling pH. “Hybrid” surfaces, Primaria™ and L-PPE:O,N, show lower [NH2], in spite of high [N], ca. 5 at.%, suggesting more varied, complex functionalities (confirmed by high-resolution C1s spectra, not shown).
L-PPE:N greatly enhanced hMSC adhesion, but grafting of CS reduced it; however, this was compensated by an increased growth ratio (Figure 1). HUVEC culture confirmed that O- and NH2-rich surfaces enhance cell adhesion and growth, whereby L-PPE:N and L-PPE:O appear to yield similar results. Although Primaria™ showed excellent behavior, L-PPE:O,N did not, despite its high [O] and [NH2].
Conclusion: Both N- and O-rich surfaces have good cell-colonization properties, particularly plasma polymers, while “hybrid” surfaces are more ambiguous and call for further investigation. Samples with [NH2] enabled grafting of CS; while its low-fouling properties limited adhesion, it still allowed substantial cell growth.
This work is supported by CIHR, NSERC and the Canada Research Chairs program. The authors also thank the Fondation Pierre Arbour for a scholarship to G.B, Dr. Benoît Liberelle and Samantha Noel for their help with aminolysis and dyes, and Drs. Josianne Lefebvre and Bernard Nisol for their expertise in XPS analysis.
References:
[1] Steele, J.G. et al, Biomaterials 1995, 16 (14), 1057-1067
[2] Lahann, J., Polym. Int. 2006, 55, 1361-1370
Keywords:
Cell Adhesion,
Surface modification,
Polymeric material,
endothelialization
Conference:
10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016.
Presentation Type:
Poster
Topic:
Surface and interfacial characterization
Citation:
Boespflug
G,
Maire
M,
De La Torre Torres
J,
De Crescenzo
G,
Lerouge
S and
Wertheimer
MR
(2016). Chemical aspects of cell adhesion and -growth for vascular grafts.
Front. Bioeng. Biotechnol.
Conference Abstract:
10th World Biomaterials Congress.
doi: 10.3389/conf.FBIOE.2016.01.02346
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
27 Mar 2016;
Published Online:
30 Mar 2016.