European Cells and Materials Vol. 7. Suppl. 1, 2004 (page 45)
ISSN 1473-2262
Cell adhesion increases with the square root of time
Bigerelle M. 1& Anselme K. 2‡
1
Surfaces and Interfaces Team, Laboratory of Physical Metallurgy and Material EngineeringUMR CNRS 8517, Ecole Nationale Superieure des Arts et Metiers, 59046 Lille, France.
2
Research Laboratory on Biomaterials and Biotechnologies, University of Littoral Cote d’Opale,
62608 Berck sur mer, France.
‡
Present address: Institut de Chimie des Surfaces et Interfaces, UPR CNRS 9069, 68057
Mulhouse, France.
INTRODUCTION: A still unsolved question in
biomaterial field is how eucaryotic cells adhere on
material surface and what are the main surface
properties influencing cell adhesion 1,2 whereas
cell adhesion is one of the crucial initial events
affecting further proliferation, differentiation and
survival of cells on substrate surface 1. Here we
report for the first time the mathematical modeling
of cell adhesion on biomaterials taking into
account simultaneously the combined influence of
material nature, surface topography, and surface
chemistry.
METHODS: Using an original detachment
method3, adhesion of primary human osteoblasts
was quantified on 30 different substrates made of
3 different metals (pure titanium, titanium alloy
Ti6Al4V, 316L stainless steel) with 5 various
surface morphologies obtained by different
processes (sandblasting, electro-erosion, polishing,
machining, acid etching), 2 roughness amplitudes
(0.85 µm and 2.35 µm), coated or not with a goldpalladium layer. As this evaluation was performed
at early stage of culture (24 hours) as well as later
stages (until 21 days), the measure of adhesion
concerned either cells having proliferated or cells
adhering since the inoculation time. Therefore a
mathematical treatment of data to de-correlate
proliferation and adhesion was applied.
RESULTS: Afterwards, using more than 2000
experimental detachment data, we demonstrated
that cell detachment (δ) varied with culture time
(T) according to a power law: δ (T )=aT b . a being
independent from b. The exponent b was equal to
0.5 ±0.03 and was independent of the substrate
characteristics. On the contrary, the parameter a
we called the “adhesion power” did depend
significantly on the material nature, the surface
topography, and the surface chemistry of the
substrate. We notably demonstrated that the
adhesion power better correlated better, among 75
other surface roughness parameters, with the
Order parameter which describes the morphology
of the surface roughness.
DISCUSSION & CONCLUSIONS: This first
attempt to model cell adhesion from experimental
data allowed us to demonstrate that the cell
adhesion increased with the square root of time.
From this relationship, we suggest that a diffusionbased process may be involved in adhesion on
materials. It could be the consequence of diffusion
of proteins in the cell/material interface confirming
previous hypothesis on dynamics of cell
adhesion4.This finding will be important for
further optimization of implant surfaces.
1
REFERENCES:
K.
Anselme
(2000)
Biomaterials 21:667-681. 2 C. Zhu (2000) J
Biomech 33:23-33. 3 K. Anselme, M. Bigerelle, B.
Noel, E. Dufresne, D. Judas, A. Iost, and P.
Hardouin (2000) J Biomed Mater Res 49:155-166.
4
F. Brochard-Wyart and P. G. De Gennes (2002)
Proc Natl Acad Sci 99:7854-7859.
ACKNOWLEDGEMENTS: The authors would
to thank B. Noël and I. Loison for their technical
assistance in cell culture experiments. This work
was supported by the Fédération Biomatériaux
Nord/Pas-de-Calais and by an institutional funding
from the French Ministry of Research “Action
Concertée Incitative: Technologie pour la Santé”
grant n°02TS003.