Affiliations: Laboratoire TIMC-IMAG, Equipe DynaCell, CNRS UMR 5525, Institut de l'Ingénierie et de l'Information de Santé, Faculté de Médecine de Grenoble, 38706 La Tronche cedex, France | Laboratoire de Dynamique Moléculaire des Interactions Membranaires, CNRS UMR 5539, Université de Montpellier II, Place Eugène Bataillon (Case 107), 34095 Montpellier cedex 5, France
Note: [] Address for correspondence: Prof. J. Ohayon, Laboratoire TIMC-IMAG, Equipe DynaCell, CNRS UMR 5525, Institut de l'Ingénierie et de l'Information de Santé (IN35), Faculté de Médecine de Grenoble, 38706 La Tronche cedex, France. Tel.: +33 456 52 01 24; Fax: +33 456 52 00 22; E-mail: [email protected].
Abstract: Substrates with tunable mechanical properties are crucial for the study of cellular processes, and polyacrylamide gels (PAGs) are frequently used in this context. Several experimental techniques have been proposed to obtain the mechanical properties of PAGs. However, the range of the considered Poisson's ratio values remains quite large and no attempt has been made to propose an analytical relationship allowing the estimation of PAG Young's modulus when both bis-acrylamide and acrylamide concentrations are known. In order to complete the actual knowledge on the mechanical properties of PAGs, we took benefit of our original method based on the micropipette aspiration technique (Boudou et al., J. Biomech. 2006) for characterizing gels made with concentrations in the range 0.02% ≤[Bis]≤0.20% and 3% ≤[Acry]≤10%. We found that the PAGs Young's modulus varies nonlinearly with the acrylamide amount. Moreover, our study validates the quasi-incompressibility hypothesis usually made in studies using PAGs (mean Poisson's ratio of 0.480±0.012). More generally, and in agreement with data published by other groups, we propose an original nonlinear mathematical relationship allowing the computation of Young's modulus of PAG for any given acrylamide and bis-acrylamide amounts taken in the range of values we considered.
Keywords: Micropipette, incompressibility, cell substrate, linear elasticity
Journal: Biorheology, vol. 43, no. 6, pp. 721-728, 2006
