Table 1.

Elastic coefficients of microtubules

Elastic coefficients	Experimental value (Ref.)	Model value
Longitudinal modulus Ex	∼1 MPa (13); 0.1–0.5 GPa (14); 0.5 ± 0.1 GPa (15); 0.8 GPa (28); 1.2–2.6 GPa (16); ∼7 GPa (10)	1.4 GPa
Circumferential modulus Es	1–4 MPa (22–25,36)	2 MPa
Shear modulus G	∼1 kPa (18,37); 1 kPa–1 MPa (36); 1.4 ± 0.1 MPa (14); 1.3–19 MPa (19,39)	6 kPa
Poisson's ratio μx	0.3 (22–25,36)	0.3