Dear great people. I wonder if any of you has information regarding the stiffness of the fibril for collagen type III and I. Any helps are much appreciated. Thank you.
I guess you want the Young's modulus of the material that the collagen fiber is composed of? It is about 100 MPa (only one significant digit) for collagen-I, as back-calculated by measuring the vibrational modes of collagen fibers and measuring the fiber width using TEM. See table 2 in this paper:
The measurements are originally from a PhD thesis by one of the co-authors, which is not so easy to obtain. you'll find the reference to this thesis in the paper I recommended.
However, variations in the modulus should be expected depending on the conditions of polymerization.