3D analysis of gelatin gel networks from transmission electron microscopy imaging

This paper presents a quantitative analysis of the structural parameters of gelatin gel networks derived from transmission electron micrographs. The network gel replicas were obtained by a quick-freezing, deep-etching and rotary replication method adapted to the study of fragile physical networks by Favard P. et al. (Biol. Cell 67 (1989) 201-207). Stereo electron micrographs were taken by tilting the replicas at increasing angles between – 35 to + 30○. A 3D reconstruction of the filamentous network was performed by stereoscopic and tomographic procedures. These procedures allowed us to measure the thicknesses of the replicas. The average length of filaments (triple helices) per unit volume and the average distance between filaments (mesh sizes of the networks) were derived for two polymer concentrations ($c=2~\%$ and $c=10~\%$). The results are in full agreement with optical rotation and small-angle neutron scattering measurements