Aggregation of collagen molecules

Fig. 15. Schematic two-dimensional view of variou.s modes of aggregation of collagen molecules in vitro, illustrating the generation of the various periodicities. The stagger responsible for the 210 A and the A periods is not necessarily all in...

Scaffolds are made by freeze drying a dispersion or solution of collagen. Freezing the dispersion or solution leads to the formation of ice crystals that force and aggregate the collagen molecules into the interstitial spaces. 

When collagen IV prepared from the EHS tumor is incubated at 37°C, it self-assembles, forming aggregates containing polygonal structures. These lateral associations are stabilized by the interaction between the domain NCI and sites that occur along the triple helix and are separated from one another by about 100 nm (Tsilibary and Charonis, 1986). The additional possibility of lateral aggregation of the molecules would lead to a much more complex three-dimensional structure. 

Figure 5.125 Structure of collagen fibers based on collagen molecule, microfibrils and fibrillar aggregation. Reprinted, by permission, from I. V. Yannas, in Biomaterials Science, B. D. Ratner, A. S. Hoffman, F. J. Schoen, and J. E. Lemons, eds., p. 86. Copyright 1996 by Academic Press.

Fig. 13. Longitudinal section through models of collagen mineralization, a) Triple helix (Th) with water molecules in native state b) Triple helix with apatite nuclei (Ap) (not very likely) c) Two-dimensional presentation of 0.4 D-final overlappings of 5 triple helices d) Aggregation of 5 triple helices to form subfibrils (Sf) and formation of apatite nuclei between subfibrils. (After Hohling etal.641>)...

---