Structural alteration of collagen fibres--spectroscopic and mechanical studies.

Fourier Transform Near Infrared Raman Spectroscopy has been used to monitor the molecular changes of collagen in a tendon subjected to strain. In the Raman spectrum of the unstrained tendon, some protein bands, mainly assigned to collagen, can be observed: amide I (1666 cm-1) and III (1266 and 1248 cm-1) vibrational modes and skeletal (C-C) stretching vibrations (816 and 940 cm-1). The position of these bands is changing with the increasing strain values. It is concluded that elastin and non-helical domains of collagen are initially involved in the load transfer and triple helices of collagen are gradually joining this process.