Résumé
The structural organization of collagen plays a crucial role in biological function and biomaterial design due to its characteristic triple-helical structure. Understanding its self-assembly under varying conditions is crucial for biomaterials and regenerative medicine applications. In this study, we employ Vibrational Sum Frequency Generation (VSFG) spectroscopy to investigate the self-assembly of collagen at different pH levels. We compare telocollagen, which retains telopeptides known to facilitate fibrillogenesis, with atelocollagen, which lacks these terminal peptides, therefore leading to more heterogeneous assembly.VSFG is a surface-sensitive technique that enables the analysis of structural changes at interfaces. Although collagen is usually considered a α-helical triple helix, our results reveal unexpected deviations of the 3D structure with the spectral signature of β-sheet formation, suggesting alternative secondary structures at interfaces that challenge the conventional α-helix model. Furthermore, the presence or absence of telopeptides not only influences the fibrillary arrangement but also alters the chiral organization of collagen. This study provides new insights into the molecular mechanisms governing collagen self-assembly, the role of telopeptides and pH modulating both chirality and secondary structure.