Two-Dimensional Nanoscale Structural and Functional Imaging in Individual Collagen Type I Fibrils

• Published in: Biophysical journal 2010-06, Vol.98 (12), p.3070-3077
• Main Authors: Harnagea, Catalin, Vallières, Martin, Pfeffer, Christian P., Wu, Dong, Olsen, Bjorn R., Pignolet, Alain, Légaré, François, Gruverman, Alexei
• Format: Article
• Language: English
• Subjects: Animals; Anisotropy; Biomechanical Phenomena; Biomolecules; Bundles; Collagen Type I - chemistry; Collagen Type I - metabolism; Collagen Type I - ultrastructure; Collagens; Electric properties; Electricity; Fibers; Mice; Microscopy; Microscopy, Atomic Force; Models, Molecular; Molecular Imaging; Musculoskeletal system; Nanostructure; Nanotechnology; Orientation; Piezoelectricity; Protein Structure, Tertiary; Proteins; Spectroscopy, Imaging, and Other Techniques; Time Factors; Tissues
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/j.bpj.2010.02.047

The piezoelectric properties of single collagen type I fibrils in fascia were imaged with sub-20 nm spatial resolution using piezoresponse force microscopy. A detailed analysis of the piezoresponse force microscopy signal in controlled tip-fibril geometry revealed shear piezoelectricity parallel to the fibril axis. The direction of the displacement is preserved along the whole fiber length and is independent of the fiber conformation. It is shown that individual fibrils within bundles in skeletal muscle fascia can have opposite polar orientations and are organized into domains, i.e., groups of several fibers having the same polar orientation. We were also able to detect piezoelectric activity of collagen fibrils in the high-frequency range up to 200 kHz, suggesting that the mechanical response time of biomolecules to electrical stimuli can be ∼5 μs.