Share Email Print

Proceedings Paper

Second harmonic generation quantitative measurements on collagen fibrils through correlation to electron microscopy
Author(s): S. Bancelin; C. Aimé; Ivan Gusachenko; Laura Kowalczuk; G. Latour; T. Coradin; M.-C. Schanne-Klein
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

Type I collagen is a major structural protein in mammals that shows highly structured macromolecular organizations specific to each tissue. This biopolymer is synthesized as triple helices, which self-assemble into fibrils (Ø =10-300 nm) and further form various 3D organization. In recent years, Second Harmonic Generation (SHG) microscopy has emerged as a powerful technique to probe in situ the fibrillar collagenous network within tissues. However, this optical technique cannot resolve most of the fibrils and is a coherent process, which has impeded quantitative measurements of the fibril diameter so far.

In this study, we correlated SHG microscopy with Transmission Electron Microscopy to determine the sensitivity of SHG microscopy and to calibrate SHG signals as a function of the fibril diameter in reconstructed collagen gels. To that end, we synthetized isolated fibrils with various diameters and successfully imaged the very same fibrils with both techniques, down to 30 nm diameter. We observed that SHG signals scaled as the fourth power of the fibril diameter, as expected from analytical and numerical calculations. This calibration was then applied to diabetic rat cornea in which we successfully recovered the diameter of hyperglycemia-induced fibrils in the Descemet’s membrane without having to resolve them. Finally we derived the first hyperpolarizability from a single collagen triple helix which validates the bottom-up approach used to calculate the non-linear response at the fibrillar scale and denotes a parallel alignment of triple helices within the fibrils. These results represent a major step towards quantitative SHG imaging of nm-sized collagen fibrils.

Paper Details

Date Published: 5 March 2015
PDF: 6 pages
Proc. SPIE 9329, Multiphoton Microscopy in the Biomedical Sciences XV, 93292M (5 March 2015); doi: 10.1117/12.2077958
Show Author Affiliations
S. Bancelin, Lab. d'optique et Biosciences, CNRS, INSERM (France)
C. Aimé, Lab. de Chimie de la Matière Condensée de Paris, Sorbonne Univ., Univ. Paris 6, CNRS (France)
Ivan Gusachenko, Lab. d’Optique et Biosciences, Ecole Polytechnique (France)
Laura Kowalczuk, Therapeutic Innovations (France)
G. Latour, Lab. d'optique et Biosciences, CNRS, INSERM (France)
T. Coradin, Lab. de Chimie de la Matière Condensée de Paris, Sorbonne Univ., Univ. Paris 6, CNRS (France)
M.-C. Schanne-Klein, Lab. d'optique et Biosciences, CNRS, INSERM (France)

Published in SPIE Proceedings Vol. 9329:
Multiphoton Microscopy in the Biomedical Sciences XV
Ammasi Periasamy; Peter T. C. So; Karsten König, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?