The Impact of Collagen Fibril Polarity on Second Harmonic Generation Microscopy
Biophysical Journal. 2015-12-01; 109(12): 2501-2510
DOI: 10.1016/j.bpj.2015.10.040
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1. Biophys J. 2015 Dec 15;109(12):2501-10. doi: 10.1016/j.bpj.2015.10.040.
The Impact of Collagen Fibril Polarity on Second Harmonic Generation Microscopy.
Couture CA(1), Bancelin S(1), Van der Kolk J(2), Popov K(2), Rivard M(1), Légaré
K(1), Martel G(3), Richard H(3), Brown C(4), Laverty S(3), Ramunno L(2), Légaré
F(5).
Author information:
(1)Institut National de la Recherche Scientifique, Centre Énergie Matériaux
Télécommunications, Varennes, Quebec, Canada.
(2)Department of Physics, University of Ottawa, Ottawa, Ontario, Canada.
(3)Comparative Orthopaedic Research Laboratory, Faculté de Médecine Vétérinaire,
University of Montreal, Sainte Hyacinthe, Quebec, Canada.
(4)University of Oxford, Botnar Research Center, NDORMS, Oxford, United Kingdom.
(5)Institut National de la Recherche Scientifique, Centre Énergie Matériaux
Télécommunications, Varennes, Quebec, Canada. Electronic address:
.
In this work, we report the implementation of interferometric second harmonic
generation (SHG) microscopy with femtosecond pulses. As a proof of concept, we
imaged the phase distribution of SHG signal from the complex collagen
architecture of juvenile equine growth cartilage. The results are analyzed in
respect to numerical simulations to extract the relative orientation of collagen
fibrils within the tissue. Our results reveal large domains of constant phase
together with regions of quasi-random phase, which are correlated to respectively
high- and low-intensity regions in the standard SHG images. A comparison with
polarization-resolved SHG highlights the crucial role of relative fibril polarity
in determining the SHG signal intensity. Indeed, it appears that even a
well-organized noncentrosymmetric structure emits low SHG signal intensity if it
has no predominant local polarity. This work illustrates how the complex
architecture of noncentrosymmetric scatterers at the nanoscale governs the
coherent building of SHG signal within the focal volume and is a key advance
toward a complete understanding of the structural origin of SHG signals from
tissues.
Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights
reserved.
DOI: 10.1016/j.bpj.2015.10.040
PMCID: PMC4699883
PMID: 26682809 [Indexed for MEDLINE]