Analysis of forward and backward Second Harmonic Generation images to probe the nanoscale structure of collagen within bone and cartilage.
Collagen ultrastructure plays a central role in the function of a wide range of connective tissues. Studying collagen structure at the microscopic scale is therefore of considerable interest to understand the mechanisms of tissue pathologies. Here, we use second harmonic generation microscopy to characterize collagen structure within bone and articular cartilage in human knees. We analyze the intensity dependence on polarization and discuss the differences between Forward and Backward images in both tissues. Focusing on articular cartilage, we observe an increase in Forward/Backward ratio from the cartilage surface to the bone. Coupling these results to numerical simulations reveals the evolution of collagen fibril diameter and spatial organization as a function of depth within cartilage.
Institut National de la Recherche Scientifique - Centre Énergie, Matériaux et Télécommunication, 1650 boulevard Lionel-Boulet, Varennes, QC, J3X 1S2, Canada.
Marie-Andrée
MA
Houle
Institut National de la Recherche Scientifique - Centre Énergie, Matériaux et Télécommunication, 1650 boulevard Lionel-Boulet, Varennes, QC, J3X 1S2, Canada.
Charles-André
CA
Couture
Institut National de la Recherche Scientifique - Centre Énergie, Matériaux et Télécommunication, 1650 boulevard Lionel-Boulet, Varennes, QC, J3X 1S2, Canada.
Stéphane
S
Bancelin
University of Ottawa, Department of Physics, MacDonald Hill, 150 Louis Pasteur, ON, K1N 6N5, Canada.
Jarno
J
Van der Kolk
Institut National de la Recherche Scientifique - Centre Énergie, Matériaux et Télécommunication, 1650 boulevard Lionel-Boulet, Varennes, QC, J3X 1S2, Canada.
Etienne
E
Auger
University of Oxford, Botnar Research Center, NDORMS, UK.
Cameron
C
Brown
University of Ottawa, Department of Physics, MacDonald Hill, 150 Louis Pasteur, ON, K1N 6N5, Canada.
Konstantin
K
Popov
University of Ottawa, Department of Physics, MacDonald Hill, 150 Louis Pasteur, ON, K1N 6N5, Canada.
Lora
L
Ramunno
Institut National de la Recherche Scientifique - Centre Énergie, Matériaux et Télécommunication, 1650 boulevard Lionel-Boulet, Varennes, QC, J3X 1S2, Canada. legare@emt.inrs.ca.
François
F
Légaré
D000671:Amputation, Surgical; D002358:Cartilage, Articular / Q000378:metabolism / Q000648:ultrastructure*; D003094:Collagen / Q000378:metabolism / Q000648:ultrastructure*; D003198:Computer Simulation; D006801:Humans; D007717:Knee; D018613:Microscopy, Confocal / Q000379:methods*; D008859:Microscopy, Polarization / Q000379:methods*; D008954:Models, Biological; D013977:Tibia / Q000378:metabolism / Q000648:ultrastructure*
D003094:Collagen
Second Harmonic Generation; bone; cartilage; forward/backward ratio; nonlinear microscopy