title: Chiral imaging of collagen by second-harmonic generation circular dichroism.
abstract: We provide evidence that the chirality of collagen can give rise to strong second-harmonic generation circular dichroism (SHG-CD) responses in nonlinear microscopy. Although chirality is an intrinsic structural property of collagen, most of the previous studies ignore that property. We demonstrate chiral imaging of individual collagen fibers by using a laser scanning microscope and type-I collagen from pig ligaments. 100% contrast level of SHG-CD is achieved with sub-micrometer spatial resolution. As a new contrast mechanism for imaging chiral structures in bio-tissues, this technique provides information about collagen morphology and three-dimensional orientation of collagen molecules.
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: H
authors.initials: H
authors.lastname: Lee
authors.forename: M J
authors.initials: MJ
authors.lastname: Huttunen
authors.forename: K-J
authors.initials: KJ
authors.lastname: Hsu
authors.forename: M
authors.initials: M
authors.lastname: Partanen
authors.forename: G-Y
authors.initials: GY
authors.lastname: Zhuo
authors.forename: M
authors.initials: M
authors.lastname: Kauranen
authors.forename: S-W
authors.initials: SW
authors.lastname: Chu
keywords: (170.3880) Medical and biological imaging; (180.4315) Nonlinear microscopy; (190.2620) Harmonic generation and mixing