Journal
JOURNAL OF PHYSICAL CHEMISTRY B
Volume 115, Issue 44, Pages 12759-12769Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jp206308k
Keywords
-
Categories
Ask authors/readers for more resources
Collagen (type I) fibers are readily visualized with second harmonic generation (SHG) microscopy though the molecular origin of the signal has not yet been elucidated. In this study, the molecular origin of SHG from type I collagen is investigated using the time-dependent coupled perturbed Hartree-Fock calculations of the hyperpolarizibilities of glycine, proline, and hydroxyproline. Two effective nonlinear dipoles are found to orient in-the-plane of the amino acids, with one of the dipoles aligning close to the pitch orientation in the triple-helix, which provides the dominant contribution to the SHG polarization properties. The calculated hyperpolarizability tensor element ratios for the collagen triple. helix models: [(Gly(3))(n)](3), [(Gly-Pro(2))(n)](3), and [(Gly-Pro-Hyp)(n)](3), are used to predict the second-order nonlinear susceptibility ratios, chi((2))(zzz)/chi((2))(iiz) and chi((2))(zii)/chi((2))(iiz) of collagen fibers. From SHG microscopy polarization in, polarization out (PIPO) measurements of type I collagen in human lung tissue, a theoretical method is used to extract the triple-helix orientation angle with respect to the collagen fiber. The study shows the dominant role of amino acid orientation in the triple-helix for determining the polarization properties of SHG and provides a method for determining the triple-helix orientation angle in the collagen fibers.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available