Spectroscopic characterization of collagen cross-links in bone

J Bone Miner Res. 2001 Oct;16(10):1821-8. doi: 10.1359/jbmr.2001.16.10.1821.


Collagen is the most abundant protein of the organic matrix in mineralizing tissues. One of its most critical properties is its cross-linking pattern. The intermolecular cross-linking provides the fibrillar matrices with mechanical properties such as tensile strength and viscoelasticity. In this study, Fourier transform infrared (FTIR) spectroscopy and FTIR imaging (FTIRI) analyses were performed in a series of biochemically characterized samples including purified collagen cross-linked peptides, demineralized bovine bone collagen from animals of different ages, collagen from vitamin B6-deficient chick homogenized bone and their age- and sex-matched controls, and histologically stained thin sections from normal human iliac crest biopsy specimens. One region of the FTIR spectrum of particular interest (the amide I spectral region) was resolved into its underlying components. Of these components, the relative percent area ratio of two subbands at approximately 1660 cm(-1) and approximately 1690 cm(-1) was related to collagen cross-links that are abundant in mineralized tissues (i.e., pyridinoline [Pyr] and dehydrodihydroxylysinonorleucine [deH-DHLNL]). This study shows that it is feasible to monitor Pyr and DHLNL collagen cross-links spatial distribution in mineralized tissues. The spectroscopic parameter established in this study may be used in FTIRI analyses, thus enabling the calculation of relative Pyr/DHLNL amounts in thin (approximately 5 microm) calcified tissue sections with a spatial resolution of approximately 7 microm.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acids / metabolism*
  • Animals
  • Bone and Bones / metabolism*
  • Cattle
  • Chickens
  • Collagen / metabolism*
  • Cross-Linking Reagents*
  • Dipeptides / metabolism*
  • Humans
  • Spectroscopy, Fourier Transform Infrared / methods


  • Amino Acids
  • Cross-Linking Reagents
  • Dipeptides
  • 5,5'-dihydroxylysylnorleucine
  • delta-hydroxylysylnorleucine
  • pyridinoline
  • deoxypyridinoline
  • Collagen