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Correlation between the distribution of nanometer sized apatitic paracrystalline particles and the acidic sites of phosphoproteins as apatitic nucleators in developing hard tissues
Author(s) -
Höhling H. J.,
Arnold S.,
Höhling J. M.,
Plate U.,
Wiesmann H. P.
Publication year - 2001
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/1521-4052(200102)32:2<149::aid-mawe149>3.0.co;2-w
Subject(s) - paracrystalline , macromolecule , nanometre , crystallography , selected area diffraction , apatite , biomineralization , materials science , crystal (programming language) , chemistry , mineralogy , nanotechnology , chemical engineering , transmission electron microscopy , composite material , biochemistry , engineering , programming language , computer science
On ultrathin sections of developing dentine and other hard tissues we have observed primary apatitic chains (strands) composed of nanometer‐sized islands (dots). By energy‐filtering selected area electron diffraction patterns (SAED) in the Zeiss EM902 we have found that these apatitic chains are already orientated parallel to the bipolar apatite c‐axis. The probability of crystal growth in c‐axis direction for the developing islands was equal for both directions parallel to the fibrous matrix macromolecules, so that the center‐to‐center distances between these nanometer apatitic paracrystalline islands should reflect the distances between the crystal nucleating sites along the fibrous matrix macromolecules. For early mineralized apatitic chains on the collagen surface they lie in the range from 2 to 8 nm (Arnold et al. 1996, 1997). Further, the amino acid sequence of different dentine phosphoproteins and sialoproteins were inspected. We have defined a group of about five neighbored acidic groups (amino acids) as an acidic site (cluster). It was often found that 10–20 neighbored amino acids lie between the centers of such acidic sites. Taking the existence of the pleated sheet structure for noncollagenous proteins bound immobilized at the surface of collagen fibers, mainly phosphoproteins, the projected distance range between the acidic centers along the fibrous noncollagenous macromolecule are mainly in the range of 3.5–7.0 nm. This corresponds to the range of the center‐to‐center distances between the nanometer sized apatitic paracrystalline islands in the mineral chains at the collagen surface. This agreement supports our idea that these acidic sites might be the crystal nucleating sites.