Fi
brillar collagens in connective tissues are organized into complex and diverse hierarchical networks. In dermis,
bone, and tendon, one common phenomenon at the micrometer scale is the organization of fi
brils into
bundles. Previously, we have reported that collagen fi
brils in these tissues exhi
bit a 10 nm width distri
bution of
D-spacing values. This study expands the o
bservation to a higher hierarchical level
by examining fi
bril
D-spacing distri
bution in relation to the
bundle organization. We used atomic force microscopy imaging and two-dimensional fast Fourier transform analysis to investigate dermis, tendon, and
bone tissues. We found that, in each tissue type, collagen fi
bril
D-spacings within a single
bundle were nearly identical and frequently differ
by less than 1 nm. The full 10 nm range in
D-spacing values arises from different values found in different
bundles. The similarity in
D-spacing was o
bserved to persist for up to 40 渭m in
bundle length and width. A nested mixed model analysis of variance examining 107
bundles and 1710 fi
brils from dermis, tendon, and
bone indicated that fi
bril
D-spacing differences arise primarily at the
bundle level (76%), independent of species or tissue types.<
br>
Keywords:
bs.acs.org/action/doSearch?action=search&searchText=collagen+bundle&qsSearchArea=searchText">collagen bundle; bs.acs.org/action/doSearch?action=search&searchText=fibril+D%5C-spacing&qsSearchArea=searchText">fibril D-spacing; bs.acs.org/action/doSearch?action=search&searchText=AFM&qsSearchArea=searchText">AFM; bs.acs.org/action/doSearch?action=search&searchText=2D+FFT&qsSearchArea=searchText">2D FFT; bs.acs.org/action/doSearch?action=search&searchText=mixed+model+ANOVA&qsSearchArea=searchText">mixed model ANOVA