Biomedical Engineering Reference
In-Depth Information
FIgurE 18.7 (a) Photo of biosynthesized cellulose tube. (b) SHG image measured on a cellulose tube and show-
ing the detailed material fiber structure. (c) Radial profile of a cellulose tube obtained from a montage of SHG
images, luminal side to the right. Regions of relatively compact, homogeneous material are interspersed by denser
structures and voids.
by hydrogen bonds (Bodin et al. 2007b). Furthermore, the cellulose has shown good biocompatibility
(Helenius et al. 2006), but the degradability of the material needs to be further evaluated.
Figures 18.7b and c show SHG microscopy images measured on a cellulose tube in its natural state
without special sample preparation for microscopy. Detailed information on the morphology at a fibril-
lar level can be seen in the close-up of Figure 18.7b whereas the montage of images in Figure 18.7c shows
a full radial profile of the tube presenting the morphology on a larger scale.
Figure 18.8 shows SHG images measured on a cellulose tube that has been implanted in a sheep dur-
ing 1 year for evaluation of the tube as a blood vessel replacement. The images were measured on the
outer side of the graft in the contact region between cellulose and the collagen of the surrounding native
tissue. Both materials are visible in the image and the SHG signal from collagen (bright image struc-
tures to the left) is much stronger than that of the cellulose (darker gray image structures to the right)
allowing them to be distinguished from each other. The magnified view of Figure 18.8b shows the close
FIgurE 18.8 SHG images measured on a cellulose blood vessel graft, previously implanted in a sheep during
1 year. Both native collagen tissue and cellulose are detected in the image with high (bright structures) and low
(dark gray structures) SHG signals, respectively. (a) 100 × 100 μm overview. (b) Close-up image corresponding to
the region indicated by the white square in (a) showing a detailed view of the integration between the cellulose graft
and native collagen tissue.
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