Biomedical Engineering Reference
In-Depth Information
Fig. 3.2.4-9 (A) Weft knit inflammatory response at 4 weeks (Golaski Microkit); (B) Warp knit inflammatory response at 3 days
(Microvel).
as to make the graft easier to preclot and to increase the
extent of tissue incorporation into the graft wall.
A sketch of a flat braiding machine is included in
Fig.
3.2.4-11.
Processing and finishing
Braids
Braids have found their way into medical use primarily in
the manufacture of suture materials and anterior cruciate
ligament (ACL) prostheses. Common braided structures
involve the interlacing of an even number of yarns,
leading to diamond, regular, and Hercules structures that
can be either two-or three-dimensional (see Fig 3.2.4-
10). A myriad of structural forms can be achieved with
3D braiding, such as ''I'' beams, channels, and solid tubes.
Once a fabric has been produced from yarn, the sub-
sequent processing steps are known as finishing. As
mentioned previously, the starting yarn may contain ad-
ditives that can result in cytotoxicity and adverse re-
actions when in contact with tissue. Some of these
additives, such as titanium dioxide, which is used as
a delusterant to increase the amount of light reflected,
are inside the spun fiber and cannot be removed in the
