Materials for nonabsorbable sutures

Traditional textile-based fibers like silk, nylon, polyester and PP are the bases for most nonabsorbable sutures. 

All silks are not, however, chemically identical. Different silkworm species produce fibrous proteins that contain different sequences and proportions of amino acids. These compositional differences in turn influence the mechanical properties of the fibers. The most common form of sUk, produced by the silkworm Bombyx mori from which most silk sutures are made, has a predominant six-residue sequence Gly-Ser-Gly-Ala-Gly-Ala, which repeats itself for long distances along the chain. This sequence accounts for a large proportion of the amino acid residues that are present. 

The moisture regain of a typical sUk fiber is about 9.9% due to the high concentration of polar side groups in amino add residues. Water molecules absorbed by silk fibers would reside in the amorphous domains and compete with the amino adds in the amorphous chain segments for inter- and intramolecular interaction (Robson, 1985). SUk sutures also have very good handling properties with exceUent knot security. 

However, sUk sutures are known to have undesirable in vivo loss of tensile strength and somewhat higher tissue reactions and ingrowth. Ways of countering these undesirable sUk suture properties have been suggested. 

There are three types of nonabsorbable polyester-based sutures  

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