Effect of Manufacturing Conditions on Structural and Handling Properties of Braided Polyamide Suture
Suture performances include handling characteristics and knot mechanical properties. These performances depend mainly on frictional, flexural, and compressive forces. The interaction between these forces developed inside the suture knot governs the displacement mode and the deformability of the suture yarn inside the knot. In the present work, we studied the effect of manufacturing conditions on structural properties and handling characteristics. Obtained results show that manufacturing parameters have significant impact on slipperiness, flexibility, and compressibility. Consequently, suture performances widely depend on manufacturing parameters. We show that after a hot stretch step, suture structure becomes more uniform and compact. Furthermore, after this treatment, lateral deformation, friction force, and bending rigidity are reduced and knot performances are improved.
Development and characterization of antibacterial braided polyamide suture coated with chitosan-citric acid biopolymer
Braided polyamide sutures are frequently used in dermatologic surgery for wound closure. However, braided sutures promote bacteria proliferation. In order to prevent wound complications due to this effect, antibacterial sutures should be used. The main objective of this study is the development of new non-absorbable antibacterial polyamide braided suture. This paper suggests new coating process that leads to obtain suture uniformly covered by antibacterial film enclosing chitosan, which is known for its antibacterial benefit. Mechanical properties and surface morphology of developed sutures were investigated by using mechanical tests. Sutures surfaces were also examined by scanning electron microscope, to perceive spreading of coating product on suture surface. In order to identify potential reactions between chemical compounds present in coating solution and suture material, sutures were analyzed by ATR-IF spectroscopy. It has been demonstrated that many eventual bonds between compounds present in coating solutions and polyamide macromolecular chain may occur. The existence of these bonds implies the fixation of biopolymer coating on suture surface. It has been demonstrated that uniform surface may be obtained by progressively applying coating solution containing little amount of chitosan on suture surface. We have also found that developed coating process has not affected mechanical properties of suture, which still meet United States Pharmacopeia requirement. Finally, antibacterial effects against four colonies, very widespread in hospitals, were studied. Prominent antibacterial effects of braided polyamide suture against two gram-positive (S Aureus, S epidermidis) and two gram-negative (E coli and P aeruginosa) colonies are presented. Optimal result of best properties is obtained by applying three layers of biopolymer coating comprising 1% chitosan and 10% citric acid. The new developed suture coating process appears as a promising method for obtaining important antibacterial effect with smooth suture surface.
Scaliness of Wool Fibres
ACCORDING to a theory of milling which was developed some years ago, fabrics are capable of undergoing milling shrinkage only when some or all of the component fibres possess a surface scale structure, are easily deformed, and show perfect recovery from deformation1. It should, therefore, be possible to make wool unshrinkable by modifying its elastic properties instead of by the customary method of attacking the surface-scale structure. The truth of this deduction has been established in a number of ways2,3,4. Perhaps the most convincing is the recent demonstration that woollen flannel can be made unshrinkable by treatment with mercuric acetate or benzoquinone4. Both reagents increase the resistance of the fibres to deformation; both increase the scaliness of the fibres, as measured in soap solution by means of the lepidometer5,6. In the light of these results it was concluded that mercuric acetate and benzoquinone make wool unshrinkable by modifying the elastic properties of the fibres, and not by attacking or masking the surface-scale structure.