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.
Investigating the Knot Performance of Silk, Polyamide, Polyester, and Polypropylene Sutures
The knot performance of four different nonabsorbable sutures—silk, polyester, polyamide, and polypropylene—is investigated by using square knots with two and three throws. All sutures are USP 2/0 in size. An instrument that can be mounted on the Instron tensile tester measures the knot performance of the sutures. The results are given as stress-elongation graphic, knot slippage, and knot break values. The effects of the number of throws and the structure of the sutures on knot performance are studied. For the knot performance tests, the effect of the physical structure (braided or monofilament) is clearly seen. For monofilament polyamide and polypropylene sutures, the knot with two throws unties before it breaks. For silk and polyester braided sutures, which have reasonably good two-throw square knot strength, the added throw does not remarkably increase strength and at the same time places more suture material in the tissue, which increases the risk of infection. Three-throw knot results reveal that the suture material plays an important role in knot strength.
Atomistic insight into novel co-delivery of doxorubicin and paclitaxel using fullerene modified by dimethyl acrylamide trimethyl chitosan: A computational study

 Background: The distribution of drugs could not be controlled in the conventional drug delivery system. This has led to the development of a smart nanoparticle-based drug delivery system, known as smart drug delivery systems. In cancer research, novel biocompatible nanocarriers have received much attention for various ranges of anticancer drugs.In the current study, the effect of a novel co-polymer "dimethyl acrylamide-trimethyl chitosan" was investigated on drug delivery of doxorubicin and paclitaxel utilizing modified fullerene nanocarrier. This study was performed via molecular dynamics simulation based on acidic pH sensitivity of the cancer microenvironment. Furthermore, hydrogen bonds, diffusion coefficient, gyration radius, and drug-carrier interaction energies were investigated here. Interestingly, a simultaneous pH and temperature-sensitive system was proposed for paclitaxel and doxorubicin for a co-polymer. A pH-sensitive and temperature-sensitive copolymer was used based on trimethyl chitosan and dimethyl acrylamide, respectively. In such a dualistic approach, co-polymer makes an excellent option to have two properties in one bio-polymer. Results: The results suggest the dramatic and indisputable role of the co-polymer in the release of doxorubicin and paclitaxel in cancerous tissues, as well as an increased biocompatibility and drug uptake in a neutral state. The validation test was performed by repeated simulations of a similar article. The results are very close to those of the reference paper .Conclusions: Overall, conjugated fullerene and dimethyl acrylamide-trimethyl chitosan (DMAA-TMC) as carriers can be a good proposition for loading, delivery, and release of anti-cancer drugs based on a pH/temperature-sensitive smart drug delivery system.