Biofios: fios de sutura biodegradáveis de quitosana como sistema de liberação controlada de N-Acetil-D-Glucosamina.

Abstract

Surgical sutures are biomaterials whose main purpose is to close lesion. Therefore, they must have adequate mechanical and biological properties for the healing process to be effective. However, this work aimed at the development of chitosan threads, optimizing the mechanical / biological properties for application as biodegradable absorbable sutures. In addition, chitosan yarn has been used as a controlled release system with N-Acetyl-D-glucosamine (GlcNAc), which, like chitosan, is a chitin derivative, to combin the pharmacological properties of GlcNAc with biological properties of Chitosan. Chitosan concentrations of 1, 2, 3 and 4% were initially characterized from rheological assays, and concentrations of 3 and 4% (w/v) were chosen because they are more viable for the spinning process. Therefore, the chitosan strands, coagulated in sodium hydroxide solution, were obtained from the wet spinning technique, using concentrations of 3 and 4% (w/v) of chitosan. 3 and 4% Optical Microscopy (MO), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Mechanical Traction Assay, Swelling Degree (GI), In vitro Biodegradation in Buffered Saline followed phosphate (PBS) PBS/lysozyme assay and in vitro cytotoxicity. From the morphological tests, it was found that the wires are cylindrical and well defined. By XRD it was observed that the 4% tensioned wires presented higher crystallinity, which resulted in higher load resistance, as seen in the tensile tests. The swelling degree evaluation showed that the 3% (m/v) strands presented greater swelling, due to the lower degree of crystallinity, that is, the higher degree of amorphous region in the strand. In the in vitro biodegradation assay, total degradation was found to occur within 49 days for the 3 and 4% PBS/lysozyme samples. GlcNAc (0.2 g) was added to 4% chitosan threads, which are within the Surgical Suture Yarn Standards. The morphological aspect was observed by OM and SEM, as well as the physicochemical aspects by the Fourier Transform Infrared Spectroscopy (FTIR) technique. The mechanical properties, contact angle, in vitro biodegradation and drug release profile, cytotoxicity by agar diffusion method and wound evaluation in animal wound surgery were also investigated. After the addition of GlcNAc it was found that the yarn morphology was preserved, but the tensile strength (N) decreased. However, the values remained within the specifications of the 6-0 surgical suture standard. It was also found that the biodegradation process was accelerated in the presence of GlcNAc and its release in 50% occurred in approximately 34 days. As for release kinetics, the best fit model was Order Zero, followed by Peppas-Sahlin and Hopfenberg models, controlled by the diffusion and erosion model, suggesting that GlcNAc is concentration independent, a desirable situation in the release formulation. sustained as it minimizes fluctuations in the concentration of drugs in the blood. In vitro cytotoxicity data of 4% chitosan and chitosan / GlcNAc strands for L929 cells showed that they are not toxic to these cells. From the clinical evaluation performed on the surgical wound of animals on days 0, 1, 2, 3, 4, 5, 6, 7 and 14 days, it was observed that animals sutured with 4% chitosan suture / GlcNAc presented closure. complete. wound within 4 days, and the process of formation of the new tissue began. For chitosan wire, this closure occurred within 7 days. For chrome catgut wire, closure was observed after 14 days. Thus, GlcNAc chitosan threads are promising for use as an absorbable suture, either for veterinary use or in human medicine. Additionally, this medical device may be able to improve

healing processes, relieve pain and minimize infection at the surgical site due to prolonged release of GlcNAc.