http://lattes.cnpq.br/4237136708419469; SILVA, Henrique Nunes da.
Resumo:
The objective of this work was to develop meshes from the weaving of monofilament
and multifilaments chitosan threads obtained by wet spinning for possible biomedical
applications. In addition, wet spinning process steps have been optimized to obtain
fibers with mechanical properties suitable for the weaving process. For the wet
spinning process 4% chitosan solution (w / v) and coagulation bath containing 70%
(0.5M) sodium hydroxide/30% methanol were used. Fiber coagulation kinetics was
evaluated by Optical Microscopy (OM); The drying methodology was evaluated by
Thermogravimetric Analysis (TGA), X-ray Diffractometry (XRD) and tensile test. The
ideal coagulation time was determined and the drying methodology was efficient. From
the results of tensile and XRD, it was chosen for the condition of drying of the wires
under tension. The monofilament and multifilaments wires obtained were characterized
by tensile test and Scanning Electron Microscopy (SEM). The configuration of the yarn
affected its mechanical properties. Moreover, it was verified from the morphological
tests that the yarns preserve the characteristics of the individual filaments present the
typical microstructure of fibers obtained by wet spinning. The woven meshes obtained
were evaluated by OM, tensile test, swelling degree, in vitro enzymatic biodegradation
and in vitro cytotoxicity. From the tensile and OM tests it was decided to coat with a
1,5% chitosan solution (w / v). The woven mesh obtained from the tri-filament yarns
withstood higher loads. The tensile strength of the samples in the wet state was similar
to the human dermis. The configuration of the yarn used in weaving directly influenced
the amount of water absorbed and the enzymatic degradation kinetics of the fabrics.
The results of the in vitro cytotoxicity test showed that the samples showed no
cytotoxicity and were classified as satisfactory. Thus, chitosan woven mesh with good
mechanical, biodegradable and biocompatible properties were obtained, with potential
for biomedical applications, such as bioactive dressings, tissue engineering grafts, soft
tissue reinforcement or even as a controlled drug release system.