Resumo:
The chemically modified of chitosan lactate are among the chitosan derivatives that
have much superior non-cytotoxic properties when compared to other chitosan
derivatives. Chitosan lactate, has a solubility close to physiological pH (pH=7.0) which
significantly improves its applications in controlled drug release systems. Chitosan
lactate has been proposed for various biomedical applications as wound dressings and
dental membranes. In the present work, the synthesis of chitosan lactate from methyl
and ethyl lactate with chitosan was performed, the modification was proven by the
techniques of infrared spectroscopy with Fourier transform (FTIR), thermogravimetric
analysis (TGA), calorimetric differential scanning (DSC), proton nuclear magnetic
resonance (1H NMR). The characterization techniques of DSC and 1H NMR showed
that in the chemical modification of chitosan in addition to chitosan lactate grafts of
poly(lactic acid) oligomers were obtained in the chitosan chain (QUI-g-PLA).
Electrospinning of chemically modified chitosan QUI-g-PLA containing the complex of
chondroitin sulfate (SC) and silver nanoparticles (NPsAg) was performed and then the
controlled release of silver nanoparticles and chondroitin sulfate was studied, since the
nanoparticles silver have antimicrobial activity and chondroitin sulfate has cell
proliferation properties. The study of antimicrobial activity was carried out, which
showed inhibition for both Gram positive and Gram negative bacteria and a cytotoxicity
study was also carried out, showing that the produced nanofibers do not have a
negative effect on cell viability, actually showing an increase in cell proliferation. So
far, the author of this doctoral proposal has not observed any work that mentions the
use of QUI-g-PLA/SC:NPsAg nanofibers as dressings, on this aspect it seems to be
important to develop dressings for the treatment of wounds in its various modalities:
burns, contact wounds, among others, which have antimicrobial properties combined
with increased healing of cell tissue.
