RODRIGUES, J. F. B.; RODRIGUES, JOSÉ FILIPE BACALHAU.; BACALHAU RODRIGUES, JOSÉ FILIPE.; http://lattes.cnpq.br/4896638137311286; RODRIGUES, José Filipe Bacalhau.
Abstract:
Burns, a term defined as tissue damage caused by heat, is a big public health
challenge in Brazil and worldwide. A burn causes besides tissue loss, the possibility
of infection generated by lesion and microorganisms, which can aggravate the
patient's clinical condition if not properly treated. Therefore, several studies have
been conducted in search of the development of products based on polymers that
help in the moisture and microbiological activity control of the lesion, as well as to
promote the cicatrization, reepithelization and infection prevention in patients. Among
these products are gels made of synthetic and/or natural polymers. In this work, we
made use of two biodegradable polymers, a natural (O-carboxymethylchitosan – O-
CMQ) and synthetic (polyvinyl alcohol - PVA), associated with silver nanoparticles.
Thus, silver nanoparticles were synthesized by the chemical reduction method of
silver ions with sodium borohydride (NaBH4), in the presence of hydrogen peroxide
(H2O2), polyvinylpyrrolidone (PVP) and sodium citrate (SCT). With regard to the gels,
we obtained and studied O-CMQ/PVA/AgNPs gels by using PVA/AgNPs solutions in
different proportions. Silver nanoparticles (AgNPs) were characterized by UV-Vis
Spectroscopy, Dynamic Light Scattering (DLS), Zeta Potential, Atomic Force
Microscopy (AFM), Field Emission Scanning Electron Microscopy (SEM) and X-Ray
Diffraction (XRD. Thermal, chemical and rheological properties of O-CMQ/PVA gels
were studied by gravimetry mass loss assays, UV-Vis Spectroscopy degradation
kinetics, thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy
(FTIR) and rheological analysis, respectively. The antimicrobial and cytotoxicological
properties (Agar Diffusion Method and MTT) of AgNPs, O-CMQ/PVA and O-
CMQ/PVA/AgNPs gels were evaluated. As results, stable and monodisperse
triangular AgNPs-PVP with an average size of 38,17 ± 1,37 nm (unchanged over 1
month) were obtained, showing no toxicity against L929 cells or antimicrobial activity
against S. strains. aureus (ATCC 25923) and E. coli (ATCC 25922). O-CMQ/PVA
gels showed low moisture loss, degradation time of 1 day, behaving like Newtonian
fluid. The O-CMQ/PVA/AgNPs extracts and gels showed no toxicity in any of their
compositions, however, was not observed microbiological activity against S. aureus
and E. coli strains. Thus, we obtained non-toxic O-CMQ/PVA/AgNPs gels with
promising rheological, physical and chemical properties for use in the treatment of
burns and injuries in general. However, microbiological studies involving the required
AgNPs concentration for this gel should continue with the aim of providing
microbiological control during its application.