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1.
Anal Chim Acta ; 1034: 63-73, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30193641

RESUMO

A novel non-enzymatic glucose sensor was constructed based on the nanolayered Co(OH)2 deposited on polymeric graphitic carbon nitride (Co(OH)2-g-C3N4) via chemical bath deposition. The two-dimensional nanocomposite was used to modify a carbon paste electrode and its electrochemical performance of electrode was carefully evaluated. The electrochemical oxidation of glucose at modified electrode was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 0.2 M KOH. It revealed a remarkable electrocatalytic behavior and noticeably synergistic effect as a result of decent exfoliation of graphitic carbon nitride in the presence of Co(OH)2. The amperometric response achieved by the modified electrode showed two calibration ranges with an excellent selectivity. A single-frequency impedance method was applied for glucose determination as an alternative to conventional EIS methods. The developed sensor represents a high sensitivity, wide concentration range (25 µM - 420.0 mM by impedimetry and 6.6-9800 µM by amperometry), and high reproducibility. The modified electrode showed a good selectivity for glucose over potentially interfering materials such as dopamine, ascorbic acid, urea, and uric acid. Finally, the Co(OH)2-g-C3N4-CPE was utilized for quantification of glucose in blood serum samples.


Assuntos
Cobalto/química , Técnicas Eletroquímicas , Glucose/análise , Grafite/química , Hidróxidos/química , Nanoestruturas/química , Nitrilas/química , Espectroscopia Dielétrica , Eletrodos
2.
Carbohydr Polym ; 200: 82-92, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30177212

RESUMO

This study investigated the effects of topical application of chitosan-capped silver nanoparticles (Ch/AgNPs) on burn wound healing. The chitosan-capped silver nanoparticles were synthesized in one step from the silver nitrate, sodium borohydride, and chitosan and were characterized using transmission electron microscopy, fourier transform infrared spectroscopy, and X-ray diffraction methods. The antioxidant assay was performed to evaluate the scavenging rate. The effects of Ch/AgNPs on burn wound healing was also evaluated by histopathological, molecular, and biochemical evaluations after 7, 14 and 28 days of treatment in a rat model. In comparison to the negative control and silver sulfadiazine groups, the Ch/AgNPs treated wounds exhibited significantly lower inflammatory reaction as determined by the reduced level of interleukin-1ß (IL-1ß) and neutrophil counts. Treatment by Ch/AgNPs also significantly enhanced re-epithelialization, so that complete epithelialization was achieved in the lesions of the animals of this group, at the 7th day post-wounding. Rapid re-epithelialization, improved granulation tissue formation, reduced IL-1ß expression, mild inflammation, and increased transforming growth factor-ß1 and basic fibroblast growth factor, at 7 days post-wounding, are convincing reasons to confirm this idea that Ch/AgNPs are effective in speeding up the wound healing stages. Our histopathological findings are in agreement with the molecular and biochemical results and strongly demonstrate that Ch/AgNPs stimulate burn wound healing by decreasing the length of repair phases. Therefore, on the basis of our findings, Ch/AgNPs can be a promising candidate in stimulating wound repair and regeneration.


Assuntos
Queimaduras/fisiopatologia , Quitosana/química , Nanopartículas Metálicas/química , Prata/química , Prata/farmacologia , Cicatrização/efeitos dos fármacos , Administração Tópica , Animais , Antibacterianos/administração & dosagem , Antibacterianos/química , Antibacterianos/farmacologia , Queimaduras/metabolismo , Queimaduras/microbiologia , Colágeno/metabolismo , Hidroxiprolina/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Prata/administração & dosagem
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