Resumo O objetivo deste estudo foi avaliar in vitro o efeito antimicrobiano de uma bandagem oral bioadesiva de quitosana com clorexidina para o tratamento de infecções dos tecidos orais. Cinco bandagens de diferentes composições foram testadas: Quitosana 5% (G1); Quitosana 5% ± clorexidina a 0,2% (G2), Quitosana 5% ± clorexidina a 0,6% (G3), Quitosana 5% ± clorexidina a 1,0% (G4) e Quitosana 5% ± clorexidina a 2,0% (G5). Foram testados também 5 tipos de géis nas seguintes composições: Gel de Quitosana 5% (G6), Gel de clorexidina a 0,2% (G7), Gel de clorexidina a 2,0% (G8), Gel de Quitosana 5% ± clorexidina a 0,2% (G9) e Gel de Quitosana 5% ± clorexidina a 2,0% (G10). A ação antimicrobiana das amostras foi testada contra Candida albicans e Streptococcus mutans por meio do antibiograma, medindo o halo de inibição. Os dados foram analisados pelo teste de Kruskal-Wallis e ANOVA a um critério seguido pelo teste de Tukey (p<0,05). A membrana com 2,0% de clorexidina (G5) e os discos contendo gel com 2,0% de clorexidina (G8) apresentaram os maiores halos de inibição para os dois microrganismos, com diferença estatisticamente significativa em relação aos demais grupos testados (p=0,008) apenas nos resultados de inibição de C. albicans. Todas as outras formulações de membranas e géis apresentaram halo de inibição, mas sem diferença estatisticamente significativa. A bandagem oral bioadesiva de quitosana com gel de 2% de clorexidina foi a mais efetiva em inibir os microrganismos testados.

Abstract This study aimed to evaluate in vitro the antimicrobial effect of a bioadhesive chitosan-based oral membrane with chlorhexidine for local treatment of infections in the oral tissues. Five oral membranes of different compositions were tested: 5% chitosan (G1); 5% chitosan ± 0.2% chlorhexidine (G2), 5% chitosan ± 0.6% chlorhexidine (G3), 5% chitosan ± 1.0% chlorhexidine (G4), and 5% chitosan ± 2.0% chlorhexidine (G5). Also, five gel types were tested according to the following compositions: 5% chitosan gel (G6), 0.2% chlorhexidine gel (G7), 2.0% chlorhexidine gel (G8), 5% chitosan gel ± 0.2% chlorhexidine gel (G9), and 5% chitosan gel ± 2.0% chlorhexidine gel (G10). The antimicrobial action of the samples was tested against Candida albicans and Streptococcus mutans through antibiogram by measuring the inhibition halos. Data were statistically analyzed by Kruskal-Wallis and one-way ANOVA followed by Tukey test (p<0.05). The 2.0% chlorhexidine membrane (G5) and the disks containing 2.0% chlorhexidine gel (G8) showed the greatest inhibition halos for both microorganisms, with statistically significant difference when compared to others tested groups (p=0.008) only for Candida albicans inhibitions results. All the other formulations of membranes and gels showed inhibition halos, but without statistically significant difference. The bioadhesive chitosan-based oral membrane with 2% chlorhexidine and 2% chlorhexidine gel were the most effective in inhibiting the tested microorganisms.

The main aim of this study was to develop scaffolds based on alginate, chitosan and hybrid fibers with and without glycerol. The scaffolds developed underwent assessments for tensile property, swelling ratio and weight loss, cellular viability, degradation and biomineralization, as well as DSC/TGA thermal analysis. Tenacity values showed that use of glycerol and the interaction between alginate and chitosan as a hybrid fiber were associated with increasing tenacity values. In the swelling and weight loss study, the scaffolds containing glycerol presented lower weight loss and higher water absorption values in all scaffolds, compared to scaffolds without glycerol, indicating that glycerol acted as a stabilizer. None of the alginate, chitosan and hybrid scaffolds, with or without glycerol, decreased cell viability. On the third day of the biomineralization assay, chitosan without glycerol indicated the presence of apatite crystals. The degradation study showed that glycerol may have acted as a stabilizer.

The present work aimed to study sugarcane bagasse fibers pre-treated with fungi and using NaOH/ anthraquinone (AQ) in chemical pulping processes for applications in composite materials. Bagasse was decayed with 250 mg of Ceriporiopsis subvermispora inoculum in a 20 L bioreactor. After that, samples were submitted to similar conditions of decaying without inoculum charge. Decayed and undecayed fibers were treated with NaOH 12.5 wt%, 0.15 of AQ and a 12:1 (v/w) liquor:bagasse ratio at 160°C. Then, all obtained fibers were characterized according to their chemical composition. Dried biotreated (decayed) and control (undecayed) fibers were mixed through an extruder process with polypropylene. Later, composite granulates were injected directly in mold with cavities for tensile, flexural and shear tests. Composite materials with 10 and 20 wt% fibers were submitted to static mechanical standard tests and DMA (Dynamic Mechanical Analysis) to evaluate the effect of biotreatment. Biotreatment, cook time (pulping), and fiber content contributed to improvements in the mechanical properties of the composites. The interface between fiber and matrix was increased with the biotreatment and pulping of fibers. Furthermore, DMA results also showed that fiber incorporation into PP improved the modulus, mainly for biotreated fibers/PP composites. The Tg (tan δ data) from composites was dislocated at lower temperatures with respect to neat PP due to the influence of fibers on matrix.