Comparison of the properties of compacted and porous lamellar chitosan-xanthan membranes as dressings and scaffolds for the treatment of skin lesions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Compacted and porous lamellar membranes of xanthan (Xn) and chitosan (Ch) at mass ratios of 1 : 1 and 1.2 : 0.8 were prepared and tested to verify possible applications in the treatment of skin lesions. All membranes were prepared by complexation of the polysaccharides in solution and subsequent casting. The porous membranes were obtained by adding either Tween 80 or Pluronic F68 to the polysaccharide complexes before casting. Membranes prepared in the absence of surfactants at a mass ratio of Xn to Ch of 1 : 1 proved ideal for use as wound dressings, as they were thin (around 0.10 mm in thickness) and transparent and had low in vitro cytotoxicity to L929 cells, a tensile strength at break of 25 MPa, water absorption after 24 h of around 86 g/g and simulated body fluid absorption of 16% and adequate stability in the presence of the same solutions. Membranes prepared at the mass ratio of Xn to Ch of 1 : 1 in the presence of Pluronic F68 showed the most favorable characteristics for application as scaffolds for tissue engineering. These membranes consisted of a matrix with interconnected pores which were distributed homogeneously throughout the structure and had a thickness of 1.84 mm, high capacity for FBS uptake (around 18 g/g) and cell culture medium uptake (8.6 g/g), a loss of mass in the culture medium of 33% after 144 h, and low in vitro toxicity to L929 cells. In conclusion, membranes of Ch and Xn produced in the presence or absence of the surfactant Pluronic F68 have a high potential for use as scaffolds in tissue engineering or as dermal dressings, respectively, whereas in contrast, membranes prepared in the presence of Tween 80, regardless of the mass ratio of Xn to Ch, were very cytotoxic to L929 cells and therefore were not appropriate for any of the proposed applications. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 20121252SIE421E431Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Hydrophobic fractions from Strongyloides venezuelensis for use in the human immunodiagnosis of strongyloidiasis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The objective of the present research was to evaluate detergent and aqueous phases of total saline (TS) and alkaline extracts of Strongyloides venezuelensis for human strongyloidiasis immunodiagnosis. Total extracts and detergent and aqueous antigenic fractions were separated using Triton X-114 and were examined by enzyme-linked immunosorbent assay (ELISA) and immunoblotting (IB) tests to detect immunoglobulin G (IgG). Serum samples were obtained from 120 individuals: 40 strongyloidiasis patients (group I), 40 patients with other parasitic diseases (group II), and 40 apparently healthy individuals (group III). Each extract provided a different profile of antigenic components as recognized by IgG in TB. The detergent fraction of the TS extract demonstrated the highest sensitivity and specificity for ELISA and IB. The results indicated that the detergent saline fraction, purified from S. venezuelensis, furnished the most valid results for the strongyloidiasis immunodiagnosis and could be employed as an alternative antigen and as a useful source of specific polypeptides. (C) 2010 Elsevier Inc. All rights reserved.672153161Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Federal University of Uberlandia, BrazilCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq