Currently some principles of sustainability, eco-efficiency and green chemistry are guiding the development of a new generation of materials as an alternative to conventional polymers based on petroleum. Then, in the field of biodegradable polymers one of the most promising investigations is focused on the use of microbial cellulose MC , biocellulose or bacterial cellulose. MC has received substantial interest since it is synthesized from the bacterium Gluconacetobacter genus from a variety of carbon sources such as glucose, fructose, galactose, etc. MC is an interesting emerging biomaterial, with no toxicity, and since its discovery has shown tremendous potential in various fields, because the structural aspect of MC is far superior to those of plant cellulose. Thus, the main focus of the chapter review involves detailed aspects about the biosynthesis and recent advances on microbial production, including mechanism for the biochemistry of the cellulose synthesis, new sources for culture medium, main aspects about static and air-reactor productions and genetic modifications. We also revised microbial cellulose devices for biomedical applications artificial skin, artificial blood vessels and microvessels, wound dressing of second-or third-degree burn ulcers, scaffolds for tissue engineering, drug delivery systems, dental implants, among others.
a b s t r a c tNanostructured films prepared by Layer-by-Layer technique and containing silk fibroin, antigenic peptide NS5A-1 derived from hepatitis C virus (HCV) NS5A protein and YVO 4 :Eu 3 þ luminescent nanoparticles, were utilized in sensing of hepatitis C. Detection system exploits the biorecognition between the antibody anti-HCV and the antigenic peptide NS5A-1 through changes in luminescence properties. Films deposition was monitored by UV-vis Absorption and Fluorescence Spectroscopy measurements at each bilayer deposited. The Eu 3 þ luminescence properties were evaluated in the presence of anti-HCV for optical detection of specific antibody and anti-HIV used as negative control. Significant changes in luminescence were observed in the presence of anti-HCV concentrations. A new immunosensor platform is proposed for optical detection of hepatitis C.& 2015 Elsevier B.V. All rights reserved. Recently, our group reported an electrochemical immunosensor for HCV that explores biorecognition between an antigenic peptide (PPLLESWKDPDYVPPWHG) derived from the HCV NS5A-1 protein and anti-HCV [19], where the peptide was immobilized into Layerby-Layer (LbL) films, alternated with silk fibroin (SF). Using cyclic voltammetry, it was possible to detect the anti-HCV antibody for concentrations between 0.01 and 0.2 μg mL À 1 .
Biocellulose Chloroaluminum phthalocyanine Yttrium vanadate nanoparticles lanthanide ions photodynamic therapy photosensitizers drug delivery systems biomaterials composite membranes YVO 4 :(Yb 3+ -Er 3+ /Ho 3+ ) nanoparticles were incorporated in biocellulose membranes obtained from Gluconacetobacter xylinus. Materials present the property of converting near-infrared (NIR) into higher-energy visible light. Nanoparticles were prepared by optimizing towards higher emission intensity at the absorption wavelength range of chloroaluminum phthalocyanine (ClAlPc) used as a photosensitizer in the photodynamic therapy. The NIR excitation wavelength is advantageous for biological applications, as it allows deeper penetration into tissues than the UV-visible radiation commonly used for luminescence excitation. Up-conversion emission spectra obtained under excitation at 980 nm showed a preferential green emission for the Yb 3+ -Er 3+ system and a red emission for the Yb 3+ -Ho 3+ one. In the last case, by using mixtures of nanoparticles and ClAlPc the red emission (680 nm) of the phtalocyanine was observed through excitation by the up-converted emission of the nanoparticles (650 nm) which were excited in NIR (980 nm).
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