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Novel carbohydrate-based hybrids combining chitosan and chemically modified chitosan with CdS inorganic nanoparticles were designed and prepared via aqueous route at room temperature. N,N,N-trimethylchitosan (TM-chitosan) was synthesized aiming at substantially improving the water solubility of chitosan for producing stable colloidal systems. UV-vis spectroscopy, photoluminescence spectroscopy, Nuclear magnetic resonance spectroscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the synthesis and the relative stability of biopolymer-capped CdS nanocrystals. The results have clearly indicated that chitosan and chitosan-derivative (TM-chitosan) were remarkably effective on nucleating and stabilizing CdS nanoparticles in aqueous suspensions. In addition, the CdS nanocrystals were produced in the so-called "quantum-size confinement regime", with the calculated average size below 3.5 nm and fluorescent activity in the visible range of the spectra. Therefore, a new single-step process was developed for the bioconjugation of quantum dots with water soluble chemically functionalized carbohydrates at room temperature for potential biomedical applications., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

In the present work, it is reported for the first time the bioconjugation of CdS quantum dots (QDs) directly with bovine serum albumin (BSA) using a one-step procedure via aqueous route at room temperature by methods of colloidal chemistry. Essentially, the bioconjugates were developed based on BSA as capping ligand for the nucleation and stabilization of CdS nanoparticles using cadmium perchlorate and thioacetamide as precursors. UV-visible spectroscopy was used to characterize the kinetics and the relative stability of CdS nanoparticles. The CdS nanocrystals were produced with the calculated average particle size below 4.0 nm, indicating they were in the so-called "quantum-size confinement range". The results have clearly indicated that BSA was effective on nucleating and stabilizing the colloidal CdS quantum dots., (Copyright © 2011 Elsevier B.V. All rights reserved.)

In the present research it is reported the development and characterization of novel polymer blends based on chitosan and poly(vinyl alcohol) (PVA). The hybrid polymeric network was synthesized and modified by chemical crosslinking using genipin for potential use in a variety of biomedical applications. The micro and nanostructures of the blended hydrogels and hybrids were characterized through Fourier Transform Infrared spectroscopy (FTIR) and swelling test analysis. Moreover, cytotoxicity and cell viability were also performed by MTT assay with cell culture. The chemical crosslinking was achieved via the relative intensity of the band at 1650 cm(-1) which is mostly associated with the reaction of genipin carboxymethyl group with the amino group of chitosan forming amides. It was found that by increasing the chitosan content relative to PVA the swelling index of the blend has decreased, reflecting the reduction on the mobility of polymer network and the hydrophilic behavior of the blend. The tested hydrogels have clearly presented adequate cell viability, non-toxicity and suitable properties which can be tailored for potential use in bioengineering applications.

In the present work we report the synthesis, characterization, and preliminary biocompatibility of polymer blends based on Chitosan and poly(vinyl alcohol) (PVA) with low degree of hydrolysis and chemically crosslinked by glutaraldehyde for potential application on skin tissue repairing. The microstructure and morphology of the blended hydrogels were characterized through Fourier Transform Infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM/EDX) analysis. Hydrogels were investigated by swelling as preliminary in vitro test using simulated body fluid. In addition, biocompatibility, cytotoxicity, and cell viability were assessed via MTT assay with VERO cell culture and cell spreading-adhesion analysis. It was found that by increasing the chitosan to PVA ratio, simulated body fluid uptake of the material was significantly altered. All the tested hydrogels have clearly presented adequate cell viability, non-toxicity, and suitable properties which can be tailored for prospective use in skin tissue engineering.

Protein adsorption onto solid surfaces is a complex process playing an important role in biological systems, being crucial to maintain the three-dimensional conformation during molecules interaction. Polymers hybrid network could be used to perform immunoassays with the required high level specificity. We have developed a novel route for incorporating recombinant protein from Bovine Herpesvirus into a network using as template Poly(vinyl alcohol) chemically tailored with five organosilanes followed by FTIR spectroscopy characterization. Protein expressed in E. coli was incorporated into hybrid network; all the PVA-hybrids interacted with this biomolecule and FTIR vibrational bands have endorsed the results. PVA hybrids modified with 3-(triethoxysilyl) propylisocyanate-TESPI presented the best result in the immunoassay, enhancing the sera specificity in comparison with the commercial microplate. We have successfully developed organic-inorganic hybrid based on PVA-silane to be used in serological tests with recombinant protein as a promising tool for the development and production new diagnostic assays.

There is a constant need for bone substitutes. This work was focused on developing a porous substrate based on Portland cement with air-voids introduced by outgassing reaction product from lime and aluminum powder. The structures were obtained through two routes of raw-materials and processing. Water absorption and compressive strength measurements and scanning electron microscopy, X-ray diffraction, and Fourier Transformed Infrared Spectroscopy assays were conducted in order to characterize the porous substrates. The substrates have shown pore size structure compatible with bone tissue colonization. Also, the mechanical strength exhibited by the scaffolds fall in the normal ranges for trabecular bone. These characteristics indicate potential use of the developed porous scaffold for bone tissue engineering which was endorsed by in vitro experiments via cell culture.

Bioactive glasses (BaG) can bind to human bone tissues and have been used in many biomedical applications for the last 30 years. However they usually are weak and brittle. On the other hand, composites that combine polymers and BaG are of particular interest, since they often show an excellent balance between stiffness and toughness. Bioactive glass-poly(vinyl alcohol) foams to be used in tissue engineering applications were previously developed by our group, using the sol-gel route. Since bioactive glass-polymer composite derived from the sol-gel process cannot be submitted to thermal treatments at high temperatures (above 400 degrees C), they usually have unreacted species that can cause cytotoxicity. This work reports a technique for stabilizing the sol-gel derived bioactive glass/poly(vinyl alcohol) hybrids by using glutaraldehyde (GA), NH(4)OH solutions and a blocking solution containing bovine serum albumin. PVA/BaG/GA hybrids were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDX) analyses. Moreover, MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) biocompatibility and cytotoxicity assays were also conducted. The hybrids exhibited pore size varying from 80 to 820 mum. After treatments, no major changes in the pore structure were observed and high levels of cell viability were obtained.