The present work aimed to study the properties of a novel nanocomposite with promising biomedical applications. Nanocomposites were prepared by the addition of different concentrations of chitosan decorated carbon nanotubes to acrylamide-co-acrylic acid hydrogels. The nanocomposites chemical structure was characterized by Fourier Transform Infrared Spectroscopy (FT-IR). The FT-IR shows the typical bands due to the hydrogel and additionally the peaks at 1750 cm and 1450 cm that correspond to the carbon nanotubes incorporated into the polymer matrix. Mechanical properties and swelling measurements in different buffer solutions were also performed. The nanocomposites showed improved mechanical properties and a stronger pH-response. In order to evaluate antimicrobial activity, the growth and adhesion of Staphylococcus aureus to nanocomposites were studied. Cytocompatibility was also evaluated by MTT assay on MDCK and 3T3 cell lines. The nanocomposites were found to be cytocompatible and showed a reduced bacterial colonization.

Composite materials based on carbon nanotubes (CNT) and polymeric hydrogels have become the subject matter of major interest for use as carriers in drug delivery research. The aim of this study was to evaluate the in vitro cytotoxicity of the hydrogel–carbon nanotube–chitosan (hydrogel–CNT–CH) composites on intestinal cells. Oxidized CNT were wrapped with chitosan (CH), Fourier transform infrared (FT‐IR) analysis suggest that oxidized CNT interact with CH. Transmission electron microscopy (TEM) images show a CH layer lying around CNT. Chitosan wrapped CNT were incorporated to poly (acrylamide‐co‐acrylic acid) hydrogels. Swelling behavior in buffers at different pH were evaluated and revealed a significantly lower swelling when it is exposed to a acid buffer solution (pH 2.2). Mechanical properties were evaluated by measurements of elasticity and the material with CNT showed better mechanical properties. The incorporation and liberation of Egg Yolk Immunoglobulin from hydrogel–CNT–CH were also assessed and it revealed an improved performance. To evaluate the effect of these nanocomposites on cellular redox balance, intestinal cells were exposed to hydrogel–CNT–CH composites and antioxidant enzymes were assessed. Cytotoxicity and apoptosis were also evaluated. Hydrogel–CNT–CH composites induce no oxidative stress and there were no evidence of cytotoxicity or cell death. These preliminary findings suggest that hydrogel–CNT–CH composites show improved properties and good biocompatibility in vitro making these biomaterials promising systems for drug delivery purposes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41370.

Bismuth-based semiconductors are promising candidates for applications in photocatalysis, photodetection, solar cells, etc. BiSI in particular is attracting attention. It has anisotropic optoelectronic properties and comprises relatively abundant elements. However, the synthesis of this ternary compound presents several challenges. Here, we delve into the underlying chemical processes that lead to the crystal growth of BiSI nanorods and optimize a solution-based synthesis. The mechanism of formation of BiSI nanocrystals is the self-sacrifice of Bi2S3 nanostructures, which also act as templates. The crystallographic similarities between the chalcogenide and the chalcohalide allow for the solid state transformation from one to the other. However, there is also a synergy with the I3 – species formed in the reaction media needed to obtain BiSI. Our method makes use of a green solvent, avoids complicated media, and drastically reduces the reaction time compared to other methods. The obtained nanorods present a band gap of 1.6 eV, in accordance with the reported values. This work presents insight into the chemistry of bismuth-based semiconductors, while introducing an easy, green, and scalable synthesis of a promising material, which could also be applied to similar compounds and other chalcoiodides, such as SbSI. In addition, the optical properties of the BiSI nanorods show their potential in photovoltaic applications.