Progress in Conductive Polyaniline-Based Nanocomposites for Biomedical Applications: A Review.

Inherently conducting polymers (ICPs) are a specific category of synthetic polymers with distinctive electro-optic properties, which involve conjugated chains with alternating single and double bonds. Polyaniline (PANI), as one of the most well-known ICPs, has outstanding potential applications in biomedicine because of its high electrical conductivity and biocompatibility caused by its hydrophilic nature, low-toxicity, good environmental stability, and nanostructured morphology. Some of the limitations in the use of PANI, such as its low processability and degradability, can be overcome by the preparation of its blends and nanocomposites with various (bio)polymers and nanomaterials, respectively. This review describes the state-of-the-art of biological activities and applications of conductive PANI-based nanocomposites in the biomedical fields, such as antimicrobial therapy, drug delivery, biosensors, nerve regeneration, and tissue engineering. The latest progresses in the biomedical applications of PANI-based nanocomposites are reviewed to provide a background for future research.

Multilevel Morphology of Complex Nanoporous Materials.

This work exploits gas adsorption and small-angle X-ray scattering (SAXS) to determine the morphology of complex nanoporous materials. We resolve multiple classes of porosity including previously undetected large-scale texture that significantly compromises the canonical interpretation of gas adsorption. Specifically, a UVM-7 class mesoporous silica was synthesized that has morphological features on three length scales: macropores due to packing of 150 nm globules, 1.9 nm radius spherical mesopores inside the globules, and >7 nm pockets on and between the globules. The total and external surface areas, as well as the mesopore volume, were determined using gas adsorption (αs-plot) and SAXS. A new approach was applied to the SAXS data using multilevel fitting to determine the surface areas on multiple length scales. The SAXS analysis code is applicable to any two-phase system and is freely available to the public. The total surface area determined by SAXS was 12% greater than that obtained by gas adsorption. The macropore interfacial area, however, is only 30% of the external surface area determined by the αs-plot. The overestimation of the external surface area by the αs-plot method is attributed to capillary condensation in nanoscale surface irregularities. The discrepancy is resolved assuming that the macropore-globule interfaces harbor fractally distributed nooks and crannies, which lead to gas adsorption at pressures above the mesopore filling pressure.

Allergenicity reduction of bovine milk ß-lactoglobulin by proteolytic activity of lactococcus lactis BMC12C and BMC19H isolated from Iranian dairy products.

Nowadays health benefits of bioactive food constituents, known as probiotic microorganisms, are a growing awareness. Cow's milk is a nutritious food containing probiotic bacteria. However, milk allergenicity is one of the most common food allergies. The milk protein, ß-lactoglobulin (BLG), is in about 80% of all main cases of milk allergies for children and infants. With the aim of screening proteolytic strains of lactic acid bacteria to evaluate their potential for the reduction of allergenicity of the major bovine milk proteins, we isolated new proteolytic strains of cocci lactic acid bacteria from traditional Iranian dairy products. The proteases produced by these strains had strong proteolytic activity against BLG. Proteolysis of BLG, observed after sodium dodecyl sulfate-PAGE, was confirmed by the analysis of the peptide profiles by reversed-phase HPLC. The two isolates were submitted to 16S rDNA sequencing and identified as Lactcoccus lactis subsp. cremoris and Lactcoccus lactis subsp. hordniea. The competitive ELISA experiments confirmed that these isolates, with high proteolytic activity, reduce significantly the allergenicity of BLG. Accordingly, these isolates can reduce the immunoreactivity of bovine milk proteins, which can be helpful for the production of low-allergic dairy products.

Nanoadsorbents based on conducting polymer nanocomposites with main focus on polyaniline and its derivatives for removal of heavy metal ions/dyes: A review.

Water contamination by toxic heavy metal ions and dyes remains a serious public health problem for humans, so attention on specific methods and technologies to remove heavy metal ions and dyes from wastewaters/aqueous solutions are desired. Numerous adsorbents have been reported for the removal of heavy metal ions/dyes from wastewaters/aqueous solutions. Polyaniline (PANI) and its derivatives, as conducting polymers, are good adsorbents to remove various kinds of heavy metal ions and dyes from wastewaters/aqueous solutions. The nanoadsorbents based on PANI and its derivatives have received much consideration, and are extensively reported in literature. This review focuses on the PANI and its derivatives based on nanoadsorbents for water purification. Various types of these nanoadsorbents used for the removal of heavy metal ions/dyes from wastewaters/aqueous solutions are also briefly compared in this review.

Multilayered electromagnetic bionanocomposite based on alginic acid: Characterization and biological activities.

Poly(aniline-co-pyrrole)@Fe3O4@alginic acid (PACP@Fe3O4@AA) bionanocomposite was synthesized by a two-step method. In the first step, the AA@Fe3O4 nanocomposite was synthesized via the in-situ co-precipitation technique. In the second step, the PACP@Fe3O4@AA bionanocomposite was synthesized through the emulsion polymerization. Several techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, ultraviolet visible spectroscopy, scanning electron microscopy, and thermogravimetric analysis were utilized for the characterization of the synthesized materials. The presence of AA@Fe3O4 in the bionanocomposite enhanced the electrical conductivity as well as the thermal stability of the PACP@Fe3O4@AA bionanocomposite. The scanning electron micrograph of the PACP@Fe3O4@AA bionanocomposite demonstrated a nanosphere structure. The vibrating sample magnetometer analysis displayed that both AA@Fe3O4 and PACP@Fe3O4@AA bionanocomposites were super-paramagnetic at room temperature. The PACP@Fe3O4@AA bionanocomposite had good antioxidant and antibacterial activities. Furthermore, a synergistic effect was observed for the antifungal activity.