Biotemplate-SnO2 particles intercalated PANI matrix: Enhanced photo catalytic activity for degradation of MB and RY-15 dye

Optimization and Analytical Behavior of Electrochemical Sensors Based on the Modification of Indium Tin Oxide (ITO) Using PANI/MWCNTs/AuNPs for Mercury Detection

In the present study, indium tin oxide (ITO) was used as a transparent working electrode for the development of an electrochemical sensor for the detection of mercury (II) ions (Hg2+). The electrode was modified by direct electrodeposition of polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) followed by optimization of the analyte and operating conditions, aiming to improve the selectivity, sensitivity and reliability of the electrode for mercury detection. Successful immobilization of the PANI and nanomaterials (MWCNTs and AuNPs) on the ITO electrode was confirmed by Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) and Fourier Transform Infrared Spectroscopy (FTIR) analyses. The optimum conditions for mercury detection using the modified ITO electrode were pH 7.0 of Tris-HCl buffer (50 mM) in the presence of 1 mM methylene blue (MB) as a redox indicator, a scan rate of 0.10 V·s-1 and a 70 s interaction time. The electrochemical behavior of the modified electrode under the optimized conditions indicated a high reproducibility and high sensitivity of mercury detection. It is therefore suggested that the PANI/MWCNT/AuNP-modified ITO electrode could be a promising material for the development of on-site mercury detection tools for applications in fields such as diagnostics, the environment, safety and security controls or other industries.

Cytotoxic, antioxidant and antibacterial activities of copper oxide incorporated chitosan-neem seed biocomposites

In this study biopolymer-inorganic material of chitosan‑copper oxide-neem seed (CS-CuO-NS) biocomposite was successfully synthesized by simple precipitation method and characterized by FT-IR, XRD, HR-SEM, TEM and TGA analyses. From HR-SEM and TEM analysis, CS-CuO-NS biocomposite shows flower and needle like structure respectively. The size of the as prepared CS-CuO-NS biocomposite is found to be 20-100 nm. All the synthesized materials were tested for antibacterial activity against both gram positive like Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes) and gram negative like Escherichia coli (E. coli) and Klebsiella aerogenes (K. aerogenes) bacterial strains. The maximum zone of inhibition is obtained for CS-CuO-NS biocomposite against S. aureus (23 mm), S. pyogenes (21 mm), E. coli (22 mm) and K. aerogenes (20 mm). The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined. The antioxidant activity was determined by free radicals scavenging such as 1, 1-Diphenyl-2-picryhydrazyl (DPPH) and 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Furthermore, the cytotoxicity effect was investigated against human breast cancer (MCF-7) cell line and the highest cytotoxicity (IC₅₀:16.33 μg/mL) is found to be in biocomposite. From the results of antibacterial, antioxidant and cytotoxic activities, it is concluded that CS-CuO-NS biocomposite may be suitable for biomedical applications.

Chitosan Nanocomposite Coatings for Food, Paints, and Water Treatment Applications

Worldwide, millions of tons of crustaceans are produced every year and consumed as protein-rich seafood. However, the shells of the crustaceans and other non-edible parts constituting about half of the body mass are usually discarded as waste. These discarded crustacean shells are a prominent source of polysaccharide (chitin) and protein. Chitosan is a de-acetylated form of chitin obtained from the crustacean waste that has attracted attention for applications in food, biomedical, and paint industries due to its characteristic properties, like solubility in weak acids, film-forming ability, pH-sensitivity, biodegradability, and biocompatibility. We present an overview of the application of chitosan in composite coatings for applications in food, paint, and water treatment. In the context of food industries, the main focus is on fabrication and application of chitosan-based composite films and coatings for prolonging the post-harvest life of fruits and vegetables, whereas anti-corrosion and self-healing properties are the main properties considered for antifouling applications in paints in this review.

Visible-light photocatalytic capability and the mechanism investigation of a novel PANI/Sn3O4 p–n heterostructure

A novel polyaniline (PANI)/Sn₃O₄ heterojunction composed of PANI nanofibers and Sn₃O₄ nanosheets was fabricated by a facile physical milling technique. Modification of Sn₃O₄ with a PANI conductive polymer contributes to facilitating interfacial charge transfer efficiency, and thus, significantly enhances the visible-light Rhodamine B (RhB) photo-degradation. Results indicate that PANI/Sn₃O₄ heterostructures with 10 wt% PANI reached the maximum degradation efficiency (around 97%) for RhB within 5 h, which is 2.27 times higher than that of Sn₃O₄ alone. This improvement is due to the p–n heterostructure formation in PANI/Sn₃O₄. Moreover, the outcome of reactive species capturing experiments demonstrated that in PANI/Sn₃O₄, holes made the largest contribution to RhB degradation under visible light illumination, while hydroxyl radicals showed less significance under the same conditions. In addition, the photocatalytic mechanism was proposed based on evidence from the reactive species test and energy band structure analysis.

A novel polyaniline (PANI)/Sn₃O₄ heterojunction composed of PANI nanofibers and Sn₃O₄ nanosheets was fabricated by a facile physical milling technique.

Synthesis of chitosan incorporated neem seed extract (Azadirachta indica) for medical textiles

In present study, eco-friendly biosynthesis of Chitosan-Neem seed (CS-NS) composite was prepared by co-precipitation method using aqueous neem seed extract. Cotton fabrics were treated with two different crosslinking agents (Glutaraldehyde and Citric acid) then the synthesized composite coated on cotton fabric by chemical linkage between the composite and the cellulose structure. As synthesized composite materials and treated cotton fabrics were characterized by Fourier transform infrared spectroscopy for functional groups confirmation, X-ray diffraction for crystalline behavior determination, UV-vis spectroscopy analysis for optical property and High resolution scanning electron microscopy for Surface morphological properties. The antibacterial activity of CS-NS composite coated cotton fabric and CS-NS composite coated cotton fabric with crosslinking agents were tested against the gram-positive and gram negative bacteria by agar well diffusion method. The results demonstrated that CS-NS composite with crosslinked coated cotton fabric has higher antibacterial activity than without crosslinked cotton fabric. Thus the chitosan-neem seed composite may be applied to the medical textiles.