Exceptional ion-exchange selectivity for perchlorate based on polyaniline films

Fabrication of a tailor-made conductive polyaniline/ascorbic acid-coated nanofibrous mat as a conductive and antioxidant cell-free cardiac patch

Polyaniline (PANI) wasin-situpolymerized on nanofibrous polycaprolactone mats as cell-free antioxidant cardiac patches (CPs), providing electrical conductivity and antioxidant properties. The fabricated CPs took advantage of intrinsic and additive antioxidant properties in the presence of PANI backbone and ascorbic acid as a biocompatible dopant of PANI. The antioxidant nature of CPs may reduce the serious repercussions of oxidative stress, produced during the ischemia-reperfusion (I/R) process following myocardial infarction. The polymerization parameters were considered as aniline (60 mM, 90 mM, and 120 mM), ascorbic acid concentrations ([aniline]:[ascorbic acid] = 3:0, 3:0.5, 3:1, 3:3), and polymerization time (1 h and 3 h). Mainly, the more aniline concentrations and polymerization time, the less sheet resistance was obtained. 1,1 diphenyl-2-picrylhydrazyl (DPPH) assay confirmed the dual antioxidant properties of prepared samples. The advantage of the employedin-situpolymerization was confirmed by the de-doping/re-doping process. Non-desirable groups were excluded based on their electrical conductivity, antioxidant properties, and biocompatibility. The remained groups protected H9c2 cells against oxidative stress and hypoxia conditions. Selected CPs reduced the intracellular reactive oxygen species content and mRNA level of caspase-3 while the Bcl-2 mRNA level was improved. Also, the selected cardiac patch could attenuate the hypertrophic impact of hydrogen peroxide on H9c2 cells. Thein vivoresults of the skin flap model confirmed the CP potency to attenuate the harmful impact of I/R.

Hollow Polypyrrole Composite Synthesis for Detection of Trace-Level Toxic Herbicide

In this work, we successfully demonstrated the fabrication of a chemical sensor for toxic 1,1-dimethyl-3-phenylurea (fenuron) by using a hollow polypyrrole composite film. Here, we studied the interaction between negatively charged phosphate anions enclosed in the film with positively charged nitrogen atoms present in the fenuron. The electrochemical response of the film was characterized by cyclic voltammetry in which, interestingly, we observed that the bigger alkyl aryl sulphonate ions were replaced by smaller phosphate ions with the creation of hollow/pore composite films. Confirmation for ion replacement in the film and porosity of the film were studied by elemental analysis and field emission scanning electron microscopy, respectively. The tuning of hydrophilic to hydrophobic nature of the hollow composite film was tested by the wettability test (contact angle measurement). The electrocatalytic materials, as well as the fenuron sensing conditions such as pH and film thickness, were wisely optimized on glassy carbon (GC) electrodes for better performance. We can enhance the fenuron sensitivity by over 5 times as compared to that on the GC substrate. To our knowledge, this is the first electrochemical fenuron sensor based on a hollow polymer film by differential pulse voltammetry which can detect lower concentrations and show quick response compared to other reports. This method has potential applications in the electrochemical sensing platform with good sensitive and selective analysis in agriculture groundwater samples.

Perchlorate reduction in microbial electrolysis cell with polyaniline modified cathode

Excellent perchlorate reduction was obtained under various initial concentrations in a non-membrane microbial electrolysis cell with polyaniline (PANI) modified graphite cathode as sole electron donor. PANI modification is conducive to the formation of biofilm due to its porous structure and good electrocatalytic performance. Compared with cathode without biofilm, over 12% higher reduction rates were acquired in the presence of biocathode. The study demonstrates that, instead of perchlorate reduction, the main contribution of biofilm is involved in facilitate electron transfer from cathode to electrolyte. Interestingly, hairlike structure, referred as to pili-like, was observed in the biofilm as well as in the electrolyte. Additionally, the results show that pili were prone to formation under the condition of external electron field as sole electron donor. Analysis of microbial community suggests that perchlorate reduction bacteria community was most consistent with Azospiraoryzae strain DSM 13638 in the subdivision of the class Proteobacteria.