Peculiar Properties of Template-Assisted Aniline Polymerization in a Buffer Solution Using Laccase and a Laccase-Mediator System as Compared with Chemical Polymerization.

The conventional chemical polymerization of aniline has been described in multiple publications, while enzymatic polymerization has been poorly explored. A comparative study of the template-assisted enzymatic and chemical polymerization of aniline in a buffer solution of sodium dodecylbenzenesulfonate micelles was performed for the first time. The high-redox potential laccase from the fungus Trametes hirsuta was used as a catalyst and air oxygen served as an oxidant. Potentiometric and spectral methods have shown that oligomeric/polymeric products of the enzymatic polymerization of aniline are synthesized in the conducting emeraldine salt form immediately after the reaction is initiated by the enzyme. The use of the laccase-mediator system enabled a higher rate of enzymatic polymerization and a higher yield of final products. Potassium octocyanomolybdate (IV) served as a redox mediator. The products of the enzymatic polymerization of aniline were studied by the ATR-FTIR, MALDI-TOF and atomic force microscopy methods. The chemical oxidative polymerization of aniline under the same conditions resulted in forming a non-conducting dark brown product.

Deep Eutectic Solvents for Biotechnology Applications.

Deep eutectic solvents (DESs) are an alternative to traditional organic solvents and ionic liquids and meet the requirements of "green" chemistry. They are easy to prepare using low-cost constituents, are non-toxic and biodegradable. The review analyzes literature on the use of DES in various fields of biotechnology, provides data on the types of DESs, methods for their preparation, and properties. The main areas of using DESs in biotechnology include extraction of physiologically active substances from natural resources, pretreatment of lignocellulosic biomass to improve enzymatic hydrolysis of cellulose, production of bioplastics, as well as a reaction medium for biocatalytic reactions. The aim of this review is to summarize available information on the use of new solvents for biotechnological purposes.

Induction of Chirality in Atomically Thin ZnSe and CdSe Nanoplatelets: Strengthening of Circular Dichroism via Different Coordination of Cysteine-Based Ligands on an Ultimate Thin Semiconductor Core.

Chiral nanostructures exhibiting different absorption of right- and left-handed circularly polarized light are of rapidly growing interest due to their potential applications in various fields. Here, we have studied the induction of chirality in atomically thin (0.6-1.2 nm thick) ZnSe and CdSe nanoplatelets grown by a colloidal method and coated with L-cysteine and N-acetyl-L-cysteine ligands. We conducted an analysis of the optical and chiroptical properties of atomically thin ZnSe and CdSe nanoplatelets, which was supplemented by a detailed analysis of the composition and coordination of ligands. Different signs of circular dichroism were shown for L-cysteine and N-acetyl-L-cysteine ligands, confirmed by different coordination of these ligands on the basal planes of nanoplatelets. A maximum value of the dissymmetry factor of (2-3) × 10-3 was found for N-acetyl-L-cysteine ligand in the case of the thinnest nanoplatelets.

Betaine-Based Deep Eutectic Solvent as a New Media for Laccase-Catalyzed Template-Guided Polymerization/Copolymerization of Aniline and 3-Aminobenzoic Acid.

Deep eutectic solvents (DESs) can compensate for some of the major drawbacks of traditional organic solvents and ionic liquids and meet all requirements of green chemistry. However, the potential of their use as a medium for biocatalytic reactions has not been adequately studied. In this work we used the DES betaine-glycerol with a molar ratio of 1:2 as co-solvent for enzymatic template-guided polymerization/copolymerization of aniline (ANI) and 3-aminobenzoic acid (3ABA). The laccase from the basidial fungus Trametes hirsuta and air oxygen served as catalyst and oxidant, respectively. Sodium polystyrene sulfonate (PSS) was used as template. Interpolyelectrolyte complexes of homopolymers polyaniline (PANI) and poly(3-aminobenzoic acid) (P3ABA) and copolymer poly(aniline-co-3-aminobenzoic acid) (P(ANI-3ABA)) were prepared and their physico-chemical properties were studied by UV-Vis and FTIR spectroscopy and cyclic voltammetry. According to the results obtained by atomic force microscopy, PANI/PSS had a granular shape, P(ANI-3ABA)/PSS had a spherical shape and P3ABA/PSS had a spindle-like shape. The copolymer showed a greater antimicrobial activity against Escherichia coli and Staphylcocus aureus as compared with the homopolymers. The minimal inhibitory concentration of the P(ANI-3ABA)/PSS against the gram-positive bacterium S. aureus was 0.125 mg mL-1.

Enzymatic synthesis and electrochemical characterization of sodium 1,2-naphthoquinone-4-sulfonate-doped PEDOT/MWCNT composite.

The development of novel materials with improved functional characteristics for supercapacitor electrodes is of current concern and calls for elaboration of innovative approaches. We report on an eco-friendly enzymatic synthesis of a composite based on poly(3,4-ethylenedioxythiophene) (PEDOT) and multi-walled carbon nanotubes (MWCNTs). The redox active compound, sodium 1,2-naphthoquinone-4-sulfonate (NQS), was used as a dopant for the backbone of the polymer. Oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) was catalyzed by a high redox potential laccase from the fungus Trametes hirsuta. Atmospheric oxygen served as an oxidant. A uniform thin layer of NQS-doped PEDOT formed on the surface of MWCNTs as a result of the enzymatic polymerization. The PEDOT-NQS/MWCNT composite showed a high specific capacitance of ca. 575 F g-1 at a potential scan rate of 5 mV s-1 and an excellent cycling stability within a potential window between -0.5 and 1.0 V, which makes it a promising electrode material for high-performance supercapacitors.