Micellar Nanoreactors for Hematin Catalyzed Synthesis of Electrically Conducting Polypyrrole

Abstract

Enzymatic synthesis of doped polypyrrole (PPy) complexes using oxidoreductases (specifically peroxidases) is very well established "green" methods for producing conducting polypyrrole. The importance of this approach is realized by the numerous potential opportunities of using PPy in biological applications. However, due to very high costs and low acid stability of these enzymes, there is need for more robust alternate biomimetic catalysts. Hematin, a hydroxyferriprotoporphyrin, has a similar iron catalytic active center like the peroxidases and has previously shown to catalyze polymerization of phenol monomers at pH 12. The insolubility of hematin due to extensive self-aggregation at low pH conditions has prevented its use in the synthesis of conjugated polymers. In this study, we have demonstrated the use of a micellar environment with sodium dodecylbenzenesulfonate (DBSA) for biomimetic synthesis of PPy. The micellar environment helps solubilize hematin, generating nanometer size reactors for the polymerization of pyrrole. The resulting PPy is characterized using UV-visible, Fourier transform infrared, and X-ray photoelectron spectroscopy and reveals the formation of an ordered PPy/DBSA complex with conductivities approaching 0.1 S/cm.

A biomimetic enzyme modified electrode for H2O2 highly sensitive detection

“…34 In addition, the TEM image showed that the AuNPs had an approximately spherical morphology and dispersed uniformly. [35][36][37] The peaks at 1451 cm −1 and 1470.5 cm -1 are attributed to the N-H in-plane vibration, and the peak at 1649.5 cm -1 is the characteristic peak of amido due to stretching vibration of C=O, which reveals that the secondary amido bond is contained in the nanocomposite. When reaction finished, the resultant mixture was centrifuged at 14,000 rpm, then washed and re-dispersed in ultrapure water, and finally re-centrifuged.…”

Electrochemical supercapacitive properties of polypyrrole thin films: influence of the electropolymerization methods

“…The properties of PPy such as morphology, size, and shape of microstructures and nanostructures, and conductivity strongly depend on the synthetic method. Various methods of synthesis of polypyrrole have been reported in the literature [13][14][15][16][17]. Electropolymerization is a widespread method for the synthesis of PPy including three different modes of polymerization/deposition, namely, cyclic voltammetry (CV), galvanostatic (GS), and potentiostatic (PS) deposition [8].…”

Mechanistic evaluation of hematin action as a horseradish peroxidase biomimetic on the 4-aminoantipyrine/phenol oxidation reaction

“…The use of hematin as a catalyst for oxidative polymerizations of phenolic monomers and hydrogelation processes has been restricted due to its low solubility and aggregation at low pHs (Ryu et al, 2014;Sakai et al, 2010;Singh et al, 2001). Therefore, different functionalization strategies, including esterification with polyethylenglicol (PEGylatedhematin), amidation with methoxypolyethylene glycol amine and even its inclusion into micelles (Nagarajan et al, 2009;Ravichandran et al, 2012) have been attempted. Recent results by our group presented hematin as a promising alternative to HRP for decolorization reactions active at high peroxide concentrations (Córdoba et al, 2012a,b;Pirillo et al, 2010).…”