Ternary Composite of Hemin, Gold Nanoparticles and Graphene for Highly Efficient Decomposition of Hydrogen Peroxide

Abstract

A ternary composite of hemin, gold nanoparticles and graphene is prepared by a two-step process. Firstly, graphene-hemin composite is synthesized through π-π interaction and then hydrogen tetracholoroauric acid is reduced in situ by ascorbic acid. This ternary composite shows a higher catalytic activity for decomposition of hydrogen peroxide than that of three components alone or the mixture of three components. The Michaelis constant of this composite is 5.82 times lower and the maximal reaction velocity is 1.81 times higher than those of horseradish peroxidase, respectively. This composite also shows lower apparent activation energy than that of other catalysts. The excellently catalytic performance could be attributed to the fast electron transfer on the surface of graphene and the synergistic interaction of three components, which is further confirmed by electrochemical characterization. The ternary composite has been used to determine hydrogen peroxide in three real water samples with satisfactory results.

DNAzyme–aptamer or aptamer–DNAzyme paradigm: Biochemical approach for aflatoxin analysis

“…This means that aptamer–DNAzyme reach to its maximum rate at lower concentrations of substrate but as mentioned above the V max is definitely lower than that of DNAzyme–aptamer. Catalytic efficiency ( K cat / K m ) was calculated for further evaluation of activities of sequence based on various concentrations of TMB and H 2 O 2 . As seen in Table , catalytic efficiencies for DNAzyme–aptamer with TMB and H 2 O 2 are prominently higher than those of aptamer–DNAzyme.…”

ATP-enhanced peroxidase-like activity of gold nanoparticles

“…The high cost involved in synthesis and purification of these enzymes and strict working conditions have created an opportunity for the use of nanomaterials as biological enzyme mimics 1, 2 . Several reports on using nanomaterials as biological enzyme mimics exist in literature for example, nanoparticles of gold [5][6][7][8] , cerium oxide 9-13 , iron-oxide 14,15 , Co 3 O 4 16 , CuO 17 and V 2 O 5 18-20 nanowires and carbon based nanomaterials [21][22][23][24] , bi-metallic nanohybrids such as Au-Pd 25,26 , Au-carbon 27 and graphene 28 hybrids etc are the most studied nanomaterial based models that demonstrate peroxidaselike catalytic activity. In contrast to natural enzymes, nanomaterial based enzyme mimics exhibit higher stability in harsh reaction conditions, have lower cost of production, demonstrate higher flexibility in composition, shape and size control, shelf-life and can be designed for tunable catalytic efficiency 4 .…”

A novel electrochemical biosensor based on hemin functionalized graphene oxide sheets for simultaneous determination of ascorbic acid, dopamine and uric acid

“…Recently, it was reported that hemin could be adsorbed on graphene surface by -interactions to form complex nanosheets, which were exhibiting great properties and various applications. Meanwhile, it is worthy noted that many small molecules including nitric oxide [13], nitrite [15], and hydrogen peroxide [16] could be reduced or oxidized based on the active groups of hemin [17] or reversible redox potential of Fe 2+/3+ [18].…”