title: Development of a simple bioelectrode for the electrochemical detection of hydrogen peroxide using Pichia pastoris catalase immobilized on gold nanoparticle nanotubes and polythiophene hybrid.
abstract: In this paper, a simple and innovative electrochemical hydrogen peroxide biosensor has been proposed using catalase (CATpp) derived from Pichia pastoris as bioelectrocatalyst. The model biocomponent was immobilized on gold nanoparticle nanotubes (AuNPNTs) and polythiophene composite using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-hydroxysuccinimide (EDC-NHS) coupling reagent. In this present work, we have successfully synthesized gold nanoparticles (AuNPs) by ultrasonic irradiation. The tubular gold nanostructures containing coalesced AuNPs were obtained by sacrificial template synthesis. The assembly of AuNPNTs onto the graphite (Gr) electrode was achieved via S-Au chemisorption. The latter was pre-coated with electropolymerized thiophene (PTh) to enable S groups to bind AuNPNTs. The combination of AuNPNTs-PTh, i.e., an inorganic-organic hybrid, provides a stable enzyme immobilization platform. The physical morphology of the fabricated biosensor Gr/PTh/AuNPNTs/EDC-NHS/CATpp was investigated using scanning electron microscopy and energy-dispersive microscopy. The analytical performance of the bioelectrode was examined using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. Operational parameters such as working potential, pH, and thermal stability of the modified electrode were examined. The beneficial analytical characteristics of the proposed electrode were demonstrated. Our results indicate that the Gr/PTh/AuNPNTs/EDC-NHS/CATpp bioelectrode exhibits a wide linear range from 0.05 mM to 18.5 mM of H2O2, fast response time of 7 s, excellent sensitivity of 26.2 mA mM(-1) cm(-2), good detection limit of 0.12 μM and good Michaelis-Menten constant of 1.4 mM. In addition, the bioelectrode displayed good repeatability, high stability and acceptable reproducibility, which can be attributed to the AuNPNTs-PTh composite that provides a biocompatible micro-environment.
authors.affiliation: Department of Chemistry and Research Centre, N.M.K.R.V. College for Women, Jayanagar, Bangalore 560 011, India. sureshssmrv@yahoo.co.in.
authors.forename: Seetharamaiah
authors.initials: S
authors.lastname: Nandini
authors.forename: Seetharamaiah
authors.initials: S
authors.lastname: Nalini
authors.forename: Jakkid
authors.initials: J
authors.lastname: Sanetuntikul
authors.forename: Sangaraju
authors.initials: S
authors.lastname: Shanmugam
authors.forename: Pathappa
authors.initials: P
authors.lastname: Niranjana
authors.forename: Jose Savio
authors.initials: JS
authors.lastname: Melo
authors.forename: Gurukar Shivappa
authors.initials: GS
authors.lastname: Suresh
mesh_terms: D002374:Catalase / Q000378:metabolism*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006046:Gold / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis*; D053768:Metal Nanoparticles; D008855:Microscopy, Electron, Scanning; D010843:Pichia / Q000201:enzymology*; D011108:Polymers / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013876:Thiophenes / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D004800:Enzymes, Immobilized; D011108:Polymers; D013876:Thiophenes; C066730:polythiophene; D006046:Gold; D006861:Hydrogen Peroxide; D002374:Catalase