An amperometric urea biosensor based on covalently immobilized urease on an electrode made of hyperbranched polyester functionalized gold nanoparticles

Ashutosh Tiwari, Santosh Aryal, Srikanth Pilla, Shaoqin Gong

Research output: Contribution to journalArticle

93 Scopus citations

Abstract

An amperometric biosensor was fabricated for the quantitative determination of urea in aqueous medium using hematein, a pH-sensitive natural dye. The urease (Urs) was covalently immobilized onto an electrode made of gold nanoparticles functionalized with hyperbranched polyester-Boltron® H40 (H40-Au) coated onto an indium-tin oxide (ITO) covered glass substrate. The covalent linkage between the Urs enzyme and H40-Au nanoparticles provided the resulting enzyme electrode (Urs/H40-Au/ITO) with a high level of enzyme immobilization and excellent lifetime stability. The response studies were carried out as a function of urea concentration with amperometric and photometric measurements. The biosensor based on Urs/H40-Au/ITO as the working electrode showed a linear current response to the urea concentration ranging from 0.01 to 35 mM. The urea biosensor exhibited a sensitivity of 7.48 nA/mM with a response time of 3 s. The Michaelis-Menten constant for the Urs/H40-Au/ITO biosensor was calculated to be 0.96 mM, indicating the Urs enzyme immobilized on the electrode surface had a high affinity to urea.

Original languageEnglish (US)
Pages (from-to)1401-1407
Number of pages7
JournalTalanta
Volume78
Issue number4-5
DOIs
StatePublished - Jun 15 2009

Keywords

  • Amperometric detection
  • Boltron H40
  • Covalent immobilization
  • Gold nanoparticles
  • Urea biosensor

ASJC Scopus subject areas

  • Chemistry(all)

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