title: Enzymatic biosensor based on entrapment of d-amino acid oxidase on gold nanofilm/MWCNTs nanocomposite modified glassy carbon electrode by sol-gel network: Analytical applications for d-alanine in human serum.
abstract: Sensing and determination of d-alanine is studied by using an enzymatic biosensor which was constructed on the basis of d-amino acid oxidase (DAAO) immobilization by sol-gel film onto glassy carbon electrode surface modified with nanocomposite of gold nanofilm (Au-NF) and multiwalled carbon nanotubes (MWCNTs). The Au-NF/MWCNT nanocomposite was prepared by applying the potentiostatic technique for electrodeposition of Au-NF on the MWCNT immobilized on glassy carbon electrode surface. The modified electrode is investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), linear sweep voltammetry (LSV) and cyclic voltammetry(CV) techniques. The linear sweep voltammetry was used for determination of d-alanine and the results showed an excellent linear relationship between biosensor response and d-alanine concentration ranging from 0.25μM to 4.5μM with correction coefficient of 0.999 (n=20). Detection limit for the fabricated sensor was calculated about 20nM (for S/N=3) and sensitivity was about 56.1μAμM-1cm-2. The developed biosensor exhibited rapid and accurate response to d-alanine, a good stability (4 weeks) and an average recovery of 98.9% in human serum samples.
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran.
authors.forename: Yalda
authors.initials: Y
authors.lastname: Shoja
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran. Electronic address: aa_rafati@basu.ac.ir.
authors.forename: Amir Abbas
authors.initials: AA
authors.lastname: Rafati
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran.
authors.forename: Javad
authors.initials: J
authors.lastname: Ghodsi
mesh_terms: D000409:Alanine / Q000097:blood* / Q000737:chemistry; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D001774:Blood Chemical Analysis / Q000379:methods / Q000706:statistics & numerical data; D003605:D-Amino-Acid Oxidase; D004563:Electrochemistry; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D005782:Gels; D006046:Gold; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000648:ultrastructure; D015203:Reproducibility of Results; D013237:Stereoisomerism; D013552:Swine
chemical_list: D004800:Enzymes, Immobilized; D005782:Gels; D037742:Nanotubes, Carbon; D006046:Gold; D003605:D-Amino-Acid Oxidase; D000409:Alanine
keywords: Au nanostructures; Biosensor; Enzyme immobilization; MWCNT; d-Amino acid oxidase