Immobilization of barley oxalate oxidase onto gold–nanoparticle-porous CaCO3 microsphere hybrid for amperometric determination of oxalate in biological materials

• Published in: Clinical biochemistry 2012-02, Vol.45 (3), p.253-258
• Main Authors: Chauhan, Nidhi, Narang, Jagriti, Shweta, Pundir, C.S.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensing Techniques; Calcium Carbonate - chemistry; Dielectric Spectroscopy; Electrochemistry - methods; Electrodes; Enzyme electrode; Enzymes, Immobilized - metabolism; Gold - chemistry; Hordeum - enzymology; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Microspheres; Miscellaneous. Technology; Oxalate; Oxalate oxidase; Oxalates - analysis; Oxalates - urine; Oxidoreductases - metabolism; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Plasma; Porosity; Reference Standards; Urine
• ISSN: 0009-9120; 1873-2933
• DOI: 10.1016/j.clinbiochem.2011.12.004

The use of Au nanoparticles (AuNPs)–CaCO3 porous microsphere hybrid as a matrix for enzyme immobilization to increase the performance of an amperometric biosensor. A method is described for construction of an amperometric oxalate biosensor by immobilizing a barley root oxalate oxidase (OxOx) onto AuNPs–CaCO3 porous microsphere hybrid encapsulated in silica sol and deposited on Au electrode. The biosensor showed optimum response within 4s at pH 5.0 and 30°C, when polarized at +0.4V vs. Ag/agCl. The biosensor possesses high sensitivity and measures oxalate concentrations as low as 1.0μmol/L. The working linear range was from 1.0 to 1000μmol/L of oxalate. The biosensor measured urinary and plasma oxalate of normal persons and stone formers. The use of AuNPs–CaCO3 porous microsphere hybrid as a support for immobilization of OxOx has resulted into an improved amperometric oxalate biosensor. ► Constructed amperometric oxalate biosensor based on OxOx/AuNPs-CaCO3 microsphere. ► Biosensor showed optimum response within 4s at 0.4V, pH 5.0 and 30°C. ► Response was linear between 1.0-1000μmol/L oxalic acid concentrations. ► Biosensor measured urinary & plasma oxalate of normal persons and stone formers.