title: Development of a conductometric phosphate biosensor based on tri-layer maltose phosphorylase composite films.
abstract: A conductometric biosensor for phosphate detection was developed using maltose phosphorylase (MP) from recombinant Escherichia coli immobilized on a planar interdigitated electrode by cross-linking with saturated glutaraldehyde (GA) vapour in the presence of bovine serum albumin (BSA). The process parameters for the fabrication of the mono-enzymatic sensor and various experimental variables such as the enzyme loading, time of immobilization in saturated GA vapour, working buffer solution and temperature were investigated with regard to their influence on sensitivity, detection limit, dynamic range, operational and storage stability. The biosensor can work well at the temperature between 20 degrees C and 50 degrees C, and reach 90% of steady-state conductance in about 10s. The sensor has two linear ranges, one is from 1.0 microM to 20 microM phosphate with a detection limit of 1.0 microM, and the other is between 20 microM and 400 microM phosphate. When stored in citrate buffer (0.1M, pH 6.0) at 4 degrees C, the biosensor showed good stability over two months. No obvious interference from other anionic species like SO(4)(2-), Cl(-), NO(3)(-), NO(2)(-) and HCO(3)(-) was detected. The biosensor is suitable for use in real water samples.
authors.affiliation: Laboratoire de Sciences Analytiques (UMR CNRS 5180), Université Claude Bernard - Lyon 1, Université de Lyon, 69622 Villeurbanne Cedex, France.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Nicole
authors.initials: N
authors.lastname: Jaffrezic-Renault
authors.forename: François
authors.initials: F
authors.lastname: Bessueille
authors.forename: Didier
authors.initials: D
authors.lastname: Leonard
authors.forename: Siqing
authors.initials: S
authors.lastname: Xia
authors.forename: Xuejiang
authors.initials: X
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.forename: Jianfu
authors.initials: J
authors.lastname: Zhao
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D003217:Conductometry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology; D005964:Glucosyltransferases / Q000737:chemistry*; D005976:Glutaral / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D010710:Phosphates / Q000032:analysis*; D011994:Recombinant Proteins / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D004800:Enzymes, Immobilized; D008567:Membranes, Artificial; D010710:Phosphates; D011994:Recombinant Proteins; D012996:Solutions; D012710:Serum Albumin, Bovine; D005964:Glucosyltransferases; C021535:maltose phosphorylase; D005976:Glutaral