title: Fabrication of a bilayer potentiometric phosphate biosensor by cross-link immobilization with bovine serum albumin and glutaraldehyde.
abstract: Chemical cross-linking of purine nucleoside phosphorylase (PNP) and xanthine oxidase (XOD) with glutaraldehyde (GLA) and bovine serum albumin (BSA) has been used to fabricate a stable and reliable bilayer potentiometric phosphate biosensor. The bilayer arrangement consists of an inner BSA-GLA layer and an outer BSA-GLA-PNP-XOD layer. The inclusion of the inner BSA-GLA layer improves the adhesion of the outer BSA-GLA-PNP-XOD layer and ensures stability of the phosphate biosensor. Established optimum conditions for immobilization of the enzymes in the outer layer and for reliable potentiometric measurement were 4.5% v/v GLA, 6.8% w/v BSA, XOD:PNP mole ratio of 1:8, and a film drying time of 30 min. As little as 20 μM of phosphate can be detected with the BSA-GLA/BSA-GLA-XOD-PNP bilayer biosensor with a linear concentration range between 40 and 120 μM. The biosensor was very stable for 21 days, achieving a good reproducibility with a rsd of only 5.7% and, even after more than a month, the change in the initial potential value was only 10%.
authors: NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria, Australia. Sam.Adeloju@monash.edu
authors: Samuel B
authors: SB
authors: Adeloju
authors: Abdulazeez T
authors: AT
authors: Lawal
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005976:Glutaral / Q000737:chemistry*; D010710:Phosphates / Q000032:analysis*; D011199:Potentiometry / Q000379:methods*; D011683:Purine-Nucleoside Phosphorylase / Q000737:chemistry / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D014969:Xanthine Oxidase / Q000737:chemistry / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D010710:Phosphates; D012710:Serum Albumin, Bovine; D014969:Xanthine Oxidase; D011683:Purine-Nucleoside Phosphorylase; D005976:Glutaral