Enzyme biosensor based on the immobilization of HRP on SiO₂/BSA/Au composite nanoparticles.
In this work, an enzyme biosensor based on the immobilization of horseradish peroxidase (HRP) on SiO₂/BSA/Au/thionine/nafion-modified gold electrode was fabricated successfully. Firstly, nafion was dropped on the surface of the gold electrode to form a nafion film followed by chemisorption of thionine (Thi) as an electron mediator via the ion-exchange interaction between the Thi and nafion. Subsequently, the SiO₂/BSA/Au composite nanoparticles were assembled onto Thi film through the covalent bounding with the amino groups of Thi. Finally, HRP was immobilized on the SiO₂/BSA/Au composite nanoparticles due to the covalent conjugation to construct an enzyme biosensor. The surface topographies of the SiO₂/BSA/Au composite nanoparticles were investigated by using scanning electronic microscopy. The stepwise self-assemble procedure of the biosensor was further characterized by means of cyclic voltammetry and chronoamperometry. The enzyme biosensor showed high sensitivity, good stability and selectivity, a wide linear response to hydrogen peroxide (H₂O₂) in the range of 8.0 x 10⁻⁶  ~3.72 x 10⁻³ mol/L, with a detection limit of 2.0 x 10⁻⁶ mol/L. The Michaelies-Menten constant K(app)(M) value was estimated to be 2.3 mM.
Yuan
Shirong
S
Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
Yuan
Ruo
R
Chai
Yaqin
Y
Zhuo
Ying
Y
Yang
Xia
X
Yuan
Yali
Y
D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002021:Buffers; D002417:Cattle; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D053761:Nanocomposites / Q000737:chemistry*; D010640:Phenothiazines / Q000737:chemistry; D015203:Reproducibility of Results; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
D002021:Buffers; D004800:Enzymes, Immobilized; D005465:Fluorocarbon Polymers; D010640:Phenothiazines; D012710:Serum Albumin, Bovine; C040402:perfluorosulfonic acid; D006046:Gold; D012822:Silicon Dioxide; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; C009469:thionine