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.
Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
Shirong
S
Yuan
Ruo
R
Yuan
Yaqin
Y
Chai
Ying
Y
Zhuo
Xia
X
Yang
Yali
Y
Yuan
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