Sensitive fluorescent probes for determination of hydrogen peroxide and glucose based on enzyme-immobilized magnetite/silica nanoparticles.
Sensitive fluorescent probes for the determination of hydrogen peroxide and glucose were developed by immobilizing enzyme horseradish peroxidase (HRP) on Fe(3)O(4)/SiO(2) magnetic core-shell nanoparticles in the presence of glutaraldehyde. Besides its excellent catalytic activity, the immobilized enzyme could be easily and completely recovered by a magnetic separation, and the recovered HRP-immobilized Fe(3)O(4)/SiO(2) nanoparticles were able to be used repeatedly as catalysts without deactivation. The HRP-immobilized nanoparticles were able to activate hydrogen peroxide (H(2)O(2)), which oxidized non-fluorescent 3-(4-hydroxyphenyl)propionic acid to a fluorescent product with an emission maximum at 409 nm. Under optimized conditions, a linear calibration curve was obtained over the H(2)O(2) concentrations ranging from 5.0 x 10(-9) to 1.0 x 10(-5) mol L(-1), with a detection limit of 2.1 x 10(-9) mol L(-1). By simultaneously using glucose oxidase and HRP-immobilized Fe(3)O(4)/SiO(2) nanoparticles, a sensitive and selective analytical method for the glucose detection was established. The fluorescence intensity of the product responded well linearly to glucose concentration in the range from 5.0 x 10(-8) to 5.0 x 10(-5) mol L(-1) with a detection limit of 1.8 x 10(-8) mol L(-1). The proposed method was successfully applied for the determination of glucose in human serum sample.
Chang
Qing
Q
College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Zhu
Lihua
L
Jiang
Guodong
G
Tang
Heqing
H
D001786:Blood Glucose / Q000032:analysis; D004800:Enzymes, Immobilized; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D005456:Fluorescent Dyes; D005947:Glucose / Q000737:chemistry*; D006735:Horseradish Peroxidase; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D053758:Nanoparticles; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
D001786:Blood Glucose; D004800:Enzymes, Immobilized; D005456:Fluorescent Dyes; D012822:Silicon Dioxide; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D005947:Glucose; D052203:Ferrosoferric Oxide