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.
College of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Qing
Q
Chang
Lihua
L
Zhu
Guodong
G
Jiang
Heqing
H
Tang
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