Magnetite-containing spherical silica nanoparticles for biocatalysis and bioseparations.
The simultaneous entrapment of biological macromolecules and nanostructured silica-coated magnetite in sol-gel materials using a reverse-micelle technique leads to a bioactive, mechanically stable, nanometer-sized, and magnetically separable particles. These spherical particles have a typical diameter of 53 +/- 4 nm, a large surface area of 330 m(2)/g, an average pore diameter of 1.5 nm, a total pore volume of 1.427 cm(3)/g and a saturated magnetization (M(S)) of 3.2 emu/g. Peroxidase entrapped in these particles shows Michaelis-Mentan kinetics and high activity. The catalytic reaction will take place immediately after adding these particles to the reaction solution. These enzyme entrapping particles catalysts can be easily separated from the reaction mixture by simply using an external magnetic field. Experiments have proved that these catalysts have a long-term stability toward temperature and pH change, as compared to free enzyme molecules. To further prove the application of this novel magnetic biomaterial in analytical chemistry, a magnetic-separation immunoassay system was also developed for the quantitative determination of gentamicin. The calibration for gentamicin has a working range of 200-4000 ng/mL, with a detection limit of 160 ng/mL, which is close to that of the fluorescent polarization immunoassay (FPIA) using the same reactants.
Yang
Huang-Hao
HH
Material Transport & Transformation in Environmental & Life Processes Lab, The First Institute of Oceanography, SOA, Qingdao, 266061, PR China. hhyang@xmu.edu.cn
Zhang
Shu-Qiong
SQ
Chen
Xiao-Lan
XL
Zhuang
Zhi-Xia
ZX
Xu
Jin-Gou
JG
Wang
Xiao-Ru
XR
D000327:Adsorption; D002138:Calibration; D002384:Catalysis; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods*; D004655:Emulsions; D004795:Enzyme Stability; D052203:Ferrosoferric Oxide; D005839:Gentamicins / Q000032:analysis; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods; D007501:Iron; D007700:Kinetics; D008280:Magnetics; D008823:Micelles; D036103:Nanotechnology / Q000295:instrumentation*; D009584:Nitrogen; D010087:Oxides; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide; D013696:Temperature
D004655:Emulsions; D005839:Gentamicins; D008823:Micelles; D010087:Oxides; D012822:Silicon Dioxide; D007501:Iron; D006735:Horseradish Peroxidase; D009584:Nitrogen; D052203:Ferrosoferric Oxide