|HRADILOVÁ Šárka||Palacky University Olomouc, Regional Centre of Advanced Technologies and Materials|
|Spoluautoři PANÁČEK Aleš, KVÍTEK Libor, ZBOŘIL Radek|
Magnetic nanoparticles (MNPs) are due to their easy separability in the magnetic field powerful tool wherever it is necessary to isolate the target structure from a complex mixture or concentrate it prior to analysis. In 2007 was described „Intrinsic peroxidase-like activity of ferromagnetic nanoparticles“. MNPs as well as horseradish peroxidase (HRP) are able to catalyze the reaction with a suitable substrate, resulting in color change which can be quantified by spectrophotometer. With the ability to respond as a peroxidase, it combines both separation and detection in one step, which simplifies and speeds up the whole process of common used assay. MNPs react with the same substrates as HRP; however, require the presence of hydrogen peroxide. In comparison with HRP MNPs are able to catalyze a reaction in a broader range of pH and temperature and not adversely affected by toxic substances. HRP-like activity of the bare MNPs is usually higher in comparison with modified particles, because of reduce the surface volume ratio, but surface modification is necessary for the immunoassays, where specific antigen-antibody interaction is needed. Common type of surface modification is chitosan followed glutaraldehyde and antibody. Our research studies the HRP-like activity of MNPs with chitosan surface modification in comparison with the unmodified MNPs. The effect of different concentrations of hydrogen peroxide, the concentration of nanoparticles and reusability were monitored. Bare magnetic nanoparticles exhibit a higher peroxidase - like activity in comparison with particles modified by chitosan, but modified MNPs still exhibit sufficient HRP-like activity. ACKNOWLEDGEMENTS: This research has been supported by: Operational Program Research and Development for Innovations – European Regional Development Fund (projects CZ.1.05/2.1.00/03.0058 of the Ministry of Education, Youth and Sports of the Czech Republic), by the Operational Program Education for Competitiveness - European Social Fund (project CZ.1.07/2.3.00/20.0056 of the Ministry of Education, Youth and Sports of the Czech Republic), and by Internal Grants of Palacky University in Olomouc (PrF_2014_032).