METHOD OF DETERMINING CONTENT OF BACTERIA USING MODIFIED MAGNETIC NANOPARTICLES AS TAGS Russian patent published in 2017 - IPC C12Q1/06 C12N1/02 G01N33/532 B82Y5/00 

FIELD: biotechnology.

SUBSTANCE: invention relates to biotechnology, namely to electrochemical immunoassay. Method of determination of gram-negative bacteria in analyzed medium is disclosed. In aqueous medium at temperature of 37 °C bacteria are conjugated with magnetic nanoparticles Fe₃O₄, Fe⁰, NiFe₂O₄ or MgFe₂O₄, modified with dextran. Non-binding nanoparticles are separated using magnetic field. Working electrode made of gold, platinum or graphite-containing materials is placed into working medium, surface of which is modified with antibodies specific to defined strain of bacteria, for immune complex formation on electrode surface during 20 minutes at temperature of 37 °C. Electrode is washed with buffer solution containing normal horse serum and tween-20. Working electrode extracted from analyzed medium is placed in electrochemical cell containing background electrolyte. Content of bacteria is determined by value of electrochemical oxidation response of nanoparticles localized in immunocomplex on surface of working electrode.

EFFECT: invention increases sensitivity and accuracy of analysis, lowers detection limit for bacterial cells to 10 CFU/ml, reduces time of analysis.

1 cl, 7 dwg, 5 ex