▎ 摘　　要

NOVELTY - An electrode is a molded, miniaturized, carbon-based electrode comprising magnetic nanoparticles coated with gold or silver and having at least one free amine or carboxyl group on the respective surface, and at least one ligand which is capable of specifically binding to the analyte and being conjugated to the nanoparticles. The nanoparticles are adsorbed on the surface of the electrode. USE - Electrode used in biosensor for electrochemical detection of analyte e.g. vitamin (25-OH) D in biological sample (claimed) e.g. blood, plasma or serum. ADVANTAGE - The electrode for electrochemical detection improves patient compliance, samples collection using lancet for lancing device and reduces both logistical and economical pressure on the hospital/diagnostic center and on national health service. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: a biosensor for electrochemical detection of an analyte in a sample, which comprises the electrode as a working electrode , a reference electrode and a counter electrode; production of the electrode, which involves adding gold or silver-coated magnetic nanoparticles to a first solution comprising thiol compound so that the compound is adsorbed on the surface of the nanoparticles , resulting in a second solution which comprises nanoparticles comprising free amine and/or carboxyl group on the surface, depositing the second solution on the surface of a molded, miniaturized, carbon-based electrode in the presence of a magnet positioned below the electrode and allowing the liquid phase of the second solution to evaporate so that the nanoparticles are adsorbed onto the surface of the electrode, adding a third solution comprising a cross linking agent on the electrode surface, adding a fourth solution comprising at least one analyte-specific ligand to the surface of the electrode obtained and allowing it to react for sufficient time for the ligand to form a covalent bond with the compound; and electrochemical determination of the analyte in a biological sample, which involves contacting the biological sample containing the analyte with a biosensor comprising an electrode under conditions so that the analyte binds to an analyte-specific ligand present on the working electrode which results in a change in current flow between the working electrode and the counter-electrode and detecting the change in current generated by determining the presence or amount of the analyte in the sample.