Performance enhancement by particle gradient assembly patterning of electrochemiluminescence immunosensor formed using magnetolithgraphy in determination of human serum albumin.

Gradient properties facilitate the correlation of chemical and physical features of particles on the structure and adherent fate. Herein, performance enhancement is explored by particle gradient assembly patterning (PGAP) formed with magnetic field gradient (MFG) by magnetolithography (ML) in the electrochemiluminescence (ECL) measurement. Magnetic Fe3O4 nanoparticles were selected as nanocarriers and coated with a SiO2 layer for immobilization of primary antibodies. CdTe quantum dots with protein G coatings were selected as signal labels and conjugated with secondary antibodies. Magnetized 500-nm pillar, 1 μm- and 3 μm-line arrays of nickel were placed behind the working electrode modifying the sandwich-structured ECL immunosensor to form various PGAPs. A performance enhancement of ca. 2.4 times was observed when comparing the PGAP-free immunosensor to the researched gradient immunosensor, formed with a magnetized 3 μm-line array of nickel. This concludes that the sensitivity of an ECL immunosensor has been enhanced due to PGAP properties. When the immunosensor with PGAP properties was used to quantify human serum albumin, it exhibited a wide linear range (10-480 ng/mL), and a limit of detection of 10 ng/mL. PGAP properties, formed with MFG by ML, provides a simple method to improve the ECL performance.