Electrophoretic build-up of multi nanoparticle array for a highly sensitive immunoassay.
Han-J-H; Kim-H-J; Sudheendra-L; Hass-EA; Gee-SJ; Hammock-BD; Kennedy-IM
Biosens Bioelectron 2013 Mar; 41:302-308
One of the challenges in shrinking immunoassays to smaller sizes is to immobilize the biological molecules to nanometer-scaled spots.To overcome this complication, we have employed a particle- based immunoassay to create a nanostructured platform with a regular array of sensing elements. The technique makes use of an electrophoretic particle entrapment system (EPES) to immobilize nanoparticles that are coated with biological reagents into wells using a very small trapping potential. To provide useful information for controlling the trapping force and optimal design of the nanoarray, electrophoretic trapping of a nanoparticle was modeled numerically. The trapping efficiency, defined as the fraction of wells occupied by a single particle, was 91%. The performance of the array was demonstrated with a competitive immunoassay for a small molecule analyte, 3-phenoxybenzoic acid(214.2g mole-1). The limit of detection determined with a basic fluorescence microscope was 0.006 ug l-1 (30 pM); this represented a sixteen-fold improvement in sensitivity compared to a standard 96-wellplate-based ELISA; the improvement was attributed to the small size of the sample volume and the presence of light diffraction among factors unique to this structure. The EPES/nanoarray system promises to offer a new standard in applications that require portable, point-of-care and real-time monitoring with high sensitivity.
Biological-function; Molecular-biology; Molecular-structure; Nanotechnology; Particulates; Models;
Author Keywords: Nanoarray; Immunoassay; Electrophoretic particle entrapment system; 3-phenoxybenzoic acid (3-PBA)
Ian M. Kennedy, Department of Mechanical and Aerospace Engineering, University of California, Davis, California, CA 95616, USA
Cooperative Agreement; Agriculture
Biosensors and Bioelectronics
University of California - Davis