Multifunctional protein particles with dual analytical channels for colorimetric enzymatic bioassays and fluorescent immunoassays

Advanced multifunctional protein particles encapsulated enzymes and antibodies were developed for enzymatic bioassays and immunoassays with colorimetric and fluorescent channels. A colorimetric channel based on color-substrate precipitation was assigned for enzymatic bioassays for the measurement of hydrogen peroxide with the lowest detectable concentration of 10 mu M. A fluorescent channel based on fluorescent labeled antibodies was assigned for immunoassays for the measurement of mouse immunoglobulin G (MIgG) with the lowest detectable concentration of 1.25 mu g L-1. The protein microparticles were fabricated with a template-assisted self-assembly technique termed Protein Activation Spontaneous Self-assemble (PASS). The multifunctional protein particles prepared with the PASS method have the advantages of high loading of analytical biomolecules, integrated biological functions, porous structure, and more importantly, they are optically transparent and fluorescence inactive. These unique features make our protein particles a new generation of bead-based platforms to perform enzyme bioassays and immunoassays. (C) 2011 Elsevier B.V. All rights reserved.