Layer-by-layer construction of novel biofunctional fluorescent microparticles for immunoassay applications

Abstract

A novel class of biofunctional fluorescent microparticles for application in immunoassays was constructed by using the layer-by-layer self-assembly method to deposit multiple layers of fluorescently labeled polyelectrolytes onto colloidal particles, followed by deposition of a protein (immunoglobulin G, IgG) layer. Microelectrophoresis experiments revealed alternating negative and positive ζ-potentials with deposition of each successive polyelectrolyte layer, indicating that the alternate electrostatic adsorption of polyelectrolytes of opposite charge was successfully achieved. Transmission electron microscopy images showed a change of the particle surface texture after polyelectrolyte multi..