Immunoassay signal amplification on glass slides based on electroless deposition

Saturated coverage of antibodies was first constructed on glass slides coated with polyelectrolyte multiplayer; then sandwich immunoreactions were carried out. Following immunoreactions, the glass slides were immersed in a freshly prepared solution containing 0.01 wt% HAuCl4 and 0.4 mM NH2OH·HCl. The growth of immunogold nanoparticles on glass slides was monitored with UV-vis spectrometer in real time. The data indicated that the immunoassay signal amplification really depends on the time of electroless deposition process and the concentration of antigen.