Polymerization-based amplification for immunostaining and biodetection

A method of detecting a molecular recognition event between an antibody and a target protein of a cell attached to a substrate, the method comprising the steps of:

• a) treating the cell with a blocking agent;
• b) contacting the antibody with the target protein under conditions effective to form an antibody-target protein complex;
• c) removing antibody not complexed with the target protein;
• d) labeling the antibody-target protein complex with a photoinitiator label wherein the photoinitiator label comprises photoinitiator;
• e) removing photoinitiator label not attached to the antibody-target protein complex;
• f) contacting the photoinitiator-labeled antibody-target protein complex with a polymer precursor solution comprising a water soluble monomer, and a plurality of fluorescent nanoparticles, wherein the average size of the fluorescent particles is from 10 to 50 nm;
• g) exposing the photoinitiator-labeled antibody-target protein complex and the polymer precursor solution to light, thereby forming a polymer gel attached to the cell and incorporating a plurality of the fluorescent nanoparticles;
• h) removing unpolymerized polymer precursor and fluorescent nanoparticles not incorporated into the polymer gel;
• and
• i) detecting fluorescence from the nanoparticles in the polymer gel, thereby detecting the molecular recognition event.
• wherein the ratio of the fluorescence signal per unit area from nanoparticles in the polymer gel to a background fluorescence signal per unit area is greater than 5.