Novel nanostructured platform and nanoparticles for sensitive detection of biological materials

In this paper, a simple and robust sensing assay platform for detection of biological materials is reported. The fluorescence based sensing platform benefits from the combined use of our novel dye-doped nanoparticle tags and nanoporous high surface area (~1,400 m²/g) films to achieve high intrinsic signal amplification. The dye-doped nanoparticles are synthesized from poly-methylsilsesquioxane (PMSSQ) encapsulating fluorescent dye molecules that can be conjugated to antibodies and proteins. We have achieved conjugation of up to 64 dye molecules per single antibody, which represents more than an order of magnitude increase in conjugation efficiency compared to conjugation of free dye molecules. Capture of the dye-doped nanoparticle labeled antibodies by nanoporous organosilicate (NPO) films has yielded 540 fold increase in fluorescence response compared to immobilization of dye labeled antibodies on (flat) glass substrates. This assay demonstrates a general way for detection of analytes in very low concentration.