We propose to use CatAssays' novel Palladium Catalyzed Chemical Amplification (PdCCA) technology platform to develop ultra-sensitive sandwich ELISA-format bioassays to detect very low concentrations of a number of critical cancer and immunoregulatory biomarkers. CatAssays' PdCCA technology, the first example of the application of heterogeneous metal catalysis in bioassays, improves the signal generation chemistry (while using 2nd party, highly specific, state-of-the-art capture/detection antibodies) t provide a significant increase in system detection sensitivity by: a. use of heterogeneous palladium nanoparticle catalyst labels in place of an enzyme catalyst used in conventional ELISA b. use of a new high gain redox reaction - the palladium-catalyzed reduction of a tetrazolium salt by an amine borane to give a water-soluble formazan dye Initial reduction to practice of PdCCA, in which the detection antibody itself was labeled with palladium, gave an 80-fold detection sensitivity increase vs the standard enzyme-based ELISA test for t-PSA (Gen-1 PdCCA). The proposed work will develop a more commercially viable 2nd generation PdCCA technology based on the use of a universal detection label comprising polymeric nanoparticles containing a high loading of the palladium catalyst and surface functionalized with a biospecific binding reagent (e.g., Steptavidin. etc.) for attachment to any biotinylated detection antibody. This Phase 1 work will focus on: 1) synthesis of the above universal catalytic polymeric marking nanoparticles and 2) optimization of Gen 2 PdCCA technology in bioassays using model biomarkers - initially TNF?, IFN?, IL-6, followed by IL-2, IL-8, IL-10, cytokines and CA-125, SLPI and MSLN ovarian, and tPSA cancer biomarkers - to demonstrate improved sensitivity for a broad range of applications. The implementation of optimized PdCCA technology incorporating the new palladized polymeric marking nanoparticles in modified-ELISA-format assays is not time consuming, making the Phase 1 evaluation of the above 10 biomarkers readily achievable. In Phase 2 a viable commercial scale synthesis for the Gen-2 PdCCA catalytic polymeric marking nanoparticles and assay kits for specific cancer biomarker assays will be developed. At least one ovarian cancer biomarker-PdCCA assay, identified in collaboration with our medical center experts, will be submitted for FDA approval This new bioassay signal amplification technology is expected to provide a readily implementable and cost-effective significant increase in sensitivity, with no detectable loss of specificity, for the earlier detection of cancers while using the current medical laboratory infrastructure.