The goal of the proposed research is to develop a universal nanoparticle probe methodology that will enable the simultaneous detection of multiple biological threat agents using a single nanoparticle probe. The development of this methodology will ultimately provide a cost effective, flexible DNA detection platform that high specificity and sensitivity. To accomplish the stated goal, Nanosphere will develop a universal code for labeling primers used for PCR amplification that is recognized by a universal nanoparticle probe. This labeling strategy will enable Nanosphere to utilize its highly specific and sensitive DNA-modified gold nanoparticle probes for detection. The labeled PCR amplicons will be detected on a microarray containing capture sequences for each target using the universal gold nanoparticle probe in conjunction with silver development. The resulting data will be analyzed using the Nanosphere imaging system which quantifies signal at each microarray location. In phase I, Nanosphere will simultaneously detect three genes from the simulant Bacillus subtilis starting from low copy numbers (102 copies/mL) in less than one hour to demonstrate feasibility. In phase II, an integrated rapid assay will be developed for multiple biological threat agents using the universal nanoparticle probe platform.