The goal of this Phase I project is to develop a real-time nanoparticle-based optical detector for polymerase chain reaction (PCR) amplified DNA that is integrated into a portable PCR unit for use in low technology environments. The detection of target DNA oligonucleotides (ON) from PCR amplification conventionally involves either electrophoresis/staining or fluorescence indicators. Electrophoresis analysis generally takes several hours to complete and fluorescence requires the use of large, expensive equipment that limits the detection method to laboratory settings. We propose the use of nanoprobes whose visible-light absorption properties change dramatically in the presence of the target ON in the PCR solution. The optical detector has been shown to distinguish between target ON and ON with only a single mismatched base pair. A simple optical detector system, based on an LED and a phototransistor, will be integrated into a completely automated miniature PCR device already in advanced stages of engineering at Lynntech with the goal of producing a prototype detector for use in low technology environments by minimally trained individuals that will produce test results in minutes. The device can be used for in vitro medical diagnostics, detection of biological warfare agents, detection of food pathogens, etc. [unreadable] [unreadable]