Engineering Magnetic Nanoparticle for Advanced Biosensor Signal Processing and Detection of Waterborne Pathogens

The contamination of drinking, recreational, and agricultural water sources in developed and/or developing countries, including the United States, necessitate a fast, reliable detection method. The use of biological weapons by terrorists to contaminate water supplies is a more recent development that poses additional challenges since such agents are difficult to observe at the time of initial deployment and typically do not produce immediate effects. This proposal identifies and innovative and versatile approach for detection/identification of pathogens based on an integrated optical chip sensor system with improved on-chip signal processing enabled by the incorporation of magnetic nanopowders. This technology employs a multi-channel interferometer design that offers tract level detection sensitivities, rapid response, and multiple agent detection/identification capabilities in a compact package that can be used by unskilled personnel. The proposed Phase II research will build upon and expand the success achieved in Phase I, where suitable magnetic nanoparticles were synthesized and attached to an optical chip and magnetic field modulation of the phase of a guided optical wave was demonstrated. The basis of the research is to enable an advanced signal processing scheme to enhance optical biosensor detection sensitivity (sub-ppb) through magnetic field induced nanoscale displacements of tethered magnetic particles immobilized on the waveguide surface. The nanoparticles displacement will induce a phase shift in the output of a waveguide interferometer that could be utilized to discriminate noise from the collected signal through signal processing. The technology will build on the base optical sensor technology and be ultimately capable of real-time, direct detection (no labeling, additional chemical steps or reagents) of multiple biomolecules (proteins, toxins, nucleic acids) in the femtomolar concentration range and pathogens (bacteria, viruses) at concentration of <100 organisms/ml. Phase II will validate the use of functionalized magnetic nanoparticles as a means of phase modulating a guided wave and demonstrate the detection of specific biological agents based on a phase-lock detection method. It will concentrate on particle size and functionalization optimization, proper magnetic field modulation compatible with the use environment and field verification at a selected EPA site. Phase II and III efforts will be facilitated by the experience of O¿Brien & Gere; a leader in water engineering and a committed partner in commercializing the sensor for water quality monitoring. In addition to water quality, nGimat¿s sensor has the potential to fill needs within food safety, environmental remediation, homeland security, medical drug discovery, and medical point-of-care service.