Engineered Magnetic Nanoparticles for Advanced Biosensor Signal Processing and Detection of Waterborne Pathogens

The contamination of water resources (drinking, recreational, and agricultural) in developed and/or developing countries, including the United States, necessitates a fast, reliable water safety detection method. The potential use of biological weapons by terrorists to contaminate water supplies is a more recent development that poses additional challenges because such agents are difficult to observe at the time of initial deployment and typically do not produce immediate effects. This Phase II research project identifies an innovative and versatile approach for detection/identification of pathogens based on an integrated optical chip sensor system with improved on-chip signal processing. The sensor is enabled by the incorporation of magnetic nanopowders. This technology employs a multi-channel interferometer design that offers trace 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. In Phase I, nGimat demonstrated that suitable magnetic nanoparticles could be synthesized and attached to an optical chip and magnetic field modulation of the phase of a guided optical wave. The basis of this 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 nanoparticle 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 chemistry steps, or reagents) of multiple biomolecules (proteins, toxins, nucleic acids) in the femtomolar concentration range. It also will be able to detect pathogens (bacteria, viruses) at concentrations of less than 100 organisms/mL. This Phase II research project 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 U.S. Environmental Protection Agency site. Phase II and Phase 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 industries.