Nanotechnology and Biosensors

Non-Technical Summary: Nanotechnology holds much untapped potential for practical problems of society particularly in the are of biological detection. The purpose of this project is to develop, elucidate and apply novel nanoscale sensor materials, properties, and devices to problems of agriculture, food production, biosecurity, and the environment.<P> Approach: Nanocomposite Materials Immobilized Artificial Cells. Nanoscale structured materials are required to mimic cellular strategies in nonliving systems. We are developing a nanocomposite material in the form of immobilized liposomes as artificial cells that can capture the functional essence of whole cell assays in a nonliving hybrid (inorganic / organic / biological) system. We will directly apply these materials to the development of robust, inexpensive, selective and fast biosensors for the detection of pore-forming toxins (PFTs) from foodborne pathogens. Nanomaterials for Gas Phase Detection. We will fabricate nanoporous silicon sensors and sensor arrays, and apply these sensors to measure changes in the interferometric reflectance and photoluminescence spectra before and after exposed to multiple species including ammonia and odorous VFAs. Different molecules in the gas phase will be determined using gas chromatography-mass spectrometer (GC-MS). With a known composition in the gas phase, we will examine the amount and composition of different molecules condensed in the nanopores. The optical spectra will be obtained with various compositions for the gas phase and for the adsorbent species. The condensed adsorbent molecules will be analyzed using desorption electrospray ionization mass spectrometry. Nanotechnology Education. Educational modules illustrating the used of Raman microscopy for detection is being developed. Gold and Iron coated gold particles have been used to illustrate the concept of nanobiosensing. Thus educational modules will include particle synthesis and protocol development to tether biomolecules to inorganic surface via appropriate chemistry. Nanobars. Gold and silver composite nanobars are being synthesized and characterized for their physical properties by TEM as well as by single particle microscopic methods. The absorption and scattering properties are measured by spectrometer both in the visible and infrared regions. BY tuning the physical dimensions of these parameters, significant wavelength shift could be observed and utilized for multiplex sensing. Fundamental Properties at Nanoscales. By tuning the physical properties of gold and silver, nanostructures of different aspect ratios have been fabricated for multiplex detection of cell surface biomarkers. We hypothesize that wavelength shift of plasmonic bands induces a change in dielectric properties in the immediate vicinity of the nano structures, concentration changes do not affect this parameter. Hence wavelength shift of the plasmonic band could provide information biomolecular binding events at single particle sensitivity. Nanoparticles. We are synthesizing nanoparticles with non-fluorescent markers for surface enhanced resonance sensing using a confocal raman approach. Such an approach will reduce the scale of microarrays to nanoscale dimensions while enabling multiplexing at this scale. Nanoparticle Delivery. We are developing experimental and computational models to elucidate and predict mechanisms of nanoparticle uptake by cells and tissues. This work has applications both in designing nanoparticles as well as nanoparticle safety.