SBIR Phase I: Large Scale Synthesis of Hollow Metal Nanospheres: Conversion of Batch Synthesis to Continuous Flow

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is rooted in the development of a large-scale synthesis for the manufacture of highly uniform hollow metal nanospheres for use by the military in potentially contaminated zones of operation, in rural settings with limited access to healthcare laboratories, or in the agricultural field for faster and more affordable detection of lower levels of food-based toxins and pathogens. Furthermore, establishing a source of these next-generation metal nanoparticles at commercially relevant levels of quality and quantity with consistent and predictable performance would pave the way for their expansion into other industries that could also benefit from their advantages, such as photocatalysis, water purification, and photomedicine. This Small Business Innovation Research (SBIR) Phase I project will scale-up the production of hollow metal nanoparticles from the existing small-batch syntheses to a large-scale continuous flow process, with strict standards for the control of their size, shape, and optical response. Large-scale synthesis of highly uniform hollow metal nanospheres with controllable size has not been achieved to date, hampering the use and study of these advanced materials. A high-quality, high-volume production method will position hollow metal nanospheres for rapid commercial adoption in applications where they markedly outperform their solid counterparts, such as in color reporting for lateral flow assays (LFAs), where hollow gold nanospheres can offer a 10-fold improvement in assay sensitivity. The primary objective of the proposed work is to determine the parameters necessary for a high-quality, high-throughput synthesis based on continuous flow, including reactor materials, chamber dimensions, precursor concentrations, flow rates, and reaction times. The major technical hurdle lies in the identification (within a very large parameter space) of suitable conditions for a successful and controlled synthesis; accordingly, a major component of this project is in-depth analysis and characterization of synthesized nanoparticles by optical spectroscopy and electron microscopy. Characterization results will be used to inform iterative reactor improvements. The resulting high throughput reactor will both advance the state of the art of nanomaterial synthesis and enable new research by creating a consistent supply of commercially available hollow nanoparticles with reproducible physical properties. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.