Commercialization of Novel Silicon Microslit Filters for Microplastic Contamination Testing

Abstract Environmental pollution by microplastics (MPs) in fresh water and oceans is a growing problem that is now well-recognized in both the popular media and scientific literature. Concerning levels of MPs have been found in food and local waters, as well as in human tissues. Several government regulatory bodies have (or are in the process of) implementing mandatory MP drinking water testing, including the State of California, Canada, and a number of EU countries. This Phase II SBIR project addresses the need for improved tools and related services for capturing and analyzing MPs. Our precedent Phase I SBIR award established the utility of our (SiMPore's) silicon nanomembranes with micron-scale rectangular pores (“microslit filters”) for the capture and analysis of MPs. We demonstrated utility in detecting MPs in consumer beverages and throughout a spatial map of the City of Rochester (NY) water system. We created a new venture (ParVerio) commercializing MP testing services based on SiMPore's membranes. We established products' features according to voice-of-customer data, are participating in an international MP detection lab validation study, and are engaging a large instrument vendor as co-development partner for product marketing. This Phase II project will advance the manufacturing of microslit filters, automate their packaging into 13 mm discs for compatibility with existing vacuum filtration devices, and develop peripherals for rapid MP screening and filter analysis. We will scale our nanomembrane production to multi-wafer batches to reach cost-of-good targets in lined with identified pricing levels. We will develop a process for combining injection-molded 13 mm disc blanks and nanomembrane chips using pick-and-place robotics, precision glueing, and thermal curing. We will also develop two peripheral products: 1) a machined 25x75 mm footprint microscope slide to hold three 13 mm discs; and 2) a proprietary filtration apparatus with software, readouts, and transmembrane pressure sensors for rapid water sample screening. This second device will automate the identification of samples with debris and the production of optimal samples for analysis. Through subcontracts, we will support novel end-use applications at spin-out ParVerio and the University of Rochester (UR). ParVerio will develop a MP challenge test (NSF/ANSI 42 Particulate Class I Reduction standard) as a service for assessing MP removal efficiency of filtration products. At UR, the McGrath and Knox labs will develop thermal birefringence using microslit filters as a low-cost, label free approach for MP identification. The successful development of thermal birefringence would become a Parverio service and product and dramatically expand the number of end-users doing MP analysis because of low instrument costs. This Phase II project will support the commercialization of SiMPore's microslit filters to meet the expanding needs for MP capture and analysis products and related services. Our products will benefit a growing number of concerned water authorities, regulatory bodies, and researchers working to understand the scope of MP pollution and to mitigate its impacts on health and the environment.