UNIVERSAL SERS SENSORS FOR HIGH THROUGHPUT MONITORING OF FRESHWATERS – UnivSERS

Human settlements, industrial activities and agricultural runoffs continuously contaminate water resources with heavy metals, synthetic organic compounds and pathogenic organisms. In emerging countries, 80% of sewage water is directly discharged into water bodies and every year, an estimated 300-400 million tons of industrial waste are dumped in waters. The consequences of these pollutions on human health and biodiversity are enormous. In Europe, an area that benefits from water treatment plants and sanitation systems, more than 40% of freshwater fish species are in imminent danger of extinction. Due to unsafe water consumption, every year, 1.8 million people die from diarrhoeal disease, a condition that accounts for more infantile deaths than malaria or HIV.
Yet to date, we have no reliable estimation of the contaminant fluxes in water bodies across the world, which means we have no reliable estimation of the related risks and hazards. Indeed, the complexity and heterogeneity of water matrices, the diversity of contaminants and the geographical and temporal extents of the monitoring task raise enormous metrological challenges, especially in areas with constrained technological resources.
Current analytical tools to detect contaminants at trace levels are too costly, too tedious or have too low a throughput to support acquisition of data on a global scale, with a temporal resolution relevant to public health or to ecological or geochemical processes. As repeatedly stated by major development agencies (United Nations, WHO) and by earth scientists, we urgently need a technological breakthrough leading to a higher throughput of water quality data.
In this project, we aim at remediating this issue by developing universal point-of-measure sensors of freshwater contaminants based on a technique that displays striking advantages for environmental analysis: Surface Enhanced Raman Spectroscopy (SERS). SERS routinely displays extremely high sensitivities in concentration ranges relevant to trace levels of contaminants in water. Its high signal specificity makes it especially well-suited to analysis in complex mixtures. Acquisitions can be performed on the spot with a portable instrument that costs less than a compact car and can be automated in fluidic devices. Our sensors will be amenable to any contaminant a priori and we will demonstrate their universality by focusing on three prototypical pollutants: a heavy metal, a pesticide and a bacterial pathogen.
The UnivSERS sensing toolbox will combine state-of-the-art nanochemistry, statistical chemical analysis and microfluidics to feature three properties that are critical to massively increase the throughput of data acquisition: (i) it will work directly on field in unprocessed water samples, (ii) it will be easy to use, either manually or integrated into a fluidic device for automated in-line measurement and iii) it will employ scalable materials and affordable instruments to allow for massive field deployment. We believe these features will shape our sensors into truly operational tools that will foster the acquisition of the large bodies of insightful water quality data that are urgently needed to enforce sustainable management of water resources.