This SBIR project will test and expand a novel multiplex BioAssay protocol to safeguard the nation’s water
supply against chemical contaminants at concentrations that illicit a biologic effect.
The US Safe Drinking Water Act establishes the methods and frequency of water monitoring for chemical
contaminants in US drinking water. 100,000 chemicals currently are considered as potential “contaminants of
emerging concern” (CECs). Practically, the scale and cost of monitoring 100,000 unique CECs by existing
methods necessitates evidence-based prioritization. Currently, the EPA mandates public water agencies to
regularly monitor the amounts of >60 specific inorganic and organic chemicals, disinfectants and byproducts
through the water procurement process from water sourcing, storage, treatment to tap. Another 66 chemicals
currently are listed in the EPA’s “Contaminant Candidate List-5 (CCL-5)” for less frequent, exploratory
evaluation. Methods that enable affordable monitoring of all 100,000 suspect chemicals are desired. High
throughput molecular BioAssays, which report on the activity of a protein, provide one solution in which the
presence of any activity-altering contaminant(s) can be detected in a water sample.
National and international water monitoring authorities have shown interest in BioAssays as broad monitors of
the water supply. The major impediment is that current commercial BioAssays cost around $150 to report on
just one BioAssay-specific signaling pathway and many of those costly BioAssays are needed to screen across
many different chemical classes. XCellAssay’s major INNOVATION has been to develop highly multiplexed
protocols to accurately measure many different ‘bar-coded’ BioAssays affordably and simultaneously on the
same water sample added to a single well of a 384-well dish. In practice, 15 or more different BioAssays could
be readily surveyed at a total commercial price of just $30 to meet water monitoring needs.
For this SBIR application, we will develop a cost-effective, comprehensive broad BioAssay survey of water
quality. Our initial molecular targets will be proteins of the Nuclear Receptor (NR) class because of the
pervasive concerns about the prevalence of Endocrine Disrupting Chemicals (EDCs) in our surroundings.
In Phase 1, we propose to troubleshoot the development of the tools for water monitoring by:
Aim 1: developing water measurement protocols with our existing panel of five bar-coded NR BioAssays
Aim 2: implementing into our instrument database the bar-code unmixing processes for rapidly and accurately
separating an expandable number of spectrally distinct ‘green’ and ‘red’ fluorescent protein tagged BioAssays
If Specificity, Sensitivity and Reproducibility milestones are met for the pilot Phase I study, Phase II would
develop a set of Nuclear and Xenobiotic Receptor BioAssays for comprehensive EDC monitoring of the water
supply. Once the EDC platform is fully developed and validated (Phase II), the plug-and-play nature of the
platform will allow expansion to BioAssay panels for non-EDC contaminants in the water supply.
