A Customizable Real-Time Biosensor for Continuous Monitoring of Water Contaminants - Ensuring access to clean water for generations to come will involve developing novel ap-
proaches to determining the safety and composition of potable water that are practical and afford-
able. Arsenic, mercury, and cadmium are three of the top priorities among hazardous substances
commonly found at Superfund sites, as they are linked to health problems in people exposed to
them in drinking water, yet the current real-time monitoring methods for these and other contam-
inants are either extremely costly or nonexistent, making it difficult to monitor water quality with
high spatial or temporal resolution. QBiSci is developing a biosensor that uses synthetic micro-
bial sensor strains that fluoresce in response to specific toxins to continuously monitor water for
contamination. The platform will substantially improve upon currently available technologies for
toxin detection, making monitoring more affordable, continuous, and field-deployable.
Specific Aim 1: To fully characterize three synthetic E. coli strains that specifically detect ar-
senic, mercury, and cadmium in a continuous water stream. For a real-time sensor to be maxi-
mally effective, it must be able to report accurate toxin concentrations in real-time. Focusing on three
of the highest priority contaminants as a proof of feasibility, comprehensive data will be acquired
to train a machine learning algorithm to be able classify real-world samples in real-time.
Specific Aim 2: To develop and train a classification algorithm to recognize the type and amount
of each contaminant present in a continuous water stream. The ability to analyze and interpret data
in real-time from a constantly fluctuating water source will require an extensive classification train-
ing effort. QBiSci's existing machine learning framework will be trained and tested using many
contamination induction scenarios, ranging from sudden pulses to subtly varying concentrations.
Specific Aim 3: To develop a microfluidic cartridge system that reduces device complexity and
enables sensor deployment with minimal intervention. QBiSci will develop a swappable car-
tridge system using devices that are pre-loaded with biologically-stable strains and can simply
be “plugged in” to the sensor platform to achieve repeatable results in a user-friendly manner.
The development of a method for thermoplastic device fabrication will enable the more precise
connections required for a cartridge clamping system that will require little operational expertise.
A successful outcome of this proposal will lead to a biosensor capable of real-time quantifica-
tion of arsenic, mercury, and cadmium in a continuous water input. A future Phase II proposal
would focus on real-world performance evaluations of our sensors via deployment in areas of con-
cern and comparison of our results to standard techniques as well as an expansion of the platform
to detect other contaminants quantitatively and continuously.
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