Biochip with E. coli bacteria for detection of arsenic in drinking water

Abstract

Arsenic and other pollutants are often present in trace amounts in drinking water in a number of countries. In aqueous solutions the sensitivity of arsenic-responsive bacterial bioreporters is far better than the performance of chemical field test kits. However, biological detection currently requires extensive handling and expensive fluorescence microscopy. We fabricated and tested microfluidic chips with fluorescent (GFP) E. coli bacteria that respond to arsenic. Measurement results of fluorescence intensity as function of arsenic concentration and exposure time are promising, showing a clear response to concentrations of 50 μg/l of arsenite.

Development of a simple, portable, colorimetric arsenic sensor based on Molybdenum Blue Chemistry

“…A more conventional example of a continuous flow microfluidic set-up consists of a closed, single use chip (Theytaz et al 2009). Theytaz et al propose such a channel geometry which includes a filter to immobilise bacteria while the arsenic solution flows through.…”

A Comprehensive Review of Microfluidic Water Quality Monitoring Sensors

“…Bacterial bioassays have shown better performance in arsenic detection compared to a chemical field kit [173]. Theytaz et al [146] created a microfluidic chip containing immobilized E. coli biosensor bacteria (Figure 8b). The E. coli generated green fluorescent protein in response to As(III).…”

“…( a ) Three-dimensional paper-based fluorescence detection of Cu 2+ and Hg 2+ [144]; ( b ) E. coli -based fluorescence detection of As(III) [146]; and ( c ) fluorescence detection of As(III) using portable bioreporter [145]. …”

Biosensors for Inorganic and Organic Arsenicals

“…This improvement lowered the detection limit to 7.5 µg/L, and the signal-to-noise ratio doubled without reducing the background noise. Microfluidic chips were developed using E. coli expressing gfp under the control of arsR with the long-term goal of the automation of dilution series and parallel detection of multiple analytes with integrated optics [ 59 ]. The fluorescent biosensor, E. coli DH5α pProbe- gfp (tagless)- arsR -ABS, was trapped on the biochip, which showed a linear response of the fluorescent signal as a function of exposure time and arsenite concentrations ≥50 µg/L.…”