Ultrasensitive and Low-Cost Paper-Based Graphene Oxide Nanobiosensor for Monitoring Water-Borne Bacterial Contamination

Abstract

Water-borne pathogens are mostly generated due to poor sanitation, industrial effluents, and sewage sludge, leading to a significant increase in mortality rate. To prevent this, we need a simple, user-friendly, and rapid on-site detection tool of pathogens, i.e., a biosensor. As contaminated water mainly contains (80%) coliform bacteria, of which Escherichia coli is the major species, we have developed a screen-printed paper-based, label-free biosensor for the detection of E. coli in water. A nanoarchitectured graphene oxide (GO), as a fast electron-transfer flatland, was deposited on the screenprinted graphene (G) on a hydrophobic paper, followed by the immobilization of lectin Concanavalin A (ConA) as a biorecognition element for a GGO_ConA-biosensing electrode. The electrochemical characterization of GGO_ConA shows fast electron transfer with a calculated electroactive surface area of 0.16 cm 2 . The biosensor performance was tested in the sludge water and beach water (real sample) as an analyte using the electrochemical impedance spectroscopy (EIS) technique. The charge-transfer resistance (R ct ) of GGO_ConA increases linearly with the bacterial concentration in the range of 10−10 8 CFU mL −1 with an estimated limit of detection (LOD) of 10 CFU mL −1 , which indicates the ultrasensitivity of our biosensor, with 100 times more sensitivity than previous studies. Our reported biosensor, being cost-effective, eco-friendly, and ultrasensitive, may serve greatly as a portable monitoring kit for checking water-borne bacterial contamination.

Paper-based sustainable biosensors

“…This device achieved ultra-high sensitivity for detecting bacterial contamination over a wide linear range of 102–108 CFU mL −1 and ultra-low LOD of 0.1 × 10 2 CFU mL −1 without any chemical intensification. 206 In another study, a ‘ turn-off ’ fluorescent biosensing device (mCherry L199C) for sensing Hg 2+ was designed and developed via the direct modification of the chromophore environment of the fluorescent protein mCherry. The designed variant of mCherry L199C was expressed directly on the outer-membrane of E. coli cells via the cell surface display approach.…”

Paper-based sensors for bacteria detection

“…However, this sensor does not include specific receptors, and therefore detects any kind of Gram-positive or Gram-negative bacteria. To improve specificity, a similar label-free paper-based impedimetric sensor has been developed using a screen-printed graphene surface modified with graphene oxide and functionalized with lectin Concanavalin A (ConA) 142 . This assay demonstrates specific binding to mono- and oligosaccharides of E. coli (tested against Salmonella sp.…”

A Review on Microfluidics-Based Impedance Biosensors

“…Research and development of paper-based electrochemical impedance spectroscopy was conducted for the detection of microRNA 155 [141], for which gold nanoparticles changed the properties of paper-based electrodes. S. Karuppiah developed a paper-based impedance biosensor for monitoring bacteria in water [142]. The electrodes of the biosensor were screen-printed with graphene (G) and then surface-modified with graphene oxide (GO).…”