Simple, Rapid, Sensitive, and Versatile SWNT−Paper Sensor for Environmental Toxin Detection Competitive with ELISA

Abstract

Safety of water was for a long time and still is one of the most pressing needs for many countries and different communities. Despite the fact that there are potentially many methods to evaluate water safety, finding a simple, rapid, versatile, and inexpensive method for detection of toxins in everyday items is still a great challenge. In this study, we extend the concept of composites obtained impregnation of porous fibrous materials, such as fabrics and papers, by single walled carbonnanotubes (SWNTs) toward very simple but high-performance biosensors. They utilize the strong dependence of electrical conductivity through nanotubes percolation network on the width of nanotubes-nanotube tunneling gap and can potentially satisfy all the requirements outlined above for the routine toxin monitoring. An antibody to the microcystin-LR (MC-LR), one of the common culprits in mass poisonings, was dispersed together with SWNTs. This dispersion was used to dipcoat the paper rendering it conductive. The change in conductivity of the paper was used to sense the MC-LR in the water rapidly and accurately. The method has the linear detection range up to 10 nmol/L and non-linear detection up to 40 nmol/L. The limit of detection was found to be 0.6 nmol/ L (0.6 ng/mL), which satisfies the strictest World Health Organization standard for MC-LR content in drinking water (1 ng/mL), and is comparable to the detection limit of traditional ELISA method of MC-LR detection, while drastically reducing the time of analysis by more than an order of magnitude, which is one of the major hurdles in practical applications. Similar technology of sensor preparation can also be used for a variety of other rapid environmental sensors.

Non-electronic gas sensors from electrospun mats of liquid crystal core fibres for detecting volatile organic compounds at room temperature

“…Whether the gas sensors are derived from polymers [13], silicon [14], graphene oxide [15], carbon nanomaterials [10], or metal-oxide semiconductors [16], and whether they target the automotive industry [7,8,17,18], food preservation [19,20], wearable technology [21][22][23][24][25] or other fields of high societal importance, they should all fulfil the following basic requirements in order to function optimally: high sensitivity, high selectivity, fast response, low energy consumption and, ideally, low fabrication cost [2,26]. While metal-oxide semiconductor gas sensors are the most common, commercially available and displaying high levels of sensitivity [27][28][29], they operate at high temperatures, may not ensure sufficient selectivity, and the fabrication technique is often complex [2,30].…”

New Trends in Beverage Packaging Systems: A Review

“…A reusable piezoelectric AuNP immunosensor has been also developed to detect the presence of aflatoxin-B17 in contaminated milk samples [82]. In addition, conduction changes which occur when Microcystin-LR, a toxin produced by cyanobacteria, binds to the surface of anti-MCLR-coated single-walled carbon nanotubes are easily detectable in drinking water [83].…”

Nanotechnology Solutions for Global Water Challenges

“…Organophosphate pesticides have been detected using self-assembled layers of acetylcholinesterase immobilized on a CNT modified glassy carbon electrode (153). Single walled CNTs and antibodies have been combined to create a paper based sensor for the detection of microcystin-LR toxin (154). This nanosensor achieved a limit of detection of 0.6 ppb with a response time that was 28 times quicker than that obtained using an enzyme linked immunosorbent assay.…”