NanoAffix has exclusive access to an electronic sensing platform that can be used for the detection of various contaminants in water, such as heavy metal ions, bacteria, and nutrients.

Sensing platform based on rGO-Au NP structures.

The sensor is based on a field-effect transistor (FET) device with reduced graphene oxide (rGO) as the sensing channel and specific molecules attached to gold nanoparticles (Au NPs) as probes. The working principle of the sensor is that the rGO conductivity (usually measured in resistance) changes with the binding of chemicals/analytes to probes anchored on the Au NP surfaces, e.g., through chelate reactions with heavy metal ions. Therefore, the presence of the chemicals can be determined by measuring the sensor resistance change. Preliminary results have shown that the sensors can detect Pb2+ ions as low as 0.2 ppb, well below the maximum contaminant level (MCL) defined by the EPA for Pb2+ (15 ppb). Most importantly, the platform responds to Pb2+ in seconds, promising for real-time monitoring of water quality.

The rGO-Au NP-based sensing system has advantages of reliable probe immobilization, simple device structure, and rapid, sensitive, selective, label-free detection. This breakthrough technology allows real-time detection (no sample preparation) of poisonous contaminants with unprecedented sensitivity and specificity in field settings (outside a laboratory facility) for single point testing (e.g., handheld device) as well as for continuous monitoring (e.g., integrated into existing water equipment).

Graphene is an atomic-scale honeycomb lattice made of carbon atoms.

Graphene, a single layer of carbon atoms packed into a two-dimensional honeycomb lattice, is a promising electronic nanomaterial due to its unique structure and electronic properties. Intrinsic graphene is a zero-gap semiconductor that has remarkably high electron mobility (100 times greater than that of silicon), making it attractive for sensitive, high-speed chemical/biological sensors due to its high sensitivity to electronic perturbations.

In addition, due to its large specific surface area (2,630 m2·g-1), graphene is an ideal substrate for high density loading of target chemical probes, which promises both a low detection limit and a broad detection range for the sensor. Graphene can be obtained through various physical and chemical routes. A potential method to cost-effectively mass produce graphene-based devices is to first produce GO and then reduce it to obtain rGO for device applications