Copper is a widely used metal that can leak into the environment through various routes. In low concentrations, copper is an essential nutrient; however, exposure to high levels of copper even for a short period of time can cause gastrointestinal disturbance. Long term exposure causes liver or kidney damage. Most fluorescent sensors for Cu2+ detection give quenched fluorescence, because Cu2+ is a paramagnetic metal ion. These sensors are prone to false positive results because anything that can quench fluorescence could be mistakenly interpreted as Cu2+.
This new sensor can give over 13-fold enhancement in fluorescence in the presence of very low concentrations of Cu2+. Most sensors for Cu2+ detection are based on fluorescent organic molecules that can selectively bind Cu2+. Upon Cu2+ binding, these molecules usually show quenched fluorescence. Although some of these sensors are very sensitive and selective for Cu2+, their practical applications are limited due to their light-down nature. This invention can provide highly sensitive and selective detection of Cu2+ in heavy water. In this invention, Cu2+ recognition and signaling are spatially separated. Therefore, Cu2+ quenching efforts are minimized.
Sensors that can detect mercury with high sensitivity and selectivity are very useful in preventing mercury poisoning as well as understanding its distribution. Most fluorescent sensors for Hg_+ detection need an organic solvent, and have poor sensitivity or selectivity. Based on the fact that Hg_+ can bind in between T-T mismatches in DNA and stabilize the T-T mismatches, while other metals cannot, this sensor has a detection limit of 2.4 nM, which is lower than the EPA limit of Hg_+ in drinking water. The sensor is also very selective and is silent to any other metal ions with up to millimolar concentration levels.
Nanoparticle-based colormetric biosensors allow onsite, real-time qualitative or semi-quantitative detection without complicated analytical instruments. Their applications include environmental testing, industrial process monitoring, biomedical diagnostics and biodefense among others. Few biosensors currently permit simultaneous detection of multiple analytes within a single sample.
This invention allows detection of multiple molecules in the same solution. Quantum dots are fluorescent semiconductor nanocrystals. Quantum dots have an advantage over traditional organic fluorophores because under the same excitation light, difference emission wavelengths can be obtained based on the size and composition of quantum dots.
The emission of quantum dots was quenched in aggregates by incorporating quantum dots into gold nanoparticle aggregates linked by DNA aptamers. The addition of target molecules such as adenosine can disassemble the nanoparticle aggregates and thus increase the distance between gold nanoparticles and quantum dots, resulting in increased emission.
Erin Bauer and coworkers at Illinois State Water Survey have developed a method to modernize the precipitation network gauges and establish a radio network for real-time data transmission at reduced cost. The technology is geared towards collection sites where data service or satellite data service is not available, and instead data collection requires montly field visits. This technology provides an inexpensive solution (less than $300) for long term deployment. It consists of a radio hub that receives data from multiple station radios and software that parses the data, and send to the web client of near real time monitoring.