Surface Enhanced Raman Spectroscopy (SERS) is a powerful analytical method that can detect trace amounts of substances, such as narcotics, toxins, and explosives. The detection is based on the fact that molecules of different substances interacting with light from a laser will scatter the light differently, providing a unique spectrum that can be used to identify the substance, much like a fingerprint. Researchers have used a microfluidic device to orchestrate the interactions between silver nanoparticles and methamphetamine molecules in saliva. The microfluidic device allows for the controlled introduction of the sample and the nanoparticles, and the subsequent aggregation of the nanoparticles into hot-spot rich clusters that allow us to detect minute amounts of the drug.
Understanding the purpose of the molecular modifiers that annotate DNA strands - called epigenetic markers - and how they change over time will be crucial in understanding biological processes ranging from embryo development to aging and disease. But just how the markers work, and what different markers mean, is painstaking work that still has left a long way to go. Advancing this research field, scientists have now reported the first direct visualization of individual epigenetic modifications in the genome. This is a technical and conceptual breakthrough as it allows not only to quantify the amount of modified bases but also to pin point and map their position in the genome.
Colorimetric sensing techniques require only the naked eye or ordinary visible color photography and are attractive because of their low cost, use of inexpensive equipment, and above all, their simple-to-understand results. Researchers have now developed a plasmonic colorimetric assay to detect mercuric ion based on urine. Compared to other gold-nanoparticle-based colorimetric systems, it showed excellent selectivity to mercury ions and good sensitivity as high as can be used for mercury ion detection in industrial wastewater.
Nanotechnology-enabled, paper-based sensors promise to be simple, portable, disposable, low power-consuming, and inexpensive sensor devices that will find ubiquitous use in medicine, detecting explosives, toxic substances, and environmental studies. Since monitoring needs for environmental, security, and medical purposes are growing fast, the demand for sensors that are low cost, low power-consuming, high sensitivity, and selective detection is increasing as well. Paper has been recognized as a particular class of supporting matrix for accommodating sensing materials. A team of Chinese researchers has now developed low-cost gas sensors by trapping single-walled carbon nanotubes in paper and demonstrated their effectiveness by testing it on ammonia.
Trace detection of explosives generally involves the collection of vapour or particulate samples and analyzing them using a sensitive sensor system. Various factors, such as wide variety of compounds that can be used as explosives, the vast number of deployment means and the lack of inexpensive sensors providing both high sensitivity and selectivity have made trace detection a very complex and costly task. High sensitivity and selectivity, along with the availability of low-cost sensors, is essential to combat explosives-based terrorism. Nanosensors have the potential to satisfy all the requirements for an effective platform for the trace detection of explosives.
Human breath contains a number of volatile organic components (VOCs). An accurate detection of a specific VOC - i.e., a biomarker for a particular disease - in the exhaled breath, can provide useful information for diagnosis of various diseases. The critical advantage of exhaled breath analysis is that it allows for non-invasive disease diagnosis. Researchers have now shown that that a chemiresistive sensor can work as a VOCs sensing device to detect very low concentrations of acetone if the sensing materials have optimized morphology and microstructure.
Conventional electronic tongues utilize pattern recognition for analysis using arrays of synthetic materials such as polymers, artificial membranes and semiconductors, for applications in the food and beverage industries. Even with current technological advances, e-tongue approaches still cannot mimic the biological features of the human tongue with regard to identifying elusive analytes in complex mixtures, such as food and beverage products. But researchers have now developed a human bitter-taste receptor as a nanobioelectronic tongue. They utilized a human taste receptor as a sensing element for mimicking the human taste system and selective detection.
Recent advances in materials, fabrication strategies and device designs for flexible and stretchable electronics and sensors make it possible to envision a not-too-distant future where ultra-thin, flexible circuits based on inorganic semiconductors can be wrapped and attached to any imaginable surface, including body parts and even internal organs. Robotic technologies will also benefit as it becomes possible to fabricate 'electronic skin' that, for instance, could allow surgical robots to interact, in a soft contacting mode, with their surroundings through touch. Researchers have now demonstrated that they can integrate high-quality silicon and other semiconductor devices on thin, stretchable sheets, to make systems that not only match the mechanics of the epidermis, but which take the full three dimensional shapes of the fingertip - and, by extension, other appendages or even internal organs, such as the heart.