The development of nanoscale devices and applications requires ultra-sensitive sensing systems that can offer not only atomic resolution imaging but also sub nanometer scale displacement detection, zeptogram level mass sensing, or single bio-molecular sensing. Researchers have now developed a novel sensor that addresses some of the shortcomings that have plagued existing optical scanning systems , namely size, complexity, and cost. This sensing technology is completely electrical and capable of sensing very small displacement as low as in the femtometer range.
To overcome the pixel size limitation of existing digital image sensors, both new materials with enormous photoelectric properties and novel device architectures are required. In new work, researchers are now reporting ultra-high resolution nanorod digital image sensor (NDIS) which is fabricated by sandwiching vertically aligned zinc oxide nanorod arrays between orthogonal top and bottom nanostripe electrodes. The most important application of the NDIS is as a next-generation digital image sensor with ultra-high resolution, well beyond the limit of existing techniques.
With increasing sensitivity, electrical, mechanical and optical sensors are able to detect low molecular weight chemical and biological analytes under ever more dilute conditions. At the same time, though, researchers want to keep the sensing process as simple as possible without complex functionalization and complicated preparation steps for the in situ detection. A novel graphene-gold metasurface-based biosensing architectures makes extreme phase singularities possible due to a strong field enhancement on the graphene-gold interface.
A typical preliminary test for tuberculosis includes culturing the samples for at least 1-2 weeks in a lab, followed by examination under a fluorescence microscope. The lack of rapid, accurate, and inexpensive point-of-care tools for detecting low amounts of M. Tuberculosis is a critical bottleneck in early diagnosis and appropriate treatment. Researchers have now developed a rapid and flexible nano-biosensor for diagnosing TB in early stages using smart phones.
Among others, a significant area for nanopaper applications are sensors. 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. New work describes various nanopaper-based nanocomposites that exhibit plasmonic or photoluminescent properties that can be modulated using different reagents. These can be used for simple, disposable and versatile sensing platforms.
Magnetic field sensors are in very high demand for precise measurements of position, proximity and motion. The most commonly used Hall Effect devices are fabricated with silicon. The sensitivities of these sensors - voltage and current - depend on the device materials electronic properties such as charge carrier mobility and density. However, for futuristic advanced applications higher sensitivity Hall sensors are required than can be achieved with silicon. Researchers now have set a new world record for the sensitivity of Hall sensors using highest quality graphene encapsulated in hexagonal boron nitride.
Presently, several techniques for detecting mRNAs are available,which include in situ hybridization and polymerase chain reaction. However, these single-point and end-point techniques require the killing of the cells and are thus unable to capture the expression of mRNA in real time and locality with high precision. In new work, scientists describe a new way of preparing functional DNA nanostructures that can provide accurate quantification and visualization of mRNA transcripts in living cells.
While the actual toxicity of Bisphenol A (BPA) is still debated, the direct measurement of BPA is difficult because of the weak response given by conventional electrochemical sensors, and current optical analysis methods are susceptible to the influence of interfering substances. A novel aptamer/graphene oxide FRET biosensor now provides a method for the rapid detection and risk assessment of BPA with high sensitivity and selectivity.