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.
Researchers have developed a magnetic bead based sensor that combines magnetic separation (MS) and magnetic relaxation switch (MRS) for one-step detection of bacteria and viruses with high sensitivity and reproducibility. Compared to conventional assays for detection of bacteria and viruses, this novel MS-MRS assay is easy to operate without laborious pre-treatment, purification and can be adaptable to point-of-care tests easily.
So far, there have been very few research reports on single electrode materials that enable the simultaneous detection of different metabolites - such as glucose, urea, cholesterol, and triglycerides - in whole blood. Moreover, it is a considerable challenge to integrate all required materials and devices on a single chip to ultimately produce a multiplexing biosensor array. In new work, researchers demonstrate that biosensors based on conducting polymer hydrogels enable the precise and full-range detection of different metabolites in human blood.
As a prime example of how the integration of multiple disparate nanotechnology fields allows the realization of novel or expanded functionalities, researchers have demonstrated a multimodal sensing device which integrates the functionalities of three traditional single mode sensors. Specifically, the team fabricated a graphene-based multimodal biosensing device, capable of transducing protein binding events into optical, electrical, and mechanical signals.
The nanotechnology-enabled detection of a change in individual cells, for instance cell surface charge, presents a new alternative and complementary method for disease detection and diagnosis. Since diseased cells, such as cancer cells, frequently carry information that distinguishes them from normal cells, accurate probing of these cells is critical for early detection of a disease. For this purpose, researchers have now designed a graphene-based optical refractive index sensor.