The concept of e-noses - electronic devices which mimic the olfactory systems of mammals and insects - is well developed and has become a booming area of research thanks to a better understanding of the reception, signal transduction and odor recognition mechanisms for mammals, combined with achievements in material science, microelectronics and computer science. Researchers have now started replacing the sensing elements in e-noses with nanowires, achieving excellent sensing performance which is comparable or even better compared to the best thin film counterparts.
The oxidation-assisted temperature measurement with carbon nanotube nanothermometers that contain liquid gallium is a novel and reliable method that can be used over a moderate temperature range and can be applied in any environment where air is present. All the other available techniques that are capable to measure temperature at the nanometer scale are limited by either that they are only workable in a very narrow temperature range or that they can only be applied in a special environment.
Nanoscale sensors based on silicon nanowires and carbon nanotubes are capable of detecting molecules at ultra low concentrations. The potential applications include early detection of cancer and fast sequencing of genome. However, for these applications, the time taken by the sensor to reach stable response is crucial. This time is dictated by the diffusion of molecules (e.g. cancer markers) through the solution and their subsequent capture at the sensor surface. Researchers at Purdue University show that this response is governed by the geometry of diffusion of the system and that nanobiosensors are capable of detecting bio-molecules at much lower concentration than the classical planar sensors.
New research shows that ZnO nanostructures are suitable for electrochemical biosensors. The enzyme used for glucose detection, glucose oxidase, was attached to ZnO nanocombs which resulted in a biosensor that exhibits a high affinity, high sensitivity, and fast response for glucose detection. This simple method of fabricating ZnO based biosensor can be extended to immobilize other enzymes and other bioactive molecules on various 1D metal oxide nanostructures, and form versatile electrodes for biosensor studies.
Researchers in Germany report a novel approach for the design of environmental sensors based on fluorescence interference contrast (FLIC) of semiconductor nanocrystals near a reflecting silicon surface. Their method is based on nanocrystals incorporated into polymer layers grafted onto reflecting surfaces.
Researchers took inspiration from the packaging and transduction processes of the cochlea and cilia in the inner ear to design acoustic sensors made from nanowires. Specifically, they used nanowires of magnetostrictive materials as artificial cilia to sense acoustic signals. Any acoustic sensor application may benefit from this work.
The sensitivity of solid-state gas sensors can be improved if the surface-to-volume ratio of the material used for the sensor is increased. An international group of researchers demonstrated that three-dimensional tungsten oxide nanowire networks can serve as a high-surface area material for building ultrasensitive and highly selective gas sensors. The results highlight that the 3-D nanowires technology can be adopted for the development of gas sensors with performances suitable for practical applications.
A new approach promotes the use of zinc oxide nanomaterials as signal enhancing platforms for rapid, multiplexed, high-throughput, highly sensitive, DNA sensor arrays. Engineered nanoscale ZnO structures can be effectively used for the identification of the biothreat agent, Bacillus anthracis, by successfully discriminating its DNA sequence from other genetically related species.