Metal-breathing bacteria could transform electronics, biosensors, and more

Science Daily  July 28, 2020 Some bacteria that are adapted to specific geochemical or biochemical environments can create interesting and novel materials. Researchers at the Rensselaer Polytechnic Institute synthesised molybdenum disulfide nanomaterials at the site of S. oneidensis biofilms grown in the presence of molybdenum trioxide and sodium thiosulfate. Analysis revealed the presence of molybdenum disulfide nanoparticle aggregates 50–300 nm in diameter with both hexagonal and rhombohedral polytypes. The use of S. oneidensis offers the advantage of significantly reduced heat and chemical solvent input compared to conventional methods of synthesizing molybdenum disulfide nanoparticles. The process can be used for the generation […]

Liquid crystals create easy-to-read, color-changing sensors

Nanowerk  July 11, 2020 Inspired by the ability of chameleons to change color by using temperature to direct the skin tissue that contains nanocrystals reflecting light, to expand or contract, an international team of researchers (USA – University of Chicago, University of South Carolina, University of North Texas, Cornell University, Argonne National Laboratory, Mexico, Turkey, Colombia) has developed a way to stretch and strain liquid crystals to generate different colors. They dispersed chiral droplets in polymer films and deformed it by inducing uniaxial or biaxial stretching. Their measurements are interpreted by resorting to simulations of the corresponding systems, thereby providing […]

‘Nanometrology lab on a chip’ within reach thanks to new compact, optical sensor

Nanowerk  May 20, 2020 On-chip compact and integrated optical motion sensing micro- and nano-optomechanical platforms that typically exploit narrow spectral resonances require tunable lasers with narrow linewidth and low spectral noise, which makes the integration of the read-out extremely challenging. Researchers in the Netherlands report a step towards the practical application of nanomechanical sensors, by presenting a sensor with ultrawide (∼80 nm) optical bandwidth. It is based on a nanomechanical, three-dimensional directional coupler with integrated dual-channel waveguide photodiodes and displays small displacement imprecision as well as large dynamic range (>30 nm). The broad optical bandwidth releases the need for a tunable laser […]

Catching nuclear smugglers: Fast algorithm could enable cost-effective detectors at borders

EurekAlert  April 30, 2020 An international team of researchers (USA – University of Michigan, University of Illinois, Los Alamos National Laboratory, UK) developed an algorithm capable of identifying weak radiation signals, such as might be seen from plutonium encased materials that absorb radiation. It works even in the presence of a high radiation background, including everyday sources such as cosmic rays from space and radon from the rock underfoot. Based on their results, they believe the use of their algorithm could improve the ability of radiation portal monitors at national borders to tell the difference between potential smuggling activity and […]

Broad spectrum: Novel hybrid material proves an efficient photodetector  April 9, 2020 The MOF compound developed by researchers in Germany comprises an organic material integrated with iron ions. The MOF forms superimposed layers with semiconducting properties, which makes it potentially interesting for optoelectronic applications. They found that the light sensitivity was dependent on temperature and wavelength from 400 to 1,575 nanometers. The spectrum of radiation goes from ultraviolet to near infrared. As the bandgap in the material is very small, only very little light energy is required to induce the electricity. The performance of the detector can be improved by cooling the detector down to lower temperatures and […]

Graphene underpins a new platform to selectively ID deadly strains of bacteria  March 24, 2020 Point-of-care diagnostics that can reduce and/or prevent unneeded antibiotic prescriptions require highly specific probes with sensitive and accurate transducers that can be miniaturized and multiplexed, and that are easy to operate and cheap. Researchers at Boston College present several advances in the use of graphene field effect transistors (G-FET) including the first use of peptide probes to electrically detect antibiotic resistant bacteria in a highly specific manner. They have reduced the needed concentration for detection by employing dielectrophoresis which allows monitoring changes in the Dirac point due to individual bacterial cells. Rapid binding of bacterial cells […]

Atomic fingerprint identifies emission sources of uranium

Science Daily  March 9, 2020 Isotopic ratios of radioactive releases into the environment are useful signatures for contamination source assessment. A ratio of uranium trace isotopes may serve as a superior oceanographic tracer. An international team of researchers (Austria, Australia, Denmark, Japan, Germany) analysed ratio on the atomic 233U/236U ratio analyzed in representative environmental samples. The ratios detected in compartments of the environment affected by releases of nuclear power production or by weapons fallout differ by one order of magnitude. Significant amounts of 233U were only released in nuclear weapons fallout. This makes the 233U/236U ratio a promising new fingerprint […]

A new AI chip can perform image recognition tasks in nanoseconds

MIT Technology Review  March 4, 2020 Visual information is captured by a frame-based camera, converted into a digital format and processed afterwards using a machine-learning algorithm such as an artificial neural network (ANN). The large amount of data passed through the entire signal chain, however, results in low frame rates and high-power consumption. Researchers in Austria built a sensor based on a reconfigurable two-dimensional semiconductor photodiode array, and the synaptic weights of the network are stored in a continuously tunable photoresponsivity matrix. The sensor can itself constitute an ANN that can simultaneously sense and process optical images without latency. They […]

Highly sensitive sensors show promise in enhancing human touch

Nanowerk  February 18, 2020 People rely on a highly tuned sense of touch to manipulate objects, but injuries to the skin and the simple act of wearing gloves can impair this ability. Researchers in China have developed a visually aided tactile enhancement system for precise motion control by combining ultrathin, highly sensitive, crack-based strain sensors and signal acquisition circuit with real-time display equipment. With the optimization of the thicknesses of the substrates and sensitive films of the strain sensors, the device has a detection limit as low as 0.01% and an ultrahigh gauge factor of 44 013 at a strain of […]

A spookily good sensor  February 19, 2020 Researchers in Japan placed a millimeter-sized sphere of yttrium iron garnet in the same resonant cavity as a superconducting Josephson junction qubit, which acted as the sensor. Because of the coupling of the sphere to resonant cavity, and, in turn, between the cavity to the qubit, the qubit could only be excited by an electromagnetic pulse if no magnetic excitations were present in the sphere. Reading the state of the qubit then reveals the state of the sphere. By using single-shot detection instead of averaging, they were able to make the device both highly sensitive and […]