International commercialization of the fluorescence probe for reactive oxygen species
New fluorescence probe for the detection of reactive oxygen species (ROS) developed by Prof. Tetsuro Majima, Specially-Appointed Assistant Professor Sooyeon Kim, and coworkers, the Institute of Scientific and Industrial Research, Osaka Univ. , was internationally commercialized by Dojindo Molecular Technologies, Inc. since 29th Feb. 2016.
In 2014, Prof. T. Majima and coworkers have reported a fluorescence probe, named “Si-DMA”, which can visualize intracellular singlet oxygen, one of the ROS (Research activities in 2014). Since the generation of singlet oxygen is the most initial and crucial step that decide therapeutic efficacy of the PDT, the fluorescence probe to visualize singlet oxygen during the procedure of PDT has been urgently requested. Si-DMA is composed of silicon-containing rhodamine and dimethylanthracene moieties, which are a red-fluorescent dye and reactive site of singlet oxygen, respectively. Because of its intrinsic chemical structure, Si-DMA could successfully detect extra- and intra-cellular singlet oxygen.
After its report in Journal of American Chemical Society (J. Am. Chem. Soc. 2014, 136(33), 11707.) and domestic/international patent application (23rd Dec. 2015, WO2015194606, A1), Si-DMA has attracted considerable attentions from researchers and practitioners in academic and industrial researches. In 2015, Dojindo Laboratories succeeded in reproducing chemical synthesis of Si-DMA and detecting singlet oxygen with the aid of advice of Majima laboratory, accelerating commercialization of Si-DMA. Finally, Dojindo Molecular Technologies, Inc. has started to sell Si-DMA with the title, “Si-DMA for Mitochondria Singlet Oxygen Imaging” (2 μg / $200.00).
Single-molecule Electrical Sequencing Technologies of DNA, RNA, and Peptide
Single-molecule electrical sequencing technologies can determine sequences of base molecules in DNA by measuring single-molecule conductance and are expected to revolutionize personalized medicine and therapeutics and result in improved crops on the basis of genomic information. Competition in the development of sequencing technologies is intensifying because these technologies are expected to open new sciences and vast new markets. Thus far, Taniguchi Laboratory has demonstrated single-molecule electrical sequencing technologies for DNA, RNA, and peptides and has been leading the competition in global development. At this turning point from empirical studies to application studies, we have published an article that reviews, from both theoretical and experimental viewpoints, the current status of single-molecule sequencing science and technologies and the issues facing their practical use.
This manuscript appeared in Nature Nanotechnology, which is published by Nature Publishing Group, on February 3, 2016. This study is part of an international joint research effort between the Department of Bio-nanotechnology and Prof. Di Ventra at the University of California, San Diego. This research has been supported by a Grant-in-Aid for Scientific Research(S), Research Project Number 26220603.
Producing spin-entangled electrons
*This study has been conducted by Riken in collaboration with Prof. Oiwa (ISIR), Assis. Prof. Kanai (ISIR) and other researchers.
*This article is sourced by permission of RIKEN.
A team from the RIKEN Center for Emergent Matter Science, along with collaborators from several Japanese institutions, have successfully produced pairs of spin-entangled electrons and demonstrated, for the first time, that these electrons remain entangled even when they are separated from one another on a chip. This research could contribute to the creation of futuristic quantum networks operating using quantum teleportation, which could allow information contained in quantum bits—qubits—to be shared between many elements on chip, a key requirement to scale up the power of a quantum computer. The ability to create non-local entangled electron pairs—known as Einstein-Podolsky-Rosen pairs—on demand has long been a dream.
Russell Deacon, who carried out the work, says, “We set out to demonstrate that spin-entangled electrons could be reliably produced. So far, researchers have been successful in creating entangled photons, since photons are extremely stable and do not interact. Electrons, by contrast, are profoundly affected by their environment. We chose to try to show that electrons can be entangled through their spin, a property that is relatively stable.”
To perform the feat, Deacon and his collaborators began the painstaking work of creating a tiny device, just a few hundred nanometers in size. The idea was to take a Cooper pair—a pair of electrons that allows electricity to flow freely in superconductors—and get them, while tunneling—a quantum phenomenon—across a junction between two superconductor leads, to pass through two separate “quantum dots”—small crystals that have quantum properties. “If we could detect a superconducting current,” Deacon continues, “this would mean that the electrons, which can be used as quantum bits—the qubits, or bits used in quantum computing—remain entangled even when they have been separated between the quantum dots. We confirm this separation by measuring a superconducting current that develops when they split and are recombined in the second lead.”
The quantum dots, each around 100 nanometers in size, were grown at random positions on a semiconductor chip. This chip was painstakingly examined using an atomic force microscope to discover pairs of dots that were close enough that they might function properly. “We observed thousands of dots and identified around a hundred that were suitable. From these we made around twenty devices. Of those just two worked.”
By measuring the superconducting current, the team was able to show clearly that the spin of the electrons remained entangled as they passed through the separate quantum dots. “Since we have demonstrated that the electrons remain entangled even when separated,” says Deacon, “this means that we could now use a similar, albeit more complex, device to prepare entangled electron pairs to teleport qubit states across a chip.”
According to Seigo Tarucha, leader of the laboratory that conducted the work, “This discovery is very exciting, as it could lead eventually to the development of applications such as quantum networks and quantum teleportation. Though it is technically difficult to handle, electron spin is a very promising property for these applications, as it is relatively free from the environment and lasts comparatively long. It could be combined with photons, by using the spin-entangled electrons to create photons that themselves would be entangled. This could allow us to create large networks to share quantum information in a widely distributed way.”
The work, published in Nature Communications, was done by RIKEN in collaboration with the University of Tokyo, University of Osaka, and was funded by JST and DFG.
False color scanning electron microscope image of the device
The two green spots are the quantum dots located in the gap between the two (red) electrodes.
Schematic of the device