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Tag: NUST MISIS

Scientists get photons to interact, taking step towards long-living quantum memory

Posted on by Lyudmila Dozhdikova

An international research team obtained experimental evidence for effective interaction between microwave photons via superconductive qubits for the first time. The study, published in npj Quantum Materials, maybe a step towards the implementation of a long-living quantum memory and the development of commercial quantum devices.

Scientists believe that individual light particles, or photons, are ideally suited for sending quantum information. Encoded with quantum data, they could literally transfer information at the speed of light. However, while photons would make for great carriers because of their speed, they don’t like to interact with each other, making it difficult to achieve quantum entanglement.

A team of scientists from NUST MISIS, Russian Quantum Center, the Ioffe Institute St. Petersburg and Karlsruhe Institute of Technology, for the first time, made photons interact with each other effectively using an array of superconducting qubits and a waveguide. In their experiments, the researchers used photons with the frequency of a few GHz and the wavelength of a few centimeters.

“We used superconducting cubits, which are basically artificial atoms, because they have been proven to strongly interact with light. Interaction between natural atoms and natural light is weak due to the small size of natural atoms. Superconducting cubits are man-built, their size can reach up to 0.1mm, which makes it possible to significantly increase their dipole moment and polarity, engineering strong interaction between light and matter,” noted Prof. Alexey Ustinov, Head of the Laboratory for Superconducting Metamaterials at NUST MISIS and Group Head at Russian Quantum Center, who co-authored the study.

Superconducting qubits are a leading qubit modality today that is currently being pursued by industry and academia for quantum computing applications. However, they require milli-Kelvin (mK) temperatures to operate. The most powerful of the existing superconducting quantum devices contains under 100 qubits.

As you add qubits, the number of operations a quantum computer can perform grows exponentially, but the maximum number of qubits that can be integrated in a quantum computer is limited by the size of refrigerators used to cool them down to operational temperatures. Taking this into account, the efforts of the scientific community have been recently focused on increasing the processing power of a quantum computer by transmitting quantum signals from one refrigerator to another.

To engineer this transmission, the scientists coupled an array of eight superconducting transmon qubits to a common waveguide — a structure that guides waves, e.g. light waves.

“By employing dedicated flux-bias lines for each qubit, we establish control over their transition frequencies. It was derived and experimentally verified that multiple qubits obtain an infinite range photon mediated effective interaction, which can be tuned with the inter-qubit distance,” says Alexey Ustinov.

The circuit of this work extends experiments with one and two qubits toward a full-blown quantum metamaterial, thus paving the way for large-scale applications in superconducting waveguide quantum electrodynamics.

Scientists improve contrast in noninvasive imaging of cancer cells

Posted on by Lyudmila Dozhdikova

A Russian-German research team has come up with a new technique for magnetic resonance imaging of cancer cells. The study, published in Pharmaceutics, shows that heterologous expression of encapsulin systems from Quasibacillus thermotolerans with functional cargo proteins and iron transporter leads to increased contrast in MRI imaging of mammalian tumor cells.

Many advances in cancer treatment would come from a better understanding of tumor biology, particularly the elucidation of carcinogenesis mechanisms.

Currently, the primary method of live-cell imaging is direct labeling of cells with a probe or contrast agent before transplantation. However, any synthetic contrast agent for cell labeling has a critical drawback—it dilutes as the cells divide, which leads to loss of the signal after several cycles of divisions. In contrast, genetically encoded reporters propagate to daughter cells with each cell division. Moreover, because genetically encoded reporters rely on essential cellular processes, their signal is selective for viable cells.

The most commonly studied genetically encoded labels use an optical signal generated by either bioluminescent or fluorescent reporter protein. Although these methods have very high sensitivity, their use is limited by light scattering in biological tissues.

MRI has the advantage of deep tissue penetration with relatively high spatial resolution. Ferritin, a blood protein that contains iron, is the most studied genetically encoded agent so far. Nevertheless, ferritin’s MRI performance is severely limited by its weak magnetic properties and highly conservative structure. The latter excludes significant improvement in ferritin relaxivity by bioengineering.

“One of the most promising approaches is based on the heterologous expression of bacterial protein nanocompartments—encapsulins— in mammalian cells. Encapsulins, which are bacterial protein nanocompartments, can serve as genetically controlled labels for multimodal detection of cells. Such nanocompartments can host various guest molecules inside their lumen,” says Maxim Abakumov, head of the NUST MISIS Biomedical Nanomaterials Laboratory, senior researcher at the Medicinal Nanobiotechnology Department, N.I. Pirogov Russian National Research Medical University.

“These include, for example, fluorescent proteins or enzymes with ferroxidase activity leading to biomineralization of iron oxide inside the encapsulin nanoshell. Besides, these reporters do not suffer from dilution during cell division.”

In their experiments, a team of scientists from NUST MISIS, V. Serbsky National Medical, N.I. Pirogov Russian National Research Medical University, Technical University of Munich, Helmholtz Center Munich have implemented, for the first time, heterologous expression of encapsulin systems from Quasibacillus thermotolerans using a fluorescent reporter protein and ferroxidase in human hepatocellular carcinoma cells.

Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype, as the final effect. The researchers loaded the nanoshell with the natural ferroxidase cargo from Q. thermotolerans and a synthetic fluorescent cargo protein derived from mScarlet-I.

The successful expression of self-assembled encapsulin nano compartments with functional cargo proteins was then confirmed by fluorescence microscopy and transmission electron microscopy. Also, coexpression of encapsulin nanoshells, ferroxidase cargo, and iron transporter led to an increase in contrast in magnetic resonance imaging of cancer cells. The encapsulin cargo system from Q. thermotolerans may be suitable for multimodal imaging of cancer cells, the researhers believe.