2021, Ta, Huy Q., Mendes, Rafael G., Liu, Yu, Yang, Xiaoqin, Luo, Jingping, Bachmatiuk, Alicja, Gemming, Thomas, Zeng, Mengqi, Fu, Lei, Liu, Lijun, Rümmeli, Mark H.

In recent years, two-dimensional (2D) materials have attracted a lot of research interest as they exhibit several fascinating properties. However, outside of 2D materials derived from van der Waals layered bulk materials only a few other such materials are realized, and it remains difficult to confirm their 2D freestanding structure. Despite that, many metals are predicted to exist as 2D systems. In this review, the authors summarize the recent progress made in the synthesis and characterization of these 2D metals, so called metallenes, and their oxide forms, metallene oxides as free standing 2D structures formed in situ through the use of transmission electron microscopy (TEM) and scanning TEM (STEM) to synthesize these materials. Two primary approaches for forming freestanding monoatomic metallic membranes are identified. In the first, graphene pores as a means to suspend the metallene or metallene oxide and in the second, electron-beam sputtering for the selective etching of metal alloys or thick complex initial materials is employed to obtain freestanding single-atom-thick 2D metal. The data show a growing number of 2D metals/metallenes and 2D metal/ metallene oxides having been confirmed and point to a bright future for further discoveries of these 2D materials.

2021, Rivkin, Boris, Becker, Christian, Singh, Balram, Aziz, Azaam, Akbar, Farzin, Egunov, Aleksandr, Karnaushenko, Dmitriy D, Naumann, Ronald, Schäfer, Rudolf, Medina-Sánchez, Mariana, Karnaushenko, Daniil, Schmidt, Oliver G

Existing electronically integrated catheters rely on the manual assembly of separate components to integrate sensing and actuation capabilities. This strongly impedes their miniaturization and further integration. Here, we report an electronically integrated self-assembled microcatheter. Electronic components for sensing and actuation are embedded into the catheter wall through the self-assembly of photolithographically processed polymer thin films. With a diameter of only about 0.1 mm, the catheter integrates actuated digits for manipulation and a magnetic sensor for navigation and is capable of targeted delivery of liquids. Fundamental functionalities are demonstrated and evaluated with artificial model environments and ex vivo tissue. Using the integrated magnetic sensor, we develop a strategy for the magnetic tracking of medical tools that facilitates basic navigation with a high resolution below 0.1 mm. These highly flexible and microsized integrated catheters might expand the boundary of minimally invasive surgery and lead to new biomedical applications. Copyright © 2021 The Authors, some rights reserved.

2021, Li, Linyang, Lu, Fangyun, Xiong, Wenqi, Ding, Yu, Lu, Yangyi, Xiao, Yao, Tong, Xin, Wang, Yao, Jia, Shuangfeng, Wang, Jianbo, Mendes, Rafael G., Rümmeli, Mark H., Yuan, Shengjun, Zeng, Mengqi, Fu, Lei

Two-dimensional (2D) rare-earth oxides (REOs) are a large family of materials with various intriguing applications and precise facet control is essential for investigating new properties in the 2D limit. However, a bottleneck remains with regard to obtaining their 2D single crystals with specific facets because of the intrinsic non-layered structure and disparate thermodynamic stability of different facets. Herein, for the first time, we achieve the synthesis of a wide variety of high-quality 2D REO single crystals with tailorable facets via designing a hard-soft-acid-base couple for controlling the 2D nucleation of the predetermined facets and adjusting the growth mode and direction of crystals. Also, the facet-related magnetic properties of 2D REO single crystals were revealed. Our approach provides a foundation for further exploring other facet-dependent properties and various applications of 2D REO, as well as inspiration for the precise growth of other non-layered 2D materials.

2021, Kiontke, Andreas, Roudini, Mehrzad, Billig, Susan, Fakhfouri, Armaghan, Winkler, Andreas, Birkemeyer, Claudia

Mass spectrometry coupled to low-temperature plasma ionization (LTPI) allows for immediate and easy analysis of compounds from the surface of a sample at ambient conditions. The efficiency of this process, however, strongly depends on the successful desorption of the analyte from the surface to the gas phase. Whilst conventional sample heating can improve analyte desorption, heating is not desirable with respect to the stability of thermally labile analytes. In this study using aromatic amines as model compounds, we demonstrate that (1) surface acoustic wave nebulization (SAWN) can significantly improve compound desorption for LTPI without heating the sample. Furthermore, (2) SAWN-assisted LTPI shows a response enhancement up to a factor of 8 for polar compounds such as aminophenols and phenylenediamines suggesting a paradigm shift in the ionization mechanism. Additional assets of the new technique demonstrated here are (3) a reduced analyte selectivity (the interquartile range of the response decreased by a factor of 7)—a significant benefit in non-targeted analysis of complex samples—and (4) the possibility for automated online monitoring using an autosampler. Finally, (5) the small size of the microfluidic SAWN-chip enables the implementation of the method into miniaturized, mobile LTPI probes.

2021, Nikitin, S.E., Nishimoto, S., Fan, Y., Wu, J., Wu, L.S., Sukhanov, A.S., Brando, M., Pavlovskii, N.S., Xu, J., Vasylechko, L., Yu, R., Podlesnyak, A.

[No abstract available]

2021, Kiontke, Andreas, Roudini, Mehrzad, Billig, Susan, Fakhfouri, Armaghan, Winkler, Andreas, Birkemeyer, Claudia

Correction to: Scientific Reports https://doi.org/10.1038/s41598-021-82423-w, published online 03 February 2021