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- ItemInfluence of core size and capping ligand of gold nanoparticles on the desorption/ionization efficiency of small biomolecules in AP‐SALDI‐MS(Hoboke, NJ : Wiley, 2020) Liu, Zhen; Zhang, Peng; Pyttlik, Andrea; Kraus, Tobias; Volmer, Dietrich A.Gold nanoparticles (AuNP) are frequently used in surface‐assisted laser desorption/ionization mass spectrometry (SALDI‐MS) for analysis of biomolecules because they exhibit suitable thermal and chemical properties as well as strong surface plasmonic effects. Moreover, the structures of AuNP can be controlled by well‐established synthesis protocols. This was important in the present work, which studied the influence of the nanoparticles’ structures on atmospheric pressure (AP)‐SALDI‐MS performance. A series of AuNP with different core sizes and capping ligands were investigated, to examine the desorption/ionization efficiency (DIE) under AP‐SALDI conditions. The results showed that both the AuNP core size as well as the nature of the surface ligand had a strong influence on DIE. DIE increased with the size of the AuNP and the hydrophobicity of the ligands. Chemical interactions between ligand and analytes also influenced DIE. Moreover, we discovered that removing the organic ligands from the deposited AuNP substrate layer by simple laser irradiation prior to LDI further amplified DIE values. The optimized AuNP were successfully used to analyze a wide arrange of different low molecular weight biomolecules as well as a crude pig brain extract, which readily demonstrated the ability of the technique to detect a wide range of lipid species within highly complex samples.
- ItemA Rotating Spiral Micromotor for Noninvasive Zygote Transfer(Hoboke, NJ : Wiley, 2020) Schwarz, Lukas; Karnaushenko, Dmitriy D.; Hebenstreit, Franziska; Naumann, Ronald; Schmidt, Oliver G.; Medina-Sánchez, MarianaEmbryo transfer (ET) is a decisive step in the in vitro fertilization process. In most cases, the embryo is transferred to the uterus after several days of in vitro culture. Although studies have identified the beneficial effects of ET on proper embryo development in the earlier stages, this strategy is compromised by the necessity to transfer early embryos (zygotes) back to the fallopian tube instead of the uterus, which requires a more invasive, laparoscopic procedure, termed zygote intrafallopian transfer (ZIFT). Magnetic micromotors offer the possibility to mitigate such surgical interventions, as they have the potential to transport and deliver cellular cargo such as zygotes through the uterus and fallopian tube noninvasively, actuated by an externally applied rotating magnetic field. This study presents the capture, transport, and release of bovine and murine zygotes using two types of magnetic micropropellers, helix and spiral. Although helices represent an established micromotor architecture, spirals surpass them in terms of motion performance and with their ability to reliably capture and secure the cargo during both motion and transfer between different environments. Herein, this is demonstrated with murine oocytes/zygotes as the cargo; this is the first step toward the application of noninvasive, magnetic micromotor‐assisted ZIFT.
- ItemPhotoinduced Strain‐Assisted Synthesis of a Stiff‐Stilbene Polymer by Ring‐Opening Metathesis Polymerization(Hoboke, NJ : Wiley, 2020) Krishnan, Baiju P.; Xue, Lulu; Xiong, Xinhong; Cui, JiaxiDeveloping a novel strategy to synthesize photoresponsive polymers is of significance owing to their potential applications. We report a photoinduced strain‐assisted synthesis of main‐chain stiff‐stilbene polymers by using ring‐opening metathesis polymerization (ROMP), activating a macrocyclic π‐bond connected to a stiff‐stilbene photoswitch through a linker. Since the linker acts as an external constraint, the photoisomerization to the E‐form leads to the stiff‐stilbene being strained and thus reactive to ROMP. The photoisomerization of Z‐form to E‐form was investigated using time‐dependent NMR studies and UV/Vis spectroscopy. The DFT calculation showed that the E‐form was less stable due to a lack of planarity. By the internal strain developed due to the linker constraint through photoisomerization, the E‐form underwent ROMP by a second generation Grubbs catalyst. In contrast, Z‐form did not undergo polymerization under similar conditions. The MALDI‐TOF spectrum of E‐form after polymerization showed the presence of oligomers of >5.2 kDa.
- ItemSteering Directional Light Emission and Mode Chirality through Postshaping of Cavity Geometry(Hoboke, NJ : Wiley, 2020) Wang, Jiawei; Tang, Min; Yang, Yue-De; Yin, Yin; Chen, Yan; Saggau, Christian Niclaas; Zhu, Minshen; Yuan, Xiaobo; Karnaushenko, Dmitriy; Huang, Yong-Zhen; Ma, Libo; Schmidt, Oliver G.Dielectric optical microcavities have been explored as an excellent platform to manipulate the light flow and investigate non‐Hermitian physics in open optical systems. For whispering gallery mode optical microcavities, modifying the rotational symmetry is highly desirable for intriguing phenomena such as degenerated chiral modes and directional light emission. However, for the state‐of‐the‐art approaches, namely deforming the cavity geometry by precision lithography or introducing local scatterers near the cavity boundary via micromanipulation, there is a lack of flexibility in fine‐adjusting of chiral symmetry and far‐field emission direction. Here, precise engineering of cavity boundary using electron‐beam‐induced deposition is reported based on rolled‐up nanomembrane‐enabled spiral‐shaped microcavities. The deformation of outer boundary results in delicate tailoring of asymmetric backscattering between the outer and inner rolling edges, and hence deterministically strong mode chirality. Besides, the crescent‐shaped high‐index nanocap leads to modified light tunneling channels and inflected far‐field emission angle. It is envisioned that such a localized deposition‐assisted technique for adjusting the structural deformation of 3D optical microcavities will be highly useful for understanding rich insights in non‐Hermitian photonics and unfolding exotic properties on lasing, sensing, and cavity quantum electrodynamics.
- ItemPhosphorus‐Based Composites as Anode Materials for Advanced Alkali Metal Ion Batteries(Hoboke, NJ : Wiley, 2020) Zhou, Junhua; Shi, Qitao; Ullah, Sami; Yang, Xiaoqin; Bachmatiuk, Alicja; Yang, Ruizhi; Rummeli, Mark H.Alkaline metal ion batteries, such as lithium‐ion batteries have been increasingly adopted in consumer electronics, electric vehicles, and large power grids because of their high energy density, power density and working voltage, and long cycle life. Phosphorus‐based materials including phosphorus anodes and metal phosphides with high theoretical capacity, natural abundance, and environmental friendliness show great potential as negative electrodes for alkaline metal ion batteries. In this review, based on the understanding of the storage mechanism of alkali metal ions, the scientific challenges are discussed, the preparation methods and solutions to address these challenges are summarized, the application prospects are demonstrated, and finally possible future research directions of phosphorus‐based materials are provided.
- Item3D Self‐Assembled Microelectronic Devices: Concepts, Materials, Applications(Hoboke, NJ : Wiley, 2020) Karnaushenko, Daniil; Kang, Tong; Bandari, Vineeth K.; Zhu, Feng; Schmidt, Oliver G.Modern microelectronic systems and their components are essentially 3D devices that have become smaller and lighter in order to improve performance and reduce costs. To maintain this trend, novel materials and technologies are required that provide more structural freedom in 3D over conventional microelectronics, as well as easier parallel fabrication routes while maintaining compatability with existing manufacturing methods. Self‐assembly of initially planar membranes into complex 3D architectures offers a wealth of opportunities to accommodate thin‐film microelectronic functionalities in devices and systems possessing improved performance and higher integration density. Existing work in this field, with a focus on components constructed from 3D self‐assembly, is reviewed, and an outlook on their application potential in tomorrow's microelectronics world is provided.