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In this study, the components of 0.55Bi(1-x)LaxFeO3-0.45PbTiO3(BF-PT45: La (x)) are designed to construct the T-R morphotropic phase boundary (MPB). A strain of 0.28% as well as a hysteresis of 26.4% at 50 kV/cm is obtained at MPB with x = 0.32. The selected area electron diffraction (SAED) results show that there is 1/2 (ooo) superlattice reflection in BF-PT45: La (0.32) ceramics. Atomic resolution aberration-corrected scanning transmission electron microscopy (AC-STEM) combined with electron energy loss spectroscopy (EELS) confirmed that superlattice reflections are caused by a−b−b− antiphase oxygen octahedral tilting rather than chemical ordering. At the same time, atomic resolution displacement vectors confirmed the coexistence of T-phase and R-phase nano-domains, and the coordination between cation displacement and oxygen octahedral tilt was evaluated using AC-STEM enhanced annular bright-field (eABF) images. Such a nano-domain structure has a low energy barrier, which is conducive to flexible dynamic polarization rotation under external stimulus. These results will have implications for understanding ferroelectric atomic-level structures and provide an effective method to attain excellent electrical properties. [ABSTRACT FROM AUTHOR]

Using ZnO nanowires as needle anodes in gas discharge is helpful for maintaining continuous discharge with a relatively low voltage. It is necessary that the ZnO nanowires are far enough apart to guarantee no electric field weakening and that the nanowire anodes are easy to assemble together with the discharging devices. An AC/DC electric-field-assisted wet chemical method is proposed in this paper. It was used to grow ZnO nanowires directly on discharging devices. The nanowires covered the whole electrode in the case in which only a DC field was applied. Moreover, the tips of the nanowires were scattered, similar to the results observed under the application of AC fields. The average distance between the tips of the highest nanowires was approximately equal to 4 μm, which almost meets the requirement of gas discharge. The research concerning growing ZnO nanowires directly on PCBs shown that, at the current time, ZnO nanowires on PCBs did not meet the requirements of gas discharge; however, in this study, the parameters regarding ZnO nanowire growth were established. [ABSTRACT FROM AUTHOR]

At the ferroelectric ABO3 perovskite heterointerface, the broken translational symmetry significantly alters the octahedral network and cation sublattices. Experimentally revealing the interaction between the polarization and atomic structure parameters is beneficial not only for understanding the novel physical phenomena but also for realizing exotic physical functionalities at the materials surface science. Here, it is demonstrated that the induced polarization can be realized by the cooperative interaction between the octahedral distortion and the cation sublattices at the paraelectric‐ferroelectric heterointerface in the (K,Na)NbO3 epitaxial thin film. It is found that the cation–cation displacement scales with the tetragonality of the perovskite unit cell but not with the polarization, which is minimal in the substrate but increases substantially in the thin film. Nevertheless, the oxygen octahedral distortion in the substrate, accompanied by octahedral rotation, is stronger than that in the film, resulting in a translated and stable polarization across the interface. These results demonstrate the octahedral network plays a significant role in the ferroelectric polarization and can also greatly advance the understanding of the heterointerface science for ferroelectrics. [ABSTRACT FROM AUTHOR]

Achieving a high strain under a low electric field is critical for actuator applications, and so is something which has always been pursued. Here, an enhanced strain was achieved by introducing Sr0.7Bi0.2TiO3 (SBT) into Bi1/2(Na0.84K0.16)1/2TiO3 (BNKT) under the guidance of phase boundary engineering and domain design. The introduction of the SBT induces a phase transition from the dominant rhombohedral to the dominant tetragonal and strong relaxor behaviour, as well as increased ergodicity. The enhanced and anti-fatigue strain of 0.57% was obtained in BNKT-8SBT ceramics under a relatively low electric field of 50 kV cm−1, accompanied by a large of 1140 pm V−1. An atomic-resolution displacement vector map reveals the coexistence of R and T nanodomains induced by local structural inhomogeneity. The coexistent nanodomains contribute to a flexible domain structure. This unique domain structure is suggested to be the origin of the relaxor features and the enhanced strains. This result is helpful to understand the excellent performance from a structural point of view and could promote further development of high-performance materials. [ABSTRACT FROM AUTHOR]

Dielectric materials as capacitors with high energy storage performance have received substantial attention for applications as important components in modern electrical and electronic systems. Relaxor ferroelectrics, as one of the popular dielectric materials, have demonstrated extraordinary energy storage performance. However, the origin of this extraordinary performance is not fully understood due to the complex atomic structural heterogeneity. Here, aberration-corrected scanning transmission electron microscopy is employed to study the atomistic structure of a Sr0.7Bi0.2TiO3 lead-free relaxor ferroelectric thin film, which shows high energy density of 77.8 J cm−3, good energy efficiency of 67.8%, and high frequency, temperature and antifatigue stability simultaneously. A slush-like polar structure with 2–4 nm multi-domains and low-angle domain walls, rather than polar nanoregions, is observed, revealed and quantitively described in the Sr0.7Bi0.2TiO3 relaxor ferroelectric thin film. This slush-like polar structure is considered to enable flexible domain switching under an electric field, and is proposed as the mechanism for the high energy storage performance. These results benefit the understanding of the atomic-scale structure of relaxor ferroelectrics and provide guidance for the exploration of new relaxor ferroelectrics with high energy storage performance. [ABSTRACT FROM AUTHOR]

As a crucial kind of pervasive gene, long noncoding RNAs (lncRNAs) are abundant and key players in brain function as well as numerous neurological disorders, especially ischemic stroke. The mechanisms underlying ischemic stroke include angiogenesis, autophagy, apoptosis, cell death, and neuroinflammation. Inflammation plays a vital role in the pathological process of ischemic stroke, and systemic inflammation affects the patient's prognosis. Although a great deal of research has illustrated that various lncRNAs are closely relevant to regulate neuroinflammation and microglial activation in ischemic stroke, the specific interactional relationships and mechanisms between lncRNAs and neuroinflammation have not been described clearly. This review aimed to summarize the therapeutic effects and action mechanisms of lncRNAs on ischemia by regulating inflammation and microglial activation. In addition, we emphasize that lncRNAs have the potential to modulate inflammation by inhibiting and activating various signaling pathways, such as microRNAs, NF‐κB and ERK. [ABSTRACT FROM AUTHOR]

Stem cells have attracted increasing research interest in the field of regenerative medicine due to their unique abilities to differentiate into multiple cell lineages. Label-free, real-time, and long-term monitoring for stem cell differentiation is requisite in studying directional differentiation and development mechanisms for tissue engineering applications, but a great challenge because of the rigorous demands for sensitivity, stability and biocompatibility of devices. In this article, a label-free and real-time monitoring approach using a zinc oxide (ZnO) nanorod field effect transistor (FET) is proposed to detect cell traction forces (CTFs) exerted by cells on underlying substrates. The ZnO nanorod FET with the approach of difference-frequency lock-in detection achieves high sensitivity, good stability, and excellent biocompatibility, by which real-time and long-term (over 20 days) monitoring of cellular mechanical changes in osteogenic differentiation of mesenchymal stem cells (MSCs) is successfully achieved. We also employ electrical impedance monitoring using microelectrode array chips and microscopic observation to investigate cell migration and nodular aggregation behaviors of MSCs in osteogenic differentiation. Various biochemical assays including alkaline phosphatase (ALP), osteopontin expression and alizarin red staining are utilized to verify osteogenic differentiation of MSCs. We propose a combination of cell traction force measurement, impedance measurement and microscopic observation to provide multimodal profiling of cell morphology, and cellular biomechanical and electrophysiological phenotypes, which can track cellular dynamics in stem cell development and help to deeply understand the mechanism of osteogenic differentiation. [ABSTRACT FROM AUTHOR]

Electrical stimulation (ES) as an easy and effective inducing method has been widely used in induction differentiation of stem cells, e.g. osteogenic differentiation of mesenchymal stem cells (MSCs) for bone healing and bone tissue therapies. However, the micro-effect of an inhomogeneous electric field has rarely been investigated for ES in induction differentiation, and conventionally used ex situ assays may preclude accurate assessment due to variation from cell inoculation and treatments. Here, a novel electrical stimulation method with a microelectrode array chip is proposed for osteogenic differentiation of MSCs. The electric field applied onto the MSCs by the microelectrode array is designed similarly with a natural aggregation distribution of differentiated MSCs. The proposed ES method accelerates osteoblast proliferation and differentiation in the electrode array region and generates a larger amount of mineralized deposits, which are assayed via in situ alizarin red staining and morphology observation as well as immunocytochemistry. In addition, this method allows a direct in situ assessment to compare the osteogenic differentiation of MSCs with and without ES on a single chip to avoid culture environment difference. The method provides a fundamental platform for investigating induced differentiation of stem cells and allows integration with multifunctional cell assays to achieve in situ tracking for the differentiation process of stem cells. [ABSTRACT FROM AUTHOR]

High electrostability and long life-time of planar chip technology are crucial for electrophysiological measurements such as ionic current recording through ion channel proteins embedded in biological cell membrane. In this paper, we propose a novel planar microchip integrated with microelectrochemical cell array toward to a feasible solution for ion channel screening with high resolution and long life-time. In order to reduce the interference from the leakage currents, a synthetic lipid bilayer is applied to form a high sealing resistance. The whole-cell electrical access can be constructed via electroporating the lipid bilayer in close proximity to the cell membrane. Parameters of electroporation including amplitude and time scale are firstly optimized by using parallel electroporation to the lipid bilayers. In this approach, individual cells can be trapped to the target positions by applying dielectrophoresis (DEP) manipulation. Poly(ethylene glycol) (PEG) is employed with low concentration to facilitate the closed contact between the cells and the lipid bilayer to increase the efficiency of the whole-cell mode construction. Through this chip based method, stable current recordings through inward rectifier potassium (Kir) ion channels embedded in rat basophilic leukemia (RBL-1) cell membrane are achieved with high electrical sealing resistance (over 1 GΩ). In addition, without need for complex fluidic connections, this method allows for an easy operation and further miniaturization of the measuring system. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is the most common and malignant intracranial tumor in adults. Despite continuous improvements in diagnosis and therapeutic method, the prognosis is still far away from expectations. The invasive phenotype of GBM is the main reason for the poor prognosis. Epithelial-mesenchymal transition (EMT) is recognized as a participator in this invasive phenotype. Resveratrol, a natural plant-derived compound, is reported to be able to regulate EMT. In the present study, we used TGF-β1 to induce EMT and aimed to evaluate the effect of resveratrol on EMT and to explore the underline mechanism in GBM. Western blotting was used to detect the expression of EMT-related markers, stemness markers, and Smad-dependent signaling. Wound healing assay and transwell invasion assay were performed to evaluate the migratory and invasive ability of GBM cells. Gliosphere formation assay was used to investigate the effect of resveratrol on the ability of self-renewal. Xenograft experiment was conducted to examine the effect of resveratrol on EMT and Smad-dependent signaling in vivo. Our data validated that resveratrol suppressed EMT and EMT-associated migratory and invasive ability via Smad-dependent signaling in GBM cells. We also confirmed that resveratrol obviously inhibited EMT-induced self-renewal ability of glioma stem cells (GSCs) and inhibited EMT-induced cancer stem cell markers Bmi1 and Sox2, suggesting that resveratrol is able to suppress EMT-generated stem cell-like properties in GBM cells. Furthermore, we also showed the inhibitory effect of resveratrol on EMT in xenograft experiments in vivo. Overall, our study reveals that resveratrol suppresses EMT and EMT-generated stem cell-like properties in GBM by regulating Smad-dependent signaling and provides experimental evidence of resveratrol for GBM treatment. [ABSTRACT FROM AUTHOR]

The ability to precisely deliver molecules into single cells while maintaining good cell viability is of great importance to applications in therapeutics, diagnostics, and drug delivery as it is an advancement toward the promise of personalized medicine. This paper reports a single-cell individualized electroporation method with real-time impedance monitoring to improve cell perforation efficiency and cell viability using a microelectrode array chip. The microchip contains a plurality of sextupole-electrode units patterned in an array, which are used to perform in situ electroporation and real-time impedance monitoring on single cells. The dynamic recovery processes of single cells under electroporation are tracked in real time via impedance measurement, which provide detailed transient cell states and facilitate understanding the whole recovery process at the level of single cells. We define single-cell impedance indicators to characterize cell perforation efficiency and cell viability, which are used to optimize electroporation. By applying the proposed electroporation method to different cell lines, including human cancer cell lines and normal human cell lines individually, optimum stimuli are determined for these cells, by which high transfection levels of enhanced green fluorescent protein (EGFP) plasmid into cells are achieved. The results validate the effectiveness of the proposed single-cell individualized electroporation/transfection method and demonstrate promising potential in applications of cell reprogramming, induced pluripotent stem cells, adoptive cell therapy, and intracellular drug delivery technology. Electroporation: Single-cell electroporation with real-time monitoring using a microelectrode chip Electroporation involves applying an electrical field to cells to facilitate molecule delivery in therapeutics or diagnostics for personalized medicine, and a novel technique allows single-cell individualized electroporation with real-time monitoring using a microelectrode chip. Electroporation employs electrical stimulation to increase the permeability of cell membranes, but achieving high perforation efficiency while maintaining good cell viability remains a great challenge. A team headed by Rong Zhu at Tsinghua University, Beijing, China succeeded in developing an electroporation method at the single-cell level, offering improved cell perforation efficiency and cell viability by means of a microelectrode array chip. The technique allowed real-time monitoring of single-cell electroporation. The authors believe their system has considerable potential in various applications related to cell reprogramming, induced pluripotent stem cells, adoptive cell therapy, and intracellular drug delivery. [ABSTRACT FROM AUTHOR]

Retraction of 'Microelectrochemical cell arrays for whole-cell currents recording through ion channel proteins based on trans-electroporation approach' by Tianyang Zheng et al., Analyst, 2020, 145, 197–205. [ABSTRACT FROM AUTHOR]

Correction for 'Microelectrochemical cell arrays for whole-cell currents recording through ion channel proteins based on trans-electroporation approach' by Tianyang Zheng, et al., Analyst, 2020, DOI: 10.1039/c9an01737b. [ABSTRACT FROM AUTHOR]