Explore the vast range of titles available.

Piezoelectric electronics possess great potential in flexible sensing and energy harvesting applications. However, they suffer from low electromechanical performance in all-organic piezoelectric systems due to the disordered and weakly-polarized interfaces. Here, we demonstrated an all-polymer piezo-ionic-electric electronics with PVDF/Nafion/PVDF (polyvinylidene difluoride) sandwich structure and regularized ion-electron interfaces. The piezoelectric effect and piezoionic effect mutually couple based on such ion-electron interfaces, endowing this electronics with the unique piezo-ionic-electric working mechanism. Further, owing to the massive interfacial accumulation of ion and electron charges, the electronics obtains a remarkable force-electric coupling enhancement. Experiments show that the electronics presents a high d 33 of ~80.70 pC N −1 , a pressure sensitivity of 51.50 mV kPa −1 and a maximum peak power of 34.66 mW m −2 . It is applicable to be a transducer to light LEDs, and a sensor to detect weak physiological signals or mechanical vibration. This work shows the piezo-ionic-electric electronics as a paradigm of highly-optimized all-polymer piezo-generators. Low electromechanical performance is a limiting factor for all-organic piezoelectric systems. Here, Xu et al. report an all-polymer piezo-ionic-electric electronics, coupling the piezoelectric effect with the piezoionic effect for enhanced performance.

Background MicroRNAs (miRNAs) play an important role in tumor occurrence. The role of miR-378a-5p and CDK1 in colorectal cancer (CRC) was investigated in this study. Methods Investigation of TCGA database and the detection of miR-378a-5p expression in colorectal cancer pathological tissues and colorectal cancer cell lines were undertaken by using qRT-PCR. We performed cell function experiments (CCK-8 assay, EdU assay, colony formation assay, wound healing assay, transwell assay, cell apoptosis assessment, and cell cycle assessment) and nude mouse tumor formation experiments to evaluate the effects of miR-378a-5p on proliferation, metastasis, and invasion to explore the role of miR-378a-5p in vivo and in vitro. Next, through TCGA database, immunohistochemical staining of pathological tissues, and cell function experiments, the role of the target gene CDK1 of miR-378a-5p was verified by database prediction, and dual luciferase reporter gene experiments in colorectal cancer cells were performed. Finally, whether upregulation of CDK1 restores the inhibitory effect of overexpression of miR-378a-5p on the proliferation of CRC cells was studied by overexpression of CDK1. Results Bioinformatic analysis showed significant downregulation of miR-378a-5p levels in colorectal cancer (CRC). Cell function experiments and tumor xenograft mouse models confirmed the low expression of miR-378a-5p within CRC tissues, which indicated the tumor suppressive role of miR-378a-5p in CRC. To better explore the regulation of miR-378a-5p in CRC, we predicted and validated cell cycle-dependent protein kinase 1 (CDK1) as the miR-378a-5p target gene and observed that miR-378a-5p suppressed CRC cell proliferation by targeting CDK1. Conclusion The results of this study help to elucidate the mechanism by which miR-378a-5p can be used as a tumor marker to inhibit the growth of colorectal cancer and CDK1, which is related to the prognosis of colorectal cancer patients. MiR-378a-5p inhibits CRC cell proliferation by suppressing CDK1 expression, which may become a possible therapeutic target for treatment of CRC.

Bioinspired soft robots hold great potential to perform tasks in unstructured terrains. Ferroelectric polymers are highly valued in soft robots for their flexibility, lightweight, and electrically controllable deformation. However, achieving large strains in ferroelectric polymers typically requires high driving voltages, posing a significant challenge for practical applications. In this study, we investigate the role of crystalline domain size in enhancing the electrostrain performance of the relaxor ferroelectric polymer poly(vinylidene fluoride‐trifluoroethylene‐chlorofluoroethylene‐fluorinated alkynes) (P(VDF‐TrFE‐CFE‐FA)). Leveraging its remarkable inverse piezoelectric coefficient (|d33*| = 701 pm V−1), we demonstrate that the planar films exhibit a five times larger bending angle than that of commercial PVDF films at low electric fields. Based on this material, we design a petal‐structured soft robot that achieves a curvature of up to 4.5 cm−1 at a DC electric field of 30 V μm−1. When integrated into a bipedal soft robot, it manifests outstanding electrostrain performance, achieving rapid locomotion of ~19 body lengths per second (BL s−1) at 10 V μm−1 (560 Hz). Moreover, the developed robot demonstrates remarkable abilities in climbing slopes and carrying heavy loads. These findings open new avenues for developing low‐voltage‐driven soft robots with significant promise for practical applications. To overcome the limitation of conventional electroactive materials that require high electric fields, we prepared a relaxor ferroelectric material featuring fine domains, enabling significant strains under low electric fields. This breakthrough in electrostrain performance paves the way for bionic robots to achieve fast locomotion at low electric fields, which provides new opportunities for designing high‐performance soft robots.

Piezoelectric nanofibers have received extensive attention in the field of electronic devices, but they are still restricted for further development, due to their limited dipole arrangement. Herein, we propose spatially confined MXene/polyvinylidene fluoride (PVDF) nanofibers for piezoelectric application, with dual functions of pressure sensing and energy harvesting. The spatial confinement of MXene/PVDF nanofibers can actively induce the optimally aligned –CH 2 –/–CF 2 – dipoles of PVDF and dramatically boost spontaneous polarization for piezoelectric enhancement. The voltage and current generated by fabricated MXene/PVDF (0.8 wt%) nanofiber piezoelectric electronic devices  are respectively 3.97 times and 10.1 times higher than those generated by pure PVDF nanofibers. Based on these results, the developed bifunctional electronic devices are applied to monitor various human movements and to harvest energy. Notably, the results of this work allow for the development of nanofibers with excellent piezoelectric performance using a spatial confinement mechanism. Graphical Abstract

With the increasing demand for flexible piezoelectric sensor components, research on polyvinylidene fluoride (PVDF) based piezoelectric polymers is mounting up. However, the low dipole polarization and disordered polarization direction presented in PVDF hinder further improvement of piezoelectric properties. Here, we constructed an oriented tertiary structure, consisting of molecular chains, crystalline region, and MXene sheets, in MXene/PVDF nanocomposite via a temperature-pressure dual-field regulation method. The highly oriented PVDF molecular chains form approximately 90% of the β phase. In addition, the crystalline region structure with long-range orientation achieves out of plane polarization orientation. The parallel orientation arrangement of MXene effectively enhances the piezoelectric performances of the nanocomposite, and the current output of the device increases by nearly 23 times. This high output device is used to monitor exercise action, exploring the potential applications in wearable electronics.

Real-time monitoring of ball–shoe interactions can provide essential information for high-quality instruction in personalized soccer training, yet existing monitoring systems struggle to reflect specific forces, loci, and durations of action. Here, we design a self-powered piezoelectric sensor constructed by the gradient carbon nanotube/polyvinylidene fluoride (CNT/PVDF) composite to monitor the interactions between the ball and the shoe. Two-dimensional Raman mapping demonstrates the gradient structure of CNT/PVDF prepared by programmable electrospinning combined with a hot pressing. Benefitting from the synergistic effect of local polarization caused by the enrichment of CNT and the reduced diffusion of silver patterns in gradient structure, the as-prepared composite exhibits enhanced force-electric coupling with an excellent sensitivity of 80 mV/N and durability over 15,000 cycles. On this basis, we conformally attach a 3 × 3 sensor array to a soccer shoe, enabling real-time acquisition of kick position and contact force, which could provide quantitative assessment and personalize guidance for the training of soccer players. This self-powered piezoelectric sensor network system offers a promising paradigm for wearable monitoring under strong impact forces.

Introducing oxygen vacancies in transition-metal oxides is an effective method to improve electrocatalytic water oxidation activity. However, controlled defect engineering in metal oxides remains a challenge. In this study, high oxygen vacancy content is achieved in transition-metal oxides by regulating the pyrolysis temperature of corresponding metal hydroxides. Specifically, Co 3 O 4 nanoflowers with a large amount of oxygen vacancies were obtained by pyrolysis of Co(OH) 2 in air at 400°C. The high oxygen vacancy content may be due to the rich porous structure and atomic rearrangement of Co and O. Electrochemical results showed that oxygen vacancy defect-rich Co 3 O 4 prepared at 400°C (Co 3 O 4 -400) has the lowest overpotential η of 321 mV for oxygen evolution reaction at a current density j of 10 mA cm −2 in 1.0 mol L −1 KOH compared with Co 3 O 4 -300 (348 mV) and Co 3 O 4 -500 (366 mV). Theoretical calculations and experiments verified the beneficial effect of oxygen vacancies in Co 3 O 4 . This study offers an efficient strategy to develop highly active transition-metal oxides with optimized oxygen vacancies.

Respiration is a critical physiological process of the body and plays an essential role in maintaining human health. Wearable piezoelectric nanofiber-based respiratory monitoring has attracted much attention due to its self-power, high linearity, noninvasiveness, and convenience. However, the limited sensitivity of conventional piezoelectric nanofibers makes it difficult to meet medical and daily respiratory monitoring requirements due to their low electromechanical conversion efficiency. Here, we present a universally applicable, highly sensitive piezoelectric nanofiber characterized by a coaxial composite structure of polyvinylidene fluoride (PVDF) and carbon nanotube (CNT), which is denoted as PS-CC. Based on elucidating the enhancement mechanism from the percolation effect, PS-CC exhibits excellent sensing performance with a high sensitivity of 3.7 V/N and a fast response time of 20 ms for electromechanical conversion. As a proof-of-concept, the nanofiber membrane is seamlessly integrated into a facial mask, facilitating accurate recognition of respiratory states. With the assistance of a one-dimensional convolutional neural network (CNN), a PS-CC-based smart mask can recognize respiratory tracts and multiple breathing patterns with a classification accuracy of up to 97.8%. Notably, this work provides an effective strategy for monitoring respiratory diseases and offers widespread utility for daily health monitoring and clinical applications. Graphical abstract

Hepatocyte nuclear factor 1b (HNF1b) is a transcription factor belonging to the HNF family. We aimed to investigate the role of HNF1b in white adipocyte differentiation. The expression of HNF1b was reduced in white adipose tissue (WAT) of both diet-induced and genetic obese mice and decreased during the process of 3T3-L1 adipocyte differentiation. Downregulation of HNF1b enhanced 3T3-L1 adipocyte differentiation and upregulation of HNF1b inhibited this process. Upregulation of HNF1b inhibited peroxisome proliferator-activated receptor γ (PPAR γ ) and its target gene expression, while downregulation of HNF1b increased those genes expression. Overexpression of PPAR γ suppressed HNF1b upregulation-induced inhibition of adipocyte differentiation. HNF1b can directly bind with the promoter of PPAR γ in 3T3-L1 cells, which was decreased after adipogenic differentiation. HNF1b promoted apoptotic and autophagic cell death in early differentiated adipocytes through regulation of cell cycle progress and cell death-related factors, and thus inhibited the process of mitotic clonal expansion (MCE). HNF1b acted as an antioxidant regulator through regulating various antioxidant enzymes via binding with antioxidant response element. Oxidant treatment suppressed HNF1b upregulation-induced inhibition of adipocyte differentiation. Overall, our results suggest that HNF1b is a novel negative regulator of adipocyte differentiation through regulation of PPAR γ signaling, MCE and redox state.