Ultrafast Laser Manufacture of Stable, Efficient Ultrafine Noble Metal Catalysts Mediated with MOF Derived High Density Defective Metal OxidesGuo, Shuailong; Zhao, Yunkun; Yuan, Hao; Wang, Chengxiong; Jiang, Haoqing; Cheng, Gary J.
doi: 10.1002/smll.202000749pmid: 32285619
Supported metal nanoparticles (MNPs) undergo severe aggregation, especially when the interaction between MNPs and their supports are limited and weak where their performance deteriorates dramatically. This becomes more severe when catalysts are operated under high temperature. Here, it is reported that MNPs including Pt, Au, Rh, and Ru, with sub‐2 nm size can be stabilized on densely packed defective CeO2 nanoparticles with sub‐5 nm size via strong coupling by direct laser conversion of corresponding metal ions encapsulated cerous metal–organic frameworks (Ce‐MOFs). Ce‐MOF serves as an ideal dispersion precursor to uniformly encapsulate noble metal ions in their orderly arranged pores. Ultrafast laser vaporization and cooling forms uniform, ultrasmall, well‐mixed, and exceptionally dense nanoparticles of metal and metal oxide concurrently. The laser‐induced ultrafast reaction (within tens of nanoseconds) facilitates the precipitation of CeO2 nanoparticles with abundant surficial defects. Due to the well‐mixed ultrasmall Pt and CeO2 components with strong coupling, this catalyst exhibits exceptionally high stability and activity both at low and high temperatures (170–1100 °C) for CO oxidation in long‐term operation, significantly exceeding catalysts prepared by traditional methods. The scalable feature of laser and huge MOF family make it a versatile method for the production of MNP‐based nanocomposites in wide applications.
Nuclear Mechanics within Intact Cells Is Regulated by Cytoskeletal Network and Internal NanostructuresZhang, Jitao; Alisafaei, Farid; Nikolić, Miloš; Nou, Xuefei A.; Kim, Hanyoup; Shenoy, Vivek B.; Scarcelli, Giuliano
doi: 10.1002/smll.201907688pmid: 32243075
The mechanical properties of the cellular nucleus are extensively studied as they play a critical role in important processes, such as cell migration, gene transcription, and stem cell differentiation. While the mechanical properties of the isolated nucleus have been tested, there is a lack of measurements about the mechanical behavior of the nucleus within intact cells and specifically about the interplay of internal nuclear components with the intracellular microenvironment, because current testing methods are based on contact and only allow studying the nucleus after isolation from a cell or disruption of cytoskeleton. Here, all‐optical Brillouin microscopy and 3D chemomechanical modeling are used to investigate the regulation of nuclear mechanics in physiological conditions. It is observed that the nuclear modulus can be modulated by epigenetic regulation targeting internal nuclear nanostructures such as lamin A/C and chromatin. It is also found that nuclear modulus is strongly regulated by cytoskeletal behavior through a robust mechanism conserved in different culturing conditions. Given the active role of cytoskeletal modulation in nearly all cell functions, this work will enable to reveal highly relevant mechanisms of nuclear mechanical regulations in physiological and pathological conditions.
Phase‐Regulated Sensing Mechanism of MoS2 Based Nanohybrids toward Point‐of‐Care Prostate Cancer DiagnosisYing, Zi; Feng, Lingyan; Ji, Dongqing; Zhang, Yuan; Chen, Wei; Dai, Yifan; Janyasupab, Metini; Li, Xinxin; Wen, Weijia; Liu, Chung‐Chiun
doi: 10.1002/smll.202000307pmid: 32250065
Alpha‐methylacyl‐CoA racemase (AMACR) has been proven to be consistently overexpressed in prostate cancer epitheliums, and is expected to act as a positive biomarker for the diagnosis of prostate carcinoma in clinical practice. Here, a strategy for specific determination of AMACR in real human serum by using an electrochemical microsensor system is presented. In order to implement the protocol, a self‐organized nanohybrid consisting of metal nanopillars in a 2D MoS2 matrix is developed as material for the sensing interface. The testing signal outputs are strongly enhanced with the presence of the nanohybrids owing to that the metal pillars provide an efficient mass difussion and electron transfer path to the MoS2 film surface. Furthermore, the phase‐regulated sensing mechanism over MoS2 is noticed and demonstrated by density functional theory calculation and experiments. The explored MoS2 based nanohybrids are employed for the fabrication of an electrochemical microsensor, presenting good linear relationship in both ng µL−1 and pg µL−1 ranges for AMACR quantification. The sampling analysis of human serum indicates that this microsensor has good diagnostic specificity and sensitivity toward AMACR. The proposed electrochemical microsensor system also demonstrates the advantages of convenience, cost‐effectiveness, and disposability, resulting in a potential integrated microsystem for point‐of‐care prostate cancer diagnosis.
Integration of Binary Active Sites: Co3V2O8 as Polysulfide Traps and Catalysts for Lithium‐Sulfur Battery with Superior Cycling StabilityZhang, Linlin; Wan, Fang; Cao, Hongmei; Liu, Lili; Wang, Yijing; Niu, Zhiqiang
doi: 10.1002/smll.201907153pmid: 32285595
Lithium‐sulfur (Li‐S) batteries as a promising energy storage candidate have attracted attention due to their high energy density (2600 Wh kg−1). However, the serious shuttle effect caused by the dissolution of the lithium polysulfides (LiPS) in electrolyte significantly degrades their cycling life and rate performance. Herein, the “binary active sites” concept in a Li‐S battery system via the design of a cobalt vanadium oxide (CVO) modified multifunctional separator is designed. In the case of CVO, active vanadium sites simultaneously anchor the LiPS through the chemical affinity and active cobalt sites can dominate a rapid kinetic conversion. Such a synergistic effect contributes to improving the utilization of sulfur in the electrochemical process for the enhanced electrochemical performance. As a result, the Li‐S battery with the CVO modified separator possesses a high reversible capacity of 1585.5 mAh g−1 at 0.1 C and superior cycling stability with 0.012% capacity decay cycle−1 after 3000 cycles. More impressively, the assembled soft‐packaged Li‐S devices can exhibit the excellent stability under bending states. This binary active sites strategy provides a route to design the functional materials for modifying separators of Li‐S batteries to improve the performance.
A Single Molecule Drug Targeting Photosensitizer for Enhanced Breast Cancer Photothermal TherapyZou, Yang; Li, Mingle; Xiong, Tao; Zhao, Xueze; Du, Jianjun; Fan, Jiangli; Peng, Xiaojun
doi: 10.1002/smll.201907677pmid: 32307872
Targeting is one of the most important strategies for enhancing the efficacy of cancer photothermal therapy (PTT) and reducing damage to surrounding normal tissues. Compared with the traditional targeting approaches, the active targeting of breast cancer cells in PTT using chemotherapeutic drugs, such as tamoxifen (TAM), in combination with single‐molecule photothermal photosensitizers has superior selectivity and therapeutic effects. However, single‐molecule drug‐targeting photosensitizers for improved PTT efficacy are not widely reported. Accordingly, herein, a near‐infrared induced small‐molecule photothermal photosensitizer (CyT) is developed that actively targets the estrogen receptors (ERs) of breast cancer cells as well as targets mitochondria by structure‐inherent targeting. Cell uptake and cytotoxicity studies using different types of cells show that CyT enhances the efficiency of TAM‐based PTT by targeting ER‐overexpressing breast cancer cells and selectively killing them. In vivo experiments demonstrate that CyT can be used as a photothermal agent for fluorescence imaging‐guided PTT. More importantly, the intravenous injection of CyT results in better targeting and efficiency of tumor inhibition compared with that achieved with the TAM‐free control molecule Cy. Thus, the study presents an excellent small‐molecule photothermal agent for breast cancer therapy with potential clinical application prospects.