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  • 1.

    【2hr】Prostate-specific membrane antigen targeted gold nanoparticles for prostate cancer radiotherapy: does size matter for targeted particles?

    包量

    机译 用于前列腺癌放射治疗的前列腺特异性膜抗原靶向金纳米颗粒：靶向颗粒的大小重要吗？
    摘要：Since the introduction of PSA testing, significantly more men have been diagnosed and treated for prostate cancer. Localized prostate cancer typically is treated with prostatectomy, however there is still a high risk of recurrence after surgery, and adjuvant radiation has been shown to mitigate disease progression. X-ray therapy is frequently used as an adjuvant to treat prostate cancer, but is an imperfect tool. In this report we describe the development of a targeted-radiosensitizing nanoparticle that significantly improves X-ray therapy. Taking advantage of the demonstrated radiosensitizing activity of gold nanoparticles (AuNPs) we developed targeted AuNPs and varied both surface ligand density and AuNP size to develop an optimized AuNP for X-ray radiotherapy. We conjugated a prostate-specific membrane antigen (PSMA) targeting ligand, PSMA-1, to AuNPs and found that the targeting ligand dramatically improved gold uptake by PSMA-expressing PC3pip cells compared with PC3flu cells lacking the PSMA receptors. Further, enhancement of radiotherapy was significantly more pronounced by internalization of smaller PSMA targeted-AuNPs. Our studies provide a foundation for design of size-selected AuNPs for targeted radiotherapy and, for the first time, systematically investigate both the effect of ligand and AuNP size on the cell uptake, tumor targeting and radiotherapy efficacy.
  • 2.

    【2hr】Seconds-resolved pharmacokinetic measurements of the chemotherapeutic irinotecan in situ in the living body

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    机译 活体体内原位化疗伊立替康的秒分辨药代动力学测量
    摘要：The ability to measure drugs in the body rapidly and in real time would advance both our understanding of pharmacokinetics and our ability to optimally dose and deliver pharmacological therapies. To this end, we are developing electrochemical aptamer-based (E-AB) sensors, a seconds-resolved platform technology that, as critical for performing measurements in vivo, is reagentless, reversible, and selective enough to work when placed directly in bodily fluids. Here we describe the development of an E-AB sensor against irinotecan, a member of the camptothecin family of cancer chemotherapeutics, and its adaptation to in vivo sensing. To achieve this we first re-engineered (via truncation) a previously reported DNA aptamer against the camptothecins to support high-gain E-AB signaling. We then co-deposited the modified aptamer with an unstructured, redox-reporter-modified DNA sequence whose output was independent of target concentration, rendering the sensor's signal gain a sufficiently strong function of square-wave frequency to support kinetic-differential-measurement drift correction. The resultant, 200 μm-diameter, 3 mm-long sensor achieves 20 s-resolved, multi-hour measurements of plasma irinotecan when emplaced in the jugular veins of live rats, thus providing an unprecedentedly high-precision view into the pharmacokinetics of this class of chemotherapeutics.
  • 3.

    【2hr】Achieving high performance poly(vinylidene fluoride) dielectric composites via in situ polymerization of polypyrrole nanoparticles on hydroxylated BaTiO3 particles

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    机译 通过在羟基化的BaTiO3颗粒上原位聚合聚吡咯纳米颗粒获得高性能的聚偏二氟乙烯介电复合材料
    摘要：Polymer dielectric composites have widespread applications in many fields ranging from energy storage, microelectronic devices, and sensors to power driven systems, etc. and attract much attention of researchers. However, it is still challenging to prepare advanced polymer dielectric composites with a high dielectric constant (ε′), low dielectric loss (tan δ) and simultaneously high breakdown strength (Ebd). In this work, conductive polypyrrole (PPy) nanoparticles were in situ synthesized in a reaction system containing the common barium titanate (BaTiO3, BT) or hydroxylated BaTiO3 (BTOH) particles, and then the PPy@BT and PPy@BTOH composite particles were incorporated into poly(vinylidene fluoride) (PVDF) to prepare the composites. The morphologies and microstructures of the PPy@BT and PPy@BTOH composite particles and the corresponding PVDF composites were comparatively investigated. The results showed that the PPy@BTOH composite particles had a ‘mulberry’-like morphology with a rough surface and the self-assembled structure could be maintained in the PVDF composites, which was apparently different from the PVDF/PPy@BT composites, in which most of the PPy nanoparticles dissociatively dispersed in the PVDF matrix. Electrical conductivity measurements showed that at high particle content (≥20 wt%), the PPy@BTOH composite particles endowed the composites with lower electrical conductivity compared with the PPy@BT composite particles. Dielectric property measurements showed that the ‘mulberry’-like PPy@BTOH composite particles endowed the PVDF composites with extremely high ε′, ultralow tan δ and high Ebd compared with the PVDF/PPy@BT composites with dissociatively dispersed PPy nanoparticles and BaTiO3 particles. The polarization and loss mechanisms of the composites were then proposed based on the morphologies and the microstructures of the composites. This work provides an alternative way to fabricate functional dielectric particles through trace functional groups inducing in situ polymerization of conductive polymers, and these particles can be used to fabricate advanced dielectric composites.
  • 4.

    【2hr】Hierarchically porous carbons as supports for fuel cell electrocatalysts with atomically dispersed Fe–Nx moieties

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    机译 分层多孔碳作为具有原子分散的Fe–Nx部分的燃料电池电催化剂的载体
    摘要：The development of high-performance non-platinum group metal (non-PGM) catalysts for the oxygen reduction reaction (ORR) is still of significance in promoting the commercialization of proton exchange membrane fuel cells (PEMFCs). In this work, a “hierarchically porous carbon (HPC)-supporting” approach was developed to synthesize highly ORR active Fe–phenanthroline (Fe–phen) derived Fe–Nx–C catalysts. Compared to commercial carbon black supports, utilizing HPCs as carbon supports can not only prevent the formation of inactive iron nanoparticles during pyrolysis but also optimize the porous morphology of the catalysts, which eventually increases the amount of reactant-accessible and atomically dispersed Fe–Nx active sites. The prepared catalyst therefore exhibits a remarkable ORR activity in both half-cells (half-wave potential of 0.80 V in 0.5 M H2SO4) and H2–air PEMFCs (442 mA cm–2 at a working voltage of 0.6 V), making it among the best non-PGM catalysts for PEMFCs.
  • 5.

    【2hr】Cobalt-catalyzed acylation-reactions of (hetero)arylzinc pivalates with thiopyridyl ester derivatives

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    机译 （杂）芳基锌新戊酸酯与硫代吡啶酯衍生物的钴催化酰化反应
    摘要：A cobalt-catalyzed acylation reaction of various primary, secondary and tertiary alkyl, benzyl and (hetero)aryl S-pyridyl thioesters with (hetero)arylzinc pivalates is reported. The thioesters were prepared directly from the corresponding carboxylic acids under mild conditions, thus tolerating sensitive functional groups. Acylations of α-chiral S-pyridyl esters proceeded with very high stereoretention leading to optically enriched α-chiral ketones.
  • 6.

    【2hr】A cruciform phthalocyanine pentad-based NIR-II photothermal agent for highly efficient tumor ablation

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    机译 基于十字形酞菁五单元组的NIR-II光热剂，用于高效消融肿瘤
    摘要：Photothermal therapy in the second near-infrared window (NIR-II, 1000–1700 nm) exhibits a significant advantage over the first near-infrared window (NIR-I, 650–950 nm) in terms of both maximum permissible exposure (MPE) and penetration depth. However, the thus far reported NIR-II photothermal agents (PTAs) have been focused just on inorganic semiconducting and organic polymeric semiconducting nanoparticles. Herein a novel cruciform phthalocyanine pentad was designed, synthesized, and characterized for the first time. The water-soluble nanoparticles (Zn4–H2Pc/DP NPs) assembled from this single molecular material with the help of DSPE–PEG2000–OCH3 exhibit characteristic absorption in the NIR-II region at 1064 nm with a large extinction coefficient of 52 L g–1 cm–1, high photothermal conversion efficiency of 58.3%, and intense photoacoustic signal. Moreover, both in vitro and in vivo studies reveal the good biocompatibility and notable tumor ablation ability of Zn4–H2Pc/DP NPs under 1064 nm laser irradiation. Theoretical density functional theory calculations interpret the two-dimensional compressional wave energy-dissipation pathway over the broad saddle curved framework of the cruciform conjugated phthalocyanine pentad, rationalizing the efficient photothermal properties of corresponding Zn4–H2Pc/DP NPs in the NIR-II window.
  • 7.

    【2hr】In situ real-time tracing of hierarchical targeting nanostructures in drug resistant tumors using diffuse fluorescence tomography

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    机译 扩散荧光层析成像技术在耐药性肿瘤中靶向纳米结构的原位实时追踪
    摘要：Nanoparticles that respond to specific endogenous or exogenous stimuli in tumor tissues are actively being developed to address multidrug resistance owing to multiple advantages, including a prolonged circulation time, enhanced permeability and retention effect, and superior cellular uptake. Although some exciting results have been obtained, existing nanoparticles have limited routes to overcome the drug resistance of tumor cells; this limitation results in a failure to ablate resistant tumors via intravenous administration. To resolve this dilemma, we developed a smart theranostic nanoplatform with programmable particle size, activatable target ligands and in vivo multimodal imaging. This nanoplatform, which includes stealth zwitterionic coating, was shown to be quickly trapped in tumor tissue from the blood circulation within 5 min. Subsequently, the targeting moieties were activated in response to the acidic tumor microenvironment by triggering the zwitterionic shell detachment, driving the peeled nanoparticles to penetrate into tumor cells. These smart nanoparticles completely inhibited drug-resistant tumor growth and did not cause any damage to normal organ tissues in live animals. The designed nanoplatforms simultaneously acted as a nanoprobe for fluorescence imaging. Moreover, we also used noninvasive pharmacokinetic diffuse fluorescence tomography (DFT) to dynamically monitor and in situ real-time trace the nanoplatforms' behavior throughout the entire tumor in live animals. The nanoplatforms enabled rapid drug accumulation and deep penetration throughout the entire tumor. The rate of drug accumulation after the administration of nanoplatforms was five-fold higher compared with that after the administration of the free drug, which resulted in increased drug delivery efficiency and improved antitumor efficacy. Collectively, this hierarchical vehicle design provides promising insights for the development of theragnosis for multidrug resistant tumors.
  • 8.

    【2hr】A quantitative uncertainty metric controls error in neural network-driven chemical discovery

    包量

    机译 定量不确定性度量控制神经网络驱动化学发现中的误差
    摘要：Machine learning (ML) models, such as artificial neural networks, have emerged as a complement to high-throughput screening, enabling characterization of new compounds in seconds instead of hours. The promise of ML models to enable large-scale chemical space exploration can only be realized if it is straightforward to identify when molecules and materials are outside the model's domain of applicability. Established uncertainty metrics for neural network models are either costly to obtain (e.g., ensemble models) or rely on feature engineering (e.g., feature space distances), and each has limitations in estimating prediction errors for chemical space exploration. We introduce the distance to available data in the latent space of a neural network ML model as a low-cost, quantitative uncertainty metric that works for both inorganic and organic chemistry. The calibrated performance of this approach exceeds widely used uncertainty metrics and is readily applied to models of increasing complexity at no additional cost. Tightening latent distance cutoffs systematically drives down predicted model errors below training errors, thus enabling predictive error control in chemical discovery or identification of useful data points for active learning.
  • 9.

    【2hr】Before Förster. Initial excitation in photosynthetic light harvesting

    包量

    机译 在福斯特之前。光合光收集中的初始激发
    摘要：Electronic 2D spectroscopy allows nontrivial quantum effects to be explored in unprecedented detail. Here, we apply recently developed fluorescence detected coherent 2D spectroscopy to study the light harvesting antenna 2 (LH2) of photosynthetic purple bacteria. We report double quantum coherence 2D spectra which show clear cross peaks indicating correlated excitations. Similar results are found for rephasing and nonrephasing signals. Analysis of signal generating quantum pathways leads to the conclusion that, contrary to the currently prevailing physical picture, the two weakly coupled pigment rings of LH2 share the initial electronic excitation leading to quantum mechanical correlation between the two clearly separate absorption bands. These results are general and have consequences for the interpretation of initially created excited states not only in photosynthesis but in all light absorbing systems composed of weakly interacting pigments where the excitation transfer is commonly described by using Förster theory. Being able to spectrally resolve the nonequilibrium dynamics immediately following photoabsorption may provide a glimpse to the systems' transition into the Förster regime.
  • 10.

    【2hr】Nanoscale electrostatic gating of molecular transport through nuclear pore complexes as probed by scanning electrochemical microscopy

    包量

    机译 纳米级静电门控分子通过核孔配合物的传输，如通过扫描电化学显微镜探测的
    摘要：The nuclear pore complex (NPC) is a large protein nanopore that solely mediates molecular transport between the nucleus and cytoplasm of a eukaryotic cell. There is a long-standing consensus that selective transport barriers of the NPC are exclusively based on hydrophobic repeats of phenylalanine and glycine (FG) of nucleoporins. Herein, we reveal experimentally that charged residues of amino acids intermingled between FG repeats can modulate molecular transport through the NPC electrostatically and in a pathway-dependent manner. Specifically, we investigate the NPC of the Xenopus oocyte nucleus to find that excess positive charges of FG-rich nucleoporins slow down passive transport of a polycationic peptide, protamine, without affecting that of a polyanionic pentasaccharide, Arixtra, and small monovalent ions. Protamine transport is slower with a lower concentration of electrolytes in the transport media, where the Debye length becomes comparable to the size of water-filled spaces among the gel-like network of FG repeats. Slow protamine transport is not affected by the binding of a lectin, wheat germ agglutinin, to the peripheral route of the NPC, which is already blocked electrostatically by adjacent nucleoporins that have more cationic residues than anionic residues and even FG dipeptides. The permeability of NPCs to the probe ions is measured by scanning electrochemical microscopy using ion-selective tips based on liquid/liquid microinterfaces and is analysed by effective medium theory to determine the sizes of peripheral and central routes with distinct protamine permeability. Significantly, nanoscale electrostatic gating at the NPC can be relevant not only chemically and biologically, but also biomedically for efficient nuclear import of genetically therapeutic substances.
  • 11.

    【2hr】Low-valent homobimetallic Rh complexes: influence of ligands on the structure and the intramolecular reactivity of Rh–H intermediates

    包量

    机译 低价同双金属Rh复合物：配体对Rh–H中间体的结构和分子内反应性的影响
    摘要：Supporting two metal binding sites by a tailored polydentate trop-based (trop = 5H-dibenzo[a,d]cyclohepten-5-yl) ligand yields highly unsymmetric homobimetallic rhodium(i) complexes. Their reaction with hydrogen rapidly forms Rh hydrides that undergo an intramolecular semihydrogenation of two CC bonds of the trop ligand. This reaction is chemoselective and converts CC bonds to a bridging carbene and an olefinic ligand in the first and the second semihydrogenation steps, respectively. Stabilization by a bridging diphosphine ligand allows characterization of a Rh hydride species by advanced NMR techniques and may provide insight into possible elementary steps of H2 activation by interfacial sites of heterogeneous Rh/C catalysts.
  • 12.

    【2hr】Electrochemical oxidation induced selective tyrosine bioconjugation for the modification of biomolecules

    包量

    机译 电化学氧化诱导的选择性酪氨酸生物共轭修饰生物分子
    摘要：Directly introducing a beneficial functional group into biomolecules under mild, clean and easy-to-handle conditions is of great importance in the field of chemical biology and pharmacology. Herein, we described an electrochemical strategy to perform the bioconjugation of tyrosine residues with phenothiazine derivatives in a rapid and simple manner. In this electrochemical system, various polypeptides and proteins were successfully labelled with excellent site- and chemo-selectivity, and metals, oxidants or additives were also avoided.
  • 13.

    【2hr】Fluoro-electrochemical microscopy reveals group specific differential susceptibility of phytoplankton towards oxidative damage

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    机译 荧光电化学显微镜显示浮游植物对氧化损伤的群体特异性差异敏感性
    摘要：In the vicinity of an electrode creating a highly oxidising environment the fluorescence – arising from the presence of chlorophyll-a – of single cellular phytoplankton becomes inhibited. Even for phytoplankton that are very comparable in size (ca. 2–20 μm) the rate of this (electro)chemically induced fluorescence inhibition differs significantly between phytoplankton species; the fluorescence signal of the freshwater algae Stichococcus bacillaris turns off ∼70 times faster than that of the marine coccolithophore Emiliana huxleyi. The varying behaviour reflects the differing susceptibility of these globally important phytoplankton species towards extreme levels of radical induced oxidative stress, indicating the physical and chemical properties of the plankton cell wall and membrane are very different between species, and are important in determining their susceptibility. These results have potential implications for the analytical detection and characterisation of phytoplankton cells in the natural environment.
  • 14.

    【2hr】Pore-size dominated electrochemical properties of covalent triazine frameworks as anode materials for K-ion batteries

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    机译 共价三嗪骨架作为K离子电池阳极材料的孔大小主导的电化学性能
    摘要：Two homologous covalent triazine frameworks (CTFs) have been developed for the first time as anode materials for high performance K-ion batteries (KIBs). The two-dimensional sheet-like structure as well as the regular channels in CTFs enable the process of intercalation/deintercalation of K-ions into/from the CTF interlayers reversibly. Particularly, a size effect of the porous structure is found to dominate the K-ion storage behavior. CTF-0 with a smaller pore size displays a higher K-ion storage capacity than CTF-1. Molecular simulations reveal the operation mechanism, showing that the depotassiation process in CTF-0 is exothermic while the depotassiation in CTF-1 is endothermic, which makes the deintercalation of K-ions from CTF-0 more feasible than from CTF-1 and contributes to the higher reversible capacity of CTF-0. This work provides a promising strategy for rational design of high-performance organic anode materials by structural modulation at the molecular scale.
  • 15.

    【2hr】Anthracene-based mechanophores for compression-activated fluorescence in polymeric networks

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    机译 基于蒽的机制用于聚合物网络中压缩激活的荧光
    摘要：The recent attention given to functionalities that respond to mechanical force has led to a deeper understanding of force transduction and mechanical wear in polymeric materials. Furthermore, polymers have been carefully designed such that activation of “mechanophores” leads to productive outputs, such as material reinforcement or changes in optical properties. In this work, a crosslinker containing an anthracene–maleimide linkage was designed and used to prepare networks that display a fluorescence response when damaged. The pressure-dependent damage of poly(N,N-dimethylacrylamide) networks was monitored using solid-state fluorescence spectroscopy, with increasing compressive forces leading to higher degrees of mechanophore activation. When a stamp was used to compress the networks, only the areas in contact with the raised portion of the stamp underwent mechanophore activation, resulting in the generation of patterns that were only visible under UV light. Finally, an isomeric “flex” mechanophore was designed and used to prepare networks that were compressed and compared to the previously described networks.
  • 16.

    【2hr】Relayed hyperpolarization from para-hydrogen improves the NMR detectability of alcohols

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    机译 来自对氢的中继超极化改善了醇的NMR检测能力
    摘要：The detection of alcohols by magnetic resonance techniques is important for their characterization and the monitoring of chemical change. Hyperpolarization processes can make previously inpractical measurements, such as the determination of low concentration intermediates, possible. Here, we investigate the SABRE-Relay method in order to define its key characteristics and improve the resulting 1H NMR signal gains which subsequently approach 103 per proton. We identify optimal amine proton transfer agents for SABRE-Relay and show how catalyst structure influences the outcome. The breadth of the method is revealed by expansion to more complex alcohols and the polarization of heteronuclei.
  • 17.

    【2hr】Tumour suppression by targeted intravenous non-viral CRISPRa using dendritic polymers

    包量

    机译 使用树突状聚合物通过靶向静脉内非病毒CRISPRa抑制肿瘤
    摘要：Aberrant gene expression is a hallmark of cancer. Although transcription is traditionally considered ‘undruggable’, the development of CRISPR-associated protein 9 (Cas9) systems offers enormous potential to rectify cancer-associated transcriptional abnormalities in malignant cells. However delivery of this technology presents a critical challenge to overcome in order to realize clinical translation for cancer therapy. In this article we demonstrate for the first time, a fully synthetic strategy to enable CRISPR-mediated activation (CRISPRa) of tumour suppressor genes in vivo using a targeted intravenous approach. We show this via highly efficient transcriptional activation of two model tumour suppressor genes, Mammary Serine Protease Inhibitor (MASPIN, SERPINB5) and cysteine-rich 61/connective tissue growth factor/nephroblastoma-overexpressed 6 (CCN6, WISP3), in a mouse model of breast cancer. In particular, we demonstrate that targeted intravenous delivery of can be achieved using a novel nanoscale dendritic macromolecular delivery agent, with negligible toxicity and long lasting therapeutic effects, outlining a targeted effective formulation with potential to treat aggressive malignancies.
  • 18.

    【2hr】Unraveling the structural and chemical features of biological short hydrogen bonds

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    机译 揭示生物短氢键的结构和化学特征
    摘要：The three-dimensional architecture of biomolecules often creates specialized structural elements, notably short hydrogen bonds that have donor–acceptor separations below 2.7 Å. In this work, we statistically analyze 1663 high-resolution biomolecular structures from the Protein Data Bank and demonstrate that short hydrogen bonds are prevalent in proteins, protein–ligand complexes and nucleic acids. From these biological macromolecules, we characterize the preferred location, connectivity and amino acid composition in short hydrogen bonds and hydrogen bond networks, and assess their possible functional importance. Using electronic structure calculations, we further uncover how the interplay of the structural and chemical features determines the proton potential energy surfaces and proton sharing conditions in biological short hydrogen bonds.
  • 19.

    【2hr】A sterically encumbered photoredox catalyst enables the unified synthesis of the classical lignan family of natural products

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    机译 在空间上受阻的光氧化还原催化剂可实现经典木脂素天然产物家族的统一合成
    摘要：Herein, we detail a unified synthetic approach to the classical lignan family of natural products that hinges on divergence from a common intermediate that was strategically identified from nature's biosynthetic blueprints. Efforts toward accessing the common intermediate through a convergent and modular approach resulted in the discovery of a sterically encumbered photoredox catalyst that can selectively generate carbonyl ylides from electron-rich epoxides. These can undergo concerted [3 + 2] dipolar cycloadditions to afford tetrahydrofurans, which were advanced (2–4 steps) to at least one representative natural product or natural product scaffold within all six subtypes in classical lignans. The application of those synthetic blueprints to the synthesis of heterolignans bearing unnatural functionality was demonstrated, which establishes the potential of this strategy to accelerate structure–activity-relationship studies of these natural product frameworks and their rich biological activity.
  • 20.

    【2hr】Uncovering two kinetic factors in the controlled growth of topologically distinct core–shell metal–organic frameworks

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    机译 在拓扑不同的核-壳金属-有机框架的受控生长中发现两个动力学因素
    摘要：Constructing core–shell metal–organic frameworks (MOFs) based on two topologically distinct MOFs is a great way to increase MOF material complexity and explore their new functions. However, such a nucleation process is energetically less favored compared to epitaxial growth due to mismatched unit cell parameters. Here, two kinetic factors, nucleation kinetics and dissolution kinetics, are revealed to be two key factors in overcoming this challenge. Through kinetic control, we demonstrate the growth of 4 types of Zr/Hf-MOF shells uniformly and contiguously on 7 different core MOFs including ZIF-8, an acid labile core. Taking advantage of the modular synthesis of Zr-MOFs, we demonstrate that post-synthetic covalent surface modification on a non-functionalizable MOF surface can be made possible through core–shell construction. We also demonstrated that the size selective catalytic behavior can be systematically tuned through changing either the ligand length or ligand functionality.
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