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In this work, by capitalizing on the density functional theory (DFT) and the time-dependent density functional theory (TD-DFT) methods, it has been systematically studied that the excited state double intramolecular proton transfer (ESDPT) process and the photophysical properties of 1,8-dihydroxy-2-naphthaldehyde (DHNA) are affected by the distinct external electric fields (EEFs). The obtained intramolecular hydrogen bond (IHB) parameters containing bond lengths and angles, as well as infrared (IR) vibrational spectra demonstrate that IHB strength changes in the distinct EEFs. Moreover, not only do the potential energy surfaces (PESs) indicate that the ESDPT process of DHNA is stepwise, but also increasing the positive EEF results in a decrease in the energy barrier accordingly, while vice versa. The absorption and fluorescence spectra also undergo a corresponding red or blue shift in the EEF; for instance, when the EEF changes from +10 × 10−4 a.u. to +20 × 10−4 a.u., the fluorescence peak undergoes a blue shift from 602 nm to 513 nm in the keto2 form. In a nutshell, the ESDPT process of DHNA can be influenced by the EEF, which will serve as a reference in regulating and controlling proton transfer that causes luminescence. [ABSTRACT FROM AUTHOR]

The human cardiac organoid (hCO) is three-dimensional tissue model that is similar to an in vivo organ and has great potential on heart development biology, disease modeling, drug screening and regenerative medicine. However, the construction of hCO presents a unique challenge compared with other organoids such as the lung, small intestine, pancreas, liver. Since heart disease is the dominant cause of death and the treatment of such disease is one of the most unmet medical needs worldwide, developing technologies for the construction and application of hCO is a critical task for the scientific community. In this review, we discuss the current classification and construction methods of hCO. In addition, we describe its applications in drug screening, disease modeling, and regenerative medicine. Finally, we propose the limitations of the cardiac organoid and future research directions. A detailed understanding of hCO will provide ways to improve its construction and expand its applications. [ABSTRACT FROM AUTHOR]

Fabricating an organic–inorganic nanocomposite hydrogel platform with antibacterial, anti-inflammatory, and osteoinductive properties that mimic bone extracellular matrix composition is decisive for guiding bone development in orthopedic practice. Despite significant progress in developing hydrogels for tissue repair, little attention has been paid to replicating the natural bone ECM microenvironments and addressing the importance of anti-inflammatory agents during osteogenesis. Herein, we developed ciprofloxacin and dexamethasone loaded strontium (Sr) and/or iron (Fe) substituted hydroxyapatite (HAp) nanomaterials precipitated in collagen (Col) to construct a multifunctional bioactive nanocomposite hydrogel platform to prevent inflammation and bacterial adhesion, leading to augmenting bone development in the defect site. The fabricated nanocomposite hydrogels (Sr:HAp-Col, Fe:HAp-Col, and Sr/Fe:HAp-Col) were physicochemically characterized and demonstrated high loading and prolonged drug release, and excellent antibacterial activity against Gram-positive and Gram-negative bacteria. In in vitro experiments, the Sr/Fe:HAp-Col sample exhibited enhanced bioactivity against the preosteoblast MC3T3-E1 cell line, with high alkaline phosphatase and bone-like inorganic calcium deposition, as well as increased gene expression of osteogenesis-related differentiation markers, including OPN, OCN, and RUNX2. Furthermore, in vivo experiments revealed that the Sr/Fe:HAp-Col matrix degraded over time by controlling the release of ions into the body, without causing acute inflammation at the implanted site or in the blood serum, or in the internal organs, including the heart, lungs, liver, and kidney of the Sprague–Dawley rat model. The micro-CT scan and histological examination showed high bone mineral density and more mature bone formation at the nanocomposite hydrogel implanted site associated with the ColMA hydrogel in the femur defect of the rat model. The strategy of applying collagen hydrogel supplemented with HAp to bone regeneration is promising due to its ability to mimic the natural bone ECM. Overall, the developed bioactive nanocomposite hydrogel may have great potential not only in bone regeneration but also in repairing nonunion-infected defects of other tissues. [ABSTRACT FROM AUTHOR]

Wound healing is a multifaceted process that involves hemostasis, inflammation, proliferation, and remodeling stages. Diabetic wounds affect the transition of the organized phases and result in delayed healing due to impaired angiogenesis, chronic inflammation, bacterial infection, and insufficient growth factors. Multifunctional heterostructural nanoparticles enriched minimally invasive hydrogels for on-demand procedural distribution to aid wound healing at various stages has become a promising strategy. Herein, silk fibroin-hyaluronic acid based injectable hydrogels incorporated with mace-like Au–CuS heterostructural nanoparticles (gAu–CuS HSs) were used to cure diabetic wounds. SF–HA and the rough surface of gAu–CuS HSs confer a synergistic hemostatic phase with a nano-bridge effect and rapidly close the wounds. During the inflammation stage, gAu–CuS HSs perform in-space resonance energy transfer under 808 nm laser irradiation which in return produces reactive oxygen species for bacterial destruction. The unusual mace-like rough structure of nanoparticles causes macrophage transfer to the M2 phenotype, regulates cytokine expression (interleukin 6, transforming factor-β1, interferon γ, and interleukin-10), promotes angiogenesis, and promotes cell multiplication and fibroblast emigration to the wound area during the proliferation and remodeling phase. Overall, the gAu–CuS HSs reinforced injectable hydrogel programmatically accelerates wound healing and could represent a versatile strategy for advanced diabetic wound healing. [ABSTRACT FROM AUTHOR]

Nylon 4F is a fully bio-based nylon material. Its raw materials 1,4-tetramethylenediamine (TMDA) and 2,5-furandicarboxylic acid (FDCA) can be prepared by biological methods using biomass. The high-performance polymer materials require high-quality monomers. In this report, we found and obtained three novel crystal forms of nylon 4F salt: form I is anhydrous; form HI and form HII are monohydrates. Their crystal structures were determined and analyzed by single crystal X-ray diffraction (SCXRD) and powder X-ray diffraction (PXRD). Meanwhile, we investigated the solid–liquid equilibrium of nylon 4F salt in different proportions of ethanol–water mixtures at different temperatures and correlated the solubilities with temperature and the solvent ratio using the (CNIBS)/Redlich–Kister model, modified Apelblat model and van't Hoff equation. It was proved that the solubility of nylon 4F salt increases with the increase of temperature and decreases with the increase of ethanol content. Besides that, the thermal behavior and phase transformation process were investigated in detail. Form HII, prepared by a quenching method, was an unstable crystal form and easily transformed into form HI during storage. Form I and form HI were enantiotropic in water–ethanol solution, and the phase diagram of the phase transformation was determined. In order to ensure that each crystal form can be synthesized under control, the control strategy was developed from the phase transformation relationship and relevant thermodynamic data. The lattice energy and crystal density were calculated to explain the relative stability of the different forms. [ABSTRACT FROM AUTHOR]

Hydrogel-based wound dressings with tissue adhesion abilities are widely used for wound closure. However, currently developed hydrogel adhesives are still poor at continuing to seal wounds while bleeding is ongoing. Herein, we demonstrate an antibacterial and hemostatic hydrogel adhesive with low-swelling properties and toughness for wound healing. The hydrogel was composed of Pluronic F127 diacrylate, quaternized chitosan diacrylate, silk fibroin, and tannic acid, and it was not only able to maintain good tissue adhesion abilities in a moist environment but it also showed guaranteed tissue adhesion and mechanical strength after absorbing water due to its low-swelling and toughness properties. Furthermore, in vitro and in vivo tests demonstrated that the hydrogel also had antibacterial, antioxidant, and hemostatic properties, which could promote tissue regeneration. All these findings demonstrate that this hydrogel with multifunctional properties is a promising material for clinical wound healing applications. [ABSTRACT FROM AUTHOR]

Flexible pressure sensors with excellent pressure sensing performance have been developed rapidly in recent years, but they still suffer from the disadvantages of a complex manufacturing process and high cost. Here, a flexible paper-based (PB) capacitive pressure sensor is constructed by using daily use materials such as paper, polyester conductive tape and polyimide tape. Thanks to the simplicity of the fabrication method, the proposed PB pressure sensor can be even fabricated via a do-it-yourself approach. The rough surface microstructure of paper and polyester conductive tape endows the PB pressure sensor with good pressure sensing performance properties. Specifically, the optimized PB pressure sensor with two-sided microstructure interfaces exhibits a wide pressure detection range (0.1–80 kPa), an acceptable sensitivity of 0.23 kPa−1 (0.1–2 kPa), a low detection limit of about 3 Pa, fast response speed (∼41 ms at the finger tapping), and good durability (5000 cycles at 10 kPa). The pressure sensing mechanism of the PB pressure sensor is explained by analyzing the in situ cross-sectional optical photographs and video of the sensor at different pressures. Like many flexible pressure sensors based on complex technologies and high cost, the PB pressure sensor has also been successfully applied in many application scenarios (e.g., finger bending, wrist pulse, nasal respiration, recording walking steps, early stage of Parkinson's disease, and proximity switch). Given the simple fabrication method, low cost and acceptable pressure sensing performance, we believe that the proposed PB pressure sensor is of extensive and practical application values in the field of wearable electronics and some underdeveloped areas, and is expected to help ordinary people become "home" engineers. [ABSTRACT FROM AUTHOR]

In recent years, paper-based bending strain (PBS) sensors for bending deformation and angle detections have attracted much attention in flexible electronics. However, PBS sensors based on a surface microcrack sensing mechanism have drawbacks of small response and poor water resistance. Herein, we construct a cross-section interface between two conductive papers to form a PBS sensor that can be encapsulated using adhesive tape. Benefiting from the cross-section interface response mechanism of the PBS sensor, it can be directly encapsulated with polyimide tape without worrying about the destruction of the paper surface microstructure. Therefore, the PBS sensor shows excellent water resistance. Meanwhile, the proposed PBS sensor has good bending strain properties. Taking the bending angle of 35.7° as an example, the PBS sensor has a very high response (36.5, relative current ratio after and before bending), good repeatability (2000 times) and acceptable response/recovery times (0.34/0.35 s). In addition, the potential applications of the PBS sensor in the human body and security doors are confirmed. This work not only proposes a novel, high-response, waterproof, and low-cost PBS sensor, but also provides new strategies for the development of bending strain sensors from cross-section interfaces with surface encapsulation. [ABSTRACT FROM AUTHOR]

Malignant tumor is one of the major public health problems seriously threatening the health of people all over the world. Great effort is being devoted to the development of theranostic nanoplatforms to satisfy the demand for precise diagnosis and efficient therapy. Recently, the Fe3O4 nanoparticles (NPs) approved by the Food and Drug Administration (FDA) have been extensively explored in cancer diagnosis and the administration of therapeutic drugs thanks to their unique properties such as T1/T2-weighted magnetic resonance (MR) imaging, magnetic targeting, magnetic hyperthermia, and photodynamic/photothermal therapy. Thus, Fe3O4 NPs together with other organic or inorganic materials are developed as theranostic nanoplatforms, thereby having the chance to compete with Gd-based contrast agents in clinics. Therefore, Fe3O4-based theranostic nanoplatforms have the potential to be used in individual therapies in the near future. In this review, the recent progress in fabricating Fe3O4-based theranostic nanoplatforms is summarized and their applications in biomedical area are also highlighted. [ABSTRACT FROM AUTHOR]

Hydrogels, especially injectable hydrogels, are promising materials due to their high water content and mechanical properties similar to natural tissues. Compared to the traditional hydrogels, injectable hydrogels can form in situ and reduce the invasiveness, which in turn reduces surgical and recovery costs. The past few years have seen a significant interest in the development of injectable hydrogels in research and clinical treatment. However, how to construct injectable biocompatible hydrogels rapidly and efficiently with proper mechanical properties remains a challenge. The 'Click' reaction, with its property of easy preparation and rapid reaction rate, has emerged as the most versatile and innovative technology, especially the bio-orthogonal reactions which provide a new opportunity as a unique tool for fabricating fast-forming injectable biocompatible hydrogels. In this review, we summarize the recent advances in fabricating injectable hydrogels via bio-orthogonal reactions. [ABSTRACT FROM AUTHOR]

An injectable BMSC-encapsulated double network (DN) hydrogel was fabricated via silk fibroin (SF) and poly(ethylene glycol) (PEG), which could efficiently support the survival and proliferation of BMSCs in vitro as well as cartilage repair in vivo, and provides a new strategy for cartilage tissue engineering. [ABSTRACT FROM AUTHOR]

2,5-Diformylfuran dioxime (DFFD), a rigid bio-based material, is a promising precursor for the manufacturing of advanced functional polymers. An acid autocatalytic oximation of bio-based 2,5-diformylfuran (DFF) initiated with 0.10 wt% HCl in 50 wt% aqueous hydroxylamine (AHA) at 30 °C yielded more than 99% DFFD within 5 min. The utilization efficiency of AHA and the conversion of DFF were 93% and 100%, respectively, through a stepwise AHA feeding strategy. The produced DFFD was easily separated at the kilogram scale by simple filtration, as DFFD was insoluble in water. During the reaction, the pH decreased continually from 6.0 to 2.0 along with the rapid generation of DFFD, which provided enough H+ to efficiently autocatalyse the oximation. Compared with hydroxylamine hydrochloride, AHA was much more efficient, and the generation of waste salts and wastewater decreased by 99.94% and 25%, respectively. Hence, we provide an efficient and clean DFFD production route, which is promising for the green utilization of bio-based furanic compounds. [ABSTRACT FROM AUTHOR]

Articular cartilage has limited self-healing ability due to its lack of abundant nutrients and progenitor cells. In this study, an injectable hydrogel system consisting of collagen type I-tyramine (Col-TA) and hyaluronic acid-tyramine (HA-TA) was fabricated as the bone marrow mesenchymal stem cell (BMSC)-laden hydrogel system for cartilage regeneration. Next, the physiochemical properties of this hydrogel system were well characterized and optimized, including gelation time, stiffness, water absorption and degradability. Further, the proliferation and differentiation of BMSCs within the Col-HA hydrogel were evaluated, and the ability of in vivo cartilage repair was also examined in the presence of the transforming growth factor-β1 (TGF-β1). These results illustrate that this hydrogel can offer a great microenvironment for BMSC growth and cartilage differentiation both in vitro and in vivo, and the Col-HA hydrogel can serve as an ideal hydrogel for cartilage tissue regeneration. [ABSTRACT FROM AUTHOR]

Defining the axis of a molecular rotation is vital for the bottom-up design of molecular rotors. The rotation of tin-phthalocyanine molecules on the Ag(111) surface is studied by scanning tunneling microscopy and atomic/molecular manipulation at 4 K. Tin-phthalocyanine acts as a molecular rotor that binds to Ag adatoms and the substrate. Four different rotation axes are constructed at positions from the center to the periphery of the molecule. Furthermore, using the asymmetric appearance of the modified molecule, the rotation direction of the molecules is identified. This work provides a new approach for designing molecular rotors or motors with definable rotation radii and functions. [ABSTRACT FROM AUTHOR]

A new type of two-dimensional crystal comprising supramolecular pentamers on Au(111) is studied using an ultra-high vacuum low-temperature scanning tunnelling microscope. (2E,4E)-3-Methyl-5-(2,6,6-trimethylcyclohex-1-enyl)penta-2,4-dienoic acid molecules form pentamers through five-fold O…H–O hydrogen bonds. In ordered arrays, pentamers interact with each other via van der Waals interactions. The impacts of different annealing temperatures and substrates on the formation of pentamer patterns are systemically investigated. [ABSTRACT FROM AUTHOR]

Collagen is the main protein and component of extracellular matrix, and it can promote the osteogenic differentiation of stem cells. Herein, a scaffold composed of carboxymethyl chitosan, hyaluronic acid and collagen was fabricated through covalent crosslinking, followed by investigating the physical and chemical properties of the scaffold. Thereafter, BMSCs were seeded into the scaffold and cultured in complete DMEM. The adhesion, proliferation and live/dead status of BMSCs in the scaffold were measured by a WST kit and live/dead kit. Finally, the alkaline phosphatase activity and osteocalcin secretion were investigated at various time points. The results demonstrated that the collagen-based scaffold could promote the adhesion, proliferation and osteogenic differentiation of BMSCS in comparison with the non-collagen scaffold. This 3D scaffold system provides a general strategy for fabricating collagen-based scaffolds, which can be used as 3D scaffolds in bone tissue engineering. [ABSTRACT FROM AUTHOR]

The construction of in situ grown porous structures can enlarge the contact area between electrodes and electrolyte and shorten the distance for ion diffusion, boosting the electrochemical properties of electrode materials. Herein, we combine molten-salt electrodeposition and AlP-assisted solvothermal phosphorization to design porous NiCoP in situ grown on Ni foam (p-NiCoP/NF). Even with a high mass loading of 10.1 mg cm−2, the as-prepared p-NiCoP/NF exhibits a remarkable mass specific capacity (Qm) of 1279.2 C g−1 (0.99 A g−1) and good rate capability. Furthermore, the p-NiCoP/NF//AC device, assembled using p-NiCoP/NF and active carbon (AC), presents a high energy density of 45.5 W h kg−1 at a power density of 124.2 W kg−1 and superior cycling stability (92.86% retention after 10 000 cycles). Finally, we introduce a four-electrode system to study the effect of the potential window of the positive and negative electrodes in an asymmetric supercapacitor (ASC) on its energy density, where it boosts the energy density and rate capability at the optimal working state. [ABSTRACT FROM AUTHOR]

Aromatic end-capped acceptors are important in constructing donor materials and non-fullerene acceptors in organic solar cells. However, their features (such as electron-withdrawing ability and subtle change in planarity) and effects on molecular stacking and photovoltaic performance, lack a systematic study. This manuscript reports four molecules, namely, BT-RCN, BT-BA, BT-RA, and BT-ID, which are terminated by different acceptors in the same backbone. We quantify the molecular planarity through their dipole moment in the Z direction and investigate the effect of the degree of planarity on molecular properties and device performances. The four acceptors are classified into two groups based on acceptor strength: medium-strong and strong acceptors. Molecules based on medium-strong acceptors exhibit excellent efficiencies as follows: 10.1% for BT-ID, 9.6% for BT-RA, and 8.5% for BT-BA. Their decreased efficiency is quite consistent with their lowered hole mobility. Grazing incidence X-ray diffraction results demonstrate the positive relationship between the non-planarity of the acceptors and d-spacing distance in the π–π stacking direction, which are detrimental to mobility. BT-RCN, with a strong acceptor, obtains the lowest efficiency of 6.1%. These findings indicate the importance of matching the electron-donating ability of donor units and electron-withdrawing ability of acceptor units, and the subtle planarity change in molecular properties and aggregation. [ABSTRACT FROM AUTHOR]

As potential catalytic materials for the oxygen evolution reaction, abundant and eco-friendly iron-based materials are often limited by inferior electrical conductivity. Herein, we propose a cost-effective and facile strategy to prepare a Fe/C heterostructured composite (Fe/Fe3C–F@CNT) via ultra-fast pyrolysis of ferrocene based on the induction and microwave thermal effect of multiwalled carbon nanotubes (CNTs). Fe/Fe3C–F@CNT exhibits a novel heterostructure where carbon-encapsulated Fe/Fe3C nanoparticles are uniformly distributed on the surface of CNTs and small iron-based nano-clusters exist on the surface of carbon layer, thus improving the electrical conductivity and dispersion of active sites. Fe/Fe3C–F@CNT shows superior OER catalytic performance, which is better than that of many Co- and Ni-based catalysts and even superior to that of RuO2. Furthermore, the catalytic performance further improved by loading Fe/Fe3C–F@CNT on the commercial foam iron. The resultant composite required a low overpotential (286 mV) to reach the current density of 10 mA cm−2. The durable catalytic stability, exhibiting no significant degradation at 100 mA cm−2 after 320 h, makes Fe/Fe3C–F@CNT a promising efficient, low-cost and environmentally-friendly OER catalyst for application in water electrolysis and metal–air batteries. More importantly, this study greatly shortens the preparation time required to fabricate uniform Fe/C heterostructures. This study brings a new inspiration for fabricating various materials for application as green energy sources. [ABSTRACT FROM AUTHOR]

Tuning the spin-dependent electron transport through molecules is of fundamental importance in single-molecule spintronics. Here, the transport properties of iron phthalocyanine on Au(111) was investigated by a combination of scanning tunneling microscopy and density functional theory calculations. Using high-resolution scanning tunneling spectroscopy performed at 0.5 K, a Kondo resonance was observed on FePc. After removing its eight outermost hydrogen atoms, the spectroscopic feature changed into a double-step structure, which reflected inelastic transitions of molecular spin states. The density functional theory calculations revealed that the coupling between Fe and Au(111) became much weaker after cutting the hydrogen atoms. This explained the change of the spin-related fingerprints in the differential spectra. [ABSTRACT FROM AUTHOR]

The activation of C–H bonds in terminal alkynyl groups at room temperature was achieved in the reaction of 2,5-diethynyl-1,4-bis(4-bromophenylethynyl)benzene on Ag(111). Scanning tunneling microscopy studies showed the formation of organometallic species, whose stabilization was confirmed by density functional theory calculations, at room temperature as the product of C–H bond activation. The partial conversion of organometallic structures into covalent products of the homocoupling between the terminal alkynes was achieved by further annealing the sample at 420 K. Detached Br adatoms were suggested to play a key role in promoting the C–H bond activation. This proposal was supported by the theoretical study based on a simplified model of the system, showing the weakening of the C–H bond in the alkynyl group by an approaching Br atom. The results provide a new strategy for on-surface C–H bond activation under mild conditions, which register great potential applications in on-surface synthesis and bottom-up preparation of functional nanomaterials. [ABSTRACT FROM AUTHOR]

Sierpiński triangles up to the fourth order were successfully prepared using 4,4′′-dicyano-1,1′:3′,1′′-terphenyl molecules and Fe or Co atoms with the coexistence of the third molecules (C60 or MnPc) on a reconstructed Au(111) substrate. Sierpiński triangles could be disturbed and restored by C60 molecules after annealing at 400 and 360 K, respectively. The dispersed MnPc molecules did not affect the formation of Sierpiński triangles when annealed at high temperatures. The selective adsorption of MnPc molecules at certain holes of Sierpiński triangles was observed. [ABSTRACT FROM AUTHOR]

MgO–rGO hybrid catalysts with a sandwich structure have been successfully prepared through a simple “solid–solid” method. Obviously enhanced reactivity is observed on the hybrid catalysts in ethylbenzene dehydrogenation reactions, which is attributed to the sandwich structure and the synergistic effect between MgO and rGO. [ABSTRACT FROM AUTHOR]

Macromolecular contrast agents labeled with targeting ligands are now receiving growing interest in tumor-targeted magnetic resonance imaging. In this study, a macromolecular contrast agent based on PEGylated chitosan was synthesized and characterized, and its application as an MRI contrast agent was then demonstrated both in vitro and in vivo. First, the chitosan backbone was partially grafted with poly(ethylene glycol), which was used to improve the in vivo stability, followed by modifying with azide groups. Second, alkynyl-terminated PAMAM dendron modified with gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) was synthesized and conjugated onto the chitosan backbone through click chemistry. Finally, the obtained mCA was further functionalized with folic acid to improve the target specificity. The obtained FA labeled mCA exhibited higher relaxivity (9.53 mM−1 s−1) relative to Gd-DTPA (4.25 mM−1 s−1) and showed negligible toxicity as determined by the WST assay. In vivo MRI results suggested that a relatively high signal enhancement was observed in the tumor region, which made it a promising candidate for tumor-targeted MRI CA. [ABSTRACT FROM AUTHOR]

Hierarchical self-assembly of 13-cis-retinoic acid on Au(111) and Ag(111) was investigated using low-temperature scanning tunnelling microscopy. On both surfaces, molecules form dimers by hydrogen bonds and the dimers arrange into ordered two-dimensional arrays through van der Waals forces. Three packing modes are observed on Au(111) and only one on Ag(111). We tentatively attribute the different patterns on the two surfaces to a stronger molecule–substrate interaction on Ag(111) and site-dependent molecular adsorption on different atomic lattices. In addition, 13-cis-ReA on Au(111) can be made to carry a localized spin. [ABSTRACT FROM AUTHOR]

This review summarizes recent research progress in the measurement and tuning of the electron spins of alien atoms and molecules adsorbed on well-defined substrates. After a brief introduction to the main experimental techniques employed to study surface electron spins, some well-explored systems consisting of atomic and molecular spin-carriers at surfaces are overviewed from a chemist's viewpoint, focusing on the experimental measurements and chemical modifications of the electron spin states of the alien entities at the surfaces on the atomic/molecular level. Finally, personal perspectives have been provided, aiming at describing some of the remaining issues that need to be addressed in the future and proposing potential applications in surface chemistry. [ABSTRACT FROM AUTHOR]

Crystalline structures with Sierpiński triangles as building blocks were constructed via a templating method in an ultra-high vacuum and studied by low-temperature scanning tunneling microscopy. Cobalt atoms and 4,4′′-dicyano-1,1′:3′,1′′-terphenyl molecules were used to build the Sierpiński triangles. The Au(100)-(hex), Au(111)-22 ×UGRAPHIC DISPLAY="INLINE" ID="UGT1" SRC="UGT1"/, and stepped Au(111) surfaces were used as templates to guide the packing of Sierpiński triangles. One-dimensional double chains and two-dimensional small domains of Sierpiński triangles were successfully prepared using the method in experiments. [ABSTRACT FROM AUTHOR]

Kinetically controlled hierarchical self-assemblies of all-trans-retinoic acid on Au(111) were investigated via low-temperature scanning tunneling microscopy in ultra-high vacuum. The dominant molecular hierarchical superstructure could be selectively controlled to dimer, tetramer, or pentamer patterns, which were stabilized by hydrogen bonds and van der Waals interactions. [ABSTRACT FROM AUTHOR]

Ordered two-dimensional arrays of silver adatoms with tunable metal atom density stabilized by 1,4-diethynyl-2,5-dimethylbenzene, a terminal alkyne, were prepared on Ag(111) and scrutinized by scanning tunneling microscopy and density functional theory calculations. Stabilization of the adatom arrays was attributed to the substrate-mediated electron localizations of the Ag adatom and terminal alkynyl in the molecule. [ABSTRACT FROM AUTHOR]

As the rate-limiting step in the water-splitting system, the oxygen evolution reaction (OER) is restricted by sluggish kinetics. Therefore, highly efficient and earth-abundant catalysts are required to lower the anodic overpotential and accelerate the reaction rate. In this study, we developed a cobalt–iron phytate (Co–Fe–phy) nanoparticle oxygen-evolving electrocatalyst that possesses a great degree of amorphization, nanoporous structure and large electrochemically active surface area. These merits with the addition of the synergistic interaction between metals and phytate most probably lead to a superior activity. It can be noted that this catalyst displays a low overpotential of 278 mV to reach a 10 mA cm−2 current density and a small Tafel slope of 34 mV dec−1 in 1 M KOH, of which the performance exceeds commercial RuO2. Moreover, its exceptional durability was evaluated with the current density decreases approximately 5.6% after 10 h when compared to the initial value. More significantly, Co–Fe–phy as an anode shows a decrease in energy consumption in the practical hydrogen production configuration when compared with RuO2 and a commercial electrolyzer. This study not only highlights that the bimetallic phytate-based-catalyst owns extraordinary performance that a monometallic system can hardly reach, but also enables it as an extremely promising catalyst to substitute noble metal catalysts in water electrolysis and other devices. [ABSTRACT FROM AUTHOR]

Aptamers are short single-stranded DNA or RNA, which can be selected from a random combinatorial library by the systematic evolution of ligands by exponential enrichment (SELEX) in vitro. In order to obtain novel selective light-up ligands for berberine, we selected DNA aptamers for berberine by a modified affinity chromatography-based SELEX. The ssDNA library was coupled on streptavidin-coated agarose beads through the hybridization with a biotin labeled complementary oligonucleotide capture strand, and the aptamer sequences were released from agarose beads through berberine binding. This method to isolate the aptamers was simple, straightforward and effective, and three aptamers with low micromolar dissociation constants (Kds) were achieved after only 6 rounds of selection. The best of them was further optimized, and the shortened aptamers showed similar Kds to the full length sequences. The light-up phenomenon of the berberine–aptamer pair was also investigated and the final minimized 21-mer aptamer which showed higher fluorescence enhancement than G-quadruplex structures could be used as a novel light-up fluorescent probe for various biosensing applications. [ABSTRACT FROM AUTHOR]

In this study, a novel protein–polymer conjugate, d-α-tocopheryl polyethylene glycol succinate modified reduced bovine serum albumin (TPGS–Re-BSA, TRB), was synthesized for lipophilic anticancer drug delivery, and its unique ability to overcome drug resistance was explored. This conjugate was extensively characterized for its chemical structure, average molecular weight, secondary structure, degree of substitution, hydrophobicity, particle size and zeta potential. PTX-loaded nanoparticles (NPs) with diameters of 170–370 nm and drug loading efficiency of up to 13.62% were successfully prepared by the dialysis method. These drug-loaded NPs were found to exhibit a sustained release of PTX at pH 7.4, 6.5 and 5.5. Moreover, great anti-tumor activity in drug sensitive MCF-7 cells was observed in the in vitro anti-tumor studies. In particular, enhanced cytotoxicity and PTX-induced apoptosis were observed in the drug-resistant MCF-7/ADR cells compared to the Taxol and PTX-loaded BSA NPs. This could be attributed to the significant inhibition of P-gp activity and reduced ATP levels due to the presence of TRB NPs. Lastly, in vivo tumor inhibition assay verified the higher efficacy of TRB NPs. Overall, the results suggest that this TRB NPs could provide an effective carrier system for the delivery of anticancer agents. [ABSTRACT FROM AUTHOR]