Search

SnTe, as one type of topological crystal insulator (TCI), has crystal-symmetry-protected surface states, which is sensitive to its structure and lattice symmetry. Herein, the monolayer SnTe was well synthesized, presenting with tetragonal and hexagonal lattice symmetries, respectively. The lattice symmetry was found to be connected with precursors, as thermal evaporation of SnTe compounds led to a tetragonal type symmetry while co-deposition of Sn and Te elements can synthetize the hexagonal type. As a consequence of lattice mismatch with the underlying Au(111) substrate, SnTe with tetragonal lattice exhibits reconstructive stripe pattern, which would transform into hexagonal lattice symmetry with moiré pattern upon annealing at high temperature. Due to coupling with the substrate, SnTe exhibits metallicity in both symmetries, verified by corresponding differential conductance spectra (dI/dV). Comparative study on Cu(111) substrate was carried out and only copper telluride structures were formed, which may be related to the stronger surface decomposition of SnTe precursors on Cu(111) and direct copper tellurizing. Our work paves a practical way to control the surface structure and lattice symmetry of SnTe, providing a promising candidate for potential TCI applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) chromium selenide with different stoichiometries have attracted considerable interest because of their exotic electronic and magnetic properties. Herein, the monolayer CrSe2 on the Au(111) substrate was synthesized by molecular beam epitaxy and annealed to form monolayer Cr2Se3, which was revealed by the scanning tunneling microscopy. Moiré superstructure in CrSe2/Au(111) was observed with a twist angle of ∼1.5°, and the stacking position-dependent p-type semiconducting characteristic of CrSe2 on Au(111) was recorded by scanning tunneling spectroscopy. Due to the annealing induced strong interfacial interaction, structural and electronic properties transited from CrSe2 to Cr2Se3, with the latter exhibiting metallic feature. Correspondingly, the original Se8 molecules surrounding CrSe2 assembled into 3 × 3 R30°-Se/Au reconstruction, which further verified the structural transition. Our work provides a basis for fundamental study of stoichiometric-dependent physics and potential applications in data storage devices. [ABSTRACT FROM AUTHOR]

Immunogenic cell death (ICD) induced by calcium ion (Ca2+) overload has attracted significant attention owing to its ability to activate the immune system and generate durable antitumor immune responses. However, the slow release of Ca2+ by commonly used nanomodulators provides tumor cells with the opportunity to efficiently eliminate excess Ca2+ through ion channels, thus diminishing the therapeutic efficacy. Consequently, it is crucial to explore strategies for rapid Ca2+ release. To address this issue, a glutathione‐triggered Ca(IO3)2@starch‐based Ca2+ nanobomb is presented. This nanobomb not only enables accurate and efficient Ca2+ delivery to the tumor site but also exploits glutathione‐triggered photoacoustic (PA) imaging‐guided photothermal precise control of TRPV1 ion channel activation for enhancing the Ca2+ influx. Both in vitro and in vivo results confirm that the photothermally regulated Ca2+ influx based on this Ca2+ nanobomb effectively promotes ICD and stimulates immune infiltration in tumor tissues, ultimately leading to the effective inhibition of tumor growth and metastasis. The developed Ca2+ nanobomb presents a potential strategy to enhance ICD based on Ca2+ overload, thus addressing the challenges associated with precise and timely regulation of Ca2+ influx and offering prospects for improved antitumor immunotherapy. [ABSTRACT FROM AUTHOR]

Pancreatic cancer, a prevalent malignancy of the digestive system, has a poor 5‐year survival rate of around 10%. Although numerous minimally invasive alternative treatments, including photothermal therapy and photodynamic therapy, have shown effectiveness compared with traditional surgical procedures, radiotherapy, and chemotherapy. However, the application of these alternative treatments is constrained by their depth of penetration, making it challenging to treat pancreatic cancer situated deep within the tissue. Sonodynamic therapy (SDT) has emerged as a promising minimally invasive therapy method that is particularly potent against deep‐seated tumors such as pancreatic cancer. However, the unique characteristics of pancreatic cancer, including a dense surrounding matrix, high reductivity, and a hypoxic tumor microenvironment, impede the efficient application of SDT. Thus, to guide the evolution of SDT for pancreatic cancer therapy, this review addresses these challenges, examines current strategies for effective SDT enhancement for pancreatic cancer, and investigates potential future advances to boost clinical applicability. This article is categorized under:Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease [ABSTRACT FROM AUTHOR]

Copper sulfide based phototherapy, including photothermal therapy and photodynamic therapy, is an emerging minimally invasive treatment of tumor, which the light was converted to heat or reactive oxygen to kill the tumor cells. Compared with conventional chemotherapy and radiation therapy, Cu2−xS based phototherapy is more efficient and has fewer side effects. However, considering the dose‐dependent toxicity of Cu2−xS, the performance of Cu2−xS based phototherapy still cannot meet the requirement of the clinical application to now. To overcome this limitation, engineering of Cu2−xS to improve the phototherapy performance by increasing light absorption has attracted extensive attention. For better guidance of Cu2−xS engineering, we outline the currently engineering method being explored, including (1) structural engineering, (2) compositional engineering, (3) functional engineering, and (4) performance engineering. Also, the relationship between the engineering method and phototherapy performance was discussed in this review. In addition, the further development of Cu2−xS based phototherapy is prospected, including smart materials based phototherapy, phototherapy induced immune microenvironment modulation et al. This review will provide new ideas and opportunities for engineering of Cu2−xS with better phototherapy performance. This article is categorized under:Diagnostic Tools > In Vivo Nanodiagnostics and ImagingTherapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease [ABSTRACT FROM AUTHOR]

PbSe, a predicted two-dimensional (2D) topological crystalline insulator (TCI) in the monolayer limit, possess excellent thermoelectric and infrared optical properties. Native defects in PbSe take a crucial role for the applications. However, little attention has been paid to the defect induced doping characteristics. Here, we provide an experimental and theoretical investigation of defect induced p-type characteristic on epitaxial monolayer PbSe on Au(111). Scanning tunneling microscopy (STM) measurements demonstrate an epitaxial PbSe monolayer with a fourfold symmetric lattice. Combined scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations reveal a quasi-particle bandgap of 0.8 eV of PbSe. STM results unveil that there are two types of defects on the surface, one is related the vacancies of Pb atoms and the other is the replacement of the absent Se atoms by Pb. Corresponding theoretical optimization confirms the structures of the defects. More importantly, both STS measurements and DFT calculations give evidence that the Pb vacancies move the Fermi energy inside the valence band and produce extra holes, leading to p-type characteristics of PbSe. Our work provides effective information for the future research of device performance based on PbSe films. [ABSTRACT FROM AUTHOR]

Radionuclides theranostic are ideal "partners" for bispecific antibodies to explore the immune response of patients and synergistic treatment. A bispecific single-domain antibody-Fc fusion protein, KN046, exhibits a good treatment effect by binding to programmed cell death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). An ionizing-radiation stimulus mediated by a low-dose of [131I] may be used for immunopotentiation. In this study, we established [131I]-labeled KN046 as a novel radioimmunotherapy agent to treat malignant melanoma and explored the mechanism. Methods: After intravenous injection of [131I]-KN046, SPECT/CT imaging was applied to identify candidate targets for KN046 immunotherapy. [18F]-FDG and [68 Ga]-NOTA-GZP (granzyme B-specific PET imaging agent) micro-PET/CT imaging was used to assess the immune response in vivo after [131I]-KN046 treatment. The synergistic treatment effect of [131I]-KN046 was evaluated by exploring the [131I]-based radionuclide-induced release of tumor immunogenicity-related antigens as well as the histology and survival of tumor-bearing mice after treatment. Results: The constructed [131I]-KN046 exhibited high affinity and specificity for PD-L1/CTLA-4 immune targets and had excellent in vivo intratumoral retention capability so as to achieve good antitumor efficacy. More importantly, the combination of low-dose [131I] and KN046-enhanced immunosensitivity increased the immunotherapy response rates significantly. Exposure of tumor cells to [131I]-KN046 led to upregulated expression of MHC-I and Fas surface molecules and significant increases in the degree of T-cell activation and counts of tumor-infiltrating immunocytes. Conclusion: Use of low-dose [131I] combined with a dual-target immunosuppressant could be exploited to identify the subset of treatment responders but also exhibited great potential for enhancing antitumor immune responses. [ABSTRACT FROM AUTHOR]

Germanene has attracted much attention because the material was predicted to host Dirac fermions. However, the synthesis of germanene is still in its infancy; moreover, the predicted tiny bandgap induced by the spin–orbit coupling is far from practical applications for nanoelectronic devices. Herein, quasi-freestanding germanene with linear dispersion relation of the band structure is well grown on a WSe2/Au(100) substrate. Band structure calculations reveal that the interaction of germanene with the substrate destroys the sublattice symmetry. The energy-dependent contribution of σ orbitals responsible for band crossing at the Fermi level around the Γ point induces asymmetric density of states at the Dirac point. Upon annealing in ultra-high vacuum, we observe a bandgap opening in germanene of about ∼0.17 eV, which is attributed to a sublattice symmetry breaking in germanene and the emergence of a net electric field. This work provides an effective method to tune or tailor the electronic properties of germanene, paving the way to germanene-based field-effect applications. [ABSTRACT FROM AUTHOR]

Background: Endogenous hydrogen sulfide (H2S)-responsive theranostic agents have attracted extensive attention due to their specificity for colon cancer. However, the development of such agents with high enrichment in tumors and excellent photothermal performance remains challenging. Results: We prepared hyaluronic acid (HA)-coated Bi-doped cuprous oxide (Bi:Cu2O@HA) via a one-pot method. The HA specifically targets colon cancer tumor cells to improve the enrichment of Bi:Cu2O@HA at tumor sites, while the doped Bi both enhances the photothermal performance of the H2S-triggered Cu2O and serves as an agent for tumor imaging. The results in this work demonstrated that the Bi:Cu2O@HA nanoparticles exhibit good biocompatibility, target colon cancer tumor cells, facilitate computed tomography imaging, and enhanced H2S-responsive photothermal therapy performance, resulting in an excellent therapeutic effect in colon cancer. Conclusions: The novel Bi:Cu2O@HA nanoparticles exhibit excellent tumor targeting and photothermal therapeutic effects, which provide new strategies and insights for colon cancer therapy. [ABSTRACT FROM AUTHOR]

Combinations of immune checkpoint therapies show encouraging results in the treatment of many human cancers. However, the higher costs and greater side effects of such combinations compared with single‐agent immunotherapies limit their further applications. In this work, a novel smart agent, KN046@19F‐ZIF‐8, is developed to overcome these limitations. KN046 is a novel recombinant humanized PD‐L1/CTLA‐4 bispecific single‐domain antibody‐Fc fusion protein, which can bind to both PD‐L1 and CTLA‐4 effectively. ZIF‐8 is a smart delivery system, which can safely and effectively deliver KN406 to a tumor. In vitro and in vivo results demonstrate that the smart agent KN046@19F‐ZIF‐8 not only improves the immune response rate of the antibody drug in treatment of tumors but also reduces its toxic side effects, thereby achieving excellent antitumor efficacy. This study provides an engineering strategy for clinical applications of a more effective immunotherapy. [ABSTRACT FROM AUTHOR]

Gd–chelate magnetic resonance imaging (MRI) contrast agents used in conventional clinical medicine still have some shortcomings, such as their low relaxation rates and poor imaging sensitivity. In this work, a Gd–chelate (Gd–DTPA), with a comparison made to the commercial contrast agent Magnevist was loaded into a zeolitic imidazolate framework (ZIF-8) to construct the efficient T1 MRI contrast agent Gd–DTPA@ZIF-8. At 0.5 T, the longitudinal relaxivity value (r1) of Gd–DTPA@ZIF-8 reaches 29.60 mM−1 s−1, which is about 6 times higher than that of Gd–DTPA. In terms of the retention of Gd–DTPA in ZIF-8, no obvious Gd3+ ions are released in water and complete culture solution over a long time period. Haemolysis and cytotoxicity experiments revealed that Gd–DTPA@ZIF-8 has good biocompatibility. In addition, the in vivo MRI results prove that Gd–DTPA@ZIF-8 can significantly enhance the T1-weighted MRI contrast effect of the tumour site. These advantages make Gd–DTPA@ZIF-8 a potential candidate for biomedical applications. [ABSTRACT FROM AUTHOR]

Intensive efforts have been devoted to surface Ullmann-like coupling in recent years, due to its appealing success towards on-surface synthesis of tailor-made nanostructures. While attentions were mostly drawn on metallic substrates, however, Ullmann dehalogenation and coupling reaction on semimetal surfaces has been seldom addressed. Herein, we demonstrate the self-assembly of 2, 7-dibromopyrene (Br2Py) and the well controllable dehalogenation reaction of Br2Py on the Bi(111)–Ag substrate with a combination of scanning tunnelling microscopy (STM) and density functional theory calculations (DFT). By elaborately investigating the reaction path and formed organic nanostructures, it is revealed that the pristinely inert bismuth layer supported on the silver substrate can initiate Ullmann-like coupling in a desired manner by getting alloyed with Ag atoms underneath, while side products have not been discovered. By clarifying the pristine nature of Bi–Ag(111) and Ullmann-like reaction mechanisms, our report proposes an ideal template for thoroughly exploring dehalogenative coupling reaction mechanisms with atomic insights and on-surface synthesis of carbon-based architectures. [ABSTRACT FROM AUTHOR]

Second near-infrared window (NIR-II, 1000–1700 nm) absorption and fluorescent agents have attracted great attention because they can overcome the penetration limitation of the first near-infrared window (NIR-I, 750–1000 nm). However, these always "on" agents face the severe problem of being susceptible to retention and phagocytosis by the reticuloendothelial system after intravenous administration, which results in signal interference during diagnosis and side effects during treatment. Accordingly, tumor microenvironment-responsive smart agents (smart NIR-II agents), whose imaging and therapeutic functions can only be triggered in tumors, can overcome this limitation. Thus, NIR-II smart agents, which exhibit a combined response to the tumor microenvironment and NIR-II, make full use of the advantages of both triggers and improve the precision diagnosis and effective treatment of cancer. This review summarizes the recent advances in tumor microenvironment-activated NIR-II agents for tumor diagnosis and treatment, including smart NIR-II fluorescence imaging, photoacoustic imaging, photothermal therapy and photodynamic therapy. Finally, the challenges and perspectives of NIR-II smart agents for tumor diagnosis and treatment are proposed. [ABSTRACT FROM AUTHOR]

A small Fe3O4 nanoparticles-based T1 contrast agent was assembled into a pH- and glutathione-responsive T2–T1 switching contrast agent, Fe3O4–ZIF-8. In vivo T1-weighted images of mice showed that Fe3O4–ZIF-8 displayed darkening contrast enhancement for liver sites, while darkening to brightening contrast enhancement at tumor sites, giving large inverse contrast for distinguishing the normal and tumor tissues. [ABSTRACT FROM AUTHOR]

Expression of a high concentration of H2S is closely related to the formation of colon cancer tumors. However, only a few H2S‐triggered theranostics agents for colon cancer have been reported to date. Now, a turn‐on theranostics agent was developed by utilizing the in situ reaction of Cu2O and endogenous H2S at colon tumor sites. Based on in vitro and in vivo experiments, excellent photoacoustic imaging and photothermal therapy were both confirmed by this in situ reaction‐activated colon cancer theranostics method. This work established a simple and efficient strategy for both diagnosis and treatment of colon cancer with a novel trigger mechanism, which provides a new route for colon cancer theranostics based on the in situ reactions at the tumor sites. A turn‐on theranostics agent was developed by utilizing the in situ reaction of Cu2O (see picture: brown) and endogenous H2S (yellow) at colon tumor sites. Based on in vitro and in vivo experiments, excellent photoacoustic imaging and photothermal therapy were both confirmed after being triggered by this in situ reaction. Cu9S8 shown in green. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

By exploiting the amorphous–crystalline transition of CuS, which results in greatly increased absorption throughout the entire near-infrared region, a novel smart off–on CuS photoacoustic imaging agent with good photostability and low cost is developed. More importantly, the photoacoustic imaging ability of CuS can be effectively activated by body temperature for in vivo cancer imaging. [ABSTRACT FROM AUTHOR]

Water-soluble polymer nanoparticles NP-1 and NP-2 were prepared by using a three-component self-assembly of an iridium complex, poly(4-vinyl pyridine-b-ethylene oxide) (P4VP-b-PEO), and methane sulfonic acid (MSA). Due to the unique metal-ligand charge-transfer transition property and the heavy-atom effect of the iridium atom, NP-1 and NP-2 showed bright phosphorescence and generated the singlet oxygen (1O2) species effectively under visible-light irradiation ( λ>400 nm) with a power density of 300 mW cm−2. NP-2, an example of the polymer nanoparticles, showed minimal cytotoxic activity in the dark. Laser confocal fluorescence and flow-cytometry microscopy experiments demonstrated that NP-2 could be taken up by a model cancer-cell line of 4T1 cells, which could be used as a phosphorescent probe for cell imaging by preferentially staining the cytoplasm. After 6 hours of incubation with NP-2 (100 μg mL−1), the cell viability of 4T1 cells decreased to approximately 10 % upon visible-light irradiation ( λ>400 nm, 300 mW cm−2) only for 10 minutes as a result of the generation of the 1O2 species, thus indicating a proof of concept for effective photodynamic therapy for cancer cells. [ABSTRACT FROM AUTHOR]

A nanotheranostic agent has been fabricated by direct deposition of Bi2Se3 nanoparticles on graphene oxide (GO) in the presence of polyvinylpyrrolidone (PVP) using a one-pot solvothermal method. The resulting GO/Bi2Se3/PVP nanocomposites show low in vitro cytotoxicity, negligible hemolytic activity and little in vivo toxicity. GO/Bi2Se3/PVP nanocomposites could serve as an efficient bimodal contrast agent to simultaneously enhance X-ray computed tomography imaging and photoacoustic imaging in vivo. In addition, the nanocomposites exhibit significant photothermal cytotoxicity to cancer cells under 808 nm laser irradiation. After intratumoral or intravenous injection of the nanocomposites, irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using 808 nm laser irradiation. All of the positive results highlight that the GO/Bi2Se3/PVP nanocomposites can be developed as a promising nanoplatform for efficient tumor theranostic applications. [ABSTRACT FROM AUTHOR]

With the development of personalized medicine, the research of theranostic agents with good biocompatibility, stability, and targeting properties remains meaningful. Herein, we report a two-step process to construct heteropoly blue (HPB) doped polymer nanoparticles (HPB/P4VP-b-PEO NPs) with efficient near-infrared (NIR) light absorption and photothermal conversion efficiency of ∼23% to simultaneously perform photoacoustic imaging and photothermal therapy in vivo. After intravenous injection into the 4T1 xenograft model, in vivo photoacoustic imaging confirmed the targeted property of HPB/P4VP-b-PEO NPs due to the enhanced EPR effect. The photoacoustic signal in the tumor at 24 h p.i. was more than ∼10 times that of the pre-injection group. By virtue of their EPR effect, HPB/P4VP-b-PEO NPs achieved a good photothermal therapeutic efficacy in vivo. [ABSTRACT FROM AUTHOR]

Direct synthesis of hierarchical zeolites currently relies on the use of surfactant-based templates to produce mesoporosity by the random stacking of 2D zeolite sheets or the agglomeration of tiny zeolite grains. The benefits of using nonsurfactant polymers as dual-function templates in the fabrication of hierarchical zeolites are demonstrated. First, the minimal intermolecular interactions of nonsurfactant polymers impose little interference on the crystallization of zeolites, favoring the formation of 3D continuous zeolite frameworks with a long-range order. Second, the mutual interpenetration of the polymer and the zeolite networks renders disordered but highly interconnected mesopores in zeolite crystals. These two factors allow for the synthesis of single-crystalline, mesoporous zeolites of varied compositions and framework types. A representative example, hierarchial aluminosilicate (meso-ZSM-5), has been carefully characterized. It has a unique branched fibrous structure, and far outperforms bulk aluminosilicate (ZSM-5) as a catalyst in two model reactions: conversion of methanol to aromatics and catalytic cracking of canola oil. Third, extra functional groups in the polymer template can be utilized to incorporate desired functionalities into hierarchical zeolites. Last and most importantly, polymer-based templates permit heterogeneous nucleation and growth of mesoporous zeolites on existing surfaces, forming a continuous zeolitic layer. In a proof-of-concept experiment, unprecedented core-shell-structured hierarchical zeolites are synthesized by coating mesoporous zeolites on the surfaces of bulk zeolites. [ABSTRACT FROM AUTHOR]

The morphology-selective synthesis of well-aligned Cu2-xSe nanostructures including nanosheets, nanoribbons, and heterostructures on copper substrate has been achieved by a simple hydrothermal route; the micropatterned assembly of Cu2-xSe nanostructures has been realized using a copper grid to direct the growth on prescribed arbitrary patterns with unprecedented control and selectivity. The control experimental conditions, such as hydrothermal temperature and time, and concentration of NaOH have been found to be important parameters for the growth process of the Cu2-xSe nanostructures. So-called “coordination assembly” has shown to be dominant in the formation of the Cu2-xSe nanostructures, consisting of an initial nucleation and subsequent vertical growth on the copper substrate. The wettability properties of the Cu2-xSe nanostructures have been investigated, and the water contact angle from these nanostructured materials has been measured to be up to 160°, showing a superhydrophobicity. These results might provide a facile route for the preparation of novel micropatterned and high assemblies of nanostructures on other metal substrates (e.g.Al, Zn, Mg, etc.), for which a number of promising applications in microelectronic fields can be envisioned. [ABSTRACT FROM AUTHOR]

The doping level of Si is crucial for its optical and electrical properties, and only highly doped porous Si nanowires have been reported in recent studies. Herein, we demonstrate the fabrication of lightly doped single crystalline porous Si nanowire arrays through metal-assisted chemical etching from lightly doped n-type (100) Si wafers. In this process, though the etching temperature and concentration of H2O2in the etchant have significant effects on the uniformity and density of the porosity of the Si nanowires, the forming porous Si nanowires is available without the use of H2O2in the etchant, which is different from the previous cases of fabricating porous Si nanowires from a highly doped Si wafer. Importantly, as-fabricated lightly doped porous Si nanowire arrays possess improved optical and electrical properties: the current value range of individual porous Si nanowire is ∼3 times as large as that of an individual solid Si nanowire under the same applied voltages range, suggesting that porous Si nanowires have enhanced electrical conductivity; an intensive photoluminescence emission peak is centered at 560 nm, showing a blue-shift of 90–120 nm compared with those of highly doped Si nanowires. The results indicate that the lightly doped single crystalline porous Si nanowires may shed light on new opportunities for nanoscale optoelectronic devices, electronics, photo-catalytic substrates and sensors. [ABSTRACT FROM AUTHOR]

UCNPs (NaYF4) were efficiently converted to a self-assembled network of a low molecular-weight gelator, thus reinforcing the gel structure and leading to the formation of hybrid multi-colour system through excitation by NIR light. [ABSTRACT FROM AUTHOR]

Self-assembled strategy has been proven to be a promising vista in constructing organized low-dimensional nanostructures with molecular precision and versatile functionalities on solid surfaces. Herein, we investigate by a combination of scanning tunneling microscopy (STM) and dispersion-corrected density functional theory (DFT), the adsorption of tetracene molecules on the silver substrate and the mechanism mediating the self-assembly on Ag(110). As expected, ordered domain is formed on Ag(110) after adsorption with adjacent molecules being imaged with alternating bright or dim pattern regularly. While such behavior has been assigned previously to the difference of molecular adsorption height, herein, it is possible to investigate essentially the mechanism leading to the periodic alternation of brightness and dimness for tetracene adsorbed on Ag(110) thanks to the consideration of Van der Waals (vdW) dispersion force. It is demonstrated that the adsorption height in fact is same for both bright and dim molecules, while the adsorption site and the corresponding interfacial charge transfer play an important role in the formation of such pattern. Our report reveals that vdW dispersion interaction is crucial to appropriately describe the adsorption of tetracene on the silver substrate, and the formation of delicate molecular architectures on metal surfaces might also offers a promising approach towards molecular electronics. [ABSTRACT FROM AUTHOR]

Considerable efforts have been focused on the exploitation of macromolecule ligands for synthesis of magnetic Fe3O4 nanoparticles as T1 magnetic resonance imaging (MRI) contrast agents, but studies that concern macromolecule ligands with different charges and coordination groups are still limited. Herein, we used poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and polyvinyl alcohol (PVA), which possess negative, positive and neutral charges with carboxylic acid, amino and hydroxyl groups respectively, as templates and stabilizers to fabricate Fe3O4 nanoparticles through coprecipitation reaction. The obtained Fe3O4-PAA, Fe3O4-PAH, and Fe3O4-PVA nanoparticles showed T1 contrast performance with r1 relaxivities of 23.4, 60.3, and 30.6 mM s−1 at 0.5 T (25 °C), and a r2/r1 ratio of 2.62, 3.82, and 7.26, respectively. The cell viability assay revealed that Fe3O4-PAA and Fe3O4-PVA exhibited good biocompatibility, while Fe3O4-PAH displayed high cytotoxicity. In vivo T1-weighted (1 T) mice showed that both Fe3O4-PAA and Fe3O4-PVA were able to display remarkably brighten the contrast enhancement for the mice tumor and kidney sites, but Fe3O4-PAA had better contrast performance. This work highlights that the macromolecule ligands play an important role in the biocompatibility and T1 contrast performance of magnetic Fe3O4 nanoparticles. [ABSTRACT FROM AUTHOR]

To optimize the iron oxide nanoparticles as T1-weight contrast for in vivo magnetic resonance imaging (MRI), numbers of macromolecule ligands have been explored with considerable effort. However, reports refer to the comparison of the T1-weight contrast performances of iron oxide nanoparticles modified with natural and artificial macromolecule ligands are still limited. In this work, we used a typical natural protein macromolecule (bovine serum albumin, BSA) and an artificial macromolecule (poly(acrylic acid)-poly(methacrylic acid), PMAA-PTTM) as surface ligands to fabricate Fe3O4-BSA and Fe3O4-PMAA-PTTM nanoparticles with similar size and magnetization by the coprecipitation method and compared their MRI performances. In vitro and in vivo experiments revealed that Fe3O4-BSA with lower cytotoxicity exhibited higher r2/r1 ratio in solution and darkening contrast enhancement for liver and kidney sites of mice under T1-weight imaging, while Fe3O4-PMAA-PTTM displayed much lower r2/r1 ratio in solution and brighter contrast enhancement for liver and kidney sites. These remarkably different MRI behaviors demonstrated that the surface ligands play an important role for optimizing the MRI performance of Fe3O4 nanoparticles. We expect these results may facilitate the design of macromolecule ligands for developing an iron oxide–based T1-weight contrast agent. [ABSTRACT FROM AUTHOR]

The oxygen concentration dependence of sonodynamic therapy (SDT) and bioreductive therapy can be utilized to design the strategy of synergistic therapy. Herein, holmium‐doped hollow silica nanospheres are synthesized and then sequentially modified with chlorin e6, carboxyl poly(ethylene glycol) silane, and prostate stem cell antigen (PSCA) monoclonal antibody. The resultant nanocomposite designated as HHSN‐C/P‐mAb has good biocompatibility and can specifically target cancer cells overexpressing PSCA. Due to the inner cavity structure and Ho doping, HHSN‐C/P‐mAb shows high ultrasound (US) imaging contrast capability and excellent high‐field magnetic resonance contrast performance. HHSN‐C/P‐mAb can act as a nanocarrier for loading the bioreductive pro‐drug tirapazamine (TPZ), and the degradation of the hollow nanospheres under the trigger of acidic microenvironment favors the pH responsive release of TPZ from the material. Upon US irradiation, HHSN‐C/P‐mAb produces reactive oxygen species to kill the cancer cells, and importantly, the oxygen consumption during SDT induces an intratumoral hypoxic environment to activate the therapeutic function of codelivered TPZ, resulting in a high‐effective synergistic therapy. The findings of this study highlight that HHSN‐C/P‐mAb is a versatile theranostic nanoplatform for efficient cancer treatment. A nanotheranostic platform based on holmium‐doped hollow silica nanospheres, designated as HHSN‐C/P‐mAb, is developed for ultrasound/magnetic resonance imaging and sonodynamic/bioreductive combined therapy. The sonodynamic therapy using HHSN‐C/P‐mAb induces a hypoxic environment in the tumor to activate the bioreductive pro‐drug tirapazamine released from the carriers by pH‐responsiveness, resulting in a high‐effective synergistic therapy. [ABSTRACT FROM AUTHOR]

A new synthetic strategy is developed for fabricating hierarchically structured zeolite materials, which features the use of cationic non‐surfactant polymers as dual‐functional templates. Y. Han and co‐workers show, on page 1881, that the mutual interpenetration of the polymer and the zeolite networks renders disordered but highly interconnected mesopores in zeolite crystals. This strategy also enables the synthesis of unprecedented core‐shell‐structured hierarchical zeolites. [ABSTRACT FROM AUTHOR]