Construction Of Nanostructures Research Articles

Oxygen Vacancy Formation at Metal‒TiO₂ Interface Yielding Enhanced Photocatalytic Hydrogen Generation.

Strong Metal-Support Interaction (SMSI) is a key concept in heterogeneous catalysis, but itremains underexplored in the context of photon-to-hydrogen conversion, as coupling of metallic nanoparticles with photocatalysts is overlooked and only discussed in terms of Schottky barrier formation. In this study, we provide deep insights into the effect of Au encapsulation with TiO2 overlayer on enhancing photocatalytic hydrogen generation. Our findings reveal that the construction of a SMSI-like nanostructure induces the formation of oxygen vacancies at the Au‒TiO2 interface which actively facilitate charge carrier separation throughinterfacial band reconstruction. The presence of defects is evidenced by Electron Paramagnetic Resonance and X-ray Photoelectron Spectroscopy, unveiling their relationship with photocatalytic activities. Consistent with experimental results, Density Functional Theory (DFT) calculations demonstrate that Au promotes oxygen vacancy formation. Thesevacancies located at the TiO2 surface significantly enhances H2O and MeOH adsorptionduring H2 evolution reactions. The SMSI-like concept was extended to Pt, Pd, and Ag, in which the oxygen vacancy formation energy at the metal-semiconductor interface varied depending on the metal, as computed by DFT. The results suggest that photocatalytic activity is related to the ease of oxygen vacancy formation, which is influenced by the nature of the metals.

Single-Molecule Detection of Optical Signals Using DNA-Based Plasmonic Nanostructures

Single-molecule optical signal detection provides high sensitivity and specificity for the detection of biomolecules and chemical substances, which is of significant importance in fields such as biomedicine, environmental monitoring, and materials science. In recent years, DNA-based plasmonic nanostructures have emerged as powerful tools for achieving single-molecule optical signal detection due to their unique self-assembly properties and excellent optical performance. In particular, DNA origami technology enables the precise construction of metallic nanostructures with specific shapes and functions, which can effectively enhance the interaction between light and matter, thereby significantly increasing signal intensity and detection sensitivity. Furthermore, the programmability of DNA not only simplifies the implementation of single-molecule operations but also allows researchers to design and optimize nanostructures according to specific detection requirements. This review will explore the applications of DNA-based plasmonic nanostructures in single-molecule optical signal detection, including surface-enhanced Raman spectroscopy and enhanced fluorescence for single-molecule signal detection. We will analyze their working principles, advantages, current research progress, and future research directions. By summarizing the work in this field, we hope to provide references and insights for researchers, contributing to the advancement of biomedicine and environmental monitoring.

Controlled Assembly of Bimetallic PtRh-Modified Tin Oxide Hollow Nanotubes with High Sensing Activity for Ultrasensitive Formaldehyde Detection.

Gas sensors for rapid identification of formaldehyde (HCHO) exposure risks are of great significance, given the volatility, toxicity, and near-imperceptibility of HCHO. However, the precise design of highly reactive sensing materials remains a substantial challenge that limits the application of gas sensors. Here, PtRh-modified tin oxide (PtRh/SnO2) hollow nanotubes with an open hollow nanostructure and bimetallic sensitization are proposed for regulating the reactivity to achieve ideal improvement in HCHO-sensing performance. The prepared 1.5% PtRh/SnO2 hollow nanotube-based sensor achieves a high sensing response (Ra/Rg = 265.8-25 ppm of HCHO), fast response and recovery rate (2.6 and 6.1 s), good selectivity, and strong anti-interference toward HCHO at 200 °C. Based on the ex/in situ characterizations and density functional theory (DFT) calculations, the enhanced sensing properties are mainly attributed to the construction of hierarchical hollow nanostructures providing sufficient active sites for gas absorption, as well as the oxygen spillover effect from Pt, the catalytic property of Rh, and their synergistic effects. Hence, the architecture demonstrates enhanced adsorption capacity and interfacial reactivity toward HCHO, thereby improving the sensing response and selectivity. In addition, the PtRh/SnO2 sensor was used to monitor the HCHO in oysters, providing promising applications in real-time aquatic product HCHO monitoring.

Soliton wall and Au adatom-induced trans-to-cis isomerization promoting the formation of multiple pairs of chiral isomers of methylcyano-functionalized molecules

The modulation of molecular adsorption configurations on surfaces, particularly regarding chirality andtrans-cisisomerization, holds significant importance for interfacial molecular science and the construction of functional nanostructures. However, limited studies have focused on the formation of multiple chiral isomer pairs from monomolecular species and the exploration of more strategies for stimulatingtrans-cisisomerization. Herein, we characterize chiral behavior of methylcyano-functionalized molecules upon adsorption on Au(111) and elucidate theirtranstocisisomerization. The soliton wall of reconstructed Au(111) surface functions as a confinement, hindering molecules from crossing the fcc region and instead prompting those in close proximity to undergotranstocisisomerization. Additionally, during the thermal annealing process, the released Au adatoms coordinate with cyano groups, inducing their flipping and leading to the formation of paired molecular chains exclusively composed ofcis-configured molecules. Three chiral enantiomeric pairs are generated from monomolecular species. The morphological changes are characterized by scanning probing measurements. Our work establishes a solid platform for fundamental research on the adsorption of methylcyano-functionalized molecules on metal surfaces and advance the understanding of surface-induced isomerization mechanisms and their dependence on substrate topology.

Programmable Protein‐DNA Composite Nanostructures: from Nanostructure Construction to Protein‐Induced Micro‐Scale Material Self‐Assembly and Functionalization

Abstract The integration of DNA and protein‐designed nanostructures represents a transformative approach to the development of programmable biopolymers for nanoscale construction. While DNA nanostructures excel in the readily programmable precision and scalability of base pairing, protein assemblies exploit the chemical diversity of amino acids for greater functional versatility. Here a platform is presented that unifies these two paradigms by combining coiled‐coil protein origami with DNA nanostructures through orthogonal protein‐protein (SpyCatcher‐SpyTag) and protein‐DNA (DCV‐DNA) covalent conjugation strategies. This dual‐functionalization strategy enables the construction of stable and versatile protein‐DNA composites capable of hierarchical self‐assembly. This shows that these composites drive the transformation of DNA nanotubes into large‐scale, patterned nanofibers or nanorods, with the proteins regularly distributed over their surface and retaining their enzymatic and fluorescent functions. In addition, a DNA‐luciferase circuit is developed through split enzyme reconstitution to achieve reversible regulation of enzymatic activity, highlighting the dynamic functionality of these composites. This introduces a modular approach to producing multifunctional bio‐nanomaterials, highlighting the potential of protein‐DNA composite nanostructures as a bridge between molecular design and functional nanomaterials and paves the way for the development of dynamic bio‐devices and programmable biomaterials.

Polyvalent Nucleic Acid Nanoprobes for Cancer Diagnosis and Therapy.

Nucleic acids, as essential biomacromolecules, have garnered considerable scientific interest in diagnosis and therapy owing to their unique molecular characteristics, including sequence-specific programmability, precise molecular recognition capabilities, and diverse biological functionalities. In recent years, with the deepening of the understanding of the physicochemical properties of nucleic acids and the development of nanotechnology, nucleic acid-based nanoprobes with sophisticated structures and functions have been gradually developed, opening up a new direction for efficient diagnosis, followed by customized therapy for diseases. Despite the progress, the affinity and stability of nucleic acids to target sites still suffer from severe challenges, especially in complex physiological environments. Polyvalent nucleic acids, integrated with different functional elements, have demonstrated enormous advantages in effectively solving the above limitations by the elaborate design and construction of multifunctional DNA nanostructures, making them promising candidates for smart-responsive nanoprobes. In this review, we commence with an exploration of nucleic acids, subsequently delineating state-of-the-art strategies for the fabrication of polyvalent nucleic acid nanostructures. We then predominantly underscore the latest advancements in these nanostructures as innovative platforms for cancer theranostics. Further, we critically examine the biomedical applications of polyvalent nucleic acids, alongside addressing the prevailing challenges and future prospects in the realm of nucleic acid-facilitated diagnostics and therapeutics.

Dynamic hierarchical ligand anisotropy for competing macrophage regulation in vivo.

Dynamic hierarchical ligand anisotropy for competing macrophage regulation in vivo.

Surface Organic Nanostructures Mediated by Extrinsic Components: from Assembly to Reaction.

Surface organic nanostructures demonstrate great potential across multidisciplinary fields ranging from molecular electronics to energy conversion and storage. In the regime of surface chemistry, their preparation generally relies on intrinsic components originally involved in the molecule-substrate systems to drive molecular assembly and reaction. The recent paradigm shift employs extrinsic components as functional mediators to precisely regulate nanostructure formation pathways and the resulting molecular nanostructures. This review highlights three categories of extrinsic modulators, including small gas molecules, metals, and their combinations, that allow the construction and modification of surface organic nanostructures through tailored assembly and reaction. In addition, their detailed roles and regulatory mechanisms at the single-molecule level are also discussed. This emerging extrinsic-components-mediated assembly and reaction methodology displayed herein enriches the preparation toolbox for surface organic nanostructures and further allows the modification of their physicochemical properties, opening new frontiers in supramolecular engineering, nanomaterials development, etc.

Construction of a Mirror-Image RNA Nanostructure for Enhanced Biostability and Drug Delivery Efficiency.

The development of stable and efficient drug delivery systems is essential for advancing therapeutic applications. Here, we present an innovative approach using a mirror-image RNA (l-RNA) nanostructure to enhance the biostability and drug delivery efficiency. We engineered an l-RNA three-way junction structure conjugated with both small interfering RNA (siRNA) targeting MCL1 and the chemotherapeutic agent doxorubicin for targeted and synergistic drug delivery. This codelivery strategy leverages the combined effects of doxorubicin and MCL1 siRNA, achieving improved therapeutic outcomes. The l-RNA nanostructure demonstrates superior stability compared with natural d-RNA, resulting in reduced toxicity in healthy cells while maintaining therapeutic efficacy in cancer cells. This indicates that l-RNA nanostructures may offer enhanced biosafety when applied as therapeutic agents. The addition of folic acid (FA) to the nanostructure surface substantially increases both delivery specificity and endosomal escape efficiency, optimizing targeted delivery. Structural modeling also suggests a distinctive binding conformation of doxorubicin with l-DNA, setting it apart from native DNA interactions. This study highlights the potential of mirror-image nucleic acid nanostructures as robust and precise platforms for combinatorial drug delivery in cancer treatment.

Intensive electron transfer of a single-atom Fe-based catalytic ceramic membrane for municipal wastewater treatment: The synergistic effects of nitrogen vacancy defect and ultrathin nanostructure.

Intensive electron transfer of a single-atom Fe-based catalytic ceramic membrane for municipal wastewater treatment: The synergistic effects of nitrogen vacancy defect and ultrathin nanostructure.

Janus Asymmetric Cellulosic Triboelectric Materials Enabled by Gradient Nano‐Doping Strategy

Abstract The rapid development of wearable electronic devices has posed higher demands on the design strategies of advanced sensing materials. Multidimensional functionality and energy self‐sufficiency have consistently been focal points in the field of wearable sensing. The construction of biomimetic nanostructures in sensing materials can endow sensors with intrinsic response characteristics and derivative performance. Here, inspired by the Janus structure and function of human skin, a gradient nano‐doping strategy is proposed for developing cellulosic triboelectric materials with biomimetic‐ordered Janus asymmetric structures. This strategy integrates the complementary advantages of internal components and structures to meet the complex requirements of self‐powered sensing materials. The triboelectric material simultaneously achieves high electrical output power (2.37 W m−2), excellent mechanical properties (withstanding tensile forces over 20 080 times its weight), and thermal conductivity. The wearable self‐powered wireless sensing system designed accordingly demonstrates excellent sensitivity (27.3 kPa−1) and sustained performance fidelity (15 000 cycles), faithfully recording human motion training information. This research holds significant research value and practical implications for the material structure, mechanical properties, and application platforms of wearable electronic devices.

Genetically Encoded Nucleic Acid Nanostructures for Biological Applications.

Nucleic acid, as a carrier of genetic information, has been widely employed as a building block for the construction of versatile nanostructures with pre-designed sizes and shapes through complementary base pairing. With excellent programmability, addressability, and biocompatibility, nucleic acid nanostructures are extensively applied in biomedical researches, such as bio-imaging, bio-sensing, and drug delivery. Notably, the original gene-encoding capability of the nucleic acids themselves has been utilized in these structurally well-defined nanostructures. In this review, we will summarize the recent progress in the design of double-stranded DNA and mRNA-encoded nanostructures for various biological applications, such as gene regulation, gene expression, and mRNA transcription. Furthermore, the challenges and future opportunities of genetically encoded nucleic acid nanostructures in biomedical applications will be discussed.

Folding an RCA Scaffold into an Intelligent Coiled Nanosnake for Precise/Synergistic RNAi-/Chemotherapy of Cancer.

An RCA product is a promising scaffold for the construction of DNA nanostructures, but so far, there is no RCA scaffold-based dynamic reconfigurable nanorobot for biological applications. In this contribution, we develop an intracellular stimuli-responsive reconfigurable coiled DNA nanosnake (N-Snake) by using incomplete aptamer-functionalized (A) DNA tetrahedrons (T) to fold a long tandemly repetitive DNA strand synthesized by rolling circle amplification reaction (R) with the help of palindromic fragment (P). A DNA-assembled product, ARTP, including spiked aptamers, can retain the structural integrity even if exposed to fetal bovine serum (FBS) for 24 h and displays substantially enhanced target molecule-dependent cellular internalization efficiency. ARTP contains tetrahedral containers and linear containers, so that there are 500 doxorubicins (DOXs) and 12.5 siRNAs per ARTP. Moreover, ARTP can precisely transport anticancer drugs to cancerous sites and controllably release via the structural reconfiguration upon intracellular stimuli, almost 100% inhibiting tumor growth without detectable systemic toxicity owing to the synergistic RNAi-/Chemotherapy. Apparently, coiled N-snake, DOX/siPlk1-loaded ARTP, can specifically enter tumor cells, uncoil upon intracellular stimuli, and attack the cells from the inside, exerting precise cancer therapy.

Atomic Observation on Diamond (001) Surfaces with Near-Contact Atomic Force Microscopy.

Achieving atomic-level characterization of the diamond (001) surface has been a persistent goal over recent decades. This pursuit aims to understand the smooth growth of diamonds and investigate surface defects and adsorbates relevant to applications. However, the inherently low conductivity and the short C-C bonds present significant challenges for atomic resolution imaging. Here, we successfully addressed these challenges using near-contact atomic force microscopy with reactive Si tips, achieving atomic resolution, even at room temperature. Density-functional-theory calculations revealed that the formation of tilted Si-C bonds between scanning probes and surfaces, coupled with the reordering of surface C-C dimers, are critical factors for achieving atomic resolution. Beyond surface characterization, these advancements in atomic-resolution microscopy are poised to drive future progress in diamond technologies, facilitating the identification of dopants and the construction of artificial nanostructures.

Construction of metal-organic nanostructures and their structural transformations on metal surfaces.

Metal-organic nanostructures, composed of organic molecules as building blocks and metal atoms as linkers, exhibit high reversibility and flexibility and open up new vistas for the creation of novel metal-organic nanomaterials and the fabrication of functional molecule-based nanodevices. With the rapid development of emerging surface science and scanning probe microscopy, various metal-organic nanostructures, ranging from zero to two dimensions, have been prepared with atomic precision on well-defined metal surfaces in a bottom-up manner and further visualized at the submolecular (or even atomic) level. In such processes, the metal-organic interactions involved and the synergy and competition of multiple intermolecular interactions have been clearly discriminated as the cause of the diversity and preference of metal-organic nanostructures. Moreover, structural transformations can be controllably directed by subtly tuning such intermolecular interactions. In this perspective, we review recent exciting progress in the construction of metal-organic nanostructures on metal surfaces ranging from zero to two dimensions, which is mainly in terms of the selection of metal types (including sources), in other words, different metal-organic interactions formed. Subsequently, the corresponding structural transformations in response to internal or external conditions are discussed, providing mechanistic insights into precise structural control, e.g., by means of metal/molecule stoichiometric ratios (including through scanning probe microscopy (SPM) manipulations), thermodynamic control, introduction of extrinsic competing counterparts, etc. In addition, some other regulatory factors, such as the functionalization of organic molecules and the choice of substrates and lattices, which also crucially govern the structural transformations, are briefly mentioned in each part. Finally, some potential perspectives for metal-organic nanostructures are evoked.

Precise construction of Pd superstructures with modulated defect properties for solar-driven organic transformation.

Precisely controlling the spatial arrangement of nanostructures offers unique opportunities for tuning physical and chemical properties; however, it remains a great challenge due to the lack of effective synthetic methods. Herein, we present a wet-chemistry strategy for the synthesis of three-dimensional (3D) Pd superstructures (Pd SSs) by manipulating the growth kinetics. The strategy consists of two steps including (1) the formation of a tetrahedron-shaped Pd nanocrystal core and (2) the growth of four legs on each tip of the core. Interestingly, each leg can be built from one, two, or three arrowhead-like Pd nanocrystals. Moreover, Pd SSs exhibit unique defect-induced modulated structure properties due to the existence of periodic Pd vacancies, which can provide active sites for reactant molecule adsorption and activation. The Pd SSs exhibit excellent catalytic performance toward the oxidation of o-phenylenediamine (OPDA) under visible and near-infrared (NIR) light illumination. Both theoretical and experimental results demonstrate that the superior photocatalytic activity of Pd SSs is derived from the well-ordered 3D architecture, unique modulated defect properties, high-index facets, and large local electric field enhancement. This research sheds new light on the rational design and precise construction of 3D nanostructures, with potential applications in the fields of catalysis, nanotechnology, and biotechnology.

Triggerless Bio-Orthogonal Proximity-Induced PNA Ligation Using 2,5-Dioxopentanyl (DOP) Functionality.

Peptide nucleic acids (PNAs) are emerging tools in the construction of nanostructures possessing self-assembly properties similar to those of DNA but featuring enhanced stability and chemical flexibility. Templated-ligation approaches can be exploited to stabilize the formed nanoproducts, with bio-orthogonal methods preferred for compatibility with natural components. This chapter outlines design requirements and protocols for conducting triggerless bio-orthogonal PNA ligation in solution and on glass surfaces, along with an electrophoretic monitoring protocol for assessing the outcome of solution ligation.

Beyond Dimerization: Harnessing Tetrameric Coiled‐Coils for Nanostructure Assembly

Versatile DNA and polypeptide‐based structures have been designed based on complementary modules. However, polypeptides can also form higher oligomeric states. We investigated the introduction of tetrameric modules as a substitute for coiled‐coil dimerization units used in previous modular nanostructures. Tetramerizing helical bundles can run in parallel or antiparallel orientation, expanding the number of topological solutions for modular nanostructures. Furthermore, this strategy facilitates the construction of nanostructures from two identical polypeptide chains. Importantly, tetrameric modules substantially stabilized protein nanostructures against air–water interface denaturation, enabling the determination of the first cryo‐electron microscopy three‐dimensional structure of a coiled‐coil‐based nanostructure, confirming the designed agreement of the modules forming a tetrahedral cage.

Beyond Dimerization: Harnessing Tetrameric Coiled‐Coils for Nanostructure Assembly

Abstract Versatile DNA and polypeptide‐based structures have been designed based on complementary modules. However, polypeptides can also form higher oligomeric states. We investigated the introduction of tetrameric modules as a substitute for coiled‐coil dimerization units used in previous modular nanostructures. Tetramerizing helical bundles can run in parallel or antiparallel orientation, expanding the number of topological solutions for modular nanostructures. Furthermore, this strategy facilitates the construction of nanostructures from two identical polypeptide chains. Importantly, tetrameric modules substantially stabilized protein nanostructures against air–water interface denaturation, enabling the determination of the first cryo‐electron microscopy three‐dimensional structure of a coiled‐coil‐based nanostructure, confirming the designed agreement of the modules forming a tetrahedral cage.

Electrochemically Controlled Deposition of Low-Crystalline Covalent Organic Frameworks on Nanocarbon Electrode Toward Metal-Free Oxygen Reduction Electrocatalyst.

Morphology-controlled synthesis of covalent organic frameworks (COFs) offers significant potential for electrochemical applications. However, controlling the deposition of nanometer-scale COFs on carbon supports remains challenging due to the need for a slow COF generation rate and the dispersion of carbon supports in liquid-phase synthesis. In this study, nanometer-scale COF/carbon composites are fabricated using electrochemically generated acid (EGA) to assist in the formation of imine-type COFs, which are then deposited onto pre-cast nanocarbon supports on an electrode. A monomer combination of tri(4-aminophenyl)-1,3,5-triazine and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde is utilized due to their suitable oxidation potentials, with 1,2-diphenylhydrazine serving as the EGA source. Through proton generation driven by electrolysis conditions, controlled COF formation is achieved at the single nanometer scale, ranging from 6 to 30nm, on various nanocarbon supports. The COF/carbon electrode is evaluated as an oxygen reduction reaction (ORR) electrocatalyst, demonstrating superior performance compared to other COF-based electrode materials containing the 1,3,5-triazine moiety. The findings experimentally validate the efficacy of the EGA-assisted COF deposition method for nanostructure construction and its ability to enhance the properties of COF-based electrodes through morphology tuning.