The diverse magnetic properties of lanthanide-based magnetic molecular materials are introduced in the following organization.First,the general aspects of magnetic molecular materials and electronic states of lanthani...The diverse magnetic properties of lanthanide-based magnetic molecular materials are introduced in the following organization.First,the general aspects of magnetic molecular materials and electronic states of lanthanide ions are introduced.Then the structures and magnetic properties are described and analyzed for molecules with one lanthanide ion,4f-4f,4f-3d and 4f-p magnetic coupling interactions.In each section,magnetic coupling,magnetic ordering and magnetic relaxation phenomenon are briefly reviewed using some examples.Finally,some possibilities of developing magnetic molecular materials containing lanthanide ions are discussed in the outlook part.展开更多
In the near future,single-molecule surface-enhanced Raman spectroscopy(SERS)is expected to expand the family of popular analytical tools for single-molecule characterization.We provide a roadmap for achieving single m...In the near future,single-molecule surface-enhanced Raman spectroscopy(SERS)is expected to expand the family of popular analytical tools for single-molecule characterization.We provide a roadmap for achieving single molecule SERS through different enhancement strategies for diverse applications.We introduce some characteristic features related to single-molecule SERS,such as Raman enhancement factor,intensity fluctuation,and data analysis.We then review recent strategies for enhancing the Raman signal intensities of single molecules,including electromagnetic enhancement,chemical enhancement,and resonance enhancement strategies.To demonstrate the utility of single-molecule SERS in practical applications,we present several examples of its use in various fields,including catalysis,imaging,and nanoelectronics.Finally,we specify current challenges in the development of single-molecule SERS and propose corresponding solutions.展开更多
Transforming growth factor-β （TGF-β） binds with two transmembrane serine/threonine kinase receptors, type Ⅱ （TβRII） and type Ⅰ receptors （TβRⅠ）, and one accessory receptor, type Ⅲ receptor （TβRⅢ）, to...Transforming growth factor-β （TGF-β） binds with two transmembrane serine/threonine kinase receptors, type Ⅱ （TβRII） and type Ⅰ receptors （TβRⅠ）, and one accessory receptor, type Ⅲ receptor （TβRⅢ）, to transduce signals across cell membranes. Previous biochemical studies suggested that TβRI and TβRIII are preexisted homo-dimers. Using single-molecule microscopy to image green fluorescent protein-labeled membrane proteins, for the first time we have demonstrated that TβRI and TβRⅢ could exist as monomers at a low expression level. Upon TGF-β1 stimu- lation, TβRI follows the general ligand-induced receptor dimerization model for activation, but this process is TβRⅡ- dependent. The monomeric status of the non-kinase receptor TβRⅢ is unchanged in the presence of TGF-β1. With the increase of receptor expression, both TβRI and TβRIII can be assembled into dimers on cell surfaces.展开更多
Efficient electronic coupling is the key to constructing optoelectronic functionalπsystems.Generally,the delocalization ofπelectrons must comply with the framework constructed by covalent bonds(typicallyσbonds),rep...Efficient electronic coupling is the key to constructing optoelectronic functionalπsystems.Generally,the delocalization ofπelectrons must comply with the framework constructed by covalent bonds(typicallyσbonds),representing classic through-bond conjuga-tion.However,through-space conjugation offers an alternative that achieves spatial electron communica-tionwith closely stacked π systems instead of covalent bonds thus enabling multidimensional energy and charge transport.展开更多
Benefiting from the development of molecular electronics and molecular plasmonics, the interplay of light and electronic transport in molecular junctions has attracted growing interest among researchers in both fields...Benefiting from the development of molecular electronics and molecular plasmonics, the interplay of light and electronic transport in molecular junctions has attracted growing interest among researchers in both fields, leading to a new research direction of "single-molecule optoelectronics". Here, we review the latest developments of photo-modulated charge transport,electroluminescence and Raman spectroscopy from single-molecule junctions, and suggest future directions for single-molecule optoelectronics.展开更多
Achieving localization with molecular precision has been of great interest for extending fluorescence microscopy to nanoscopy.MINFLUX pioneers this transition through point spread function(PSF)engineering,yet its perf...Achieving localization with molecular precision has been of great interest for extending fluorescence microscopy to nanoscopy.MINFLUX pioneers this transition through point spread function(PSF)engineering,yet its performance is primarily limited by the signal-to-background ratio.Here we demonstrate theoretically that two-photon MINFLUX(2p-MINFLUX)could double its localization precision through PSF engineering by nonlinear effect.Cramér-Rao Bound(CRB)is studied as the maximum localization precision,and CRB of two-photon MINFLUX is halved compared to single-photon MINFLUX(1p-MINFLUX)in all three dimensions.Meanwhile,in order to achieve same localization precision with 1p-MINFLUX,2p-MINFLUX requires only 1/4 of fluorescence photons.Exploiting simultaneous two-photon excitation of multiple fluorophore species,2p-MINFLUX may have the potential for registration-free nanoscopy and multicolor tracking.展开更多
Charge transport characterization of single-molecule junctions is essential for the fundamental research of single-molecule physical chemistry and the development towards single-molecule electronic devices and circuit...Charge transport characterization of single-molecule junctions is essential for the fundamental research of single-molecule physical chemistry and the development towards single-molecule electronic devices and circuits. Among the single-molecule conductance characterization techniques,the single-molecule break junction technique is widely used in tens of worldwide research laboratories which can generate a large amount of experimental data from thousands of individual measurement cycles. However,data interpretation is a challenging task for researchers with different research backgrounds,and the different data analysis approaches sometimes lead to the misunderstanding of the measurement data and even reproducibility issues of the measurement. It is thus a necessity to develop a user-friendly all-in-one data analysis tool that automatizes the basic data analysis in a standard and widely accepted way. In this work,we present the XMe Code (Xiamen Molecular Electronics Code),an intelligent all-in-one data analysis tool for the comprehensive analysis of single-molecule break junction data. XMe code provides end-to-end data analysis that takes in the original experimental data and returns electronic characteristics and even charge transport mechanisms. We believe that XMe Code will promote the transparency of the data analysis in single-molecule electronics and the collaborations among scientists with different research backgrounds.展开更多
This work reports the single-molecule detection of gossypol by flow injection analysis with chemiluminescence method. The method is based on the reaction of luminol with ferricyanid in sodium hydroxide medium sensitiz...This work reports the single-molecule detection of gossypol by flow injection analysis with chemiluminescence method. The method is based on the reaction of luminol with ferricyanid in sodium hydroxide medium sensitized by gossypol. Under the optimum conditions, the CL intensity is proportional to the concentration of gossypol over the range of 1.11×10^-17-2.78×10^-16 mol/L in acid solution and 8.00×10^-11-7.39×10^-8mol/L in neutral solution with correlation coefficients 0.9983 and 0.9905, respectively. The detection limits is 1.60×10^-18 mol/L （S/N=3）. The proposed method has been applied for the determination of the gossypol in cottonseeds and pharmaceutical formulations with satisfactory results.展开更多
Electrochemical analysis of single molecules is a method with the strong ability of the enhanced efficiency and ultra-sensitivity.Here,we demonstrate that the electrochemical confined space could efficiently convert s...Electrochemical analysis of single molecules is a method with the strong ability of the enhanced efficiency and ultra-sensitivity.Here,we demonstrate that the electrochemical confined space could efficiently convert single molecule characteristics into measurable electrochemical signatures with high temporal resolution.The human telomere repeat sequence T8 was used as a probe to determine the electrochemical confined effect in a nanopore.Our results show that the nanopore with comparable confined space of the telomere repeat sequence exhibits the most distinguishable single-molecule signals which suggest the folded conformation of T8.This method will greatly extend the lifetime of a metastable conformation for a single biomolecule by strong analyte-nanopore interactions,which brings the new insight into the understanding of the biomolecule's function at single-molecule level.展开更多
On account of the complicated magnetic exchange interactions between lanthanide ions,binuclear lanthanide complexes have broad application prospect in the field of single-molecule magnets.Therefore,it is necessary to ...On account of the complicated magnetic exchange interactions between lanthanide ions,binuclear lanthanide complexes have broad application prospect in the field of single-molecule magnets.Therefore,it is necessary to develop reasonable bridging ligands to manipulate the directional assembly of binuclear lanthanide complexes.Herein,we selected the macrocyclic ligand L^(N_(8)O_(2))to build up two new dilanthanide complexes[Ln_(2)(LN_(8)O_(2))(OpyO)_(2)(H_(2)O)2](NO_(3))_(2)(1-Ln,Ln=Dy,Tb;LN_(8)O_(2)=hexamethyl-tetraaza-dioxe-dipyrazolacycloicosaphane-2,9,12,19-tetraene;OpyOH=2-pyridinol-1-oxide).Dynamic magnetic studies show that 1-Dy exhibits slow relaxation behavior under a 1 kOe applied field.Further fitting analysis of relaxation times gives the effective energy barrier of 38.2 cm^(−1),and reveals that the slow magnetic relaxation behavior is dominated by the Orbach and Raman processes.High-resolution luminescence emission spectrum indicates the energy gap of 36.8 cm^(−1)between the ground state and the first excited state,consistent with the magnetic measurement results.1-Tb exhibits brilliant characteristic green light emission under UV light excitation.The absolute quantum yield of 1-Tb is 44.8%,and its first-order fitted decay lifetime is 779.21μs at room temperature.This study provides the way for directional construction of high-performance molecular materials with magnetic and optical dual-function.展开更多
Mechanically interlocked molecules(MIMs)are prototypical molecular machines with parts that enable controlled,large-amplitude movement with one component positioned relative to another.Incorporating MIMs into polymeri...Mechanically interlocked molecules(MIMs)are prototypical molecular machines with parts that enable controlled,large-amplitude movement with one component positioned relative to another.Incorporating MIMs into polymeric matrices is promising for the designing of functional materials with unprecedented properties.However,the central issue is the challenges involved with establishing the mechanistic linkage between the single-molecule and the bulk material.Herein,we explore the mechanochemical properties and energetic details of a linear poly[2]catenane with strong intercomponent hydrogen bonding(IHB)revealed by single-molecule force spectroscopy.Our results showed that the individual linear poly[2]catenane chain exhibited typical sawtooth pattern,corresponding to the reversible unlocking and relocking transitions under external force or upon stimulations to dissociate or re-form the strong IHB.Furthermore,when a poly[2]catenane-based polymer gel was prepared using a thiol-ene click reaction between thiol-ended poly[2]catenane and a low-molecule-weight cross-linker,the resultant gel showed excellent mechanical adaptability and dynamic properties,which correlated well with the molecular-level observations.The unique poly[2]catenane structure also contributed to the gel formation with an extraordinary IHB-mediated swelling behavior and shape memory property.Thus our present results demonstrate the functioning of bulk material in a linear tandem manner from the behavior of a single molecule,a finding which should be applicable to other systems with versatile properties and promising applications.展开更多
The carbonic anhydrases(CAs)are a group of enzymes that play an important role in the absorption and transportation of CO_(2) in Saccharina japonica.They are encoded by a superfamily of genes with seven subtypes that ...The carbonic anhydrases(CAs)are a group of enzymes that play an important role in the absorption and transportation of CO_(2) in Saccharina japonica.They are encoded by a superfamily of genes with seven subtypes that are unrelated in sequence but share conserved function in catalyzing the reversible conversion of CO_(2) and HCO_(3)^(-).Here we have characterized the CA members in the transcriptome of S.japonica using Single-molecule real-time(SMRT)sequencing technology.Approximately 9830.4 megabases from 5,028,003 quality subreads were generated,and they were assembled into 326,512 full-length non-chimeric(FLNC)reads,with an average flnc read length of 2181 bp.After removing redundant sequences,79,010 unique transcripts were obtained of which 38,039 transcripts were successfully annotated.From the full-length transcriptome,we have identified 7 full-length cDNA sequences for CA genes(4α-CAs,1β-CAs and 2γ-CAs)and assessed for their potential functions based on phylogenetic analysis.Characterizations of CAs will provide the ground for future studies to determine the involvement of CAs in inorganic carbon absorption and transportation in S.japonica.展开更多
In quantum mechanics,when an electron is quickly ripped off from a molecule,a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside,which has been called ch...In quantum mechanics,when an electron is quickly ripped off from a molecule,a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside,which has been called charge migration(CM).Experimentally,extracting such dynamics at its natural(attosecond)timescale is quite difficult.We report the first such experiment in a linear carbon-chain molecule,butadiyne(C_(4)H_(2)),via high-harmonic spectroscopy(HHS).By employing advanced theoretical and computational tools,we showed that the wave packet and the CM of a single molecule are reconstructed from the harmonic spectra for each fixed-in-space angle of the molecule.For this onedimensional molecule,we calculate the center of charge <x>(t) to obtain v_(cm),to quantify the migration speed and how it depends on the orientation angle.The findings also uncover how the electron dynamics at the first few tens to hundreds of attoseconds depends on molecular structure.The method can be extended to other molecules where the HHS technique can be employed.展开更多
Cigarette smoking is a well-known risk factor for cardiovascular disease. Smoking can cause vascular endothelial dysfunction and consequently trigger haemostatic activation and thrombosis. However, the mechanism of ho...Cigarette smoking is a well-known risk factor for cardiovascular disease. Smoking can cause vascular endothelial dysfunction and consequently trigger haemostatic activation and thrombosis. However, the mechanism of how smoking promotes thrombosis is not fully understood. Thrombosis is associated with the imbalance of the coagulant system due to endothelial dysfunction. As a vital anticoagulation cofactor, thrombomodulin (TM) located on the endothelial cell surface is able to regulate intravascular coagulation by binding to thrombin, and the binding results in thrombosis inhibition. This work focused on the effects of cigarette smoke extract (CSE) on TM-thrombin binding by atomic force microscopy (AFM) based single-molecule force spectroscopy. The results from both in vitro and live-cell experiments indicated that CSE could notably reduce the binding probability of TM and thrombin. This study provided a new approach and new evidence for studying the mechanism of thrombosis triggered by cigarette smoking.展开更多
Single-molecule electrical and spin switches have been one of the main research focuses in molecular electronics and spintronics because they may form the most important elements for the future information technology,...Single-molecule electrical and spin switches have been one of the main research focuses in molecular electronics and spintronics because they may form the most important elements for the future information technology,thus attracting great attention in the scientific community and witnessing significant progresses benefiting from the combination of physics,chemistry,materials,and engineering.The key issue of constructing single-molecule switches is the development of stimulus-responsive systems that provide bistable or multiple states.In this review,we summarize the recent advances of this field in terms of the external stimulus that induces the switching.A variety of external stimuli,such as light,electric field,magnetic field,mechanical force,and chemical stimulus,have been successfully employed to activate the reversible switching in single-molecule junctions by manipulating molecular structures,conformations,electronic states,and spin states.As a burgeoning field,we finally put forward the challenges in molecular electronics and spintronics that need to be solved,which will initiate intense research.展开更多
It is important and challenging to analyze nanocluster structure with atomic precision.Herein,α-hemolysin nanopore was used to identify nanoclusters at the single molecule level by providing two-dimensional(2D)dwell ...It is important and challenging to analyze nanocluster structure with atomic precision.Herein,α-hemolysin nanopore was used to identify nanoclusters at the single molecule level by providing two-dimensional(2D)dwell time–current blockage spectra and translocation event frequency which sensitively depended on their structures.Nanoclusters such as Anderson,Keggin,Dawson,and a few lacunary Dawson polyoxometalates with very similar structures,even with only a two-atom difference,could be discriminated.This nanopore device could simultaneously measure multiple nanoclusters in a mixture qualitatively and quantitatively.Furthermore,molecular dynamics(MD)simulations provided microscopic understandings of the nanocluster translocation dynamics and yielded 2D dwell time–current blockage spectra in close agreement with experiments.The nanopore platform provides a novel powerful tool for nanocluster characterization.展开更多
Ubiquitous van der Waals(vdW)forces are very importa nt for nano structures.Although the vdW forces between two surfaces(or two layers)have been measured for several decades,a direct detection at the single-molecule l...Ubiquitous van der Waals(vdW)forces are very importa nt for nano structures.Although the vdW forces between two surfaces(or two layers)have been measured for several decades,a direct detection at the single-molecule level is still difficult.Herein,we report a novel method to solve this problem in high vacuum by means of AFM-based sin gle-molecule force spectroscopy(SMFS).Solve nt molecules and surface adsorbed water are removed thoroughly under high vacuum so that the situation is greatly simplified.A constant force plateau can be observed when a polymer chain is peeled off from a substrate in high vacuum.Accordingly,the vdW forces between one polymer repeating unit and the substrates can be obtained.The experimental results show that the vdW forces(typical range:21-54 pN)are dependent on the species of substrates and the size of polymer repeating unit,which is in good accordance with the theoretical results.It is expected that this novel method can be applied to detect other non-covalent interactions(such as hydrogen bond andπ-πstacking)at the single-molecule level in the future.展开更多
The electrical tunneling sensors have excellent potential in the next generation of single-molecule measurement and sequencing technologies due to their high sensitivity and spatial resolution capabilities.Electrical ...The electrical tunneling sensors have excellent potential in the next generation of single-molecule measurement and sequencing technologies due to their high sensitivity and spatial resolution capabilities.Electrical tunneling signals that have been measured at a high sampling rate may provide detailed molecular information.Despite the extraordinarily large amount of data that has been gathered,it is still difficult to correlate signal transformations with molecular processes,which creates great obstacles for signal analysis.Machine learning is an effective tool for data analysis that is currently gaining more significance.It has demonstrated promising results when used to analyze data from single-molecule electrical measurements.In order to extract meaningful information from raw measurement data,we have combined intelligent machine learning with tunneling electrical signals.For the purpose of analyzing tunneling electrical signals,we investigated the clustering approach,which is a classic algorithm in machine learning.A clustering model was built that combines the advantages of hierarchical clustering and Gaussian mixture model clustering.Additionally,customized statistical algorithms were designed.It has been proven to efficiently gather molecular information and enhance the effectiveness of data analysis.展开更多
With rational designability,versatile tunability,and quantum coherence,molecular electron spin qubits could offer new opportunities for quantum information science,enabling simplified implementation of quantum algorit...With rational designability,versatile tunability,and quantum coherence,molecular electron spin qubits could offer new opportunities for quantum information science,enabling simplified implementation of quantum algorithms and chemical-specific quantum sensing.The development of these transformative technologies relies on coherent addressing of single molecular electron spin qubits with high initialization,manipulation,and readout fidelities.This is unfeasible to conventional electron spin resonance spectroscopy,which is widely used for coherent addressing of ensemble electron spins,due to its low initialization efficiency and readout sensitivity.Taking advantage of single spin detectability of single-molecule spectroscopy,scanning tunneling microscopy,atomic force microscopy,and quantum metrology,several strategies have been developed to empower electron spin resonance spectroscopy with single qubit addressability.In this Emerging Topic,we introduce principles and technical implementation of strategies for coherent addressing of single molecular electron spin qubits,discuss their potential applicability in quantum technologies,and point out their challenges in terms of scalability,molecular design,and/or decoherence suppression.We discuss future directions to overcome these challenges and to improve single qubit addressing technologies,which will facilitate the advancement of molecular quantum information science.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20821091, 20503001)the National Basic Research Program of China (Grant Nos. 2006CB601102, 2009CB929403)
文摘The diverse magnetic properties of lanthanide-based magnetic molecular materials are introduced in the following organization.First,the general aspects of magnetic molecular materials and electronic states of lanthanide ions are introduced.Then the structures and magnetic properties are described and analyzed for molecules with one lanthanide ion,4f-4f,4f-3d and 4f-p magnetic coupling interactions.In each section,magnetic coupling,magnetic ordering and magnetic relaxation phenomenon are briefly reviewed using some examples.Finally,some possibilities of developing magnetic molecular materials containing lanthanide ions are discussed in the outlook part.
基金This work was supported by the National Natural Science Foundation of China(Nos.11434017 and 11804254)Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06C594)+8 种基金National Key R&D Program of China(No.2018YFA 0306200)Science and Technology Projects of Jiangmen[Nos.(2017)307 and 149]Program for Innovative Research Team of Jiangmen[No.(2017)385]Science and Technology Projects of Guangdong Province(No.2016A020225009)Program for Key Basic Research of Guangdong(No.2017KZDXM083)Cooperative Education Platform of Guangdong Province[No.(2016)31]Innovative Research Team in University of Guangdong(No.2015KCXTD027)Key Laboratory of Optoelectronic Materials and Applications in Guangdong Higher Education(No.2017KSYS011)2014 Leap Project Center of Education Department Key Platform Construction in Guangdong Province(No.GCZX-A1411).
文摘In the near future,single-molecule surface-enhanced Raman spectroscopy(SERS)is expected to expand the family of popular analytical tools for single-molecule characterization.We provide a roadmap for achieving single molecule SERS through different enhancement strategies for diverse applications.We introduce some characteristic features related to single-molecule SERS,such as Raman enhancement factor,intensity fluctuation,and data analysis.We then review recent strategies for enhancing the Raman signal intensities of single molecules,including electromagnetic enhancement,chemical enhancement,and resonance enhancement strategies.To demonstrate the utility of single-molecule SERS in practical applications,we present several examples of its use in various fields,including catalysis,imaging,and nanoelectronics.Finally,we specify current challenges in the development of single-molecule SERS and propose corresponding solutions.
基金This work was supported by the National Natural Science Foundation of China （90713024, 20821003, 30921004）, the National Basic Research Program of China （2007CB935601, 2010CB833706） and the Chinese Academy of Sciences.
文摘Transforming growth factor-β （TGF-β） binds with two transmembrane serine/threonine kinase receptors, type Ⅱ （TβRII） and type Ⅰ receptors （TβRⅠ）, and one accessory receptor, type Ⅲ receptor （TβRⅢ）, to transduce signals across cell membranes. Previous biochemical studies suggested that TβRI and TβRIII are preexisted homo-dimers. Using single-molecule microscopy to image green fluorescent protein-labeled membrane proteins, for the first time we have demonstrated that TβRI and TβRⅢ could exist as monomers at a low expression level. Upon TGF-β1 stimu- lation, TβRI follows the general ligand-induced receptor dimerization model for activation, but this process is TβRⅡ- dependent. The monomeric status of the non-kinase receptor TβRⅢ is unchanged in the presence of TGF-β1. With the increase of receptor expression, both TβRI and TβRIII can be assembled into dimers on cell surfaces.
基金This work was financially supported by the National Natural Science Foundation of China(21788102 and 21673082)the National Basic Research Program of Chi-na(973 Program,2015CB655004)founded by MOST+2 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar(2014A030306035)the Natural Science Foundation of Guangdong Province(2016A030312002)the Innovation and Technology Commission of Hong Kong(ITC-CNERC14SC01).
文摘Efficient electronic coupling is the key to constructing optoelectronic functionalπsystems.Generally,the delocalization ofπelectrons must comply with the framework constructed by covalent bonds(typicallyσbonds),representing classic through-bond conjuga-tion.However,through-space conjugation offers an alternative that achieves spatial electron communica-tionwith closely stacked π systems instead of covalent bonds thus enabling multidimensional energy and charge transport.
基金supported by the National Key R&D Program of China (2017YFA0204901, 2017YFA0204902)the National Natural Science Foundation of China (21673195, 61571242, 21503179, 21727806, 21722305)the Young Thousand Talent Project of China
文摘Benefiting from the development of molecular electronics and molecular plasmonics, the interplay of light and electronic transport in molecular junctions has attracted growing interest among researchers in both fields, leading to a new research direction of "single-molecule optoelectronics". Here, we review the latest developments of photo-modulated charge transport,electroluminescence and Raman spectroscopy from single-molecule junctions, and suggest future directions for single-molecule optoelectronics.
基金Beijing Natural Science Foundation(JQ18019)National Natural Science Foundation of China(62025501,31971376,61729501)+1 种基金State Key Research Development Program of China(2017YFC0110202)Shenzhen Science and Technology Program(KQTD20170810110913065)。
文摘Achieving localization with molecular precision has been of great interest for extending fluorescence microscopy to nanoscopy.MINFLUX pioneers this transition through point spread function(PSF)engineering,yet its performance is primarily limited by the signal-to-background ratio.Here we demonstrate theoretically that two-photon MINFLUX(2p-MINFLUX)could double its localization precision through PSF engineering by nonlinear effect.Cramér-Rao Bound(CRB)is studied as the maximum localization precision,and CRB of two-photon MINFLUX is halved compared to single-photon MINFLUX(1p-MINFLUX)in all three dimensions.Meanwhile,in order to achieve same localization precision with 1p-MINFLUX,2p-MINFLUX requires only 1/4 of fluorescence photons.Exploiting simultaneous two-photon excitation of multiple fluorophore species,2p-MINFLUX may have the potential for registration-free nanoscopy and multicolor tracking.
基金supported by the National Natural Science Foundation of China(22325303,21973079,22032004)the National Key R&D Program of China(2017YFA0204902)+2 种基金the Fundamental Research Funds for the Central Universities in China(Xiamen University,20720190002)IRTSTFJ,National Science Foundation of Fujian Province(2018J06004)Beijing National Laboratory for Molecular Sciences(BNLMS202005).
文摘Charge transport characterization of single-molecule junctions is essential for the fundamental research of single-molecule physical chemistry and the development towards single-molecule electronic devices and circuits. Among the single-molecule conductance characterization techniques,the single-molecule break junction technique is widely used in tens of worldwide research laboratories which can generate a large amount of experimental data from thousands of individual measurement cycles. However,data interpretation is a challenging task for researchers with different research backgrounds,and the different data analysis approaches sometimes lead to the misunderstanding of the measurement data and even reproducibility issues of the measurement. It is thus a necessity to develop a user-friendly all-in-one data analysis tool that automatizes the basic data analysis in a standard and widely accepted way. In this work,we present the XMe Code (Xiamen Molecular Electronics Code),an intelligent all-in-one data analysis tool for the comprehensive analysis of single-molecule break junction data. XMe code provides end-to-end data analysis that takes in the original experimental data and returns electronic characteristics and even charge transport mechanisms. We believe that XMe Code will promote the transparency of the data analysis in single-molecule electronics and the collaborations among scientists with different research backgrounds.
基金financial support from the National Natural Science Foundation of China(Grant No.20075017)and from Tianjin Normal University.
文摘This work reports the single-molecule detection of gossypol by flow injection analysis with chemiluminescence method. The method is based on the reaction of luminol with ferricyanid in sodium hydroxide medium sensitized by gossypol. Under the optimum conditions, the CL intensity is proportional to the concentration of gossypol over the range of 1.11×10^-17-2.78×10^-16 mol/L in acid solution and 8.00×10^-11-7.39×10^-8mol/L in neutral solution with correlation coefficients 0.9983 and 0.9905, respectively. The detection limits is 1.60×10^-18 mol/L （S/N=3）. The proposed method has been applied for the determination of the gossypol in cottonseeds and pharmaceutical formulations with satisfactory results.
基金supported by the National Natural Science Foundation of China(21421004,21505043,21327807)the Fundamental Research Funds for the Central Universities(222201718001,222201717003,222201714012)
文摘Electrochemical analysis of single molecules is a method with the strong ability of the enhanced efficiency and ultra-sensitivity.Here,we demonstrate that the electrochemical confined space could efficiently convert single molecule characteristics into measurable electrochemical signatures with high temporal resolution.The human telomere repeat sequence T8 was used as a probe to determine the electrochemical confined effect in a nanopore.Our results show that the nanopore with comparable confined space of the telomere repeat sequence exhibits the most distinguishable single-molecule signals which suggest the folded conformation of T8.This method will greatly extend the lifetime of a metastable conformation for a single biomolecule by strong analyte-nanopore interactions,which brings the new insight into the understanding of the biomolecule's function at single-molecule level.
基金Project supported by the National Natural Science Foundation of China(22131011,22071274,21821003)the Pearl River Talent Plan of Guangdong(2017BT01C161)。
文摘On account of the complicated magnetic exchange interactions between lanthanide ions,binuclear lanthanide complexes have broad application prospect in the field of single-molecule magnets.Therefore,it is necessary to develop reasonable bridging ligands to manipulate the directional assembly of binuclear lanthanide complexes.Herein,we selected the macrocyclic ligand L^(N_(8)O_(2))to build up two new dilanthanide complexes[Ln_(2)(LN_(8)O_(2))(OpyO)_(2)(H_(2)O)2](NO_(3))_(2)(1-Ln,Ln=Dy,Tb;LN_(8)O_(2)=hexamethyl-tetraaza-dioxe-dipyrazolacycloicosaphane-2,9,12,19-tetraene;OpyOH=2-pyridinol-1-oxide).Dynamic magnetic studies show that 1-Dy exhibits slow relaxation behavior under a 1 kOe applied field.Further fitting analysis of relaxation times gives the effective energy barrier of 38.2 cm^(−1),and reveals that the slow magnetic relaxation behavior is dominated by the Orbach and Raman processes.High-resolution luminescence emission spectrum indicates the energy gap of 36.8 cm^(−1)between the ground state and the first excited state,consistent with the magnetic measurement results.1-Tb exhibits brilliant characteristic green light emission under UV light excitation.The absolute quantum yield of 1-Tb is 44.8%,and its first-order fitted decay lifetime is 779.21μs at room temperature.This study provides the way for directional construction of high-performance molecular materials with magnetic and optical dual-function.
基金We are grateful to acknowledge the National Basic Research Program(2013CB834502,2013CB834503)the National Natural Science Foundation of China(91527301,21434005,21525418,51773179,11302190,and 11432012)the Open Project of State Key Laboratory of Supramolecular Structure and Materials(sklssm201611)for financial support.
文摘Mechanically interlocked molecules(MIMs)are prototypical molecular machines with parts that enable controlled,large-amplitude movement with one component positioned relative to another.Incorporating MIMs into polymeric matrices is promising for the designing of functional materials with unprecedented properties.However,the central issue is the challenges involved with establishing the mechanistic linkage between the single-molecule and the bulk material.Herein,we explore the mechanochemical properties and energetic details of a linear poly[2]catenane with strong intercomponent hydrogen bonding(IHB)revealed by single-molecule force spectroscopy.Our results showed that the individual linear poly[2]catenane chain exhibited typical sawtooth pattern,corresponding to the reversible unlocking and relocking transitions under external force or upon stimulations to dissociate or re-form the strong IHB.Furthermore,when a poly[2]catenane-based polymer gel was prepared using a thiol-ene click reaction between thiol-ended poly[2]catenane and a low-molecule-weight cross-linker,the resultant gel showed excellent mechanical adaptability and dynamic properties,which correlated well with the molecular-level observations.The unique poly[2]catenane structure also contributed to the gel formation with an extraordinary IHB-mediated swelling behavior and shape memory property.Thus our present results demonstrate the functioning of bulk material in a linear tandem manner from the behavior of a single molecule,a finding which should be applicable to other systems with versatile properties and promising applications.
基金This research was supported by Shanghai Universities Peak Discipline Project of Aquaculture and“Double First-Class Initiative”program for its First-Class Discipline of aquaculture.
文摘The carbonic anhydrases(CAs)are a group of enzymes that play an important role in the absorption and transportation of CO_(2) in Saccharina japonica.They are encoded by a superfamily of genes with seven subtypes that are unrelated in sequence but share conserved function in catalyzing the reversible conversion of CO_(2) and HCO_(3)^(-).Here we have characterized the CA members in the transcriptome of S.japonica using Single-molecule real-time(SMRT)sequencing technology.Approximately 9830.4 megabases from 5,028,003 quality subreads were generated,and they were assembled into 326,512 full-length non-chimeric(FLNC)reads,with an average flnc read length of 2181 bp.After removing redundant sequences,79,010 unique transcripts were obtained of which 38,039 transcripts were successfully annotated.From the full-length transcriptome,we have identified 7 full-length cDNA sequences for CA genes(4α-CAs,1β-CAs and 2γ-CAs)and assessed for their potential functions based on phylogenetic analysis.Characterizations of CAs will provide the ground for future studies to determine the involvement of CAs in inorganic carbon absorption and transportation in S.japonica.
基金supported by the National Key Research and Development Program of China (No. 2019YFA0308300)the National Natural Science Foundation of China (Nos. 91950202, 12225406, 12074136, 12021004, and 11934006)+2 种基金the Natural Science Foundation of Hubei Province (No. 2021CFB330)supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (No. DE-FG0286ER13491)supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (No. DE-SC0023192)
文摘In quantum mechanics,when an electron is quickly ripped off from a molecule,a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside,which has been called charge migration(CM).Experimentally,extracting such dynamics at its natural(attosecond)timescale is quite difficult.We report the first such experiment in a linear carbon-chain molecule,butadiyne(C_(4)H_(2)),via high-harmonic spectroscopy(HHS).By employing advanced theoretical and computational tools,we showed that the wave packet and the CM of a single molecule are reconstructed from the harmonic spectra for each fixed-in-space angle of the molecule.For this onedimensional molecule,we calculate the center of charge <x>(t) to obtain v_(cm),to quantify the migration speed and how it depends on the orientation angle.The findings also uncover how the electron dynamics at the first few tens to hundreds of attoseconds depends on molecular structure.The method can be extended to other molecules where the HHS technique can be employed.
基金supported by the National Basic Research Program of China(Grant No.2011CB911001)National Natural Science Foundation of China(Grant Nos.21127901 and 21121063)Chinese Academy of Sciences
文摘Cigarette smoking is a well-known risk factor for cardiovascular disease. Smoking can cause vascular endothelial dysfunction and consequently trigger haemostatic activation and thrombosis. However, the mechanism of how smoking promotes thrombosis is not fully understood. Thrombosis is associated with the imbalance of the coagulant system due to endothelial dysfunction. As a vital anticoagulation cofactor, thrombomodulin (TM) located on the endothelial cell surface is able to regulate intravascular coagulation by binding to thrombin, and the binding results in thrombosis inhibition. This work focused on the effects of cigarette smoke extract (CSE) on TM-thrombin binding by atomic force microscopy (AFM) based single-molecule force spectroscopy. The results from both in vitro and live-cell experiments indicated that CSE could notably reduce the binding probability of TM and thrombin. This study provided a new approach and new evidence for studying the mechanism of thrombosis triggered by cigarette smoking.
基金National Key R&D Program of China,Grant/Award Number:2017YFA0204901National Natural Science Foundation of China,Grant/Award Numbers:21727806,21933001Natural Science Foundation of Beijing,Grant/Award Number:Z181100004418003。
文摘Single-molecule electrical and spin switches have been one of the main research focuses in molecular electronics and spintronics because they may form the most important elements for the future information technology,thus attracting great attention in the scientific community and witnessing significant progresses benefiting from the combination of physics,chemistry,materials,and engineering.The key issue of constructing single-molecule switches is the development of stimulus-responsive systems that provide bistable or multiple states.In this review,we summarize the recent advances of this field in terms of the external stimulus that induces the switching.A variety of external stimuli,such as light,electric field,magnetic field,mechanical force,and chemical stimulus,have been successfully employed to activate the reversible switching in single-molecule junctions by manipulating molecular structures,conformations,electronic states,and spin states.As a burgeoning field,we finally put forward the challenges in molecular electronics and spintronics that need to be solved,which will initiate intense research.
基金supported by the National Key Research and Development Program of China(No.2021YFA1200104)New Cornerstone Science Foundation,the National Natural Science Foundation of China(Nos.22027807,22034004,and 22078104)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)Tsinghua-Vanke Special Fund for Public Health and Health Discipline Development(No.2022Z82WKJ003).
文摘It is important and challenging to analyze nanocluster structure with atomic precision.Herein,α-hemolysin nanopore was used to identify nanoclusters at the single molecule level by providing two-dimensional(2D)dwell time–current blockage spectra and translocation event frequency which sensitively depended on their structures.Nanoclusters such as Anderson,Keggin,Dawson,and a few lacunary Dawson polyoxometalates with very similar structures,even with only a two-atom difference,could be discriminated.This nanopore device could simultaneously measure multiple nanoclusters in a mixture qualitatively and quantitatively.Furthermore,molecular dynamics(MD)simulations provided microscopic understandings of the nanocluster translocation dynamics and yielded 2D dwell time–current blockage spectra in close agreement with experiments.The nanopore platform provides a novel powerful tool for nanocluster characterization.
基金the National Natural Science Foundation of China(Nos.21574106 and 21774102).
文摘Ubiquitous van der Waals(vdW)forces are very importa nt for nano structures.Although the vdW forces between two surfaces(or two layers)have been measured for several decades,a direct detection at the single-molecule level is still difficult.Herein,we report a novel method to solve this problem in high vacuum by means of AFM-based sin gle-molecule force spectroscopy(SMFS).Solve nt molecules and surface adsorbed water are removed thoroughly under high vacuum so that the situation is greatly simplified.A constant force plateau can be observed when a polymer chain is peeled off from a substrate in high vacuum.Accordingly,the vdW forces between one polymer repeating unit and the substrates can be obtained.The experimental results show that the vdW forces(typical range:21-54 pN)are dependent on the species of substrates and the size of polymer repeating unit,which is in good accordance with the theoretical results.It is expected that this novel method can be applied to detect other non-covalent interactions(such as hydrogen bond andπ-πstacking)at the single-molecule level in the future.
基金the National Natural Science Foundation of China(grant nos.62127818)Natural Science Foundation of Zhejiang Province(grant no.LR22F050003)Fundamental Research Funds for Central Universities。
文摘The electrical tunneling sensors have excellent potential in the next generation of single-molecule measurement and sequencing technologies due to their high sensitivity and spatial resolution capabilities.Electrical tunneling signals that have been measured at a high sampling rate may provide detailed molecular information.Despite the extraordinarily large amount of data that has been gathered,it is still difficult to correlate signal transformations with molecular processes,which creates great obstacles for signal analysis.Machine learning is an effective tool for data analysis that is currently gaining more significance.It has demonstrated promising results when used to analyze data from single-molecule electrical measurements.In order to extract meaningful information from raw measurement data,we have combined intelligent machine learning with tunneling electrical signals.For the purpose of analyzing tunneling electrical signals,we investigated the clustering approach,which is a classic algorithm in machine learning.A clustering model was built that combines the advantages of hierarchical clustering and Gaussian mixture model clustering.Additionally,customized statistical algorithms were designed.It has been proven to efficiently gather molecular information and enhance the effectiveness of data analysis.
基金supports from the National Natural Science Foundation of China(No.22273078)Hangzhou Municipal Funding,Team of Innovation(No.TD2022004).
文摘With rational designability,versatile tunability,and quantum coherence,molecular electron spin qubits could offer new opportunities for quantum information science,enabling simplified implementation of quantum algorithms and chemical-specific quantum sensing.The development of these transformative technologies relies on coherent addressing of single molecular electron spin qubits with high initialization,manipulation,and readout fidelities.This is unfeasible to conventional electron spin resonance spectroscopy,which is widely used for coherent addressing of ensemble electron spins,due to its low initialization efficiency and readout sensitivity.Taking advantage of single spin detectability of single-molecule spectroscopy,scanning tunneling microscopy,atomic force microscopy,and quantum metrology,several strategies have been developed to empower electron spin resonance spectroscopy with single qubit addressability.In this Emerging Topic,we introduce principles and technical implementation of strategies for coherent addressing of single molecular electron spin qubits,discuss their potential applicability in quantum technologies,and point out their challenges in terms of scalability,molecular design,and/or decoherence suppression.We discuss future directions to overcome these challenges and to improve single qubit addressing technologies,which will facilitate the advancement of molecular quantum information science.
