A Multistage Hemiplegic Lower-Limb Rehabilitation Robot: Design and Gait Trajectory Planning.

Most lower limb rehabilitation robots are limited to specific training postures to adapt to stroke patients in multiple stages of recovery. In addition, there is a lack of attention to the switching functions of the training side, including left, right, and bilateral, which enables patients with hemiplegia to rehabilitate with a single device. This article presents an exoskeleton robot named the multistage hemiplegic lower-limb rehabilitation robot, which has been designed to do rehabilitation in multiple training postures and training sides. The mechanism consisting of the thigh, calf, and foot is introduced. Additionally, the design of the multi-mode limit of the hip, knee, and ankle joints supports delivering therapy in any posture and training sides to aid patients with hemiplegia in all stages of recovery. The gait trajectory is planned by extracting the gait motion trajectory model collected by the motion capture device. In addition, a control system for the training module based on adaptive iterative learning has been simulated, and its high-precision tracking performance has been verified. The gait trajectory experiment is carried out, and the results verify that the trajectory tracking performance of the robot has good performance.

Asymmetric Low-Frequency Pulsed Strategy Enables Ultralong CO2 Reduction Stability and Controllable Product Selectivity.

Copper-based catalysts are widely explored in electrochemical CO2 reduction (CO2RR) because of their ability to convert CO2 into high-value-added multicarbon products. However, the poor stability and low selectivity limit the practical applications of these catalysts. Here, we proposed a simple and efficient asymmetric low-frequency pulsed strategy (ALPS) to significantly enhance the stability and the selectivity of the Cu-dimethylpyrazole complex Cu3(DMPz)3 catalyst in CO2RR. Under traditional potentiostatic conditions, Cu3(DMPz)3 exhibited poor CO2RR performance with the Faradaic efficiency (FE) of 34.5% for C2H4 and FE of 5.9% for CH4 as well as the low stability for less than 1 h. We optimized two distinguished ALPS methods toward CH4 and C2H4, correspondingly. The high selectivities of catalytic product CH4 (FECH4 = 80.3% and above 76.6% within 24 h) and C2H4 (FEC2H4 = 70.7% and above 66.8% within 24 h) can be obtained, respectively. The ultralong stability for 300 h (FECH4 > 60%) and 145 h (FEC2H4 > 50%) was also recorded with the ALPS method. Microscopy (HRTEM, SAED, and HAADF) measurements revealed that the ALPS method in situ generated and stabilized extremely dispersive and active Cu-based clusters (∼2.7 nm) from Cu3(DMPz)3. Meanwhile, ex situ spectroscopies (XPS, AES, and XANES) and in situ XANES indicated that this ALPS method modulated the Cu oxidation states, such as Cu(0 and I) with C2H4 selectivity and Cu(I and II) with CH4 selectivity. The mechanism under the ALPS methods was explored by in situ ATR-FTIR, in situ Raman, and DFT computation. The ALPS methods provide a new opportunity to boost the selectivity and stability of CO2RR.

Rare Earth Metal Anchored into Nitrogen-Doped Graphene for CO2 Electrocatalytic Reduction to C1 Products.

Single-atom catalysts (SACs) are attracting global attention due to their 100% atomic utilization rate and unique properties. Rare-earth-based SACs have shown great potential in the field of electrocatalysis in recent years. In this study, the catalytic performance of four rare earth metals (REMs) anchored into N-graphene for the CO2RR is systematically studied by density functional theory. The calculation results of formation energy show that all REM@N6-G compounds have favorable stability. In addition, the Gibbs free energy calculation results of all possible elementary reactions show that the *OCHO pathway is the optimal hydrogenation pathway for all catalysts, and they have the same potential determining step (*OCHO + e- + H+ → *HCOOH). Meanwhile, the products of the CO2RR on these catalysts are different, and the product on REM@N6-G (REM = La, Pr, and Nd) is CH4, while the product on Ce@N6-G is CH3OH. In particular, Nd@N6-G exhibits the best catalytic activity in this work, with a very low limiting potential of -0.38 V. These results may guide the development of rare-earth-based SACs for CO2RR.

Theoretical prediction of emerging high-performance trifunctional ORR/OER/HER single-atom catalysts: transition metals anchored into π-π conjugated graphitic carbon nitride (g-C10N3).

The design of high-performance trifunctional oxygen reduction/oxygen evolution/hydrogen evolution reactions (ORR/OER/HER) electrocatalysts has become the current research focus. In this work, we report a series of single-atom catalysts formed by nine kinds of transition metal (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, and Pt) anchored in g-C10N3 (namely TM@g-C10N3) as promising trifunctional electrocatalysts to replace precious metal catalysts by density functional theory methods. All TM@g-C10N3 have good thermodynamic and electrochemical stability. Especially, Rh@g-C10N3 and Ir@g-C10N3 exhibit extremely low ORR/OER overpotentials with the values of 0.26/0.28 V and 0.34/0.41 V, respectively. Besides, their hydrogen adsorption free energy values are close to Pt(111), with their values being 0.16 and -0.16 eV, respectively. The calculated results indicate that Rh@g-C10N3 and Ir@g-C10N3 can become trifunctional electrocatalysts with great probability. Through the analysis of the dynamic mechanism for Rh@g-C10N3, it can be concluded that the four-electron ORR pathway is more conducive to occurring on Rh@g-C10N3 because the energy barrier forming this pathway is lower. Besides, the step of *OH + H+ + e- → * + H2O has the highest energy barrier in dynamics, which is consistent with this step being a potential determining step in thermodynamics. Ultimately, the solvation effect considered has little effect on the catalytic performance of screened Rh@g-C10N3 and Ir@g-C10N3, and even at a high temperature of 500 K, the structures of these two catalysts have no significant distortion after 2 ps simulations. Our calculations will provide clear guidance for future experimental synthesis and design of such catalysts.

Medial tibial plateau sustaining higher physiological stress than the lateral plateau: based on 3D printing and finite element method.

BACKGROUND: Medial compartment knee osteoarthritis (KOA) accounts for most KOA cases, and increased trabecular bone volume fraction (BV/TV) is one of the pathological changes in the tibial plateau of KOA. How BV/TV changes before and after the menopause and its effects on medial compartment KOA are yet to be clarified. METHODS: Twenty femurs from twenty 12-week-old rats were included. The operated group underwent ovariectomy (to represent the osteoporosis condition), called the O group, and the non-operated group was the normal control, called the N group. Micro-CT scans of the femoral condyles were acquired 12 weeks after the surgery, and the volume of interest (VOI) of medial-, inter-, and lateral-condyle trabeculae were three-dimensional (3D) printed for uniaxial compression mechanical test and simulated by the finite element (FE) method. RESULTS: The results demonstrated that the O group indicated poorer trabecular architecture than the N group in three parts of the femoral condyle, especially in the intercondyle. Within the group, the BV/TV, trabecular thickness (Tb.Th), and trabecular number (Tb.N) ratios between the medial and lateral condyles were greater than 1 in both N and O groups. The medial condyle trabeculae's mechanical properties were higher than those of the lateral condyle, and this superiority appears to be broadened under osteoporotic conditions. FE modelling well reproduced these mechanical differentiations. CONCLUSIONS: According to Wolff's law, the higher BV/TV and mechanical properties of the medial femoral condyle may be due to inherent imbalanced loading on the knee component. Alterations in BV/TV and their corresponding mechanical properties may accompany KOA.

Linker Scissoring Strategy Enables Precise Shaping of Metal-Organic Frameworks for Chromatographic Separation.

Precise shaping of metal-organic frameworks (MOFs) is significant in both fundamental coordination chemistry and practical applications, such as catalysis, separation, and biomedicine. Herein, we demonstrated a linker scissoring strategy for precisely shaping MOFs through surface conformational pairing. In this strategy, the bidentate linkers which were designed according to the original tetratopic ligands and the coordination environment of MOF surfaces, were utilized as the covering agents. The shape of these covering agents and the surface conformation of metals onto MOFs restricted them to coordinate on specific MOF facets thus precisely controlling the shape of the MOFs. Different shapes of PCN-608 from nanoplate (PCN-NP) to nanorod (PCN-NR) have been targeted by adding different bidentate linkers. The universality of this strategy was demonstrated by controlling the shapes of the NU-MOFs from nanoplate to nanorod. This strategy provides a new guiding principle to synthesize MOF nanocrystals with controlled shapes.

Radiometric and design model for the tunable light-guide image processing snapshot spectrometer (TuLIPSS).

The tunable light-guide image processing snapshot spectrometer (TuLIPSS) is a novel remote sensing instrument that can capture a spectral image cube in a single snapshot. The optical modelling application for the absolute signal intensity on a single pixel of the sensor in TuLIPSS has been developed through a numerical simulation of the integral performance of each optical element in the TuLIPSS system. The absolute spectral intensity of TuLIPSS can be determined either from the absolute irradiance of the observed surface or from the tabulated spectral reflectance of various land covers and by the application of a global irradiance approach. The model is validated through direct comparison of the simulated results with observations. Based on tabulated spectral reflectance, the deviation between the simulated results and the measured observations is less than 5% of the spectral light flux across most of the detection bandwidth for a Lambertian-like surface such as concrete. Additionally, the deviation between the simulated results and the measured observations using global irradiance information is less than 10% of the spectral light flux across most of the detection bandwidth for all surfaces tested. This optical modelling application of TuLIPSS can be used to assist the optimal design of the instrument and explore potential applications. The influence of the optical components on the light throughput is discussed with the optimal design being a compromise among the light throughput, spectral resolution, and cube size required by the specific application under consideration. The TuLIPSS modelling predicts that, for the current optimal low-cost configuration, the signal to noise ratio can exceed 10 at 10 ms exposure time, even for land covers with weak reflectance such as asphalt and water. Overall, this paper describes the process by which the optimal design is achieved for particular applications and directly connects the parameters of the optical components to the TuLIPSS performance.

Distortion Correction for a Brewster Angle Microscope Using an Optical Grating.

A distortion-corrected Brewster angle microscope (DC-BAM) is designed, constructed, and tested based on the combination of an optical grating and a relay lens. Avoiding the drawbacks of most conventional BAM instruments, this configuration corrects the image propagation direction and consequently provides an image in focus over the entire field of view without any beam scanning or imaging reconstruction. This new BAM can be applied to both liquid and solid subphases with good spatial resolution in static and dynamic studies.

[Preparation and application of chromatographic stationary phase based on two-dimensional materials].

The stationary phase is the heart of chromatographic separation technology and a critical contributor to the overall separation performance of a chromatographic separation technique. However, traditional silicon-based materials designed for this purpose usually feature complex preparation processes, suboptimal permeability, pronounced mass-transfer resistance, and limited pH-range compatibility. These limitations have spurred ongoing research efforts aimed at developing new chromatographic stationary phases characterized by higher separation efficiency, adaptable selectivity, and a broader scope of applicability. In this context, the scientific community has made significant strides toward the development of new-generation materials suitable for use as chromatographic stationary phases. These materials include carbon-based nanomaterial arrays, carbon quantum dots, and two-dimensional (2D) materials. 2D-materials are characterized by nanometer-scale thicknesses, extensive specific surface areas, distinctive layered structures, and outstanding mechanical properties under standard conditions. Thus, these materials demonstrate excellent utility in various applications, such as electrical and thermal conductivity enhancements, gas storage and separation solutions, membrane separation technologies, and catalysis. Graphene, which is arguably the most popular 2D-material used for chromatographic separation, consists of a 2D-lattice of carbon atoms arranged in a single layer, with a large specific surface area and efficient adsorption properties. Its widespread adoption in research and various industries is a testament to its versatility and effectiveness. In addition to graphene, the scientific community has developed various 2D-materials that mirror the layered structures of graphene, such as boron nitride, transition-metal sulfides, and 2D porous organic frameworks, all of which offer unique advantages. 2D porous organic frameworks, in particular, have received attention because of their nanosheet morphology, one-dimensional pores, and special interlayer forces; thus, these frameworks are considered promising candidate chromatographic stationary phase materials. Such recognition is especially true for 2D-metal organic frameworks (MOFs) and 2D-covalent organic frameworks (COFs), which exhibit low densities, high porosities, and substantial specific surface areas. The modifiability of these materials, in terms of pore size, shape, functional groups, and layer-stacking arrangements allows for excellent separation selectivity, highlighting their promising potential in chromatographic separation. Compared with their three-dimensional counterparts, 2D-MOFs feature a simple pore structure that offers reduced mass-transfer resistance and enhanced column efficiency. These attributes highlight the advantages of 2D-MOF nanosheets as chromatographic stationary phases. Similarly, 2D-COFs, given their high specific surface area and porosity, not only exhibit great thermal stability and chemical tolerance but also support a wide selection of solvents and operational conditions. Therefore, their role in the preparation of chromatographic stationary phases is considered highly promising. This review discusses the latest research developments in 2D porous organic framework materials in the context of gas- and liquid-chromatographic stationary phases. It introduces the synthesis methods for these novel materials, elucidates their retention mechanisms, and describes the applications of other 2D-materials, such as graphene, its derivatives, graphitic carbon nitride, and boron nitride, in chromatography. This review aims to shed light on the promising development prospects and future directions of 2D-materials in the field of chromatographic separation, offering valuable insights into the rational design and application of new 2D-materials in chromatography.

Constructing highly efficient bifunctional catalysts for oxygen reduction and oxygen evolution by modifying MXene with transition metal.

Exploring highly active electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has become a growing interest in recent years. Herein, an efficient pathway for designing MXene-based ORR/OER catalysts is proposed. It involves introducing non-noble metals into Vo (vacancy site), H1 and H2 (the hollow sites on top of C and the metal atom, respectively) sites on M2CO2 surfaces, named TM-VO/H1/H2-M2CO2 (TM = Fe, Co, Ni, M = V, Nb, Ta). Among these recombination catalysts, Co-H1-V2CO2 and Ni-H1-V2CO2 exhibit the most promising ORR catalytic activities, with low overpotential values of 0.35 and 0.37 V, respectively. Similarly, Fe-H1-V2CO2, Co-VO-Nb2CO2, and Ni-H2-Nb2CO2 possess low OER overpotential values of 0.29, 0.39, and 0.44 V, respectively, suggesting they have enormous potential as effective catalysts for OER. Notably, Co-H2-Ta2CO2 possesses the lowest potential gap value of 0.53 V, demonstrating it has an extraordinary bifunctional catalytic activity. The excellent catalytic performance of these recombination catalysts can be elucidated through an electronic structure analysis, which primarily relies on the electron-donating capacity and synergistic effects between transition metals and sub-metals. These results provide theoretical guidance for designing new ORR and OER catalysts using 2D MXene materials.

Studying trabecular bone samples demonstrates a power law relation between deteriorated structure and mechanical properties - a study combining 3D printing with the finite element method.

Introduction: The bone volume fraction (BV/TV) significantly contributes to the mechanical properties of trabecular bone. However, when studies compare normal trabeculae against osteoporotic trabeculae (in terms of BV/TV decrease), only an "average" mechanical result has been determined because of the limitation that no two trabecular structures are the same and that each unique trabecular structure can be mechanically tested only once. The mathematic relation between individual structural deterioration and mechanical properties during aging or the osteoporosis process has yet to be further clarified. Three-dimensional (3D) printing and micro-CT-based finite element method (µFEM) can assist in overcoming this issue. Methods: In this study, we 3D printed structural-identical but BV/TV value-attenuated trabecular bones (scaled up ×20) from the distal femur of healthy and ovariectomized rats and performed compression mechanical tests. Corresponding µFEM models were also established for simulations. The tissue modulus and strength of 3D printed trabecular bones as well as the effective tissue modulus (denoted as Ez) derived from µFEM models were finally corrected by the side-artifact correction factor. Results: The results showed that the tissue modulus corrected, strength corrected and Ez corrected exhibited a significant power law function of BV/TV in structural-identical but BV/TV value-attenuated trabecular samples. Discussion: Using 3D printed bones, this study confirms the long-known relationship measured in trabecular tissue with varying volume fractions. In the future, 3D printing may help us attain better bone strength evaluations and even personal fracture risk assessments for patients who suffer from osteoporosis.

Real-time conformational dynamics of SARS-CoV-2 spikes on virus particles.

SARS-CoV-2 spike (S) mediates entry into cells and is critical for vaccine development against COVID-19. S is synthesized as a precursor, processed into S1 and S2 by furin proteases, and activated for fusion when human angiotensin-converting enzyme 2 (hACE2) engages the receptor-binding domain (RBD) and when the N-terminus of S2 is proteolytically processed. Structures of soluble ectodomains and native virus particles have revealed distinct conformations of S, including a closed trimer with all RBD oriented downward, trimers with one or two RBDs up, and hACE2-stabilized conformations with up to three RBD oriented up. Real-time information that connects these structures, however, has been lacking. Here we apply single-molecule Forster Resonance Energy Transfer (smFRET) imaging to observe conformational dynamics of S on virus particles. Virus-associated S dynamically samples at least four distinct conformational states. In response to hACE2, S opens into the hACE2-bound S conformation through at least one on-path intermediate, with trypsin partially activating S. Conformational preferences of convalescent patient plasma and monoclonal antibodies suggest mechanisms of neutralization involving either direct competition with hACE2 for binding to RBD or allosteric interference with conformational changes required for entry. Our findings inform on mechanisms of S recognition and on conformations for immunogen design.

Real-Time Conformational Dynamics of SARS-CoV-2 Spikes on Virus Particles.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) mediates viral entry into cells and is critical for vaccine development against coronavirus disease 2019 (COVID-19). Structural studies have revealed distinct conformations of S, but real-time information that connects these structures is lacking. Here we apply single-molecule fluorescence (Förster) resonance energy transfer (smFRET) imaging to observe conformational dynamics of S on virus particles. Virus-associated S dynamically samples at least four distinct conformational states. In response to human receptor angiotensin-converting enzyme 2 (hACE2), S opens sequentially into the hACE2-bound S conformation through at least one on-path intermediate. Conformational preferences observed upon exposure to convalescent plasma or antibodies suggest mechanisms of neutralization involving either competition with hACE2 for binding to the receptor-binding domain (RBD) or allosteric interference with conformational changes required for entry. Our findings inform on mechanisms of S recognition and conformations for immunogen design.

Preparation and second-harmonic generation properties of a self-assembled multilayer film based on nanoporous isopolyoxomolybdate and bipolar hemicyanine.

An electrostatic self-assembled multilayer film has successfully been prepared by alternating adsorption of a wheel-shaped nanoporous isopolyoxomolybdate and a bipolar hemicyanine derivative, as monitored by absorption spectroscopy. The square roots of second-harmonic intensities of the film exhibit quadratic dependence on film thickness up to 10 layers. The average titled angle of the nonlinear optical chromophores to the substrate normal is derived to be 34 degrees by polarized second-harmonic generation measurements.

Chemical Imaging of Self-Assembled Monolayers on Copper Using Compressive Hyperspectral Sum Frequency Generation Microscopy.

Sum frequency generation microscopy is a label-free optical imaging technique with intrinsic molecular vibrational contrast for surface studies. Recent developments of compressive sensing broad-band hyperspectral SFG microscopy have demonstrated the potential application for imaging monolayer at metal surfaces with micrometer spatial resolution. Here is presented the capability of chemical imaging of spatially patterned monolayers of 1-octadecanethiol (ODT) and 16-methoxy-1-hexadecanethiol (MeOHT) molecules assembled on a copper surface. The spatial distributions of the monolayer with vibrational-spectral contrast are well-demonstrated at different frequency regions through reconstruction of the hypercube using a 3-dimensional total variation regularization algorithm (3DTV). Spatial-chemical distributions of each component are also reconstructed directly from the compressive measurements by endmember unmixing (CEU) scheme. Compared to 3DTV algorithm, the reconstruction from CEU shows spatial distribution of each component on the surfaces, and demonstrates the ability to characterize the domains of mixed-molecules on surfaces.

Compressive Broad-Band Hyperspectral Sum Frequency Generation Microscopy to Study Functionalized Surfaces.

A broad-band sum frequency generation microscope has been developed for the study of molecular monolayers on surfaces. Because sum frequency generation is a vibrational spectroscopy based on a second-order optical process, it is uniquely sensitive to detecting a molecule's vibrational fingerprints specifically at interfaces. In this microscope, a structured illumination beam generated by a spatial light modulator is used to irradiate the sample with a series of sparsifying pseudorandom patterns. The spectra associated with each pattern are then input into a reconstruction algorithm to compressively recover the full hyperspectral image cube. As a proof-of-principle, this system performed molecule-specific imaging of a microcontact-printed self-assembled monolayer of alkanethiolate on copper. This hyperspectral compressive imaging effectively recovered both spatial and spectral surface features with compression greater than 80%, meaning more than a 5-fold decrease in acquisition time compared to traditional methods.

Protein-fluctuation-induced water-pore formation in ion channel voltage-sensor translocation across a lipid bilayer membrane.

We have applied a combined fluorescence microscopy and single-ion-channel electric current recording approach, correlating with molecular dynamics (MD) simulations, to study the mechanism of voltage-sensor domain translocation across a lipid bilayer. We use the colicin Ia ion channel as a model system, and our experimental and simulation results show the following: (1) The open-close activity of an activated colicin Ia is not necessarily sensitive to the amplitude of the applied cross-membrane voltage when the cross-membrane voltage is around the resting potential of excitable membranes; and (2) there is a significant probability that the activation of colicin Ia occurs by forming a transient and fluctuating water pore of ∼15 Šdiameter in the lipid bilayer membrane. The location of the water-pore formation is nonrandom and highly specific, right at the insertion site of colicin Ia charged residues in the lipid bilayer membrane, and the formation is intrinsically associated with the polypeptide conformational fluctuations and solvation dynamics. Our results suggest an interesting mechanistic pathway for voltage-sensitive ion channel activation, and specifically for translocation of charged polypeptide chains across the lipid membrane under a transmembrane electric field: the charged polypeptide domain facilitates the formation of hydrophilic water pore in the membrane and diffuses through the hydrophilic pathway across the membrane; i.e., the charged polypeptide chain can cross a lipid membrane without entering into the hydrophobic core of the lipid membrane but entirely through the aqueous and hydrophilic environment to achieve a cross-membrane translocation. This mechanism sheds light on the intensive and fundamental debate on how a hydrophilic and charged peptide domain diffuses across the biologically inaccessible high-energy barrier of the hydrophobic core of a lipid bilayer: The peptide domain does not need to cross the hydrophobic core to move across a lipid bilayer.

Single-molecule enzymatic conformational dynamics: spilling out the product molecules.

Product releasing is an essential step of an enzymatic reaction, and a mechanistic understanding primarily depends on the active-site conformational changes and molecular interactions that are involved in this step of the enzymatic reaction. Here we report our work on the enzymatic product releasing dynamics and mechanism of an enzyme, horseradish peroxidase (HRP), using combined single-molecule time-resolved fluorescence intensity, anisotropy, and lifetime measurements. Our results have shown a wide distribution of the multiple conformational states involved in active-site interacting with the product molecules during the product releasing. We have identified that there is a significant pathway in which the product molecules are spilled out from the enzymatic active site, driven by a squeezing effect from a tight active-site conformational state, although the conventional pathway of releasing a product molecule from an open active-site conformational state is still a primary pathway. Our study provides new insight into the enzymatic reaction dynamics and mechanism, and the information is uniquely obtainable from our combined time-resolved single-molecule spectroscopic measurements and analyses.

An efficient algorithm for computing attractors of synchronous and asynchronous Boolean networks.

UNLABELLED: Biological networks, such as genetic regulatory networks, often contain positive and negative feedback loops that settle down to dynamically stable patterns. Identifying these patterns, the so-called attractors, can provide important insights for biologists to understand the molecular mechanisms underlying many coordinated cellular processes such as cellular division, differentiation, and homeostasis. Both synchronous and asynchronous Boolean networks have been used to simulate genetic regulatory networks and identify their attractors. The common methods of computing attractors are that start with a randomly selected initial state and finish with exhaustive search of the state space of a network. However, the time complexity of these methods grows exponentially with respect to the number and length of attractors. Here, we build two algorithms to achieve the computation of attractors in synchronous and asynchronous Boolean networks. For the synchronous scenario, combing with iterative methods and reduced order binary decision diagrams (ROBDD), we propose an improved algorithm to compute attractors. For another algorithm, the attractors of synchronous Boolean networks are utilized in asynchronous Boolean translation functions to derive attractors of asynchronous scenario. The proposed algorithms are implemented in a procedure called geneFAtt. Compared to existing tools such as genYsis, geneFAtt is significantly [Formula: see text] faster in computing attractors for empirical experimental systems. AVAILABILITY: The software package is available at https://sites.google.com/site/desheng619/download.

Total internal reflection fluorescence microscopy imaging-guided confocal single-molecule fluorescence spectroscopy.

We have developed an integrated spectroscopy system combining total internal reflection fluorescence microscopy imaging with confocal single-molecule fluorescence spectroscopy for two-dimensional interfaces. This spectroscopy approach is capable of both multiple molecules simultaneously sampling and in situ confocal fluorescence dynamics analyses of individual molecules of interest. We have demonstrated the calibration with fluorescent microspheres, and carried out single-molecule spectroscopy measurements. This integrated single-molecule spectroscopy is powerful in studies of single molecule dynamics at interfaces of biological and chemical systems.