Surface enhanced Raman spectroscopy(SERS) and confocal Raman microscopy are applied to investigate the structure and the molecular arrangement of sub-micron furosemide and polyvinylpyrrolidone(furosemide/PVP) particle...Surface enhanced Raman spectroscopy(SERS) and confocal Raman microscopy are applied to investigate the structure and the molecular arrangement of sub-micron furosemide and polyvinylpyrrolidone(furosemide/PVP) particles produced by spray flash evaporation(SFE). Morphology, size and crystallinity of furosemide/PVP particles are analyzed by scanning electron microscopy(SEM) and X-ray powder diffraction(XRPD). Far-field Raman spectra and confocal far-field Raman maps of furosemide/PVP particles are interpreted based on the far-field Raman spectra of pure furosemide and PVP precursors.Confocal far-field Raman microscopy shows that furosemide/PVP particles feature an intermixture of furosemide and PVP molecules at the sub-micron scale. SERS and surface-enhanced confocal Raman microscopy(SECo RM) are performed on furosemide, PVP and furosemide/PVP composite particles sputtered with silver(40 nm). SERS and SECo RM maps reveal that furosemide/PVP particle surfaces mainly consist of PVP molecules. The combination of surface and bulk sensitive analyses reveal that furosemide/PVP sub-micron particles are formed by the agglomeration of primary furosemide nanocrystals embedded in a thin PVP matrix. Interestingly, both far-field Raman microscopy and SECo RM provide molecular information on a statistically-relevant amount of sub-micron particles in a single microscopic map;this combination is thus an effective and time-saving tool for investigating organic sub-micron composites.展开更多
Coherent anti-Stokes Raman scattering(CARS)microscopy is used to visualize the release of a model drug(theophylline)from a lipid(tripalmitin)based tablet during dissolution.The effects of transformation and dissolutio...Coherent anti-Stokes Raman scattering(CARS)microscopy is used to visualize the release of a model drug(theophylline)from a lipid(tripalmitin)based tablet during dissolution.The effects of transformation and dissolution of the drug are imaged in real time.This study reveals that the manufacturing process causes significant differences in the release process:tablets prepared from powder show formation of theophylline monohydrate on the surface which prevents a controlled drug release,whereas solid lipid extrudates did not show formation of monohydrate.This visualization technique can aid future tablet design.展开更多
Synchronized time lens source is a novel method to generate synchronized optical pulses to mode-locked lasers,and has found widespread applications in coberent Raman scattering microscopy.Relative timing jitter betwee...Synchronized time lens source is a novel method to generate synchronized optical pulses to mode-locked lasers,and has found widespread applications in coberent Raman scattering microscopy.Relative timing jitter between the mode-locked laser and the synchronized time-lens source is a key parameter for evaluating the synchronization peformance of such synchronized laser sys-tems.However,the origins of the relative timing jitter in such systens are not fully determined,which in turn prevents the experimental efforts to optimize the synchronization perfornance.Here,we demonstrate,through theoretical modeling and mumerical simulation,that the photo-detction could be one physical origin of the relative timing jitter.Comparison with relative timing jitter due to the intrinsic timing jitter of the mode-locked laser is also demonstrated,revealing different qualitative and quantitative behavios.Based on the nature of this photo-detection-induced timing jitter,we further propose several strategies to reduce the relative timing jitter.Our thoretical results will provide guidelines for optimizing synchronization performance in experiments.展开更多
Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth.Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level.Although...Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth.Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level.Although°uorescence microscopy has been commonly used for cancer research,bulky°uorescent probes can hardly label small lipid molecules without perturbing their biological activities.Such a challenge can be overcome by coherent Raman scattering(CRS)microscopy,which is capable of chemically selective,highly sensitive,submicron resolution and high-speed imaging of lipid molecules in single live cells without any labeling.Recently developed hyperspectral and multiplex CRS microscopy enables quantitative mapping of various lipid metabolites in situ.Further incorporation of CRS microscopy with Raman tags greatly increases molecular selectivity based on the distinct Raman peaks well separated from the endogenous cellular background.Owing to these unique advantages,CRS microscopy sheds new insights into the role of lipid metabolism in cancer development and progression.This review focuses on the latest applications of CRS microscopy in the study of lipid metabolism in cancer.展开更多
Multi-photon microscopy(MPM)and coherent anti-Stokes Raman scattering(CARS)are two advanced nonlinear optical imaging techniques,which provide complementary information and have great potential in combination for noni...Multi-photon microscopy(MPM)and coherent anti-Stokes Raman scattering(CARS)are two advanced nonlinear optical imaging techniques,which provide complementary information and have great potential in combination for noninvasive in vrito biomedical applications.This paper provides a detailed discussion of the basics,development and applications of these technologies for in vrivo skin research,covering the following topics:The principle and advantage of MPM and CARS,instrumentation development for in vino applications,MPM and CARS of normal skin,application of MPM and CARS in skin cancer and disease diagnosis;application of MPM in skin disease intervention,ie.,imaging guided two-photon photothermolysis.展开更多
This study evaluated the effects of sodium hypochlorite（NaOCl） with different concentrations and exposure time on the structural, compositional and mechanical properties of human dentin in vitro. Sixty dentin slabs ...This study evaluated the effects of sodium hypochlorite（NaOCl） with different concentrations and exposure time on the structural, compositional and mechanical properties of human dentin in vitro. Sixty dentin slabs were obtained from freshly extracted premolars, randomly distributed into four groups（n=15）, and treated with 1%, 5%, 10% NaOCl and distilled water（control group）, respectively, for a total of 60 min. Attenuated total reflection infrared（ATR-IR） spectroscopy, Raman spectroscopy and X-ray diffraction（XRD） were carried out before, 10 min and 60 min after the treatment. Scanning electron microscopy（SEM） and flexural strength test were conducted as well. The results showed that dentins experienced morphological alterations in the NaOCl groups, but not in the control group. Two-way repeated-measures analysis of variance revealed that the carbonate：mineral ratio（C：M）, Raman relative intensity（RRI）, a-axis, c-axis length and full width at half maximum（FWHM） with the increase of time and concentration in the NaOCl groups were not significantly different from those in the control group（P〉0.05）. Nevertheless, the mineral：matrix ratio（M：M） increased and the flexural strength declined with the increase of concentration and the extension of time in the NaOCl groups（P〈0.05）. Additionally, it was found that the M：M and the flexural strength remained unchanged after 1% NaOCl treatment（P〉0.05）, and the morphology changes were unnoticeable within 10 min in 1% NaOCl group. These results indicated that NaOCl has no significant effects on the inorganic mineral of human dentin; but it undermines and eliminates the organic content concentration-and time-dependently, which in turn influences the flexural strength and toughness of dentins. In addition, an irrigation of 1% NaOCl within 10 min can minimize the effects of NaOCl on the structural and mechanical properties of dentin during root canal treatment.展开更多
Super-resolution optical imaging overcomes the diffraction limit in light microscopy to enable the visualization of previously invisible molecular details within a sample.The realization of super-resolution imaging ba...Super-resolution optical imaging overcomes the diffraction limit in light microscopy to enable the visualization of previously invisible molecular details within a sample.The realization of super-resolution imaging based on stimulated Raman scattering(SRS)microscopy represents a recent area of fruitful development that has been used to visualize cellular structures in three dimensions,with multiple spectroscopic colors at the nanometer scale.Several fundamental approaches to achieving super-resolution SRS imaging have been reported,including optical engineering strategies,expansion microscopy,deconvolution image analysis,and photoswitchable SRS reporters as methods to break the diffraction limit.These approaches have enabled the visualization of biological structures,cellular interactions,and dynamics with unprecedented detail.In this Perspective,an overview of the current strategies and capabilities for achieving super-resolution SRS imaging will be highlighted together with an outlook on potential directions of this rapidly evolving field.展开更多
Molecular biomarkers play an essential role in accurate diseasediagnosis and personalized treatment.Dysregulated metabolism is closely associated with disease development and progression.The discovery of metabolic bio...Molecular biomarkers play an essential role in accurate diseasediagnosis and personalized treatment.Dysregulated metabolism is closely associated with disease development and progression.The discovery of metabolic biomarkers could remarkably promote precision diagnosis and personalized treatment.Current metabolomics approaches can profile a large number of metabolites but are primarily destructive and lack sufficient spatial resolution,which hinders quantitativemeasurements of the highly dynamic and heterogeneous intracellular metabolic processes.This further limits the discovery of metabolic biomarkers in these diseases.Stimulated Raman scattering(SRS)microscopy addresses these gaps by enabling label-free imaging with high sensitivity,molecular specificity,and subcellular resolution.Integrating Raman-active vibrational probes further extends this approach,allowing for real-time tracking of low-abundance biomolecules and metabolic processes.These capabilities have enabled the discovery of biomarkers for disease diagnosis.In this review,we focus on recent advancements in SRS imaging technologies and data analysis methods and their applications in biomarkerdiscovery and precision medicine.Furthermore,future perspectives and emerging trends in this rapidly evolving research area are discussed.展开更多
Hyperspectral stimulated Raman scattering(SRS)microscopy is rapidly becoming an established method for chemical and biomedical imaging due to the combination of high spatial resolution and chemical information contain...Hyperspectral stimulated Raman scattering(SRS)microscopy is rapidly becoming an established method for chemical and biomedical imaging due to the combination of high spatial resolution and chemical information contained within the three-dimensional data set.Chemometric analysis techniques based on linear unmixing,or multivariate analysis,have become indispensable when visualizing hyperspectral data sets.The application of spectral phasor analysis has also been extremely fruitful in this regard,providing a convenient method to retrieve the spatial and chemical components of the data set.Here,we demonstrate the application of spectral phasor analysis for unmixing the overlapping spectral features within the cell-silent region of the SRS spectrum(2000−2300 cm^(−1)).In doing so,we show it is possible to identify specific Raman signals for DNA,proteins,and lipids following glucose-d7 metabolism in dividing cells.In addition,we show that spectral phasor analysis is capable of distinguishing different bioorthogonal Raman signals including alkynes and carbon−deuterium(C−D)bonds.We demonstrate the application of spectral phasor analysis for multicomponent unmixing of bioorthogonal Raman groups for high-content cellular imaging applications.展开更多
Gout,a common form of arthritis,is characterized by the deposition of monosodium urate(MSU)crystals in joints.MSU deposition in synovial tissues would initiate arthritis flares and recurrence,causing irreversible join...Gout,a common form of arthritis,is characterized by the deposition of monosodium urate(MSU)crystals in joints.MSU deposition in synovial tissues would initiate arthritis flares and recurrence,causing irreversible joint damage.However,the dynamic deposition of MSU crystals in tissues lacks experimental observation.In this study,we used chemical-specific,label-free stimulated Raman scattering(SRS)microscopy to investigate the spatiotemporal deposition and morphological characteristics of MSU crystals in human synovial organoids.Our findings revealed a critical 12-h window for MSU deposition in the lining layer of gouty synovium.Moreover,distinctive inflammatory reactions of the lining and sublining synovial layers in gout using SRS microscopy were further verified by immunofluorescence.Importantly,we identified a crucial proinflammatory role of sublining fibroblast-like synoviocytes,indicating a need for targeted medication treatment on these cells.Our work contributes to the fundamental understanding of MSU-based diseases and offers valuable insights for the future development of targeted gout therapies.展开更多
Collagen fibrillogenesis underlies the structural and mechanical properties of the extracellular matrix in connective and other tissues,yet its molecular mechanism remains poorly understood.Here,we show that a europi...Collagen fibrillogenesis underlies the structural and mechanical properties of the extracellular matrix in connective and other tissues,yet its molecular mechanism remains poorly understood.Here,we show that a europium(Ⅲ)dipicolinate complex(EuDPA)acts as a luminescent reporter of collagen aggregation.We combine Raman microscopy,circularly polarized luminescence(CPL),and molecular dynamics(MD)simulations to study this process.While Raman imaging directly visualizes the EuDPA-enhanced fibrillar architecture,CPL reveals enantioselective EuDPA-collagen interactions that accompany the fibrillogenesis.MD simulations indicate the presence of stabilizing interactions between hydroxyproline residues and the dipicolinate ligand.The results pave the way to monitoring of protein aggregation in general,and are relevant to fibrotic pathologies and biomimetic materials design.展开更多
We quantitatively study the Raman and photoluminescence(PL)emission from single-layer molybdenum disulfide(MoS2)on dielectric(SiO2,hexagonal boron nitride,mica and the polymeric dielectric Gel-Film)and conducting subs...We quantitatively study the Raman and photoluminescence(PL)emission from single-layer molybdenum disulfide(MoS2)on dielectric(SiO2,hexagonal boron nitride,mica and the polymeric dielectric Gel-Film)and conducting substrates(Au and few-layer graphene).We find that the substrate can affect the Raman and PL emission in a twofold manner.First,the absorption and emission intensities are strongly modulated by the constructive/destructive interference within the different substrates.Second,the position of the Alg Raman mode peak and the spectral weight between neutral and charged excitons in the PL spectra are modified by the substrate.We attribute this effect to substrate-induced changes in the doping level and in the decay rates of the excitonic transitions.Our results provide a method to quantitatively study the Raman and PL emission from MoSa-based vertical heterostructures and represent the first step in ad hoc tuning the PL emission of 1L MoS2 by selecting the proper substrate.展开更多
Because of the fingerprint-like specificity of its characteristic spectrogram, Raman spectral imaging has been applied widely in various research areas. Using a combination of structured illumination with the surface-...Because of the fingerprint-like specificity of its characteristic spectrogram, Raman spectral imaging has been applied widely in various research areas. Using a combination of structured illumination with the surface- enhanced Raman scattering （SERS） technique, wide-field Raman imaging is developed with a significant improve- ment in spatial resolution. As a result of the relatively narrow Raman characteristic peaks, optically encoded SERS nanoparticles can be used to perform multiplexed imaging. The results show excellent superresolution wide-fidd multiplexed imaging performance. The developed technique has extraordinary potential for applications in biological imaging and other related fields.展开更多
We demonstrate low-frequency interferometric impulsive stimulated Raman scattering(ISRS)imaging with high robustness to distortions by optical scattering.ISRS is a pump−probe coherent Raman spectroscopy that can captu...We demonstrate low-frequency interferometric impulsive stimulated Raman scattering(ISRS)imaging with high robustness to distortions by optical scattering.ISRS is a pump−probe coherent Raman spectroscopy that can capture Raman vibrational spectra.Recording of ISRS spectra requires isolation of a probe pulse from the pump pulse.While this separation is simple in nonscattering specimens,such as liquids,scattering leads to significant pump pulse contamination and prevents the extraction of a Raman spectrum.We introduce a robust method for ISRS microscopy that works in complex scattering samples.High signal-to-noise ISRS spectra are obtained even when the pump and probe pulses pass through many scattering layers.展开更多
Photothermal nanomotors driven by near-infrared(NIR)light emerged as a promising advancement in nanoscale propulsion systems.In this study,a novel type of nanomotor actuated by NIR light was prepared by decorating sph...Photothermal nanomotors driven by near-infrared(NIR)light emerged as a promising advancement in nanoscale propulsion systems.In this study,a novel type of nanomotor actuated by NIR light was prepared by decorating spherical TiO_(2) nanoparticles with Janus Ag-Ag_(2)S nanoparticles.The motion of these nanomotors is studied using optical microscopy with a dual light source.It is found that they can be actuated with a 700 nm driving light and traverse significant distances relative to their size.Motion analysis reveals that their maximum velocity reaches~20μm·s^(-1),or about 100 diameters per second.Statistical analysis of over 400 nanomotor trajectories shows that around 60% of them move at maximum velocities of 6 to 12μm·s^(-1).Vacuum ultraviolet velocity map imaging photoemission spectroscopy(VMI-PES)is conducted on isolated TiO_(2) and Janus Ag-Ag_(2)S nanoparticles to elucidate electronic level alignment in the hybrid particle.The findings suggest that photothermal,rather than photocatalytic,effects drive nanomotor activation under NIR light.Additionally,our calculations indicate that the difference in absorption cross-sections between Ag-Ag_(2)S and TiO_(2) components generates a temperature gradient(and consequently a pressure gradient)along the nanomotor,which in turn drives its motion.The local temperature rise near the nanomotors is a result of both photothermal effects within individual nanoparticles and thermal interactions between them.展开更多
Chemical imaging based on vibrational contrasts can extract molecular information entangled in complex biological systems.To this end,nonlinear Raman scattering microscopy,midinfrared photothermal(MIP)microscopy,and a...Chemical imaging based on vibrational contrasts can extract molecular information entangled in complex biological systems.To this end,nonlinear Raman scattering microscopy,midinfrared photothermal(MIP)microscopy,and atomic force microscopy(AFM)-based force-detected photothermal microscopies are emerging with better chemical sensitivity,molecular speciffcity,and spatial resolution than conventional vibrational methods.Their utilization in bioimaging applications has provided biological knowledge in unprecedented detail.This Perspective outlines key methodological developments,bioimaging applications,and recent technical innovations of the three techniques.Representative biological demonstrations are also highlighted to exemplify the unique advantages of obtaining vibrational contrasts.With years of effort,these three methods compose an expanding vibrational bioimaging toolbox to tackle speciffc bioimaging needs,beneffting many biological investigations with rich information in both label-free and labeling manners.Each technique will be discussed and compared in the outlook,leading to possible future directions to accommodate growing needs in vibrational bioimaging.展开更多
文摘Surface enhanced Raman spectroscopy(SERS) and confocal Raman microscopy are applied to investigate the structure and the molecular arrangement of sub-micron furosemide and polyvinylpyrrolidone(furosemide/PVP) particles produced by spray flash evaporation(SFE). Morphology, size and crystallinity of furosemide/PVP particles are analyzed by scanning electron microscopy(SEM) and X-ray powder diffraction(XRPD). Far-field Raman spectra and confocal far-field Raman maps of furosemide/PVP particles are interpreted based on the far-field Raman spectra of pure furosemide and PVP precursors.Confocal far-field Raman microscopy shows that furosemide/PVP particles feature an intermixture of furosemide and PVP molecules at the sub-micron scale. SERS and surface-enhanced confocal Raman microscopy(SECo RM) are performed on furosemide, PVP and furosemide/PVP composite particles sputtered with silver(40 nm). SERS and SECo RM maps reveal that furosemide/PVP particle surfaces mainly consist of PVP molecules. The combination of surface and bulk sensitive analyses reveal that furosemide/PVP sub-micron particles are formed by the agglomeration of primary furosemide nanocrystals embedded in a thin PVP matrix. Interestingly, both far-field Raman microscopy and SECo RM provide molecular information on a statistically-relevant amount of sub-micron particles in a single microscopic map;this combination is thus an effective and time-saving tool for investigating organic sub-micron composites.
基金supported by NanoNed,a nanotechnology program of the Dutch Ministry of Economic Affairs and partly financed by the Stichting voor Fundamenteel Onderzoek der Materie(FOM),which is financially supported by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek(NWO).The Marie Curie Fellowship and the Galenos Network are acknowledged for financial support(MEST-CT-2004-404992).
文摘Coherent anti-Stokes Raman scattering(CARS)microscopy is used to visualize the release of a model drug(theophylline)from a lipid(tripalmitin)based tablet during dissolution.The effects of transformation and dissolution of the drug are imaged in real time.This study reveals that the manufacturing process causes significant differences in the release process:tablets prepared from powder show formation of theophylline monohydrate on the surface which prevents a controlled drug release,whereas solid lipid extrudates did not show formation of monohydrate.This visualization technique can aid future tablet design.
基金supported by the National Natural Science Foundation of China (11404218)the Science and Technology Innovation Commission of Shenzhen (JCYJ20160307150657874,KQJSCX-20160226194151,KQTD20150710165601017)+1 种基金the Project of Department of Education of Guangdong Province (2014KTSCX114)the Natural Science Foundation of SZU (00002701).
文摘Synchronized time lens source is a novel method to generate synchronized optical pulses to mode-locked lasers,and has found widespread applications in coberent Raman scattering microscopy.Relative timing jitter between the mode-locked laser and the synchronized time-lens source is a key parameter for evaluating the synchronization peformance of such synchronized laser sys-tems.However,the origins of the relative timing jitter in such systens are not fully determined,which in turn prevents the experimental efforts to optimize the synchronization perfornance.Here,we demonstrate,through theoretical modeling and mumerical simulation,that the photo-detction could be one physical origin of the relative timing jitter.Comparison with relative timing jitter due to the intrinsic timing jitter of the mode-locked laser is also demonstrated,revealing different qualitative and quantitative behavios.Based on the nature of this photo-detection-induced timing jitter,we further propose several strategies to reduce the relative timing jitter.Our thoretical results will provide guidelines for optimizing synchronization performance in experiments.
基金supported by the National Natural Science Foundation of China(Nos.91959120 and 62027824)Basic Research Program for Beijing-Tianjin-Hebei Coordination(19JCZDJC65500(Z))+1 种基金Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2018WNLOKF026)Fundamental Research Funds for the Central Universities(YWF-22-L-547).
文摘Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth.Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level.Although°uorescence microscopy has been commonly used for cancer research,bulky°uorescent probes can hardly label small lipid molecules without perturbing their biological activities.Such a challenge can be overcome by coherent Raman scattering(CRS)microscopy,which is capable of chemically selective,highly sensitive,submicron resolution and high-speed imaging of lipid molecules in single live cells without any labeling.Recently developed hyperspectral and multiplex CRS microscopy enables quantitative mapping of various lipid metabolites in situ.Further incorporation of CRS microscopy with Raman tags greatly increases molecular selectivity based on the distinct Raman peaks well separated from the endogenous cellular background.Owing to these unique advantages,CRS microscopy sheds new insights into the role of lipid metabolism in cancer development and progression.This review focuses on the latest applications of CRS microscopy in the study of lipid metabolism in cancer.
文摘Multi-photon microscopy(MPM)and coherent anti-Stokes Raman scattering(CARS)are two advanced nonlinear optical imaging techniques,which provide complementary information and have great potential in combination for noninvasive in vrito biomedical applications.This paper provides a detailed discussion of the basics,development and applications of these technologies for in vrivo skin research,covering the following topics:The principle and advantage of MPM and CARS,instrumentation development for in vino applications,MPM and CARS of normal skin,application of MPM and CARS in skin cancer and disease diagnosis;application of MPM in skin disease intervention,ie.,imaging guided two-photon photothermolysis.
基金supported by the National Natural Science Foundation of China(No.81470771,No.81500887)the Natural Science Foundation of Hubei Province(No.2013CFA068)
文摘This study evaluated the effects of sodium hypochlorite（NaOCl） with different concentrations and exposure time on the structural, compositional and mechanical properties of human dentin in vitro. Sixty dentin slabs were obtained from freshly extracted premolars, randomly distributed into four groups（n=15）, and treated with 1%, 5%, 10% NaOCl and distilled water（control group）, respectively, for a total of 60 min. Attenuated total reflection infrared（ATR-IR） spectroscopy, Raman spectroscopy and X-ray diffraction（XRD） were carried out before, 10 min and 60 min after the treatment. Scanning electron microscopy（SEM） and flexural strength test were conducted as well. The results showed that dentins experienced morphological alterations in the NaOCl groups, but not in the control group. Two-way repeated-measures analysis of variance revealed that the carbonate：mineral ratio（C：M）, Raman relative intensity（RRI）, a-axis, c-axis length and full width at half maximum（FWHM） with the increase of time and concentration in the NaOCl groups were not significantly different from those in the control group（P〉0.05）. Nevertheless, the mineral：matrix ratio（M：M） increased and the flexural strength declined with the increase of concentration and the extension of time in the NaOCl groups（P〈0.05）. Additionally, it was found that the M：M and the flexural strength remained unchanged after 1% NaOCl treatment（P〉0.05）, and the morphology changes were unnoticeable within 10 min in 1% NaOCl group. These results indicated that NaOCl has no significant effects on the inorganic mineral of human dentin; but it undermines and eliminates the organic content concentration-and time-dependently, which in turn influences the flexural strength and toughness of dentins. In addition, an irrigation of 1% NaOCl within 10 min can minimize the effects of NaOCl on the structural and mechanical properties of dentin during root canal treatment.
基金University of Strathclyde and the EPSRC(EP/N010914/1)for financial support.
文摘Super-resolution optical imaging overcomes the diffraction limit in light microscopy to enable the visualization of previously invisible molecular details within a sample.The realization of super-resolution imaging based on stimulated Raman scattering(SRS)microscopy represents a recent area of fruitful development that has been used to visualize cellular structures in three dimensions,with multiple spectroscopic colors at the nanometer scale.Several fundamental approaches to achieving super-resolution SRS imaging have been reported,including optical engineering strategies,expansion microscopy,deconvolution image analysis,and photoswitchable SRS reporters as methods to break the diffraction limit.These approaches have enabled the visualization of biological structures,cellular interactions,and dynamics with unprecedented detail.In this Perspective,an overview of the current strategies and capabilities for achieving super-resolution SRS imaging will be highlighted together with an outlook on potential directions of this rapidly evolving field.
基金the National Natural Science Foundation of China (62027824).
文摘Molecular biomarkers play an essential role in accurate diseasediagnosis and personalized treatment.Dysregulated metabolism is closely associated with disease development and progression.The discovery of metabolic biomarkers could remarkably promote precision diagnosis and personalized treatment.Current metabolomics approaches can profile a large number of metabolites but are primarily destructive and lack sufficient spatial resolution,which hinders quantitativemeasurements of the highly dynamic and heterogeneous intracellular metabolic processes.This further limits the discovery of metabolic biomarkers in these diseases.Stimulated Raman scattering(SRS)microscopy addresses these gaps by enabling label-free imaging with high sensitivity,molecular specificity,and subcellular resolution.Integrating Raman-active vibrational probes further extends this approach,allowing for real-time tracking of low-abundance biomolecules and metabolic processes.These capabilities have enabled the discovery of biomarkers for disease diagnosis.In this review,we focus on recent advancements in SRS imaging technologies and data analysis methods and their applications in biomarkerdiscovery and precision medicine.Furthermore,future perspectives and emerging trends in this rapidly evolving research area are discussed.
基金University of Strathclyde and the EPSRC(EP/N010914/1)for funding.
文摘Hyperspectral stimulated Raman scattering(SRS)microscopy is rapidly becoming an established method for chemical and biomedical imaging due to the combination of high spatial resolution and chemical information contained within the three-dimensional data set.Chemometric analysis techniques based on linear unmixing,or multivariate analysis,have become indispensable when visualizing hyperspectral data sets.The application of spectral phasor analysis has also been extremely fruitful in this regard,providing a convenient method to retrieve the spatial and chemical components of the data set.Here,we demonstrate the application of spectral phasor analysis for unmixing the overlapping spectral features within the cell-silent region of the SRS spectrum(2000−2300 cm^(−1)).In doing so,we show it is possible to identify specific Raman signals for DNA,proteins,and lipids following glucose-d7 metabolism in dividing cells.In addition,we show that spectral phasor analysis is capable of distinguishing different bioorthogonal Raman signals including alkynes and carbon−deuterium(C−D)bonds.We demonstrate the application of spectral phasor analysis for multicomponent unmixing of bioorthogonal Raman groups for high-content cellular imaging applications.
基金supported by the National Key R&D Program of China(grant numbers 2021YFF0502900 and SQ 2020YFA0803800)the National Natural Science Foundation of China(grant number 82072510)the Shanghai Science and Technology Committee(grant numbers 22dz1204702 and 23dz2260100)。
文摘Gout,a common form of arthritis,is characterized by the deposition of monosodium urate(MSU)crystals in joints.MSU deposition in synovial tissues would initiate arthritis flares and recurrence,causing irreversible joint damage.However,the dynamic deposition of MSU crystals in tissues lacks experimental observation.In this study,we used chemical-specific,label-free stimulated Raman scattering(SRS)microscopy to investigate the spatiotemporal deposition and morphological characteristics of MSU crystals in human synovial organoids.Our findings revealed a critical 12-h window for MSU deposition in the lining layer of gouty synovium.Moreover,distinctive inflammatory reactions of the lining and sublining synovial layers in gout using SRS microscopy were further verified by immunofluorescence.Importantly,we identified a crucial proinflammatory role of sublining fibroblast-like synoviocytes,indicating a need for targeted medication treatment on these cells.Our work contributes to the fundamental understanding of MSU-based diseases and offers valuable insights for the future development of targeted gout therapies.
基金supported by the Czech Science Foundation(23-05378S to TW and 2515726S to PB)the Ministry of Education,Youth and Sports of the Czech Republic through the e-INFRA CZ(ID:90140).
文摘Collagen fibrillogenesis underlies the structural and mechanical properties of the extracellular matrix in connective and other tissues,yet its molecular mechanism remains poorly understood.Here,we show that a europium(Ⅲ)dipicolinate complex(EuDPA)acts as a luminescent reporter of collagen aggregation.We combine Raman microscopy,circularly polarized luminescence(CPL),and molecular dynamics(MD)simulations to study this process.While Raman imaging directly visualizes the EuDPA-enhanced fibrillar architecture,CPL reveals enantioselective EuDPA-collagen interactions that accompany the fibrillogenesis.MD simulations indicate the presence of stabilizing interactions between hydroxyproline residues and the dipicolinate ligand.The results pave the way to monitoring of protein aggregation in general,and are relevant to fibrotic pathologies and biomimetic materials design.
文摘We quantitatively study the Raman and photoluminescence(PL)emission from single-layer molybdenum disulfide(MoS2)on dielectric(SiO2,hexagonal boron nitride,mica and the polymeric dielectric Gel-Film)and conducting substrates(Au and few-layer graphene).We find that the substrate can affect the Raman and PL emission in a twofold manner.First,the absorption and emission intensities are strongly modulated by the constructive/destructive interference within the different substrates.Second,the position of the Alg Raman mode peak and the spectral weight between neutral and charged excitons in the PL spectra are modified by the substrate.We attribute this effect to substrate-induced changes in the doping level and in the decay rates of the excitonic transitions.Our results provide a method to quantitatively study the Raman and PL emission from MoSa-based vertical heterostructures and represent the first step in ad hoc tuning the PL emission of 1L MoS2 by selecting the proper substrate.
基金National Natural Science Foundation of China(NSFC)(61490712,61427819,91750205,61605117)National Key Basic Research Program of China(973)(2015CB352004)+4 种基金Leading Talents of Guangdong Province Program(00201505)Natural Science Foundation of Guangdong Province(2016A030312010,2016A030310063,2017A030313351)National Key Research and Development Program of China(2016YFC0102401)Science and Technology Innovation Commission of Shenzhen(KQTD2017033011044403,KQTD2015071016560101,ZDSYS201703031605029)Excellent Young Teacher Program of Guangdong Province(YQ2014151)
文摘Because of the fingerprint-like specificity of its characteristic spectrogram, Raman spectral imaging has been applied widely in various research areas. Using a combination of structured illumination with the surface- enhanced Raman scattering （SERS） technique, wide-field Raman imaging is developed with a significant improve- ment in spatial resolution. As a result of the relatively narrow Raman characteristic peaks, optically encoded SERS nanoparticles can be used to perform multiplexed imaging. The results show excellent superresolution wide-fidd multiplexed imaging performance. The developed technique has extraordinary potential for applications in biological imaging and other related fields.
基金grateful for funding from DE-FOA-0002603(R.A.B.)Alicia Williams from the Morgridge Institute provided scientific editing supportsupport from ANR-21-ESRS-0002 IDEC,EU ICT 101016923 CRIMSON,EU EIC 101099058 VIRUSONG,and EU ERC 101052911(H.R.)and NIH 5 R21GM135772-02(J.W.W.and R.A.B.).
文摘We demonstrate low-frequency interferometric impulsive stimulated Raman scattering(ISRS)imaging with high robustness to distortions by optical scattering.ISRS is a pump−probe coherent Raman spectroscopy that can capture Raman vibrational spectra.Recording of ISRS spectra requires isolation of a probe pulse from the pump pulse.While this separation is simple in nonscattering specimens,such as liquids,scattering leads to significant pump pulse contamination and prevents the extraction of a Raman spectrum.We introduce a robust method for ISRS microscopy that works in complex scattering samples.High signal-to-noise ISRS spectra are obtained even when the pump and probe pulses pass through many scattering layers.
基金funded by the Ministry of Science,Technological development and Innovation of the Republic of Serbia under Grant Agreements No 451-03-66/2024-03/200017 and 451-03-66/2024-03/200162.
文摘Photothermal nanomotors driven by near-infrared(NIR)light emerged as a promising advancement in nanoscale propulsion systems.In this study,a novel type of nanomotor actuated by NIR light was prepared by decorating spherical TiO_(2) nanoparticles with Janus Ag-Ag_(2)S nanoparticles.The motion of these nanomotors is studied using optical microscopy with a dual light source.It is found that they can be actuated with a 700 nm driving light and traverse significant distances relative to their size.Motion analysis reveals that their maximum velocity reaches~20μm·s^(-1),or about 100 diameters per second.Statistical analysis of over 400 nanomotor trajectories shows that around 60% of them move at maximum velocities of 6 to 12μm·s^(-1).Vacuum ultraviolet velocity map imaging photoemission spectroscopy(VMI-PES)is conducted on isolated TiO_(2) and Janus Ag-Ag_(2)S nanoparticles to elucidate electronic level alignment in the hybrid particle.The findings suggest that photothermal,rather than photocatalytic,effects drive nanomotor activation under NIR light.Additionally,our calculations indicate that the difference in absorption cross-sections between Ag-Ag_(2)S and TiO_(2) components generates a temperature gradient(and consequently a pressure gradient)along the nanomotor,which in turn drives its motion.The local temperature rise near the nanomotors is a result of both photothermal effects within individual nanoparticles and thermal interactions between them.
基金the support from NIH Director’s New Innovator Award,DP2 GM140919-01.
文摘Chemical imaging based on vibrational contrasts can extract molecular information entangled in complex biological systems.To this end,nonlinear Raman scattering microscopy,midinfrared photothermal(MIP)microscopy,and atomic force microscopy(AFM)-based force-detected photothermal microscopies are emerging with better chemical sensitivity,molecular speciffcity,and spatial resolution than conventional vibrational methods.Their utilization in bioimaging applications has provided biological knowledge in unprecedented detail.This Perspective outlines key methodological developments,bioimaging applications,and recent technical innovations of the three techniques.Representative biological demonstrations are also highlighted to exemplify the unique advantages of obtaining vibrational contrasts.With years of effort,these three methods compose an expanding vibrational bioimaging toolbox to tackle speciffc bioimaging needs,beneffting many biological investigations with rich information in both label-free and labeling manners.Each technique will be discussed and compared in the outlook,leading to possible future directions to accommodate growing needs in vibrational bioimaging.
