Optical properties of metallic edge-like structures known as knife-edges are a topic of interest and possess potential applications in enhanced Raman scattering, optical trapping, etc. In this work, we investigate the...Optical properties of metallic edge-like structures known as knife-edges are a topic of interest and possess potential applications in enhanced Raman scattering, optical trapping, etc. In this work, we investigate the near-field optical polar- ization response at the edge of a triangular gold nanosheet, which is synthesized by a wet chemical method. A homemade scanning near-field optical microscope （SNOM） in collection mode is adopted, which is able to accurately locate its probe at the edge during experiments. An uncoated straight fiber probe is used in the SNOM, because it s611 preserves the prop- erty of light polarization though it has the depolarization to some extent. By comparing near-field intensities at the edge and glass substrate, detected in different polarization directions of incident light, the edge-induced depolarization is found, which is supported by the finite differential time domain （FDTD） simulated results. The depolarized phenomenon in the near-field is similar to that in the far-field.展开更多
A new method to visualize the large-scale crystal grain morphology of organic polycrystalline films is proposed. First,optical anisotropic transmittance images of polycrystalline zinc phthalocyanine（Zn Pc） films vac...A new method to visualize the large-scale crystal grain morphology of organic polycrystalline films is proposed. First,optical anisotropic transmittance images of polycrystalline zinc phthalocyanine（Zn Pc） films vacuum deposited by weak epitaxial growth（WEG） method were acquired with polarized optical microscopy（POM）. Then morphology properties including crystal grain size, distribution, relative orientation, and crystallinity were derived from these images by fitting with a transition dipole model. At last, atomic force microscopy（AFM） imaging was carried out to confirm the fitting and serve as absolute references. This method can be readily generalized to other organic polycrystalline films, thus providing an efficient way to access the large-scale morphologic properties of organic polycrystalline films, which may prove to be useful in industry as a film quality monitoring method.展开更多
Objective: To assess the missed opportunities from the diagnosis of bacilliferous pulmonary tuberculosis by optical microscopy compared to GeneXpert MTB/RIF between 2015 and 2019. Methods: This is a retrospective anal...Objective: To assess the missed opportunities from the diagnosis of bacilliferous pulmonary tuberculosis by optical microscopy compared to GeneXpert MTB/RIF between 2015 and 2019. Methods: This is a retrospective analysis of the diagnostic results of bacilliferous pulmonary tuberculosis in patients suspected of pulmonary tuberculosis at their first episode during the period. GeneXpert MTB/RIF (GeneXpert) and optical microscopy (OM) after Ziehl-Neelsen stained smear were performed on each patient’s sputum or gastric tubing fluid sample. Results: Among 341 patients suspected of pulmonary tuberculosis, 229 patients were declared bacilliferous tuberculosis by the two tests (67%), 220 patients by GeneXpert and 95 patients by OM, i.e. 64.5% versus 28% (p i.e. 58.5% of the positive cases detected by the two tests (134/229 patients) and 39.3% of the patients suspected of tuberculosis (134/341 patients). On the other hand, among 95 patients declared positive by OM, the GeneXpert ignored 9 (9.5%), i.e. 4% of all the positive cases detected by the two diagnostic tests (9/229 patients) and 3% of the patients suspected of tuberculosis (9/341 patients). The differences observed between the results of the two tests were statistically significant at the 5% threshold (p Conclusion: This study reveals missed diagnostic opportunities for bacilliferous pulmonary mycobacteriosis, statistically significant with optical microscopy than GeneXpert. The GeneXpert/optical microscopy couple could be a good contribution to the strategies for the elimination of pulmonary tuberculosis in sub-Saharan Africa.展开更多
The use of optical microscopy and labeling methods in intravital imaging allows for direct tracking of cell behavior and dynamic changes at the molecular level in the physiological or pathological microenvironment of ...The use of optical microscopy and labeling methods in intravital imaging allows for direct tracking of cell behavior and dynamic changes at the molecular level in the physiological or pathological microenvironment of living animals,revealing the spatiotemporal information of individual cells in the immune response.The liver is an immunological organ that contains unique innate and adaptive immune cells,including Kupffer cells(KCs)and different types of T cells,and is involved in coordinating multiple immune responses in the body.Using intravital imaging to visualize the movement behaviors and functions of immune cells during the reaction processes of the liver under physiological and pathological conditions has shed new light on the understanding of liver immunity,which is of great significance for the diagnosis and treatment of liver diseases.This review introduces various window models and labeling methods for the liver in intravital optical imaging and describes how it provides movement behavior and functional information about different types of immune cells,such as KCs and T cells,in the liver.Additionally,we highlight recent advances in intravital optical imaging of liver diseases,such as nonalcoholic fatty liver disease,infections,and tumors.This review aims to be a useful resource for comprehending the developments and achievements in intravital imaging of the liver and uncovering spatiotemporal information of immune response in a living microenvironment.展开更多
Optical microscopy has become an indispensable tool for visualizing sub-cellular structures andbiological processes.However,scattering in biological tissues is a major obstacle that preventshigh-resolution images from...Optical microscopy has become an indispensable tool for visualizing sub-cellular structures andbiological processes.However,scattering in biological tissues is a major obstacle that preventshigh-resolution images from being obtained from deep regions of tissue.We review commontechniques,such as multiphoton microscopy(MPM)and optical coherence microscopy(OCM),for diffraction limited imaging beyond an imaging depth of 0.5 mm.Novel implementations havebeen emerging in recent years giving higher imaging speed,deeper penetration,and better imagequality.Focal modulation microscopy(FMM)is a novel method that combines confocal spatialfltering with focal modulation to reject out-of-focus background.FMM has demonstrated animaging depth comparable to those of MPM and OCM,near-real-time image acquisition,and thecapability for multiple contrast mechanisms.展开更多
Stochastic optical reconstruction microscopy(STORM),as a typical technique of single-molecule localization microscopy(SMLM),has overcome the diffraction limit by randomly switching fluorophores between fluorescent and...Stochastic optical reconstruction microscopy(STORM),as a typical technique of single-molecule localization microscopy(SMLM),has overcome the diffraction limit by randomly switching fluorophores between fluorescent and dark states,allowing for the precise localization of isolated emission patterns and the super-resolution reconstruction from millions of localized positions of single fluorophores.A critical factor influencing localization precision is the photo-switching behavior of fluorophores,which is affected by the imaging buffer.The imaging buffer typically comprises oxygen scavengers,photo-switching reagents,and refractive index regulators.Oxygen scavengers help prevent photobleaching,photo-switching reagents assist in facilitating the conversion of fluorophores,and refractive index regulators are used to adjust the refractive index of the solution.The synergistic interaction of these components promotes stable blinking of fluorophores,reduces irreversible photobleaching,and thereby ensures high-quality super-resolution imaging.This review provides a comprehensive overview of the essential compositions and functionalities of imaging buffers used in STORM,serving as a valuable resource for researchers seeking to select appropriate imaging buffers for their experiments.展开更多
Although optical microscopy is a widely used technique across various multidisciplinary fields for inspecting small-scale objects,surfaces or organisms,it faces a significant limitation:the lateral resolution of optic...Although optical microscopy is a widely used technique across various multidisciplinary fields for inspecting small-scale objects,surfaces or organisms,it faces a significant limitation:the lateral resolution of optical microscopes is fundamentally constrained by light diffraction.Dielectric micro-spheres,however,offer a promising solution to this issue as they are capable of significantly enhancing lateral resolution through extraordinary phenomena,such as a photonic nanojet.Building upon the potential of dielectric micro-spheres,this paper introduces a novel approach for fabricating 3D micro-devices designed to enhance lateral resolution in optical microscopy.The proposed 3D micro-device comprises a modified coverslip and a micro-sphere,facilitating easy handling and integration into any existing optical microscope.To manufacture the device,two advanced femtosecond laser techniques are employed:femtosecond laser ablation and multi-photon lithography.Femtosecond laser ablation was employed to create a micro-hole in the coverslip,which allows light to be focused through this aperture.Multi-photon lithography was used to fabricate a micro-sphere with a diameter of 20μm,along with a cantilever that positions the above the processed micro-hole and connect it with the coverslip.In this context,advanced processing strategies for multi-photon lithography to produce a micro-sphere with superior surface roughness and almost perfect geometry(λ/8)from a Zr-based hybrid photoresist are demonstrated.The performance of the micro-device was evaluated using Mirau-type coherence scanning interferometry in conjunction with white light illumination at a central wavelength of 600 nm and a calibration grid(Λ=0.28μm,h>50 nm).Here,the 3D micro-device proved to be capable of enhancing lateral resolution beyond the limits achievable with conventional lenses or microscope objectives when used in air.Simultaneously,it maintained the high axial resolution characteristic of Mirau-type coherence scanning interferometry.The results and optical properties of the micro-sphere were analyzed and further discussed through simulations.展开更多
Until recently,conventional biochemical staining had the undisputed status as well-established benchmark for most biomedical problems related to clinical diagnostics,fundamental research and biotechnology.Despite this...Until recently,conventional biochemical staining had the undisputed status as well-established benchmark for most biomedical problems related to clinical diagnostics,fundamental research and biotechnology.Despite this role as gold-standard,staining protocols face several challenges,such as a need for extensive,manual processing of samples,substantial time delays,altered tissue homeostasis,limited choice of contrast agents,2D imaging instead of 3D tomography and many more.Label-free optical technologies,on the other hand,do not rely on exogenous and artificial markers,by exploiting intrinsic optical contrast mechanisms,where the specificity is typically less obvious to the human observer.Over the past few years,digital staining has emerged as a promising concept to use modern deep learning for the translation from optical contrast to established biochemical contrast of actual stainings.In this review article,we provide an in-depth analysis of the current state-of-the-art in this field,suggest methods of good practice,identify pitfalls and challenges and postulate promising advances towards potential future implementations and applications.展开更多
Optical-resolution photoacoustic microscopy(OR-PAM)has been shown to be an excellent tool for high-resolution imaging of microvasculature,and quantitative analysis of the microvascula-ture can provide valuable informa...Optical-resolution photoacoustic microscopy(OR-PAM)has been shown to be an excellent tool for high-resolution imaging of microvasculature,and quantitative analysis of the microvascula-ture can provide valuable information for the early diagnosis and treatment of various vascular-related diseases.In order to address the characteristics of weak signals,discontinuity and small diameters in photoacoustic microvascular images,we propose a method adaptive to the micro-vascular segmentation in photoacoustic images,including Hessian matrix enhancement and the morphological connection operators.The accuracy of our vascular segmentation method is quantitatively evaluated by the multiple criteria.To obtain more precise and continuous mi-crovascular skeletons,an improved skeleton extraction framework based on the multistencil fast marching(MSFM)method is developed.We carried out in vivo OR-PAM microvascular imaging in mouse ears and subcutaneous hepatoma tumor model to verify the correctness and superiority of our proposed method.Compared with the previous methods,our proposed method can extract the microvascular network more completely,continuously and accurately,and provide an ef-fective solution for the quantitative analysis of photoacoustic microvascular images with many small branches.展开更多
As a revolutionary observation tool in life science,biomedical,and material science,optical microscopy allows imaging of samples with high spatial resolution and a wide field of view.However,conventional microscopy me...As a revolutionary observation tool in life science,biomedical,and material science,optical microscopy allows imaging of samples with high spatial resolution and a wide field of view.However,conventional microscopy methods are limited to single imaging and cannot accomplish real-time image processing.The edge detection,image enhancement and phase visualization schemes have attracted great interest with the rapid development of optical analog computing.The two main physical mechanisms that enable optical analog computing originate from two geometric phases:the spin-redirection Rytov-Vlasimirskii-Berry(RVB)phase and the Pancharatnam-Berry(PB)phase.Here,we review the basic principles and recent research progress of the RVB phase and PB phase based optical differentiators.Then we focus on the innovative and emerging applications of optical analog computing in microscopic imaging.Optical analog computing is accelerating the transformation of information processing from classical imaging to quantum techniques.Its intersection with optical microscopy opens opportunities for the development of versatile and compact optical microscopy systems.展开更多
Chiral sum-frequency generation(SFG)has proven to be a versatile spectroscopic and imaging tool for probing chirality.However,due to polarization restriction,the conventional chiral SFG microscopes have mostly adopted...Chiral sum-frequency generation(SFG)has proven to be a versatile spectroscopic and imaging tool for probing chirality.However,due to polarization restriction,the conventional chiral SFG microscopes have mostly adopted noncollinear beam configurations,which only partially cover the aperture of microscope and strongly spoil the spatial resolution.In this study,we report the first experimental demonstration of collinear chiral SFG microscopy,which fundamentally supports diffraction-limited resolution.This advancement is attributed to the collinear focus of a radially polarized vectorial beam and a linearly polarized(LP)beam.The tightly focused vectorial beam has a very strong longitudinal component,which interacts with the LP beam and produces the chiral SFG.The collinear configuration can utilize the full aperture and thus push the spatial resolution close to the diffraction limit.This technique can potentially boost the understanding of chiral systems.展开更多
In this study,we propose a deep-learning-based method to correct motion artifacts in optical resolution photoacoustic microscopy(OR-PAM).The method is a convolutional neural network that establishes an end-to-end map ...In this study,we propose a deep-learning-based method to correct motion artifacts in optical resolution photoacoustic microscopy(OR-PAM).The method is a convolutional neural network that establishes an end-to-end map from input raw data with motion artifacts to output corrected images.First,we performed simulation studies to evaluate the feasibility and effectiveness of the proposed method.Second,we employed this method to process images of rat brain vessels with multiple motion artifacts to evaluate its performance for in vivo applications.The results demonstrate that this method works well for both large blood vessels and capillary networks.In comparison with traditional methods,the proposed method in this study can be easily modified to satisfy different scenarios of motion corrections in OR-PAM by revising the training sets.展开更多
Optical coherence microscopy is applied to measure scattering media'sinternal defect, which based on low coherence interferometry and confocal microscopy. Opticalcoherence microscopy is more effective in the rejec...Optical coherence microscopy is applied to measure scattering media'sinternal defect, which based on low coherence interferometry and confocal microscopy. Opticalcoherence microscopy is more effective in the rejection of out of focus and multiple scatteredphotons originating further away of the focal plane. With the three-dimension scanning, the internaldefect is detected by measuring the thickness of different points on the sample. The axialresolution is 6 μm and lateral resolution is 1. 2 μm. This method is possessed of the advantagesover the other measurement method of scattering media, such as non-destruction and high-resolution.展开更多
A Luttinger liquid is a theoretical model describing interacting electrons in one-dimensional(1D)conductors.While individual 1D conductors have shown interesting Luttinger-liquid behaviors such as spin-charge separati...A Luttinger liquid is a theoretical model describing interacting electrons in one-dimensional(1D)conductors.While individual 1D conductors have shown interesting Luttinger-liquid behaviors such as spin-charge separation and power-law spectral density,the more interesting phenomena predicted in coupled Luttinger liquids of neighboring 1D conductors have been rarely observed due to the difficulty in creating such structures.Recently,we have successfully grown close-packed carbon nanotube(CNT)arrays with uniform chirality,providing an ideal material system for studying the coupled Luttinger liquids.Here,we report on the observation of tunable hyperbolic plasmons in the coupled Luttinger liquids of CNT arrays using scanning near-field optical microscopy.These hyperbolic plasmons,resulting from the conductivity anisotropy in the CNT array,exhibit strong spatial confinement,in situ tunability,and a wide spectral range.Despite their hyperbolic wavefronts,the plasmon propagation in the axial direction still adheres to the Luttinger-liquid theory.Our work not only demonstrates a fascinating phenomenon in coupled Luttinger liquids for fundamental physics exploration,but also provides a highly confined and in situ tunable hyperbolic plasmon in close-packed CNT arrays for future nanophotonic devices and circuits.展开更多
We use the label-free microsphere-assisted microscopy to image low-contrast hexagonally close-packed polystyrene nanoparticle arrays with diameters of 300 and 250 nm.When a nanoparticle array is directly placed on a g...We use the label-free microsphere-assisted microscopy to image low-contrast hexagonally close-packed polystyrene nanoparticle arrays with diameters of 300 and 250 nm.When a nanoparticle array is directly placed on a glass slide,it cannot be distinguished.If a 30-nm-thick Ag film is deposited on the surface of a nanoparticle array,the nanoparticle array with nanoparticle diameters of 300 and 250 nm can be distinguished.In addition,the Talbot effect of the 300-nm-diameter nanoparticle array is also observed.If a nanoparticle sample is assembled on a glass slide deposited with a 30-nm-thick Ag film,an array of 300-nm-diameter nanoparticles can be discerned.We propose that in microsphere-assisted microscopy imaging,the resolution can be improved by the excitation of surface plasmon polaritons(SPPs) on the sample surface or at the sample/substrate interface,and a higher near-field intensity due to the excited SPPs would benefit the resolution improvement.Our study of label-free super-resolution imaging of low-contrast objects will promote the applications of microsphere-assisted microscopy in life sciences.展开更多
Nonlinear optical imaging is a versatile tool that has been proven to be exceptionally useful in various research fields.However,due to the use of photomultiplier tubes(PMTs),the wide application of nonlinear optical ...Nonlinear optical imaging is a versatile tool that has been proven to be exceptionally useful in various research fields.However,due to the use of photomultiplier tubes(PMTs),the wide application of nonlinear optical imaging is limited by the incapability of imaging under am-bient light.In this paper,we propose and demonstrate a new optical imaging detection method based on optical parametric amplification(OPA).As a nonlinear optical process,OPA in-trinsically rejects ambient light photons by coherence gating.Periodical poled lithium niobate(PPLN)crystals are used in this study as the media for OPA.Compared to bulk nonlinear optical crystals,PPLN crystals support the generation of OPA signal with lower pump power.Therefore,this characteristic of PPLN crystals is particularly beneficial when using high-repetition-rate lasers,which facilitate high-speed optical signal detection,such as in spec-troscopy and imaging.A PPLN-based OPA system was built to amplify the emitted imaging signal from second harmonic generation(SHG)and coherent anti-Stokes Raman scattering(CARS)microscopy imaging,and the amplified optical signal was strong enough to be detected by a biased photodiode under ordinary room light conditions.With OPA detection,ambient-light-on SHG and CARS imaging becomes possible,and achieves a similar result as PMT detection under strictly dark environments.These results demonstrate that OPA can be used as a substitute for PMTs in nonlinear optical imaging to adapt it to various applications with complex.light ing conditions.展开更多
This paper reviews the different multimodal applications based on a large ext ent of label-freeinaging modalities,ranging from linear to nonlinear optics,while also inchuding spectroscopicmeasurements.We put specific ...This paper reviews the different multimodal applications based on a large ext ent of label-freeinaging modalities,ranging from linear to nonlinear optics,while also inchuding spectroscopicmeasurements.We put specific emphasis on multimodal measurements going across the usual boundaries between imaging modalities,whereas most multimodal platforms combine techniquesbased on similar light interactions or similar hardware implementations.In this review,we limitthe scope to focus on applications for biology such as live cells or tissues,since by their nat ure ofbeing alive or fragile,we are often not free to take liberties with the image acquisition times andare forced to gather the maximum amount of information possible at one time.For such samples,imaging by a given label-free method usually presents a challenge in obt aining suficient opticalsignal or is limited in terms of the types of observable targets.Multimodal imaging is thenparticularly attractive for these samples in order to maximize the amount of measured infor-mation.While multimodal imaging is always useful in the sense of acquiring additional infor-mation from additional modes,at times it is possible to attain information that could not bediscovered using any single mode alone,which is the essence of the progress that is possible usinga multimodal approach.展开更多
Super resolution imaging capable of resolving details beyond the diffraction limit is highly desired in many scientific and application fields, including bio-medicine, nanomaterial science, and opto-electronic integra...Super resolution imaging capable of resolving details beyond the diffraction limit is highly desired in many scientific and application fields, including bio-medicine, nanomaterial science, and opto-electronic integration. Up to now, many different methods have been proposed, among which wide-field, label-free super resolution microscopy is indispensable due to its good applicability to diverse sample types, large field of view（FOV）, and high imaging speed. In recent years,nanostructures have made a crucial contribution to the wide-field, label-free subdiffraction microscopy, with various working mechanisms and configuration designs. This review summarizes the recent applications of the nanostructures in the wide-field, label-free super resolution microscopy, with the emphasis on the designs of hyperlens with hyperbolic dispersion, microsphere with ＂nano-jets＂, and nanowire ring illumination microscopy based on spatial frequency shift effect. The bottlenecks of the current techniques and possible solutions are also discussed.展开更多
Beneting from the developments of advanced optical microscopy techniques,the mysteries of biological functions at the cellular and subcellular levels have been continuously revealed.Stimulated Raman scattering(SRS)mic...Beneting from the developments of advanced optical microscopy techniques,the mysteries of biological functions at the cellular and subcellular levels have been continuously revealed.Stimulated Raman scattering(SRS)microscopy is a rapidly growing technique that has attracted broad attentions and become a powerful tool for biology and biomedicine,largely thanks to its chemical specicity,high sensitivity and fast image speed.This review paper introduces the principles of SRS,discusses the technical developments and implementations of SRS microscopy,then highlights and summarizes its applications on biological cellular machinery andnally shares our visions of potential breakthroughs in the future.展开更多
We have studied the influence of probe-sample interaction in a scanning near-field optical microscopy （SNOM） in the far field by using samples with a step structure. For a sample with a step height of - λ/4, the SN...We have studied the influence of probe-sample interaction in a scanning near-field optical microscopy （SNOM） in the far field by using samples with a step structure. For a sample with a step height of - λ/4, the SNOM image contrast between the two sides of the step changes periodically at different scan heights. For a step height of-λ/2, the image contrast remains approximately the same. The probe-sample interaction determines the SNOM image contrast here. The influence of different refractive indices of the sample has been also analysed by using a simple theoretical model.展开更多
基金Project supported by the National Key Basic Research Program of China(Grant No.2013CB934004)the Fundamental Research Funds for the Central Universities,China(Grant No.YWF-13-D2-XX-14)
文摘Optical properties of metallic edge-like structures known as knife-edges are a topic of interest and possess potential applications in enhanced Raman scattering, optical trapping, etc. In this work, we investigate the near-field optical polar- ization response at the edge of a triangular gold nanosheet, which is synthesized by a wet chemical method. A homemade scanning near-field optical microscope （SNOM） in collection mode is adopted, which is able to accurately locate its probe at the edge during experiments. An uncoated straight fiber probe is used in the SNOM, because it s611 preserves the prop- erty of light polarization though it has the depolarization to some extent. By comparing near-field intensities at the edge and glass substrate, detected in different polarization directions of incident light, the edge-induced depolarization is found, which is supported by the finite differential time domain （FDTD） simulated results. The depolarized phenomenon in the near-field is similar to that in the far-field.
基金Project supported by the National Natural Science Foundation of China(Grant No.20933010)the National Basic Research Program of China(Grant No.2013CB834800)
文摘A new method to visualize the large-scale crystal grain morphology of organic polycrystalline films is proposed. First,optical anisotropic transmittance images of polycrystalline zinc phthalocyanine（Zn Pc） films vacuum deposited by weak epitaxial growth（WEG） method were acquired with polarized optical microscopy（POM）. Then morphology properties including crystal grain size, distribution, relative orientation, and crystallinity were derived from these images by fitting with a transition dipole model. At last, atomic force microscopy（AFM） imaging was carried out to confirm the fitting and serve as absolute references. This method can be readily generalized to other organic polycrystalline films, thus providing an efficient way to access the large-scale morphologic properties of organic polycrystalline films, which may prove to be useful in industry as a film quality monitoring method.
文摘Objective: To assess the missed opportunities from the diagnosis of bacilliferous pulmonary tuberculosis by optical microscopy compared to GeneXpert MTB/RIF between 2015 and 2019. Methods: This is a retrospective analysis of the diagnostic results of bacilliferous pulmonary tuberculosis in patients suspected of pulmonary tuberculosis at their first episode during the period. GeneXpert MTB/RIF (GeneXpert) and optical microscopy (OM) after Ziehl-Neelsen stained smear were performed on each patient’s sputum or gastric tubing fluid sample. Results: Among 341 patients suspected of pulmonary tuberculosis, 229 patients were declared bacilliferous tuberculosis by the two tests (67%), 220 patients by GeneXpert and 95 patients by OM, i.e. 64.5% versus 28% (p i.e. 58.5% of the positive cases detected by the two tests (134/229 patients) and 39.3% of the patients suspected of tuberculosis (134/341 patients). On the other hand, among 95 patients declared positive by OM, the GeneXpert ignored 9 (9.5%), i.e. 4% of all the positive cases detected by the two diagnostic tests (9/229 patients) and 3% of the patients suspected of tuberculosis (9/341 patients). The differences observed between the results of the two tests were statistically significant at the 5% threshold (p Conclusion: This study reveals missed diagnostic opportunities for bacilliferous pulmonary mycobacteriosis, statistically significant with optical microscopy than GeneXpert. The GeneXpert/optical microscopy couple could be a good contribution to the strategies for the elimination of pulmonary tuberculosis in sub-Saharan Africa.
基金National Key Research and Development Program of China,Grant/Award Number:2017YFA0700403Hainan University Scientific Research Foundation,Grant/Award Number:(KYQD(ZR)20078)。
文摘The use of optical microscopy and labeling methods in intravital imaging allows for direct tracking of cell behavior and dynamic changes at the molecular level in the physiological or pathological microenvironment of living animals,revealing the spatiotemporal information of individual cells in the immune response.The liver is an immunological organ that contains unique innate and adaptive immune cells,including Kupffer cells(KCs)and different types of T cells,and is involved in coordinating multiple immune responses in the body.Using intravital imaging to visualize the movement behaviors and functions of immune cells during the reaction processes of the liver under physiological and pathological conditions has shed new light on the understanding of liver immunity,which is of great significance for the diagnosis and treatment of liver diseases.This review introduces various window models and labeling methods for the liver in intravital optical imaging and describes how it provides movement behavior and functional information about different types of immune cells,such as KCs and T cells,in the liver.Additionally,we highlight recent advances in intravital optical imaging of liver diseases,such as nonalcoholic fatty liver disease,infections,and tumors.This review aims to be a useful resource for comprehending the developments and achievements in intravital imaging of the liver and uncovering spatiotemporal information of immune response in a living microenvironment.
文摘Optical microscopy has become an indispensable tool for visualizing sub-cellular structures andbiological processes.However,scattering in biological tissues is a major obstacle that preventshigh-resolution images from being obtained from deep regions of tissue.We review commontechniques,such as multiphoton microscopy(MPM)and optical coherence microscopy(OCM),for diffraction limited imaging beyond an imaging depth of 0.5 mm.Novel implementations havebeen emerging in recent years giving higher imaging speed,deeper penetration,and better imagequality.Focal modulation microscopy(FMM)is a novel method that combines confocal spatialfltering with focal modulation to reject out-of-focus background.FMM has demonstrated animaging depth comparable to those of MPM and OCM,near-real-time image acquisition,and thecapability for multiple contrast mechanisms.
基金funded by the National Natural Science Foundation of China(No.62305041)the Natural Science Foundation of Liaoning Province(No.2023-MS-103)。
文摘Stochastic optical reconstruction microscopy(STORM),as a typical technique of single-molecule localization microscopy(SMLM),has overcome the diffraction limit by randomly switching fluorophores between fluorescent and dark states,allowing for the precise localization of isolated emission patterns and the super-resolution reconstruction from millions of localized positions of single fluorophores.A critical factor influencing localization precision is the photo-switching behavior of fluorophores,which is affected by the imaging buffer.The imaging buffer typically comprises oxygen scavengers,photo-switching reagents,and refractive index regulators.Oxygen scavengers help prevent photobleaching,photo-switching reagents assist in facilitating the conversion of fluorophores,and refractive index regulators are used to adjust the refractive index of the solution.The synergistic interaction of these components promotes stable blinking of fluorophores,reduces irreversible photobleaching,and thereby ensures high-quality super-resolution imaging.This review provides a comprehensive overview of the essential compositions and functionalities of imaging buffers used in STORM,serving as a valuable resource for researchers seeking to select appropriate imaging buffers for their experiments.
基金supported by the Marie Skłodowska-Curie Actions,under grant agreement No.101059253,as part of the European Union’s Horizon Europe research and innovation programmeIt also received support from a Feodor Lynen Postdoctoral Fellowship awarded by the Alexander von Humboldt Foundation.Additional funding was provided by Laserlab-Europe(Proposal IDs:ULF-FORTH_002794 and ULF-FORTH_025264).We further gratefully acknowledge funding by the German Federal Ministry for Economic Affairs and Climate Action under grant 16KN053050.The authors would also like to thank Mrs.Aleka Manousaki for SEM technical support.
文摘Although optical microscopy is a widely used technique across various multidisciplinary fields for inspecting small-scale objects,surfaces or organisms,it faces a significant limitation:the lateral resolution of optical microscopes is fundamentally constrained by light diffraction.Dielectric micro-spheres,however,offer a promising solution to this issue as they are capable of significantly enhancing lateral resolution through extraordinary phenomena,such as a photonic nanojet.Building upon the potential of dielectric micro-spheres,this paper introduces a novel approach for fabricating 3D micro-devices designed to enhance lateral resolution in optical microscopy.The proposed 3D micro-device comprises a modified coverslip and a micro-sphere,facilitating easy handling and integration into any existing optical microscope.To manufacture the device,two advanced femtosecond laser techniques are employed:femtosecond laser ablation and multi-photon lithography.Femtosecond laser ablation was employed to create a micro-hole in the coverslip,which allows light to be focused through this aperture.Multi-photon lithography was used to fabricate a micro-sphere with a diameter of 20μm,along with a cantilever that positions the above the processed micro-hole and connect it with the coverslip.In this context,advanced processing strategies for multi-photon lithography to produce a micro-sphere with superior surface roughness and almost perfect geometry(λ/8)from a Zr-based hybrid photoresist are demonstrated.The performance of the micro-device was evaluated using Mirau-type coherence scanning interferometry in conjunction with white light illumination at a central wavelength of 600 nm and a calibration grid(Λ=0.28μm,h>50 nm).Here,the 3D micro-device proved to be capable of enhancing lateral resolution beyond the limits achievable with conventional lenses or microscope objectives when used in air.Simultaneously,it maintained the high axial resolution characteristic of Mirau-type coherence scanning interferometry.The results and optical properties of the micro-sphere were analyzed and further discussed through simulations.
基金This project has received funding from the European Union’s Horizon 2022 Marie Skłodowska-Curie Action(grant agreement 101103200,‘MICS’to L.K.)K.C.Z.was supported in part by Schmidt Science Fellows,in partnership with the Rhodes Trust+2 种基金K.C.L.was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute(KHIDI),funded by the Ministry of Health&Welfare,Republic of Korea(grant number:HI21C0977060102002)Commercialization Promotion Agency for R&D Outcomes(COMPA)funded by the Ministry of Science and ICT(MSIT)(1711198540)This material is based upon work supported in part by the Air Force Office of Scientific Research under award number FA9550-21-1-0401,the National Science Foundation under Grant 2238845,and a Hartwell Foundation Individual Biomedical Researcher Award.
文摘Until recently,conventional biochemical staining had the undisputed status as well-established benchmark for most biomedical problems related to clinical diagnostics,fundamental research and biotechnology.Despite this role as gold-standard,staining protocols face several challenges,such as a need for extensive,manual processing of samples,substantial time delays,altered tissue homeostasis,limited choice of contrast agents,2D imaging instead of 3D tomography and many more.Label-free optical technologies,on the other hand,do not rely on exogenous and artificial markers,by exploiting intrinsic optical contrast mechanisms,where the specificity is typically less obvious to the human observer.Over the past few years,digital staining has emerged as a promising concept to use modern deep learning for the translation from optical contrast to established biochemical contrast of actual stainings.In this review article,we provide an in-depth analysis of the current state-of-the-art in this field,suggest methods of good practice,identify pitfalls and challenges and postulate promising advances towards potential future implementations and applications.
基金supported in part by the National Natural Science Foundation of China Grants[Nos.91739117 and 61701279]
文摘Optical-resolution photoacoustic microscopy(OR-PAM)has been shown to be an excellent tool for high-resolution imaging of microvasculature,and quantitative analysis of the microvascula-ture can provide valuable information for the early diagnosis and treatment of various vascular-related diseases.In order to address the characteristics of weak signals,discontinuity and small diameters in photoacoustic microvascular images,we propose a method adaptive to the micro-vascular segmentation in photoacoustic images,including Hessian matrix enhancement and the morphological connection operators.The accuracy of our vascular segmentation method is quantitatively evaluated by the multiple criteria.To obtain more precise and continuous mi-crovascular skeletons,an improved skeleton extraction framework based on the multistencil fast marching(MSFM)method is developed.We carried out in vivo OR-PAM microvascular imaging in mouse ears and subcutaneous hepatoma tumor model to verify the correctness and superiority of our proposed method.Compared with the previous methods,our proposed method can extract the microvascular network more completely,continuously and accurately,and provide an ef-fective solution for the quantitative analysis of photoacoustic microvascular images with many small branches.
基金supported by the National Natural Science Foundation of China(No.12174097)the Natural Science Foundation of Hunan Province(No.2021JJ10008)。
文摘As a revolutionary observation tool in life science,biomedical,and material science,optical microscopy allows imaging of samples with high spatial resolution and a wide field of view.However,conventional microscopy methods are limited to single imaging and cannot accomplish real-time image processing.The edge detection,image enhancement and phase visualization schemes have attracted great interest with the rapid development of optical analog computing.The two main physical mechanisms that enable optical analog computing originate from two geometric phases:the spin-redirection Rytov-Vlasimirskii-Berry(RVB)phase and the Pancharatnam-Berry(PB)phase.Here,we review the basic principles and recent research progress of the RVB phase and PB phase based optical differentiators.Then we focus on the innovative and emerging applications of optical analog computing in microscopic imaging.Optical analog computing is accelerating the transformation of information processing from classical imaging to quantum techniques.Its intersection with optical microscopy opens opportunities for the development of versatile and compact optical microscopy systems.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2020B0301030009)the National Natural Science Foundation of China (Grant Nos.91750203,91850111,11174019,12004013,92150301,and 61322509)+1 种基金the Ministry of Science and Technology of China[National Basic Research Program of China (Grant No.2013CB921904)]the China Postdoctoral Science Foundation (Grant No.2020M680220).
文摘Chiral sum-frequency generation(SFG)has proven to be a versatile spectroscopic and imaging tool for probing chirality.However,due to polarization restriction,the conventional chiral SFG microscopes have mostly adopted noncollinear beam configurations,which only partially cover the aperture of microscope and strongly spoil the spatial resolution.In this study,we report the first experimental demonstration of collinear chiral SFG microscopy,which fundamentally supports diffraction-limited resolution.This advancement is attributed to the collinear focus of a radially polarized vectorial beam and a linearly polarized(LP)beam.The tightly focused vectorial beam has a very strong longitudinal component,which interacts with the LP beam and produces the chiral SFG.The collinear configuration can utilize the full aperture and thus push the spatial resolution close to the diffraction limit.This technique can potentially boost the understanding of chiral systems.
基金This work was sponsored by National Natural Science Foundation of China,Nos.81571722,61775028 and 61528401.
文摘In this study,we propose a deep-learning-based method to correct motion artifacts in optical resolution photoacoustic microscopy(OR-PAM).The method is a convolutional neural network that establishes an end-to-end map from input raw data with motion artifacts to output corrected images.First,we performed simulation studies to evaluate the feasibility and effectiveness of the proposed method.Second,we employed this method to process images of rat brain vessels with multiple motion artifacts to evaluate its performance for in vivo applications.The results demonstrate that this method works well for both large blood vessels and capillary networks.In comparison with traditional methods,the proposed method in this study can be easily modified to satisfy different scenarios of motion corrections in OR-PAM by revising the training sets.
基金National Natural Science Foundation of China(60077031)
文摘Optical coherence microscopy is applied to measure scattering media'sinternal defect, which based on low coherence interferometry and confocal microscopy. Opticalcoherence microscopy is more effective in the rejection of out of focus and multiple scatteredphotons originating further away of the focal plane. With the three-dimension scanning, the internaldefect is detected by measuring the thickness of different points on the sample. The axialresolution is 6 μm and lateral resolution is 1. 2 μm. This method is possessed of the advantagesover the other measurement method of scattering media, such as non-destruction and high-resolution.
基金supported by the National Key R&D Program of China(Grant No.2021YFA1202902)the National Natural Science Foundation of China(Grant Nos.12374292 and 12074244)B.L.acknowledges support from the Development Scholarship for Outstanding Ph.D.of Shanghai Jiao Tong University.J.K.acknowledges support from the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(Grant No.NRF-RS-2024-00454528).
文摘A Luttinger liquid is a theoretical model describing interacting electrons in one-dimensional(1D)conductors.While individual 1D conductors have shown interesting Luttinger-liquid behaviors such as spin-charge separation and power-law spectral density,the more interesting phenomena predicted in coupled Luttinger liquids of neighboring 1D conductors have been rarely observed due to the difficulty in creating such structures.Recently,we have successfully grown close-packed carbon nanotube(CNT)arrays with uniform chirality,providing an ideal material system for studying the coupled Luttinger liquids.Here,we report on the observation of tunable hyperbolic plasmons in the coupled Luttinger liquids of CNT arrays using scanning near-field optical microscopy.These hyperbolic plasmons,resulting from the conductivity anisotropy in the CNT array,exhibit strong spatial confinement,in situ tunability,and a wide spectral range.Despite their hyperbolic wavefronts,the plasmon propagation in the axial direction still adheres to the Luttinger-liquid theory.Our work not only demonstrates a fascinating phenomenon in coupled Luttinger liquids for fundamental physics exploration,but also provides a highly confined and in situ tunable hyperbolic plasmon in close-packed CNT arrays for future nanophotonic devices and circuits.
基金Project supported by the National Natural Science Foundation of China(Grant No.61673287)。
文摘We use the label-free microsphere-assisted microscopy to image low-contrast hexagonally close-packed polystyrene nanoparticle arrays with diameters of 300 and 250 nm.When a nanoparticle array is directly placed on a glass slide,it cannot be distinguished.If a 30-nm-thick Ag film is deposited on the surface of a nanoparticle array,the nanoparticle array with nanoparticle diameters of 300 and 250 nm can be distinguished.In addition,the Talbot effect of the 300-nm-diameter nanoparticle array is also observed.If a nanoparticle sample is assembled on a glass slide deposited with a 30-nm-thick Ag film,an array of 300-nm-diameter nanoparticles can be discerned.We propose that in microsphere-assisted microscopy imaging,the resolution can be improved by the excitation of surface plasmon polaritons(SPPs) on the sample surface or at the sample/substrate interface,and a higher near-field intensity due to the excited SPPs would benefit the resolution improvement.Our study of label-free super-resolution imaging of low-contrast objects will promote the applications of microsphere-assisted microscopy in life sciences.
基金supported in part by grants from the National Institutes of Health (R01CA213149,R01CA241618).
文摘Nonlinear optical imaging is a versatile tool that has been proven to be exceptionally useful in various research fields.However,due to the use of photomultiplier tubes(PMTs),the wide application of nonlinear optical imaging is limited by the incapability of imaging under am-bient light.In this paper,we propose and demonstrate a new optical imaging detection method based on optical parametric amplification(OPA).As a nonlinear optical process,OPA in-trinsically rejects ambient light photons by coherence gating.Periodical poled lithium niobate(PPLN)crystals are used in this study as the media for OPA.Compared to bulk nonlinear optical crystals,PPLN crystals support the generation of OPA signal with lower pump power.Therefore,this characteristic of PPLN crystals is particularly beneficial when using high-repetition-rate lasers,which facilitate high-speed optical signal detection,such as in spec-troscopy and imaging.A PPLN-based OPA system was built to amplify the emitted imaging signal from second harmonic generation(SHG)and coherent anti-Stokes Raman scattering(CARS)microscopy imaging,and the amplified optical signal was strong enough to be detected by a biased photodiode under ordinary room light conditions.With OPA detection,ambient-light-on SHG and CARS imaging becomes possible,and achieves a similar result as PMT detection under strictly dark environments.These results demonstrate that OPA can be used as a substitute for PMTs in nonlinear optical imaging to adapt it to various applications with complex.light ing conditions.
基金funding from the Japan Society for the Promotionof Science(JSPS)through the Funding Program for World-Leading Innovative R&D on Science and Technology(FIR.ST Program)JSPS World Premier International Research Center Initiative Funding Program.
文摘This paper reviews the different multimodal applications based on a large ext ent of label-freeinaging modalities,ranging from linear to nonlinear optics,while also inchuding spectroscopicmeasurements.We put specific emphasis on multimodal measurements going across the usual boundaries between imaging modalities,whereas most multimodal platforms combine techniquesbased on similar light interactions or similar hardware implementations.In this review,we limitthe scope to focus on applications for biology such as live cells or tissues,since by their nat ure ofbeing alive or fragile,we are often not free to take liberties with the image acquisition times andare forced to gather the maximum amount of information possible at one time.For such samples,imaging by a given label-free method usually presents a challenge in obt aining suficient opticalsignal or is limited in terms of the types of observable targets.Multimodal imaging is thenparticularly attractive for these samples in order to maximize the amount of measured infor-mation.While multimodal imaging is always useful in the sense of acquiring additional infor-mation from additional modes,at times it is possible to attain information that could not bediscovered using any single mode alone,which is the essence of the progress that is possible usinga multimodal approach.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61735017 and 51672245)the Zhejiang Provincial Natural Science Foundation of China(Grant No.R17F050003)+4 种基金the National Key Basic Research Program of China(Grant No.2015CB352003)the Fundamental Research Funds for the Central Universities,Chinathe Program for Zhejiang Leading Team of S&T Innovation,Chinathe Cao Guangbiao Advanced Technology Program,ChinaFirst-class Universities and Academic Programs,China
文摘Super resolution imaging capable of resolving details beyond the diffraction limit is highly desired in many scientific and application fields, including bio-medicine, nanomaterial science, and opto-electronic integration. Up to now, many different methods have been proposed, among which wide-field, label-free super resolution microscopy is indispensable due to its good applicability to diverse sample types, large field of view（FOV）, and high imaging speed. In recent years,nanostructures have made a crucial contribution to the wide-field, label-free subdiffraction microscopy, with various working mechanisms and configuration designs. This review summarizes the recent applications of the nanostructures in the wide-field, label-free super resolution microscopy, with the emphasis on the designs of hyperlens with hyperbolic dispersion, microsphere with ＂nano-jets＂, and nanowire ring illumination microscopy based on spatial frequency shift effect. The bottlenecks of the current techniques and possible solutions are also discussed.
基金We acknowledge the financial supports from the National Key R&D Program of China(2021YFF0502900)the National Natural Science Foundation of China(61975033)Shanghai Municipal Science and Technology Major Project No.2018SHZDZX01 and ZJLab.
文摘Beneting from the developments of advanced optical microscopy techniques,the mysteries of biological functions at the cellular and subcellular levels have been continuously revealed.Stimulated Raman scattering(SRS)microscopy is a rapidly growing technique that has attracted broad attentions and become a powerful tool for biology and biomedicine,largely thanks to its chemical specicity,high sensitivity and fast image speed.This review paper introduces the principles of SRS,discusses the technical developments and implementations of SRS microscopy,then highlights and summarizes its applications on biological cellular machinery andnally shares our visions of potential breakthroughs in the future.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 90206003, 10374005, 10434020, 10521002, 10328407 and 90101027） and the Research Fund for the Doctoral Program of Higher Education of China （Grant No 20040001012）.
文摘We have studied the influence of probe-sample interaction in a scanning near-field optical microscopy （SNOM） in the far field by using samples with a step structure. For a sample with a step height of - λ/4, the SNOM image contrast between the two sides of the step changes periodically at different scan heights. For a step height of-λ/2, the image contrast remains approximately the same. The probe-sample interaction determines the SNOM image contrast here. The influence of different refractive indices of the sample has been also analysed by using a simple theoretical model.
