A single molecule detection technique was developed by the combination of a single channel poly （dimethylsiloxane）/glass micro-fluidic chip and fluorescence correlation spectroscopy （FCS）. This method was successf...A single molecule detection technique was developed by the combination of a single channel poly （dimethylsiloxane）/glass micro-fluidic chip and fluorescence correlation spectroscopy （FCS）. This method was successfully used to determine the proportion of two model components in the mixture containing fluorescein and the rhodamine-green succinimidyl ester.展开更多
Fluorescence correlation spectroscopy （FCS） without objective image magnification （without using con-focal microscope） was applied to observe the variation in cell size of Escherichia coli （E. coli） induced by t...Fluorescence correlation spectroscopy （FCS） without objective image magnification （without using con-focal microscope） was applied to observe the variation in cell size of Escherichia coli （E. coli） induced by the anti-cancer agent MitomycinC （MMC）. In the system without image magnification followed in this study, the suspension of E. coli cells was stirred, and the difference in movement due to the different cell sizes induced by the compulsive solution flow was detected. The addition of 0.1-0.4 pg/L of MMC elongated the E. coli cell length from about 3.6 to 7.8μm. The flow cell （i.d. = about 1 mm） also produced a size-dependent correlation curve, The present system is not based on single molecular FCS but is inexpensive and effective at observing the variation in cell size induced by environmental changes.展开更多
Deciphering the dynamics of protein and lipid molecules on appropriate spatial and temporal scales may shed light on protein function and membrane organization. However, traditional bulk approaches cannot unambiguousl...Deciphering the dynamics of protein and lipid molecules on appropriate spatial and temporal scales may shed light on protein function and membrane organization. However, traditional bulk approaches cannot unambiguously quantify the extremely diverse mobility and interactions of proteins in living cells. Fluores- cence correlation spectroscopy （FCS） is a powerful technique to describe events that occur at the singlemolecule level and on the nanosecond to second timescales; therefore, FCS can provide data on the heterogeneous organization of membrane systems. FCS can also be combined with other microscopy techniques, such as super-resolution techniques. More importantly, FCS is minimally invasive, which makes it an ideal approach to detect the heterogeneous distribution and dynamics of key proteins during development. In this review, we give a brief introduction about the development of FCS and summarize the significant contributions of FCS in understanding the organization of plant cell membranes and the dy- namics and interactions of membrane proteins .We also discuss the potential applications of this technique in plant biology.展开更多
The advantage of fluorescence correlation spectroscopy to study single chain behavior of polyelectrolytes has been demonstrated by checking the coil-to-globule transition ofpoly 2-vinylpyridine with the change ofpH va...The advantage of fluorescence correlation spectroscopy to study single chain behavior of polyelectrolytes has been demonstrated by checking the coil-to-globule transition ofpoly 2-vinylpyridine with the change ofpH value in aqueous solution. The ultra-high sensitivity of FCS allows measurement at extreme dilution where the effect of electrostatic interaction between the chains is greatly suppressed. The results exposed first-order conformation tran- sition of P2VP as detected by FCS while inter-chain aggregation occurred in the experiments of dynamic light scat- tering.展开更多
Fluorescence correlation spectroscopy （FCS） is a widely used method for measuring molecular diffusion and chemical kinetics. However, when a mixture of fluorescent species is taken into account, the conven- tional F...Fluorescence correlation spectroscopy （FCS） is a widely used method for measuring molecular diffusion and chemical kinetics. However, when a mixture of fluorescent species is taken into account, the conven- tional FCS method has limitations in extracting autocorrelations for different species and cross correla- tions between different species. Recently developed fluorescence lifetime correlation spectroscopy （FLCS） based on time-tagged time-resolved （TITR） photon recording, which can record the global and micro arrival time for each individual photon, has been used to discriminate different species according to fluorescence lifetime. Here, based on two-dimensional lifetime decay maps constructed from TITR photon stream, we have developed a quantitative lifetime-deconvolution FCS model （LDFCS） to extract precise chemical rates for chemical conversions in multi-species systems. The key point of LDFCS model is separation of different species according to the global distribution of fluorescence lifetime and then deconvolution of autocorrelations and cross-correlations from the two-dimensional lifetime decay maps constructed bv the micro arrival times of photon pairs at each delay time.展开更多
In the study, we observed the strong adsorption of CdTe/CdS QDs to antibodies and the formation of QDs-antibodies conjugates. Capillary electrophoresis with laser-induced fluorescence detection （CE-LIF）, fluorescenc...In the study, we observed the strong adsorption of CdTe/CdS QDs to antibodies and the formation of QDs-antibodies conjugates. Capillary electrophoresis with laser-induced fluorescence detection （CE-LIF）, fluorescence spectrometry and fluorescence correlation spectroscopy （FCS） were used to characterize the QDs conjugates with antibody. We found that the QDs-antibody conjugates possessed high fluorescence, small hydrodynamic radii and good stability in aqueous solution. 2009 Ji Cun Ren. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
The diffusion kinetics of a molecular probe-rhodamine B-in ternary aqueous solutions containing poly(vinyl alcohol),glycerol,and surfactants was investigated using fluorescence correlation spectroscopy and dynamic lig...The diffusion kinetics of a molecular probe-rhodamine B-in ternary aqueous solutions containing poly(vinyl alcohol),glycerol,and surfactants was investigated using fluorescence correlation spectroscopy and dynamic light scattering.We show that the diffusion characteristics of rhodamine B in such complex systems is determined by a synergistic effect of molecular crowding and intermolecular interactions between chemical species.The presence of glycerol has no noticeable impact on rhodamine B diffusion at low concentration,but significantly slows down the diffiision of rhodamine B above 3.9%(w/v)due to a dominating steric inhibition effect.Furthermore,introducing surfactants(cationic/nonionic/anionic)to the system results in a decreased diffusion coefficient of the molecular probe.In solutions containing nonionic surfactant,this can be explained by an increased crowding effect.For ternary poly(vinyl alcohol)solutions containing cationic or anionic surfactant,surfactant-polymer and surfactant-rhodamine B interactions alongside the crowding effect of the molecules slow down the overall diffiisivity of rhodamine B.The results advance our insight of molecular migration in a broad range of industrial complex formulations that incorporate multiple compounds,and highlight the importance of selecting the appropriate additives and surfactants in formulated products.展开更多
Background:The aggregation of amyloidβ(Aβ)is central in the pathogenesis of Alzheimer’s disease(AD).Recently it has been shown that specifically,larger,Thioflavin T-binding Aβaggregates are associated with increas...Background:The aggregation of amyloidβ(Aβ)is central in the pathogenesis of Alzheimer’s disease(AD).Recently it has been shown that specifically,larger,Thioflavin T-binding Aβaggregates are associated with increased neuroinflammation and cytokine release.This study was aimed to quantify fibrillary amyloid aggregates,so-called nanoplaques,and investigate their relationship with cytokines in the cerebrospinal fluid(CSF).Methods:CSF was collected from 111 patients assessed for cognitive complaints at the Oslo University Hospital Memory Clinic.The patients were grouped based on their amyloid status.The CSF nanoplaque concentration was quantified with the Thioflavin T-fluorescence correlation spectroscopy(ThT-FCS)assay.The levels of nine cytokines(eotaxin-1,granulocyte stimulating factor,interleukin[IL]-6,IL-7,IL-8,monocyte chemoattractant protein-1,gammainduced protein 10,macrophage inflammatory protein[MIP]-1α,and MIP-1β)were quantified with a magnetic bead-based multiplex assay and read on a Luminex IS 200 instrument.Results:There were 49 amyloid-negative and 62 amyloid-positive patients in the cohort;none of the cytokines differed significantly between the amyloid groups.The increased nanoplaque levels were associated with levels of MIP-1βbelow the lower limit of quantification,and with decreased levels of MIP-1αand IL-8.The associations remained significant when adjusted for age,sex,cognitive function,apolipoproteinε4 status and CSF core biomarker levels.Conclusion:The cytokine levels were not associated with amyloid status in this cohort.The nanoplaque levels were negatively associated with MIP-1β,MIP-1αand IL-8,which is in line with recent findings suggesting that the upregulation of some cytokine markers has a protective role and is negatively associated with AD progression.展开更多
基金This work was financially supported by the National Natural Science Foundation of China. （No.20271033, 20335020, 90408014）.
文摘A single molecule detection technique was developed by the combination of a single channel poly （dimethylsiloxane）/glass micro-fluidic chip and fluorescence correlation spectroscopy （FCS）. This method was successfully used to determine the proportion of two model components in the mixture containing fluorescein and the rhodamine-green succinimidyl ester.
文摘Fluorescence correlation spectroscopy （FCS） without objective image magnification （without using con-focal microscope） was applied to observe the variation in cell size of Escherichia coli （E. coli） induced by the anti-cancer agent MitomycinC （MMC）. In the system without image magnification followed in this study, the suspension of E. coli cells was stirred, and the difference in movement due to the different cell sizes induced by the compulsive solution flow was detected. The addition of 0.1-0.4 pg/L of MMC elongated the E. coli cell length from about 3.6 to 7.8μm. The flow cell （i.d. = about 1 mm） also produced a size-dependent correlation curve, The present system is not based on single molecular FCS but is inexpensive and effective at observing the variation in cell size induced by environmental changes.
文摘Deciphering the dynamics of protein and lipid molecules on appropriate spatial and temporal scales may shed light on protein function and membrane organization. However, traditional bulk approaches cannot unambiguously quantify the extremely diverse mobility and interactions of proteins in living cells. Fluores- cence correlation spectroscopy （FCS） is a powerful technique to describe events that occur at the singlemolecule level and on the nanosecond to second timescales; therefore, FCS can provide data on the heterogeneous organization of membrane systems. FCS can also be combined with other microscopy techniques, such as super-resolution techniques. More importantly, FCS is minimally invasive, which makes it an ideal approach to detect the heterogeneous distribution and dynamics of key proteins during development. In this review, we give a brief introduction about the development of FCS and summarize the significant contributions of FCS in understanding the organization of plant cell membranes and the dy- namics and interactions of membrane proteins .We also discuss the potential applications of this technique in plant biology.
文摘The advantage of fluorescence correlation spectroscopy to study single chain behavior of polyelectrolytes has been demonstrated by checking the coil-to-globule transition ofpoly 2-vinylpyridine with the change ofpH value in aqueous solution. The ultra-high sensitivity of FCS allows measurement at extreme dilution where the effect of electrostatic interaction between the chains is greatly suppressed. The results exposed first-order conformation tran- sition of P2VP as detected by FCS while inter-chain aggregation occurred in the experiments of dynamic light scat- tering.
基金supported by ‘‘Strategic Priority Research Program” of Chinese Academy of Sciences (XDA09040300)Beijing Science and Technology Project (Z151100003915077)+1 种基金Beijing Nova Programme (Z151100000315081)Beijing Talents Fund (2015000021223ZK17)
文摘Fluorescence correlation spectroscopy （FCS） is a widely used method for measuring molecular diffusion and chemical kinetics. However, when a mixture of fluorescent species is taken into account, the conven- tional FCS method has limitations in extracting autocorrelations for different species and cross correla- tions between different species. Recently developed fluorescence lifetime correlation spectroscopy （FLCS） based on time-tagged time-resolved （TITR） photon recording, which can record the global and micro arrival time for each individual photon, has been used to discriminate different species according to fluorescence lifetime. Here, based on two-dimensional lifetime decay maps constructed from TITR photon stream, we have developed a quantitative lifetime-deconvolution FCS model （LDFCS） to extract precise chemical rates for chemical conversions in multi-species systems. The key point of LDFCS model is separation of different species according to the global distribution of fluorescence lifetime and then deconvolution of autocorrelations and cross-correlations from the two-dimensional lifetime decay maps constructed bv the micro arrival times of photon pairs at each delay time.
基金supported by the National Natural Science Foundation of China(No.20705019)National High-Tech R&D Program(No.2006AA03Z324)
文摘In the study, we observed the strong adsorption of CdTe/CdS QDs to antibodies and the formation of QDs-antibodies conjugates. Capillary electrophoresis with laser-induced fluorescence detection （CE-LIF）, fluorescence spectrometry and fluorescence correlation spectroscopy （FCS） were used to characterize the QDs conjugates with antibody. We found that the QDs-antibody conjugates possessed high fluorescence, small hydrodynamic radii and good stability in aqueous solution. 2009 Ji Cun Ren. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金School of Chemical Engineering,University of Birmingham,and Engineering&Physical Science Research Council(EPSRC)with grant number EP/P007864/1ZJZ acknowledges an Industrial Fellowship with P&G,funded by the Royal Academy of Engineering(IF2021\100).
文摘The diffusion kinetics of a molecular probe-rhodamine B-in ternary aqueous solutions containing poly(vinyl alcohol),glycerol,and surfactants was investigated using fluorescence correlation spectroscopy and dynamic light scattering.We show that the diffusion characteristics of rhodamine B in such complex systems is determined by a synergistic effect of molecular crowding and intermolecular interactions between chemical species.The presence of glycerol has no noticeable impact on rhodamine B diffusion at low concentration,but significantly slows down the diffiision of rhodamine B above 3.9%(w/v)due to a dominating steric inhibition effect.Furthermore,introducing surfactants(cationic/nonionic/anionic)to the system results in a decreased diffusion coefficient of the molecular probe.In solutions containing nonionic surfactant,this can be explained by an increased crowding effect.For ternary poly(vinyl alcohol)solutions containing cationic or anionic surfactant,surfactant-polymer and surfactant-rhodamine B interactions alongside the crowding effect of the molecules slow down the overall diffiisivity of rhodamine B.The results advance our insight of molecular migration in a broad range of industrial complex formulations that incorporate multiple compounds,and highlight the importance of selecting the appropriate additives and surfactants in formulated products.
基金This work was supported by funding from the Olav Thon Foundation,The Norwegian Health Association,Swedish Foundation for Strategic Research(SBE13-0115)Swedish Research Council(VR 2018-05337)+3 种基金Olle Engkvists Foundation(199-0480)Magnus Bergvalls Foundation(2018-02642)Region Stockholm(ALF projects 20180365 and 20190561)The funding agencies had no influence on the study design,data collection,data analysis,interpretation of the data or the manuscript writing.
文摘Background:The aggregation of amyloidβ(Aβ)is central in the pathogenesis of Alzheimer’s disease(AD).Recently it has been shown that specifically,larger,Thioflavin T-binding Aβaggregates are associated with increased neuroinflammation and cytokine release.This study was aimed to quantify fibrillary amyloid aggregates,so-called nanoplaques,and investigate their relationship with cytokines in the cerebrospinal fluid(CSF).Methods:CSF was collected from 111 patients assessed for cognitive complaints at the Oslo University Hospital Memory Clinic.The patients were grouped based on their amyloid status.The CSF nanoplaque concentration was quantified with the Thioflavin T-fluorescence correlation spectroscopy(ThT-FCS)assay.The levels of nine cytokines(eotaxin-1,granulocyte stimulating factor,interleukin[IL]-6,IL-7,IL-8,monocyte chemoattractant protein-1,gammainduced protein 10,macrophage inflammatory protein[MIP]-1α,and MIP-1β)were quantified with a magnetic bead-based multiplex assay and read on a Luminex IS 200 instrument.Results:There were 49 amyloid-negative and 62 amyloid-positive patients in the cohort;none of the cytokines differed significantly between the amyloid groups.The increased nanoplaque levels were associated with levels of MIP-1βbelow the lower limit of quantification,and with decreased levels of MIP-1αand IL-8.The associations remained significant when adjusted for age,sex,cognitive function,apolipoproteinε4 status and CSF core biomarker levels.Conclusion:The cytokine levels were not associated with amyloid status in this cohort.The nanoplaque levels were negatively associated with MIP-1β,MIP-1αand IL-8,which is in line with recent findings suggesting that the upregulation of some cytokine markers has a protective role and is negatively associated with AD progression.
