A novel organic fluorophor with high solid state luminescent efficiency based on 1,4-bis(2,2-di(pyridin-2-yl)- vinyl)benzene (BDP2VB) was designed and synthesized. It emits faintly in solution, but becomes a str...A novel organic fluorophor with high solid state luminescent efficiency based on 1,4-bis(2,2-di(pyridin-2-yl)- vinyl)benzene (BDP2VB) was designed and synthesized. It emits faintly in solution, but becomes a strong emitter in the aggregate state, demonstrating its aggregation induced emission (AIE) property. According to the crystal struc- ture analysis, J-type aggregation was formed in the packing mode of the molecule, which was demonstrated to be beneficial to gain high fluorescent quantum efficiency in solid state. Additionally, the emission color of BDP2VB can change dramatically in solid state as well as in solution by the protonation stimuli.展开更多
Zero-mode waveguides have become important tools for the detection of single molecules.There are still,however,serious challenges because large molecules need to be packed into nano-holes.To circumvent this problem,we...Zero-mode waveguides have become important tools for the detection of single molecules.There are still,however,serious challenges because large molecules need to be packed into nano-holes.To circumvent this problem,we investigate and numerically simulate a novel planar sub-wavelength 3-dimension(3D)structure,which is named as near-field spot.It enables the detection of a single molecule in highly concentrated solutions.The near-field spot can produce evanescent waves at the dielectric/water interface,which exponentially decay as they travel away from the dielectric/water interface.These evanescent waves are keys for the detection of fluorescently tagged single molecules.A numerical simulation of the proposed device shows that the performance is comparable with a zero-mode waveguide.Additional degrees-of-freedom,however,can potentially supersede its performance.展开更多
Signal-to-noise ratio of fluorescence detection from a single molecule & analysed by using time-gated techniques. It is found that the optimal signal-to-noise ratio can be obtained by choosing an appropriate gate tim...Signal-to-noise ratio of fluorescence detection from a single molecule & analysed by using time-gated techniques. It is found that the optimal signal-to-noise ratio can be obtained by choosing an appropriate gate time with a certain optical background. The dependences of molecular fluorescence lifetime and the optimal signal-to-noise ratio on the appropriate gate time are respectively discussed with two kinds of background sources~ chaotic state with uniform distribution and coherent state with exponential distribution in time domain. For chaotic state background we find that a certain range for appropriate gate time can be obtained with a definite fluorescence lifetime, larger fluorescence lifetime would lower the value of optimal signal-to-noise ratios. For coherent state background we find that there is also a narrow range of appropriate gate time when lifetime of single molecule is less than that of background photons.展开更多
Research on protein-membrane interactions has been undeveloped due to the lack of proper techniques to detect the position of proteins at membranes because membranes are usually only about 4-nm thick. We have recently...Research on protein-membrane interactions has been undeveloped due to the lack of proper techniques to detect the position of proteins at membranes because membranes are usually only about 4-nm thick. We have recently developed a new method named surface-induced fluorescence attenuation (SIFA) to track both vertical and lateral kinetics of a single labelling dye in supported lipid bilayers. It takes advantage of strong interaction between a light-emitting dye and a partially reflecting surface. By applying the technique to membrane proteins being fluorescently labelled at different residues, here we show that SIFA can measure not only the insertion depth of a dye inside a lipid bilayer, but also the position of a dye in solution near the surface. SIFA can therefore be used to study membrane proteins of various types.展开更多
Properties of organelles and intracellular structures play important roles in regulating cellular functions,such as gene expression,cell motility and metabolism.The ability to directly interrogate intracellular struct...Properties of organelles and intracellular structures play important roles in regulating cellular functions,such as gene expression,cell motility and metabolism.The ability to directly interrogate intracellular structures inside a single cell for measurement and manipulation has significant implications in the understanding of subcellular and suborganelle activities,diagnosing diseases,and potentially developing new therapeutic approaches.In the past few decades,a number of technologies have been developed to study single-cell properties.However,methods of measuring intracellular properties and manipulating subcellular structures have been largely underexplored.Due to the even smaller size of intracellular targets and lower signal-to-noise ratio than that in wholecell studies,the development of tools for intracellular measurement and manipulation is challenging.This paper reviews emerging microsystems and nanoengineered technologies for sensing and quantitative measurement of intracellular properties and for manipulating structures inside a single cell.Recent progress and limitations of these new technologies as well as new discoveries and prospects are discussed.展开更多
Four novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on“push-core-pull-core-push”mole...Four novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on“push-core-pull-core-push”molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig-Horner reaction.Their chemical structures were determined to show trans-vinylene character according to infrared(IR)and 1H nuclear magnetic resonance(NMR)spectra.A very effective energy transfer from the excited units to the p-conjugated bridging unit can enhance the two-photon absorption and two-photon fluorescence.展开更多
基金973 Program,the National Natural Science Foundation of China,the Research Fund for the Doctoral Program of Higher Education of China,the Project of Jilin Province
文摘A novel organic fluorophor with high solid state luminescent efficiency based on 1,4-bis(2,2-di(pyridin-2-yl)- vinyl)benzene (BDP2VB) was designed and synthesized. It emits faintly in solution, but becomes a strong emitter in the aggregate state, demonstrating its aggregation induced emission (AIE) property. According to the crystal struc- ture analysis, J-type aggregation was formed in the packing mode of the molecule, which was demonstrated to be beneficial to gain high fluorescent quantum efficiency in solid state. Additionally, the emission color of BDP2VB can change dramatically in solid state as well as in solution by the protonation stimuli.
基金support of Southeast University for carrying out this research.This work was financially supported by Southeast University Postdoctoral Science Foundation Grant program,China(Grant No.2242018R20013),the National Key Research and Development Program of China(Grant No.2017YFA0205700),the National Natural Science Foundation of China(Grant No.61850410528),the Fundamental Research Funds for the Central Universities,and the Fundamental Research Project of Shenzhen Science&Technology Innovation Committee(Grant No.JCYJ20180306174552939).
文摘Zero-mode waveguides have become important tools for the detection of single molecules.There are still,however,serious challenges because large molecules need to be packed into nano-holes.To circumvent this problem,we investigate and numerically simulate a novel planar sub-wavelength 3-dimension(3D)structure,which is named as near-field spot.It enables the detection of a single molecule in highly concentrated solutions.The near-field spot can produce evanescent waves at the dielectric/water interface,which exponentially decay as they travel away from the dielectric/water interface.These evanescent waves are keys for the detection of fluorescently tagged single molecules.A numerical simulation of the proposed device shows that the performance is comparable with a zero-mode waveguide.Additional degrees-of-freedom,however,can potentially supersede its performance.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60378004 and 10674086, the National Key Basic Research and Development Programme of China under Grant Nos 2006CB921602 and 2006CB921102, the Shanxi Provincial Foundation for Leaders of Disciplines in Science, and PCSIRT(IRT0516).
文摘Signal-to-noise ratio of fluorescence detection from a single molecule & analysed by using time-gated techniques. It is found that the optimal signal-to-noise ratio can be obtained by choosing an appropriate gate time with a certain optical background. The dependences of molecular fluorescence lifetime and the optimal signal-to-noise ratio on the appropriate gate time are respectively discussed with two kinds of background sources~ chaotic state with uniform distribution and coherent state with exponential distribution in time domain. For chaotic state background we find that a certain range for appropriate gate time can be obtained with a definite fluorescence lifetime, larger fluorescence lifetime would lower the value of optimal signal-to-noise ratios. For coherent state background we find that there is also a narrow range of appropriate gate time when lifetime of single molecule is less than that of background photons.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574382)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDJ-SSW-SYS014)
文摘Research on protein-membrane interactions has been undeveloped due to the lack of proper techniques to detect the position of proteins at membranes because membranes are usually only about 4-nm thick. We have recently developed a new method named surface-induced fluorescence attenuation (SIFA) to track both vertical and lateral kinetics of a single labelling dye in supported lipid bilayers. It takes advantage of strong interaction between a light-emitting dye and a partially reflecting surface. By applying the technique to membrane proteins being fluorescently labelled at different residues, here we show that SIFA can measure not only the insertion depth of a dye inside a lipid bilayer, but also the position of a dye in solution near the surface. SIFA can therefore be used to study membrane proteins of various types.
文摘Properties of organelles and intracellular structures play important roles in regulating cellular functions,such as gene expression,cell motility and metabolism.The ability to directly interrogate intracellular structures inside a single cell for measurement and manipulation has significant implications in the understanding of subcellular and suborganelle activities,diagnosing diseases,and potentially developing new therapeutic approaches.In the past few decades,a number of technologies have been developed to study single-cell properties.However,methods of measuring intracellular properties and manipulating subcellular structures have been largely underexplored.Due to the even smaller size of intracellular targets and lower signal-to-noise ratio than that in wholecell studies,the development of tools for intracellular measurement and manipulation is challenging.This paper reviews emerging microsystems and nanoengineered technologies for sensing and quantitative measurement of intracellular properties and for manipulating structures inside a single cell.Recent progress and limitations of these new technologies as well as new discoveries and prospects are discussed.
基金The project was supported by the National Natural Science Foundation of China(Grant No.60678042)the Natural Science Foundation of Southeast University(Grant No.9207041399).
文摘Four novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on“push-core-pull-core-push”molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig-Horner reaction.Their chemical structures were determined to show trans-vinylene character according to infrared(IR)and 1H nuclear magnetic resonance(NMR)spectra.A very effective energy transfer from the excited units to the p-conjugated bridging unit can enhance the two-photon absorption and two-photon fluorescence.