Controlling and manipulating the fluorescence of single fluorophores is of great interest in recent years for its potential uses in improving the performance of molecular photonics and molecular electronics, such as i...Controlling and manipulating the fluorescence of single fluorophores is of great interest in recent years for its potential uses in improving the performance of molecular photonics and molecular electronics, such as in organic light-emitting devices, single photon sources, organic field-effect transistors, and probes or sensors based on single molecules. This review shows how the fluorescence emission of single organic molecules can be modified using local electromagnetic fields of metallic nanostructures and electric-field-induced electron transfer. Electric-field-induced fluorescence modulation, hysteresis, and the achievement of fluorescence switch are discussed in detail.展开更多
A method for real time observation of photo-cleavage of stretched λDNA at single molecular level by a fluorescent microscope coupled with CCD is developed. DNA molecules stained with YOYO-1 are stretched by the mo-le...A method for real time observation of photo-cleavage of stretched λDNA at single molecular level by a fluorescent microscope coupled with CCD is developed. DNA molecules stained with YOYO-1 are stretched by the mo-lecular combing technique and fixed on a modified slide. Then the process of photocleavage and relaxation of DNA under radiation of blue light is observed. We speculate that the conformation change of stretched DNA and the effect of water are likely to facilitate the effect of YOYO photocleav-age DNA molecules. The photocleavage effect of YOYO for stretched DNA may be useful to study DNA elasticity, cancer research as well as the interaction between DNA and dyes.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
基金Acknowledgements The project was sponsored by the National Basic Research Program of China （973 Program） （Grant No. 2012CB921603）, the National Natural Science Foundation of China （Grant Nos. 61527824, 11434007, 11374196, 11404200, 11504216, and U1510133）, PCSIRT （No. IRT13076）, and the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province.
文摘Controlling and manipulating the fluorescence of single fluorophores is of great interest in recent years for its potential uses in improving the performance of molecular photonics and molecular electronics, such as in organic light-emitting devices, single photon sources, organic field-effect transistors, and probes or sensors based on single molecules. This review shows how the fluorescence emission of single organic molecules can be modified using local electromagnetic fields of metallic nanostructures and electric-field-induced electron transfer. Electric-field-induced fluorescence modulation, hysteresis, and the achievement of fluorescence switch are discussed in detail.
基金supposed by the National Natural Science Foundation of China(Grant No.19890385)the fund from the Chinese Academy of Sciences(Grant Nos.STZ-00-07,KJCX-06 and KSCXI-06)the Science and Technology Commission of Shanghai(Grant No.00XD1444029).
文摘A method for real time observation of photo-cleavage of stretched λDNA at single molecular level by a fluorescent microscope coupled with CCD is developed. DNA molecules stained with YOYO-1 are stretched by the mo-lecular combing technique and fixed on a modified slide. Then the process of photocleavage and relaxation of DNA under radiation of blue light is observed. We speculate that the conformation change of stretched DNA and the effect of water are likely to facilitate the effect of YOYO photocleav-age DNA molecules. The photocleavage effect of YOYO for stretched DNA may be useful to study DNA elasticity, cancer research as well as the interaction between DNA and dyes.
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.
