The achievement of functional nanomodules for subcellular label-free measurement has long been pursued in order to fully understand cellular functions.Here,a compact label-free nanosensor based on a fiber taper and zi...The achievement of functional nanomodules for subcellular label-free measurement has long been pursued in order to fully understand cellular functions.Here,a compact label-free nanosensor based on a fiber taper and zinc oxide nanogratings is designed and applied for the early monitoring of apoptosis in individual living cells.Because of its nanoscale dimensions,mechanical flexibility,and minimal cytotoxicity to cells,the sensing module can be loaded in cells for long term in situ tracking with high sensitivity.A gradual increase in the nuclear refractive index during the apoptosis process is observed,revealing the increase in molecular density and the decrease in cell volume.The strategy used in our study not only contributes to the understanding of internal environmental variations during cellular apoptosis but also provides a new platform for nonfluorescent fiber devices for investigation of cellular events and understanding fundamental cell biochemical engineering.展开更多
High frame rate and highly sensitive imaging of refractive index changes on a surface is very promising for studying the dynamics of dissolution,mixing and biological processes without the need for labeling.Here,a hig...High frame rate and highly sensitive imaging of refractive index changes on a surface is very promising for studying the dynamics of dissolution,mixing and biological processes without the need for labeling.Here,a highly sensitive distributed feedback(DFB)dye laser sensor for high frame rate imaging refractometry without moving parts is presented.DFB dye lasers are low-cost and highly sensitive refractive index sensors.The unique multi-wavelength DFB laser structure presented here comprises several areas with different grating periods.Imagingin two dimensions of space is enabled by analyzinglaser light from all areasin parallelwith an imaging spectrometer.With this multi-resonance imaging refractometry method,the spatial position in one direction is identified from the horizontal,i.e.,spectral position of the multiple laser lines which is obtained from the spectrometer charged coupled device(CCD)array.The orthogonal spatial position is obtained from the vertical spatial position on the spectrometer CCD array as in established spatially resolved spectroscopy.Here,the imaging technique is demonstrated by monitoring the motion of small sucrose molecules upon dissolution of solid sucrose in water.The omission of moving parts improves the robustness of the imaging system and allows a very high frame rate of up to 12 Hz.展开更多
In this work, the application of a conducting polymer, poly（thionine）, modified electrode as matrix to DNA immobilization as well as transducer to label-free DNA hybridization detection was introduced. The electropo...In this work, the application of a conducting polymer, poly（thionine）, modified electrode as matrix to DNA immobilization as well as transducer to label-free DNA hybridization detection was introduced. The electropolymerization of thionine onto electrode surface was carried out by a simple two-step method, which involved a preanodization of glassy carbon electrode at a constant positive potential in thionine solution following cyclic voltammetry scans in the solution. Electrochemical detection was performed by differential pulse voltammetry in the electroactivity potential domain of poly（thionine）. The resulting poly（thionine） modified electrode showed a good stability and electroactivity in aqueous media during a near neutral pH range. Additionally, the pendant amino groups on the poly（thionine） chains enabled poly（thionine） modified electrode to immobilize phosphate group terminated DNA probe via covalent linkage. Hybridization process induced a clear decrease in poly（thionine） redox current, which was corresponding to the decrease in poly（thionine） electroactivity after double stranded DNA was formed on the polymer film. The detection limit of this electrochemical DNA hybridization sensor was 1.0 × 10^-10mol/L. Compared with complementary sequence, the hybridization signal values of 1-base mismatched and 3-base mismatched samples were 63.9% and 9.2%, respectively.展开更多
基金sponsored by the National Natural Science Foundation of China (Nos. 61925502 and 62135007)
文摘The achievement of functional nanomodules for subcellular label-free measurement has long been pursued in order to fully understand cellular functions.Here,a compact label-free nanosensor based on a fiber taper and zinc oxide nanogratings is designed and applied for the early monitoring of apoptosis in individual living cells.Because of its nanoscale dimensions,mechanical flexibility,and minimal cytotoxicity to cells,the sensing module can be loaded in cells for long term in situ tracking with high sensitivity.A gradual increase in the nuclear refractive index during the apoptosis process is observed,revealing the increase in molecular density and the decrease in cell volume.The strategy used in our study not only contributes to the understanding of internal environmental variations during cellular apoptosis but also provides a new platform for nonfluorescent fiber devices for investigation of cellular events and understanding fundamental cell biochemical engineering.
基金The authors thank JS Clausen for assistance with electron beam lithography and CLC Smith,KT Sørensen and E Højlund-Nielsen for fruitful discussionsCV acknowledges support from the Danish Research Council for Technology and Production Sciences(Grant No.12-126676).
文摘High frame rate and highly sensitive imaging of refractive index changes on a surface is very promising for studying the dynamics of dissolution,mixing and biological processes without the need for labeling.Here,a highly sensitive distributed feedback(DFB)dye laser sensor for high frame rate imaging refractometry without moving parts is presented.DFB dye lasers are low-cost and highly sensitive refractive index sensors.The unique multi-wavelength DFB laser structure presented here comprises several areas with different grating periods.Imagingin two dimensions of space is enabled by analyzinglaser light from all areasin parallelwith an imaging spectrometer.With this multi-resonance imaging refractometry method,the spatial position in one direction is identified from the horizontal,i.e.,spectral position of the multiple laser lines which is obtained from the spectrometer charged coupled device(CCD)array.The orthogonal spatial position is obtained from the vertical spatial position on the spectrometer CCD array as in established spatially resolved spectroscopy.Here,the imaging technique is demonstrated by monitoring the motion of small sucrose molecules upon dissolution of solid sucrose in water.The omission of moving parts improves the robustness of the imaging system and allows a very high frame rate of up to 12 Hz.
基金Project supported by the National Natural Science Foundation of China （No. 29875008）.
文摘In this work, the application of a conducting polymer, poly（thionine）, modified electrode as matrix to DNA immobilization as well as transducer to label-free DNA hybridization detection was introduced. The electropolymerization of thionine onto electrode surface was carried out by a simple two-step method, which involved a preanodization of glassy carbon electrode at a constant positive potential in thionine solution following cyclic voltammetry scans in the solution. Electrochemical detection was performed by differential pulse voltammetry in the electroactivity potential domain of poly（thionine）. The resulting poly（thionine） modified electrode showed a good stability and electroactivity in aqueous media during a near neutral pH range. Additionally, the pendant amino groups on the poly（thionine） chains enabled poly（thionine） modified electrode to immobilize phosphate group terminated DNA probe via covalent linkage. Hybridization process induced a clear decrease in poly（thionine） redox current, which was corresponding to the decrease in poly（thionine） electroactivity after double stranded DNA was formed on the polymer film. The detection limit of this electrochemical DNA hybridization sensor was 1.0 × 10^-10mol/L. Compared with complementary sequence, the hybridization signal values of 1-base mismatched and 3-base mismatched samples were 63.9% and 9.2%, respectively.
