This paper described a highly sensitive chemiluminescence detection system for micro-chip electrophoresis (MCE) based on luminol-hydrogen peroxide reaction catalyzed by the metal ions. The micro-chip was composed of p...This paper described a highly sensitive chemiluminescence detection system for micro-chip electrophoresis (MCE) based on luminol-hydrogen peroxide reaction catalyzed by the metal ions. The micro-chip was composed of poly(dimethylsiloxane) (PDMS) and glass, and was fabricated by micro-machining technology. The surface of channels was dynamically modified by polydimethylacrylamide (PDMA) in order to eliminate unhomogeneous electroosmotic flow (EOF) of the PDMS/glass chip, adsorption of molecules, and improve hydrophobicity on PDMS surface. The detection modes, reagent mix procedures and reaction conditions were optimized and the detection limit of 5×10 mol/L for cobalt (II) was achieved by MCE with chemiluminescence detection, which was about four orders of magnitude more sensitive than that reported in the reference.展开更多
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
The characteristics such as signal noise ratio（SNR） and sensitivity of the fluorescence detection system for micro-fluidic chip influence the performance of the whole system extremely. The confocal laser induced flu...The characteristics such as signal noise ratio（SNR） and sensitivity of the fluorescence detection system for micro-fluidic chip influence the performance of the whole system extremely. The confocal laser induced fluorescence detection system is presented. Based on the debugging of optical and circuit modules, the results of detecting the samples are given and analyzed theoretically, and the improved project is put forward.展开更多
Capillary electrophoresis (CE) suffers from a relatively small sensitivity—at least in case of optical detection transversely to the capillary axis due to the small capillary inner diameters in the range of 50 - 100 ...Capillary electrophoresis (CE) suffers from a relatively small sensitivity—at least in case of optical detection transversely to the capillary axis due to the small capillary inner diameters in the range of 50 - 100 μm. Different concepts like bubble, U-, or Z-cells have been used to tackle that problem already in the nineties of the last century. But the U- and Z-cells have typically been extra cells with larger inner channel diameters and no optimization for optical waveguiding and the bubble cell per se did not allow for optical waveguiding. In the case of on-chip capillary electrophoresis (chip-CE) a U-cell can be implemented quite easily on the chip. Here we show how leaky optical waveguiding can be employed to improve optical detection. Proper U-channel design and preparation by wet-chemical etching of the fused silica sub- and superstrate, making the U-channel bend a part of the optical input lens system, can help to achieve high coupling efficiency with loss coefficients around 2 dB and low waveguiding loss.展开更多
The microchip capillary electrophoresis devices were fabricated by using poly(methyl methacrylate)(PMMA) plastic material via an injection-molding process. The molded devices were enclosed by utilizing a mixed organic...The microchip capillary electrophoresis devices were fabricated by using poly(methyl methacrylate)(PMMA) plastic material via an injection-molding process. The molded devices were enclosed by utilizing a mixed organic solvent to another PMMA film. The channel structure was very well defined and the molded channel surfaces were very smooth. The transmissivity was in the range from 91% to 93%(at the wavelength of 400—1 000 nm). In comparison to glass microchannels, the electroosmotic flow(EOF) in native PMMA channels was low. DNA marker separation was demonstrated in these PMMA devices with a high-resolution separation of double-stranded DNA fragments, chip-to-chip and the run-to-run reproducibility was good, and the relative standard deviation(%) values were below 2.2% for run-to-run data and 2.3% for the chip-to-chip comparisons. The PCR amplification products and proteins were analyzed on the PMMA chips. Such devices lead to the production of low-cost, disposable chips suitable for a variety of separation applications, including DNA sizing, DNA sequencing, protein and medical analysis. The detection limits of Rhodamine 6G dye for the unmodified PMMA chip and the modified PMMA chips were 1.0×10 -10 and 6.67×10 -13 mol/L, respectively.展开更多
A glass capillary electrophoresis microchip with integrated amperometric detection cell equipped by replaceable micro-disk working electrode is described. The detection cell was fabricated as a buffer reservoir on the...A glass capillary electrophoresis microchip with integrated amperometric detection cell equipped by replaceable micro-disk working electrode is described. The detection cell was fabricated as a buffer reservoir on the microchip. A micro-electrode-guiding hole, which was in alignment with the exit of the separation channel, was drilled into the bottom edge of the chip. When a micro-disk copper working electrode, the outside diameter of which being matched with the inside diameter of the guiding hole, was inserted into the hole, passed through detection cell and finally got access to the exit of the separation channel, the electrode could be quasi-self-aligned to the channel exit and fixed inside the guiding hole without the help of a micro-positioner. Thus an integrated end-column amperometric detection system with replaceable disk working electrode was established on the microchip. Good reproducibility of the electrode alignment was demonstrated by a 4 1% RSD in the detection of sucrose after repeated(n=9) alignment of a micro-copper disk electrode. The developed michrochip was used for separation and detection of oligosaccharides.展开更多
文摘This paper described a highly sensitive chemiluminescence detection system for micro-chip electrophoresis (MCE) based on luminol-hydrogen peroxide reaction catalyzed by the metal ions. The micro-chip was composed of poly(dimethylsiloxane) (PDMS) and glass, and was fabricated by micro-machining technology. The surface of channels was dynamically modified by polydimethylacrylamide (PDMA) in order to eliminate unhomogeneous electroosmotic flow (EOF) of the PDMS/glass chip, adsorption of molecules, and improve hydrophobicity on PDMS surface. The detection modes, reagent mix procedures and reaction conditions were optimized and the detection limit of 5×10 mol/L for cobalt (II) was achieved by MCE with chemiluminescence detection, which was about four orders of magnitude more sensitive than that reported in the reference.
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.
基金Key Science and Technology Project Tackled of Guangdong Province(B2050070)
文摘The characteristics such as signal noise ratio（SNR） and sensitivity of the fluorescence detection system for micro-fluidic chip influence the performance of the whole system extremely. The confocal laser induced fluorescence detection system is presented. Based on the debugging of optical and circuit modules, the results of detecting the samples are given and analyzed theoretically, and the improved project is put forward.
文摘Capillary electrophoresis (CE) suffers from a relatively small sensitivity—at least in case of optical detection transversely to the capillary axis due to the small capillary inner diameters in the range of 50 - 100 μm. Different concepts like bubble, U-, or Z-cells have been used to tackle that problem already in the nineties of the last century. But the U- and Z-cells have typically been extra cells with larger inner channel diameters and no optimization for optical waveguiding and the bubble cell per se did not allow for optical waveguiding. In the case of on-chip capillary electrophoresis (chip-CE) a U-cell can be implemented quite easily on the chip. Here we show how leaky optical waveguiding can be employed to improve optical detection. Proper U-channel design and preparation by wet-chemical etching of the fused silica sub- and superstrate, making the U-channel bend a part of the optical input lens system, can help to achieve high coupling efficiency with loss coefficients around 2 dB and low waveguiding loss.
文摘The microchip capillary electrophoresis devices were fabricated by using poly(methyl methacrylate)(PMMA) plastic material via an injection-molding process. The molded devices were enclosed by utilizing a mixed organic solvent to another PMMA film. The channel structure was very well defined and the molded channel surfaces were very smooth. The transmissivity was in the range from 91% to 93%(at the wavelength of 400—1 000 nm). In comparison to glass microchannels, the electroosmotic flow(EOF) in native PMMA channels was low. DNA marker separation was demonstrated in these PMMA devices with a high-resolution separation of double-stranded DNA fragments, chip-to-chip and the run-to-run reproducibility was good, and the relative standard deviation(%) values were below 2.2% for run-to-run data and 2.3% for the chip-to-chip comparisons. The PCR amplification products and proteins were analyzed on the PMMA chips. Such devices lead to the production of low-cost, disposable chips suitable for a variety of separation applications, including DNA sizing, DNA sequencing, protein and medical analysis. The detection limits of Rhodamine 6G dye for the unmodified PMMA chip and the modified PMMA chips were 1.0×10 -10 and 6.67×10 -13 mol/L, respectively.
文摘A glass capillary electrophoresis microchip with integrated amperometric detection cell equipped by replaceable micro-disk working electrode is described. The detection cell was fabricated as a buffer reservoir on the microchip. A micro-electrode-guiding hole, which was in alignment with the exit of the separation channel, was drilled into the bottom edge of the chip. When a micro-disk copper working electrode, the outside diameter of which being matched with the inside diameter of the guiding hole, was inserted into the hole, passed through detection cell and finally got access to the exit of the separation channel, the electrode could be quasi-self-aligned to the channel exit and fixed inside the guiding hole without the help of a micro-positioner. Thus an integrated end-column amperometric detection system with replaceable disk working electrode was established on the microchip. Good reproducibility of the electrode alignment was demonstrated by a 4 1% RSD in the detection of sucrose after repeated(n=9) alignment of a micro-copper disk electrode. The developed michrochip was used for separation and detection of oligosaccharides.
