The illegal use of veterinary drugs has led to the occurrence of residues in food of animal origin.This is a hazard to people's health.In this paper,a sensitive and fast assay was developed to determine sulfametho...The illegal use of veterinary drugs has led to the occurrence of residues in food of animal origin.This is a hazard to people's health.In this paper,a sensitive and fast assay was developed to determine sulfamethoxazole (SMOZ) in PBS with a homemade surface plasmon resonance (SPR)-based biosensor which had a single flow channel and two references.The derivative of SMOZ was covalently immobilized to a carboxymethyldextran modified gold film.A recently developed monoclonal antibody against sulfamethoxazole was used to develop an inhibitive immunobiosensor assay in which the antibody was mixed with SMOZ of different concentrations prepared with PBS to construct a standard curve with a low limit of detection(LOD).The effect of matrix in milk was also studied.Calculating of the apparent concentration showed the cross-reactivity with other sulfonamides.展开更多
This paper describes a fixed-fixed beam ohmic switch in series with a fixed capacitor as a replacement for a capacitive switch.In this switch,a metal plate deposited on the dielectric ensures perfectly contact with th...This paper describes a fixed-fixed beam ohmic switch in series with a fixed capacitor as a replacement for a capacitive switch.In this switch,a metal plate deposited on the dielectric ensures perfectly contact with the dielectric layer in the down state.The area size of the metal plate directly influences the capacitance ratio of the switch,as the area size of the metal cap decreases,the capacitance ratio dramatically rises up.The down/up capacitance ratio can exceed 800 times over the conventional designs using the same materials and the equal size.Measurement results show that high capacitance ratio of the switches has a large effect on the isolation,and can actually improve the performance of the switches.展开更多
The diameter of the excitation beam was decreased greatly by integrating the fiber on the microfluidic chip as light propagation medium.The coupling efficiency of the fiber was improved with optical fiber collimation ...The diameter of the excitation beam was decreased greatly by integrating the fiber on the microfluidic chip as light propagation medium.The coupling efficiency of the fiber was improved with optical fiber collimation device coupling beam. The chip was placed in the darkroom to avoid the interference of the external light.The cost of the instrument was decreased with a high brightness blue LED as excitation source;the performance of the system was valuated by the determination of FITC fluorescein with a minimum detectable concentration of 2.2×10^(-8) mol/L,the Signal-to-Noise Ratio (SNR) S/N=5.The correlation coefficient of the detection system within the range of 1.8×10^(-7) mol/L～4×10^(-5)mol/L was 0.9972.展开更多
Solid-phase extraction method has proven efficient and amenable to microchips.A novel DNA purification microchip was demonstrated using porous silicon dioxide as the solid phase matrix.Porous SiO_2 was coated on the w...Solid-phase extraction method has proven efficient and amenable to microchips.A novel DNA purification microchip was demonstrated using porous silicon dioxide as the solid phase matrix.Porous SiO_2 was coated on the wall of the channel of the microchip to provide a surface-enlarging matrix.The porous silicon was achieved by anodisation of the silicon reactor in a HF/ethanol mixture and then was oxidized thermally at a lower increasing/decreasing rate to form porous SiO_2.Through optimization of the preparing conditions a more stable microchip was established.Compared with the microchip without the porous layer,the microchip with the porous SiO_2 layer achieved higher extracted efficiency of DNA.Genomic DNA from rat whole blood could be extracted and purified in 35 minutes.展开更多
According to the'elastic buffer mechanism'and the'variable gap mechanism',a new device,which is both micropump and active microvalve actuated by PZT bimorph cantilever,was fabricated with polydimethyis...According to the'elastic buffer mechanism'and the'variable gap mechanism',a new device,which is both micropump and active microvalve actuated by PZT bimorph cantilever,was fabricated with polydimethyisiloxane (PDMS) and silicon chip.The thickness of the micropump membrance is about 180μm.The diameter and the depth of micropump chamber cavity are 6 mm and 40μm,respectively.The performances of the micropump,such as pump rate and backpressure,were characterized.As a flow-rectifying element,the diffusers and active valve were used instead of passive check valves.The flow rate and the backpressure of the micropump are about 420μL/min and 2 kPa when applying a 100 V square wave driving voltage at frequency of 35 Hz.展开更多
The fabrication and characterization of a hybrid Silicon-PDMS micropump based on MEMS technology is presented. The micropump consists of one chamber,two passive valves and one PDMS diaphragm.A PZT bimorph working as t...The fabrication and characterization of a hybrid Silicon-PDMS micropump based on MEMS technology is presented. The micropump consists of one chamber,two passive valves and one PDMS diaphragm.A PZT bimorph working as the actuator is mounted on the PDMS diaphragm.The use of the PDMS diaphragm and the PZT bimorph can give rise to large displacements of the pump diaphragm,making the micropump more efficient and easier to be fabricated.The flow rate of the micropump is a function to the voltage and frequency of the applied square wave.When a square wave of 100V is applied,a maximum flow rate of 317μL/min and a back-pressure of 2 kPa are achieved at 20 Hz.展开更多
PCR-Chip is a function bio-chip for DNA polymerase chain reaction.The temperature control section is so important,because it decides the performance,dimension,integration of the whole chip.By means of thin-film techno...PCR-Chip is a function bio-chip for DNA polymerase chain reaction.The temperature control section is so important,because it decides the performance,dimension,integration of the whole chip.By means of thin-film technology in combination with MEMS technology,a novel thermoelectric layer can be integrated under the chamber according to Peltier model,in order to control the temperature of the chamber.Furthermore,we can switch easily between heating and cooling through changing the direction of the current.The integrated micro-fabricated PCR-Chip is composed of chamber,channel, temperature sensor and thermoelectric temperature control section.展开更多
基金The authors greatly acknowledge the financial support from the National Science Foundation of China （grant number 60427001 and 60302003）.
文摘The illegal use of veterinary drugs has led to the occurrence of residues in food of animal origin.This is a hazard to people's health.In this paper,a sensitive and fast assay was developed to determine sulfamethoxazole (SMOZ) in PBS with a homemade surface plasmon resonance (SPR)-based biosensor which had a single flow channel and two references.The derivative of SMOZ was covalently immobilized to a carboxymethyldextran modified gold film.A recently developed monoclonal antibody against sulfamethoxazole was used to develop an inhibitive immunobiosensor assay in which the antibody was mixed with SMOZ of different concentrations prepared with PBS to construct a standard curve with a low limit of detection(LOD).The effect of matrix in milk was also studied.Calculating of the apparent concentration showed the cross-reactivity with other sulfonamides.
文摘This paper describes a fixed-fixed beam ohmic switch in series with a fixed capacitor as a replacement for a capacitive switch.In this switch,a metal plate deposited on the dielectric ensures perfectly contact with the dielectric layer in the down state.The area size of the metal plate directly influences the capacitance ratio of the switch,as the area size of the metal cap decreases,the capacitance ratio dramatically rises up.The down/up capacitance ratio can exceed 800 times over the conventional designs using the same materials and the equal size.Measurement results show that high capacitance ratio of the switches has a large effect on the isolation,and can actually improve the performance of the switches.
基金financial support from the National Science Foundation of China under Grant number 20299030,60427001 and 60501020.
文摘The diameter of the excitation beam was decreased greatly by integrating the fiber on the microfluidic chip as light propagation medium.The coupling efficiency of the fiber was improved with optical fiber collimation device coupling beam. The chip was placed in the darkroom to avoid the interference of the external light.The cost of the instrument was decreased with a high brightness blue LED as excitation source;the performance of the system was valuated by the determination of FITC fluorescein with a minimum detectable concentration of 2.2×10^(-8) mol/L,the Signal-to-Noise Ratio (SNR) S/N=5.The correlation coefficient of the detection system within the range of 1.8×10^(-7) mol/L～4×10^(-5)mol/L was 0.9972.
基金The authors greatly acknowledge the financial support from the National Science Foundation of China under Grant number 20299030, 60427001 and 60501020.
文摘Solid-phase extraction method has proven efficient and amenable to microchips.A novel DNA purification microchip was demonstrated using porous silicon dioxide as the solid phase matrix.Porous SiO_2 was coated on the wall of the channel of the microchip to provide a surface-enlarging matrix.The porous silicon was achieved by anodisation of the silicon reactor in a HF/ethanol mixture and then was oxidized thermally at a lower increasing/decreasing rate to form porous SiO_2.Through optimization of the preparing conditions a more stable microchip was established.Compared with the microchip without the porous layer,the microchip with the porous SiO_2 layer achieved higher extracted efficiency of DNA.Genomic DNA from rat whole blood could be extracted and purified in 35 minutes.
基金the financial support from the National Science Foundation of China(Grant No.20299030,60427001 and 60501020).
文摘According to the'elastic buffer mechanism'and the'variable gap mechanism',a new device,which is both micropump and active microvalve actuated by PZT bimorph cantilever,was fabricated with polydimethyisiloxane (PDMS) and silicon chip.The thickness of the micropump membrance is about 180μm.The diameter and the depth of micropump chamber cavity are 6 mm and 40μm,respectively.The performances of the micropump,such as pump rate and backpressure,were characterized.As a flow-rectifying element,the diffusers and active valve were used instead of passive check valves.The flow rate and the backpressure of the micropump are about 420μL/min and 2 kPa when applying a 100 V square wave driving voltage at frequency of 35 Hz.
基金The authors greatly acknowledge the financial support from the National Science Foundation of China （Grant number 20299030, 60427001 and 60501020）.
文摘The fabrication and characterization of a hybrid Silicon-PDMS micropump based on MEMS technology is presented. The micropump consists of one chamber,two passive valves and one PDMS diaphragm.A PZT bimorph working as the actuator is mounted on the PDMS diaphragm.The use of the PDMS diaphragm and the PZT bimorph can give rise to large displacements of the pump diaphragm,making the micropump more efficient and easier to be fabricated.The flow rate of the micropump is a function to the voltage and frequency of the applied square wave.When a square wave of 100V is applied,a maximum flow rate of 317μL/min and a back-pressure of 2 kPa are achieved at 20 Hz.
基金The authors greatly acknowledge the financial support from the National Science Foundation of China （Grant number 70299030, 60341005）.
文摘PCR-Chip is a function bio-chip for DNA polymerase chain reaction.The temperature control section is so important,because it decides the performance,dimension,integration of the whole chip.By means of thin-film technology in combination with MEMS technology,a novel thermoelectric layer can be integrated under the chamber according to Peltier model,in order to control the temperature of the chamber.Furthermore,we can switch easily between heating and cooling through changing the direction of the current.The integrated micro-fabricated PCR-Chip is composed of chamber,channel, temperature sensor and thermoelectric temperature control section.
