A dichlorosilane gas and a trichlorosilane gas in ambient hydrogen were evaluated to show their different gas flow motions in a slim vertical cold wall chemical vapor deposition reactor for the Minimal Fab system. Thi...A dichlorosilane gas and a trichlorosilane gas in ambient hydrogen were evaluated to show their different gas flow motions in a slim vertical cold wall chemical vapor deposition reactor for the Minimal Fab system. This evaluation was performed for improving and controlling the film qualities and the productivities, using two quartz crystal microbalances (QCM) installed at the </span><span style="font-family:Verdana;">inlet and exhaust of the chamber by taking into account that the QCM frequency corresponds to the real time changes in the gas properties.</span><span style="font-family:Verdana;"> Typically, the time period approaching from the inlet to the exhaust was shorter for the trichlorosilane gas than that for the dichlorosilane gas. The trichlorosilane gas was shown to move like plug flow, while the dichlorosilane gas seemed to be well mixed in the entire chamber.展开更多
Citronellol is a kind of terpene produced by plants in response to external stress;thus can be used as a gas biomarker to detect black spot Ceratocystis fimbriata infection in sweetpotato.However,many contemporary ana...Citronellol is a kind of terpene produced by plants in response to external stress;thus can be used as a gas biomarker to detect black spot Ceratocystis fimbriata infection in sweetpotato.However,many contemporary analytical methods,exemplified by gas chromatography-mass spectrometry,are technically demanding,time-consuming,and require complex sample preparation procedures.In this study,a quartz crystal microbalance(QCM)-based gas sensor fabricated via a surface molecular imprinting technique was modified with a Co/Zn-ZIF@MIP composite,in which cobalt-zinc bimetallic ZIF(Co/Zn-ZIF)served as the support material.A linear relationship was observed between the frequency shift and citronellol concentrations ranging from 0.88 to 22 mg/L,with a sensitivity of−6.08 Hz/(mg·L)and a limit of detection(LOD)of 1.35 mg/L.This result indicated that this sensor has excellent selectivity for citronellol and demonstrates high repeatability,as evidenced by R^(2)value of 0.97.In evaluations with real samples,the sensor reliably identified citronellol among the complex volatile organic compounds(VOCs)emitted from black spot-infected sweetpotato,indicating a high level of selectivity.Our research achieved the rapid characterization of sweetpotato black spot disease within 4 min and provided new insights into the development of QCM-based gas sensors for the rapid assessment of agricultural product quality and safety.展开更多
Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus.The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins,of which Mytilus ...Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus.The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins,of which Mytilus edulis foot protein-1(Mefp-1)has been identified as the most abundant protein.It has been found that lipids are involved in the mussel adhesion process and can facilitate Mefp-1adhesion.In this research,the adhesion behavior of Mefp-1 on various substrate surfaces under the effect of typical seawater cations with or without the presence of lipid were investigated using a quartz crystal microbalance with dissipation(QCM-D).Results indicate that the presence of cations Ca^(2+),Mg^(2+),Na^(+),and K^(+)leads to varying degrees of reduction in the adhesion performance of Mefp-1 on different substrates.The degree of this reduction,however,was much alleviated in the presence of palmitic acid,which is involved in the mussel adhesion process.Therefore,the involvement of palmitic acid is advantageous for mussel protein adhesion to the substrate surface in the marine environment.This study illustrated the significant contribution of palmitic acid to mussel adhesion,which can help to better understand biofouling mechanisms and develop biomimetic adhesive materials.展开更多
A biosensor is an analytical device used for the detection of analytes,which combines a biological component with a physicochemical detector.Recently,an increasing number of biosensors have been used in clinical resea...A biosensor is an analytical device used for the detection of analytes,which combines a biological component with a physicochemical detector.Recently,an increasing number of biosensors have been used in clinical research,for example,the blood glucose biosensor.This review focuses on the current state of biosensor research with respect to efficient,specific and rapid detection of hepatitis B virus(HBV).The biosensors developed based on different techniques,including optical methods(e.g.,surface plasmon resonance),acoustic wave technologies(e.g.,quartz crystal microbalance),electrochemistry(amperometry,voltammetry and impedance) and novel nanotechnology,are also discussed.展开更多
As humidity is one of the most widely demanded environmental parameters,the precision of its detection is significant.An advanced humidity sensor will improve the validity of the humidity monitoring system.In this stu...As humidity is one of the most widely demanded environmental parameters,the precision of its detection is significant.An advanced humidity sensor will improve the validity of the humidity monitoring system.In this study,a facile chemical layer-by-layer self-assembly(CLS)method was developed for fabricating graphene oxide(GO)/polyethyleneimine(PEI)multilayer films.Owing to the chemical bonding between the PEI and GO,and the intrinsic stickiness of the PEI,layered films with different numbers of layers were successfully prepared using the CLS method and confirmed through ultraviolet-visible(UV-Vis)spectroscopy and the mass loading of quartz crystal microbalance(QCM).Morphological measurements revealed that the roughness and thickness of the films increased exponentially with the number of bilayers.The GO/PEI films were deposited on QCM electrodes using the CLS method to produce the humidity sensors.The humidity measurement results showed a high sensitivity(37.84 Hz/%RH)and rapid response/recovery(<5 s/8 s)of the optimal sensor,which was superior to that of recently developed QCM sensors.展开更多
We present a new polymer quartz piezoelectric crystal sensor that takes a quartz piezoelectric crystal as the basal material and a nanometer nonmetallic polymer thin film as the surface coating based on the principle ...We present a new polymer quartz piezoelectric crystal sensor that takes a quartz piezoelectric crystal as the basal material and a nanometer nonmetallic polymer thin film as the surface coating based on the principle of quartz crystal microbalance(QCM). The new sensor can be used to detect the characteristic materials of a volatile liquid. A mechanical model of the new sensor was built, whose structure was a thin circle plate composing of polytef/quartz piezoelectric/polytef. The mechanical model had a diameter of 8 mm and a thickness of 170 μm. The vibration state of the model was simulated by software ANSYS after the physical parameters and the boundary condition of the new sensor were set. According to the results of experiments, we set up a frequency range from 9.995850 MHz to 9.997225 MHz, 17 kinds of frequencies and modes of vibration were obtained within this range. We found a special frequency fspof 9.996358 MHz. When the resonant frequency of the new sensor's mechanical model reached the special frequency, a special phenomenon occurred. In this case, the amplitude of the center point O on the mechanical model reached the maximum value. At the same time, the minimum absolute difference between the simulated frequency based on the ANSYS software and the experimental measured stable frequency was reached. The research showed that the design of the new polymer quartz piezoelectric crystal sensor perfectly conforms to the principle of QCM. A special frequency value fspwas found and subsequently became one of the most important parameters in the new sensor design.展开更多
This work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance(QCM)to detect benzene,toluene,ethylbenzene,and xylene(BTEX)v...This work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance(QCM)to detect benzene,toluene,ethylbenzene,and xylene(BTEX)vapor.Notably,sensing results toward toluene vapor in different relative humidities indicates that this superhydrophobic polymer has favorable toluene/water selective detection performance.Besides,the limit of detection toward toluene is lower than 1 ppm.展开更多
N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to...N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to characterize.Limited understanding of doping-derived EDL structure hinders insight into the structure-performance relations and the rational design of high-performance materials.Thus,we analyzed the mass and chemical composition variation of EDL within electrochemical operation by electrochemical quartz crystal microbalance,in-situ X-ray photoelectron spectroscopy,and time-offlight secondary ion mass spectrometry.We found that N-doping triggers specifically adsorbed propylene carbonate solvent in the inner Helmholtz plane(IHP),which prevents ion rearrangement and enhances the migration of cations.However,this specific adsorption accelerated solvent decomposition,rendering rapid performance degradation in practical devices.This work reveals that the surface chemistry of electrodes can cause specific adsorption of solvents and change the EDL structure,which complements the classical EDL theory and provide guidance for practical applications.展开更多
The influence rules of square micro-pillar array porosity on the liquid motion characteristics of the near-surface layer are investigated by quartz crystal microbalance(QCM).QCM is a powerful and promising technique i...The influence rules of square micro-pillar array porosity on the liquid motion characteristics of the near-surface layer are investigated by quartz crystal microbalance(QCM).QCM is a powerful and promising technique in studying the interfacial behavior,which exhibits great advantages in investigating the effects of surface microstructure,roughness,and array.In our experiments,three different arrays with the same height of about 280 nm and center distance of 200μm,but different diameters of about 78μm,139μm,and 179μm are investigated.The results indicate that when the surface array has a large porosity,its influence on the liquid motion of the near surface layer is slight,thus resulting in a small increase of half-bandwidth variation due to the additional friction energy dissipation.When the surface array has a small porosity,the array tends to make the liquid film trapped in the array oscillating with the substrate,then there may be a layer of liquid film behaving like rigid film,and it also will make the liquid motion near the array layer more complicated.Thus for the#3 surface with a small porosity,both the absolute values of frequency shift|Δf3|and half-bandwidth variationΔΓ3 increase obviously.The experimental results show good consistence with the theoretical model of Daikhin and Urbakh.This study sheds light on understanding the influence mechanism of surface array porosity on the liquid motion of near-surface layer.展开更多
Finished drinking water usually contains some residual aluminum.The deposition of residual aluminum in distribution systems and potential release back to the drinking water could significantly influence the water qual...Finished drinking water usually contains some residual aluminum.The deposition of residual aluminum in distribution systems and potential release back to the drinking water could significantly influence the water quality at consumer taps.A preliminary analysis of aluminum content in cast iron pipe corrosion scales and loose deposits demonstrated that aluminum deposition on distribution pipe surfaces could be excessive for water treated by aluminum coagulants including polyaluminum chloride（PACl）.In this work,the deposition features of different aluminum species in PACl were investigated by simulated coil-pipe test,batch reactor test and quartz crystal microbalance with dissipation monitoring.The deposition amount of non-polymeric aluminum species was the least,and its deposition layer was soft and hydrated,which indicated the possible formation of amorphous Al（OH）3.Al（13） had the highest deposition tendency,and the deposition layer was rigid and much less hydrated,which indicated that the deposited aluminum might possess regular structure and self-aggregation of Al（13）could be the main deposition mechanism.While for Al（30）,its deposition was relatively slower and deposited aluminum amount was relatively less compared with Al（13）.However,the total deposited mass of Al（30） was much higher than that of Al（13）,which was attributed to the deposition of particulate aluminum matters with much higher hydration state.Compared with stationary condition,stirring could significantly enhance the deposition process,while the effect of pH on deposition was relatively weak in the near neutral range of 6.7 to 8.7.展开更多
Porphyrin-filled nanofibrous membranes were facilely prepared by electrospinning of the mixtures of poly（acrylonitrile-co-acrylic acid）（PANCAA） and porphyrins. 5,10,15,20-Tetraphenylporphyrin（TPP） and its metal-...Porphyrin-filled nanofibrous membranes were facilely prepared by electrospinning of the mixtures of poly（acrylonitrile-co-acrylic acid）（PANCAA） and porphyrins. 5,10,15,20-Tetraphenylporphyrin（TPP） and its metal-loderivatives（ZnTPP and CuTPP） were studied as filling mediators for the immobilization of redox enzyme. Results indicate that the introduction of TPP, ZnTPP and CuTPP improves the retention activity of the immobilized catalase. Among these three porphyrins, the ZnTPP-filled PANCAA nanofibrous membrane exhibits an activity retention of 93%, which is an exciting improvement. This improvement is attributed to both the strong catalase-porphyrin affinity and the possible facilitated electron transfer induced by the porphyrin as evidenced by quartz crystal microbalance （QCM） and fluorescence spectroscopy studies.展开更多
In this study, we have used a direct immunoassay where the simple binding between antigen and an antibody is detected. Immunoassays were performed in a drop system, monitoring the frequency decrease of the quartz-crys...In this study, we have used a direct immunoassay where the simple binding between antigen and an antibody is detected. Immunoassays were performed in a drop system, monitoring the frequency decrease of the quartz-crystal microbalance device because of mass increasing during immunoreaction. The QCM sensor was coated on both sides by gold electrodes, only one side of the crystal (liquid side) was in contact with the solution;the other side (contact side) was always dry. We tested a piezoelectric immunosensor for aflatoxin B1 (AFLA-B1) mycotoxin detection through the immo- bilization of DSP-anti-AFLAB1 antibody (AFLA-B1-Ab anti AFLAB1) on gold-coated quartz crystals (AT-cut/5 MHz). The DSP (3,3’-Dithiodipropionic-acid-di-N-hydroxysuccinimide ester) was used for the covalent attachment of the proteins. The piezoelectric crystal electrodes were pretreated by DSP for 15 min, rinsed with water and dried in a gentle flow of nitrogen gas. Then the DSP-coated crystals were installed in a sample holder and exposed to the anti-AFLAB1 antibody and to the AFLA-BI. Frequency and resistance shifts (Δf and ΔR) were measured simultaneously. Δf versus AFLA-BI concentrations in the range of 0.5 - 10 ppb exhibited a perfect linear correlation with a coefficient of above 0.998.展开更多
To achieve real-time monitoring of humidity in various applications,we prepared facile and ultra-thin CoAl layered double hydroxide(CoAl LDH)nanosheets to engineer quartz crystal microbalances(QCM).The characteristics...To achieve real-time monitoring of humidity in various applications,we prepared facile and ultra-thin CoAl layered double hydroxide(CoAl LDH)nanosheets to engineer quartz crystal microbalances(QCM).The characteristics of CoAl LDH were investigated by transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectric spectroscopy(XPS),Brunauer–Emmett–Telle(BET),atomic force microscopy(AFM)and zeta potential.Due to their large specific surface area and abundant hydroxyl groups,CoAl LDH nanosheets exhibit good humidity sensing performance.In a range of 11.3%and 97.6%relative humidity(RH),the sensor behaved an ultrahigh sensitivity(127.8 Hz/%RH),fast response(9.1 s)and recovery time(3.1 s),low hysteresis(3.1%RH),good linearity(R^(2)=0.9993),stability and selectivity.Besides,the sensor can recover the initial response frequency after being wetted by deionized water,revealing superior self-recovery ability under high humidity.Based on in-situ Fourier transform infrared spectroscopy(FT-IR),the adsorption mechanism of CoAl LDH toward water molecules was explored.The QCM sensor can distinguish different respiratory states of people and wetting degree of fingers,as well as monitor the humidity in vegetable packaging,suggesting excellent properties and a promising application in humidity sensing.展开更多
The fast and accurate identification of nerve tracts is critical for successful nerve anastomosis. Taking advantage of differences in acetylcholinesterase content between the spinal ventral and dorsal roots, we develo...The fast and accurate identification of nerve tracts is critical for successful nerve anastomosis. Taking advantage of differences in acetylcholinesterase content between the spinal ventral and dorsal roots, we developed a novel quartz crystal microbalance method to distinguish between these nerves based on acetylcholinesterase antibody reactivity. The acetylcholinesterase antibody was immobilized on the electrode surface of a quartz crystal microbalance and reacted with the acetylcholinesterase in sample solution. The formed antigen and antibody complexes added to the mass of the electrode inducing a change in frequency of the electrode. The spinal ventral and dorsal roots were distinguished by the change in frequency. The ventral and dorsal roots were cut into 1 to 2-mm long segments and then soaked in 250 pL PBS. Acetylcholinesterase antibody was immobilized on the quartz crystal microbalance gold electrode surface. The results revealed that in 10 minutes, both spinal ventral and dorsal roots induced a frequency change; however, the frequency change induced by the ventral roots was notably higher than that induced by the dorsal roots. No change was induced by bovine serum albumin or PBS. These results clearly demonstrate that a quartz crystal microbalance sensor can be used as a rapid, highly sensitive and accurate detection tool for the quick identification of spinal nerve roots intraoperatively.展开更多
On the basis of thin film lubrication theory, the influence of fluid film(disordered film), ordered film and adsorbed film on tribological behavior of lubricating oil in thin-film lubrication(TFL) regime was studied. ...On the basis of thin film lubrication theory, the influence of fluid film(disordered film), ordered film and adsorbed film on tribological behavior of lubricating oil in thin-film lubrication(TFL) regime was studied. The μ-L(friction coefficient versus load) curves of different oil viscosity and additive dosage were obtained by a high frequency reciprocating test rig and the adsorption capacity of additive on steel surface were measured by QCM-D. Based on the Stribeck curve and thin film lubrication theory model, some conclusions can be drawn up, namely:(1) The μ-L curves and the parameters of L0 and μ0, obtained from the high frequency reciprocating test rig with ball-disc contact, can be used to study tribological behaviors of lubricating oil under TFL conditions.(2) In comparison with the high viscosity base fluid, the lower one can enter into TFL regime under lower load and keeps a lower friction coefficient in TFL regime.(3) The polar molecules in additive formulation produce ordered adsorbed layer on steel surface to reduce friction coefficient. And in TFL regime, the molecule's polarity, layer thickness and saturation degree on steel surface probably can influence lubricant's tribological behaviors between the moving interfaces. Moreover, the further study would be focused on the competitive adsorption of different additives, the formation of dual- and/or tri-molecular adsorption layers, and other aspects.展开更多
Using the langasite crystal microbalance (LCM), the trends in film thickness produced by means of the chemical vapor deposition using trichlorosilane gas, monomethylsilane gas and their mixed gas were observed at 600?...Using the langasite crystal microbalance (LCM), the trends in film thickness produced by means of the chemical vapor deposition using trichlorosilane gas, monomethylsilane gas and their mixed gas were observed at 600?C and evaluated by comparison with the information from a transmission electron microscope (TEM). The crystalline silicon film thickness from trichlorosilane gas was comparable to that of an amorphous silicon carbide film from monomethylsilane gas. The film obtained from the gas mixture was amorphous and was the thinnest in this study. Because the thickness trend obtained by the LCM agreed with that by the TEM, the LCM is shown to be a convenient evaluation tool for the behavior of various film deposition.展开更多
The effects of surface adsorption of bovine serum albumin(BSA)and human gamma-globulin(HGG)on the tribological performance of a DLC film were investigated using a quartz crystal microbalance with dissipation(QCM-D),a ...The effects of surface adsorption of bovine serum albumin(BSA)and human gamma-globulin(HGG)on the tribological performance of a DLC film were investigated using a quartz crystal microbalance with dissipation(QCM-D),a ball-on-disk reciprocating tribometer,and a three-electrode electrochemical cell.The results showed that the wear depth in the BSA solution was higher than that in the HGG solution.In the HGG solution,the HGG-adsorbed layer could act as a lubricating layer and protect the DLC film from wear.The wear volume of DLC film in BSA and HGG mixture solution was higher than that in single HGG solution.This may be because the BSA molecules inhibit the formation of HGG adsorbed layer during sliding.展开更多
A quartz crystal microbalance （QCM） is used to determine the phase equilibrium of paclitaxel-carbon dioxide system in the pressure range of 0-11 MPa and at temperatures of 35 °C,40 °C and 45 °C.The ex...A quartz crystal microbalance （QCM） is used to determine the phase equilibrium of paclitaxel-carbon dioxide system in the pressure range of 0-11 MPa and at temperatures of 35 °C,40 °C and 45 °C.The experimental results indicated that gaseous CO2 could be absorbed poorly into paclitaxel.The swelling of paclitaxel film in CO2 was observed before paclitaxel dissolved into supercritical carbon dioxide （ScCO2） with the increase of pressure.It was found that ScCO2 was not a good solvent for paclitaxel.The mole fraction of paclitaxel in ScCO2 was in the range of （4.5×10-9）-（7.8×10-9） under all our experimental conditions.Therefore,a much higher pressure than the CO2 supercritical point and/or a cosolvent must be used in any processes wherever paclitaxel dissolution in ScCO2 is required.展开更多
A new method of determination of trace CNin water was proposed.A thin film of AgS was electrochemically deposited on both sides of a silver coated piezoelectric crystal.The AgS Ag films can react with CN selectively,w...A new method of determination of trace CNin water was proposed.A thin film of AgS was electrochemically deposited on both sides of a silver coated piezoelectric crystal.The AgS Ag films can react with CN selectively,which causes the frequency shifts of the piezoelectric crystal.The frequency shifts are proportional to the concentration of CN in the range of 106~10'g/L.XPS experiments indicated the sensing film was AgiS Ag.A coordination complex Ag-CNwas formed when AgiS Ag film contacted with solution containing CNion.A response mechanism was proposed based on the XPS data.展开更多
文摘A dichlorosilane gas and a trichlorosilane gas in ambient hydrogen were evaluated to show their different gas flow motions in a slim vertical cold wall chemical vapor deposition reactor for the Minimal Fab system. This evaluation was performed for improving and controlling the film qualities and the productivities, using two quartz crystal microbalances (QCM) installed at the </span><span style="font-family:Verdana;">inlet and exhaust of the chamber by taking into account that the QCM frequency corresponds to the real time changes in the gas properties.</span><span style="font-family:Verdana;"> Typically, the time period approaching from the inlet to the exhaust was shorter for the trichlorosilane gas than that for the dichlorosilane gas. The trichlorosilane gas was shown to move like plug flow, while the dichlorosilane gas seemed to be well mixed in the entire chamber.
基金support of the Earmarked Fund for CARS-10-Sweetpotato,China,the National Foundation of Nature and Science of China(Nos.32102083 and M2242001)the Natural Science Foundation of Shandong Province of China(Nos.ZR2021QC204 and ZR2022MC196).
文摘Citronellol is a kind of terpene produced by plants in response to external stress;thus can be used as a gas biomarker to detect black spot Ceratocystis fimbriata infection in sweetpotato.However,many contemporary analytical methods,exemplified by gas chromatography-mass spectrometry,are technically demanding,time-consuming,and require complex sample preparation procedures.In this study,a quartz crystal microbalance(QCM)-based gas sensor fabricated via a surface molecular imprinting technique was modified with a Co/Zn-ZIF@MIP composite,in which cobalt-zinc bimetallic ZIF(Co/Zn-ZIF)served as the support material.A linear relationship was observed between the frequency shift and citronellol concentrations ranging from 0.88 to 22 mg/L,with a sensitivity of−6.08 Hz/(mg·L)and a limit of detection(LOD)of 1.35 mg/L.This result indicated that this sensor has excellent selectivity for citronellol and demonstrates high repeatability,as evidenced by R^(2)value of 0.97.In evaluations with real samples,the sensor reliably identified citronellol among the complex volatile organic compounds(VOCs)emitted from black spot-infected sweetpotato,indicating a high level of selectivity.Our research achieved the rapid characterization of sweetpotato black spot disease within 4 min and provided new insights into the development of QCM-based gas sensors for the rapid assessment of agricultural product quality and safety.
基金Supported by the National Natural Science Foundation of China(No.41776177)the Qingdao Marine Science and Technology Pilot National Laboratory Fund(Nos.2016ASKJ14,QNLM2016ORP0403)。
文摘Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus.The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins,of which Mytilus edulis foot protein-1(Mefp-1)has been identified as the most abundant protein.It has been found that lipids are involved in the mussel adhesion process and can facilitate Mefp-1adhesion.In this research,the adhesion behavior of Mefp-1 on various substrate surfaces under the effect of typical seawater cations with or without the presence of lipid were investigated using a quartz crystal microbalance with dissipation(QCM-D).Results indicate that the presence of cations Ca^(2+),Mg^(2+),Na^(+),and K^(+)leads to varying degrees of reduction in the adhesion performance of Mefp-1 on different substrates.The degree of this reduction,however,was much alleviated in the presence of palmitic acid,which is involved in the mussel adhesion process.Therefore,the involvement of palmitic acid is advantageous for mussel protein adhesion to the substrate surface in the marine environment.This study illustrated the significant contribution of palmitic acid to mussel adhesion,which can help to better understand biofouling mechanisms and develop biomimetic adhesive materials.
基金Supported by National Natural Science Foundation of China,No.81371885
文摘A biosensor is an analytical device used for the detection of analytes,which combines a biological component with a physicochemical detector.Recently,an increasing number of biosensors have been used in clinical research,for example,the blood glucose biosensor.This review focuses on the current state of biosensor research with respect to efficient,specific and rapid detection of hepatitis B virus(HBV).The biosensors developed based on different techniques,including optical methods(e.g.,surface plasmon resonance),acoustic wave technologies(e.g.,quartz crystal microbalance),electrochemistry(amperometry,voltammetry and impedance) and novel nanotechnology,are also discussed.
基金financially supported by the National Natural Science Foundation of China(No.U19A2070)the National Science Funds for Excellent Young Scholars of China(No.61822106)the National Science Funds for Creative Research Groups of China(No.61421002)。
文摘As humidity is one of the most widely demanded environmental parameters,the precision of its detection is significant.An advanced humidity sensor will improve the validity of the humidity monitoring system.In this study,a facile chemical layer-by-layer self-assembly(CLS)method was developed for fabricating graphene oxide(GO)/polyethyleneimine(PEI)multilayer films.Owing to the chemical bonding between the PEI and GO,and the intrinsic stickiness of the PEI,layered films with different numbers of layers were successfully prepared using the CLS method and confirmed through ultraviolet-visible(UV-Vis)spectroscopy and the mass loading of quartz crystal microbalance(QCM).Morphological measurements revealed that the roughness and thickness of the films increased exponentially with the number of bilayers.The GO/PEI films were deposited on QCM electrodes using the CLS method to produce the humidity sensors.The humidity measurement results showed a high sensitivity(37.84 Hz/%RH)and rapid response/recovery(<5 s/8 s)of the optimal sensor,which was superior to that of recently developed QCM sensors.
基金Project supported by the National High Technology Research and Developmem Program of China ~Grant No. 2013AA030901）.
文摘We present a new polymer quartz piezoelectric crystal sensor that takes a quartz piezoelectric crystal as the basal material and a nanometer nonmetallic polymer thin film as the surface coating based on the principle of quartz crystal microbalance(QCM). The new sensor can be used to detect the characteristic materials of a volatile liquid. A mechanical model of the new sensor was built, whose structure was a thin circle plate composing of polytef/quartz piezoelectric/polytef. The mechanical model had a diameter of 8 mm and a thickness of 170 μm. The vibration state of the model was simulated by software ANSYS after the physical parameters and the boundary condition of the new sensor were set. According to the results of experiments, we set up a frequency range from 9.995850 MHz to 9.997225 MHz, 17 kinds of frequencies and modes of vibration were obtained within this range. We found a special frequency fspof 9.996358 MHz. When the resonant frequency of the new sensor's mechanical model reached the special frequency, a special phenomenon occurred. In this case, the amplitude of the center point O on the mechanical model reached the maximum value. At the same time, the minimum absolute difference between the simulated frequency based on the ANSYS software and the experimental measured stable frequency was reached. The research showed that the design of the new polymer quartz piezoelectric crystal sensor perfectly conforms to the principle of QCM. A special frequency value fspwas found and subsequently became one of the most important parameters in the new sensor design.
基金supported by National Natural Science Foundation of China(No.61527818)the financial support from Zhejiang Sci-Tech University(ZSTU,No.19012393-Y)。
文摘This work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance(QCM)to detect benzene,toluene,ethylbenzene,and xylene(BTEX)vapor.Notably,sensing results toward toluene vapor in different relative humidities indicates that this superhydrophobic polymer has favorable toluene/water selective detection performance.Besides,the limit of detection toward toluene is lower than 1 ppm.
基金the National Science Foundation for Excellent Young Scholars of China(21922815)the National Natural Science Foundation of China(22179139)+2 种基金the National Key Research and Development Program of China(2020YFB1505800)the Youth Innovation Promotion Association of CAS(2019178)the“Transformational Technologies for Clean Energy and Demonstration”Strategic Priority Research Program of the CAS(XDA21000000)。
文摘N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to characterize.Limited understanding of doping-derived EDL structure hinders insight into the structure-performance relations and the rational design of high-performance materials.Thus,we analyzed the mass and chemical composition variation of EDL within electrochemical operation by electrochemical quartz crystal microbalance,in-situ X-ray photoelectron spectroscopy,and time-offlight secondary ion mass spectrometry.We found that N-doping triggers specifically adsorbed propylene carbonate solvent in the inner Helmholtz plane(IHP),which prevents ion rearrangement and enhances the migration of cations.However,this specific adsorption accelerated solvent decomposition,rendering rapid performance degradation in practical devices.This work reveals that the surface chemistry of electrodes can cause specific adsorption of solvents and change the EDL structure,which complements the classical EDL theory and provide guidance for practical applications.
基金Project supported by the National Natural Science Foundation of China(Grant No.51905032)the National Key Research and Development Program of China(Grant No.2018YFC0810500)the Fundamental Research Funds for the Central Universities,China(Grant No.FRF-TP-18-012A2).
文摘The influence rules of square micro-pillar array porosity on the liquid motion characteristics of the near-surface layer are investigated by quartz crystal microbalance(QCM).QCM is a powerful and promising technique in studying the interfacial behavior,which exhibits great advantages in investigating the effects of surface microstructure,roughness,and array.In our experiments,three different arrays with the same height of about 280 nm and center distance of 200μm,but different diameters of about 78μm,139μm,and 179μm are investigated.The results indicate that when the surface array has a large porosity,its influence on the liquid motion of the near surface layer is slight,thus resulting in a small increase of half-bandwidth variation due to the additional friction energy dissipation.When the surface array has a small porosity,the array tends to make the liquid film trapped in the array oscillating with the substrate,then there may be a layer of liquid film behaving like rigid film,and it also will make the liquid motion near the array layer more complicated.Thus for the#3 surface with a small porosity,both the absolute values of frequency shift|Δf3|and half-bandwidth variationΔΓ3 increase obviously.The experimental results show good consistence with the theoretical model of Daikhin and Urbakh.This study sheds light on understanding the influence mechanism of surface array porosity on the liquid motion of near-surface layer.
基金supported by the National Natural Science Foundation of China(Nos.51378493,and 51178450)
文摘Finished drinking water usually contains some residual aluminum.The deposition of residual aluminum in distribution systems and potential release back to the drinking water could significantly influence the water quality at consumer taps.A preliminary analysis of aluminum content in cast iron pipe corrosion scales and loose deposits demonstrated that aluminum deposition on distribution pipe surfaces could be excessive for water treated by aluminum coagulants including polyaluminum chloride（PACl）.In this work,the deposition features of different aluminum species in PACl were investigated by simulated coil-pipe test,batch reactor test and quartz crystal microbalance with dissipation monitoring.The deposition amount of non-polymeric aluminum species was the least,and its deposition layer was soft and hydrated,which indicated the possible formation of amorphous Al（OH）3.Al（13） had the highest deposition tendency,and the deposition layer was rigid and much less hydrated,which indicated that the deposited aluminum might possess regular structure and self-aggregation of Al（13）could be the main deposition mechanism.While for Al（30）,its deposition was relatively slower and deposited aluminum amount was relatively less compared with Al（13）.However,the total deposited mass of Al（30） was much higher than that of Al（13）,which was attributed to the deposition of particulate aluminum matters with much higher hydration state.Compared with stationary condition,stirring could significantly enhance the deposition process,while the effect of pH on deposition was relatively weak in the near neutral range of 6.7 to 8.7.
基金Supported by the National High-Tech Research and Development Program of China(No.2007AA10Z301) the National Natural Science Foundation of China for Distinguished Young Scholars(No.50625309)
文摘Porphyrin-filled nanofibrous membranes were facilely prepared by electrospinning of the mixtures of poly（acrylonitrile-co-acrylic acid）（PANCAA） and porphyrins. 5,10,15,20-Tetraphenylporphyrin（TPP） and its metal-loderivatives（ZnTPP and CuTPP） were studied as filling mediators for the immobilization of redox enzyme. Results indicate that the introduction of TPP, ZnTPP and CuTPP improves the retention activity of the immobilized catalase. Among these three porphyrins, the ZnTPP-filled PANCAA nanofibrous membrane exhibits an activity retention of 93%, which is an exciting improvement. This improvement is attributed to both the strong catalase-porphyrin affinity and the possible facilitated electron transfer induced by the porphyrin as evidenced by quartz crystal microbalance （QCM） and fluorescence spectroscopy studies.
文摘In this study, we have used a direct immunoassay where the simple binding between antigen and an antibody is detected. Immunoassays were performed in a drop system, monitoring the frequency decrease of the quartz-crystal microbalance device because of mass increasing during immunoreaction. The QCM sensor was coated on both sides by gold electrodes, only one side of the crystal (liquid side) was in contact with the solution;the other side (contact side) was always dry. We tested a piezoelectric immunosensor for aflatoxin B1 (AFLA-B1) mycotoxin detection through the immo- bilization of DSP-anti-AFLAB1 antibody (AFLA-B1-Ab anti AFLAB1) on gold-coated quartz crystals (AT-cut/5 MHz). The DSP (3,3’-Dithiodipropionic-acid-di-N-hydroxysuccinimide ester) was used for the covalent attachment of the proteins. The piezoelectric crystal electrodes were pretreated by DSP for 15 min, rinsed with water and dried in a gentle flow of nitrogen gas. Then the DSP-coated crystals were installed in a sample holder and exposed to the anti-AFLAB1 antibody and to the AFLA-BI. Frequency and resistance shifts (Δf and ΔR) were measured simultaneously. Δf versus AFLA-BI concentrations in the range of 0.5 - 10 ppb exhibited a perfect linear correlation with a coefficient of above 0.998.
基金supported by the Shanghai Natural Science Foundation(No.21ZR1427500)the Agricultural Project of Shanghai Science and Technology Innovation Action Plan(No.19391901600).
文摘To achieve real-time monitoring of humidity in various applications,we prepared facile and ultra-thin CoAl layered double hydroxide(CoAl LDH)nanosheets to engineer quartz crystal microbalances(QCM).The characteristics of CoAl LDH were investigated by transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectric spectroscopy(XPS),Brunauer–Emmett–Telle(BET),atomic force microscopy(AFM)and zeta potential.Due to their large specific surface area and abundant hydroxyl groups,CoAl LDH nanosheets exhibit good humidity sensing performance.In a range of 11.3%and 97.6%relative humidity(RH),the sensor behaved an ultrahigh sensitivity(127.8 Hz/%RH),fast response(9.1 s)and recovery time(3.1 s),low hysteresis(3.1%RH),good linearity(R^(2)=0.9993),stability and selectivity.Besides,the sensor can recover the initial response frequency after being wetted by deionized water,revealing superior self-recovery ability under high humidity.Based on in-situ Fourier transform infrared spectroscopy(FT-IR),the adsorption mechanism of CoAl LDH toward water molecules was explored.The QCM sensor can distinguish different respiratory states of people and wetting degree of fingers,as well as monitor the humidity in vegetable packaging,suggesting excellent properties and a promising application in humidity sensing.
基金supported by the National Natural Science Foundation of China,No. 30973058,81171694Jiangsu Province Natural Science Foundation,No. BE2010743+2 种基金Jiangsu Graduate Student Innovation Project,No.CXZZ11_0721the Program for Development of Innovative Research Team in the First Affiliated Hospital of Nanjing Medical University,No. IRT-015a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The fast and accurate identification of nerve tracts is critical for successful nerve anastomosis. Taking advantage of differences in acetylcholinesterase content between the spinal ventral and dorsal roots, we developed a novel quartz crystal microbalance method to distinguish between these nerves based on acetylcholinesterase antibody reactivity. The acetylcholinesterase antibody was immobilized on the electrode surface of a quartz crystal microbalance and reacted with the acetylcholinesterase in sample solution. The formed antigen and antibody complexes added to the mass of the electrode inducing a change in frequency of the electrode. The spinal ventral and dorsal roots were distinguished by the change in frequency. The ventral and dorsal roots were cut into 1 to 2-mm long segments and then soaked in 250 pL PBS. Acetylcholinesterase antibody was immobilized on the quartz crystal microbalance gold electrode surface. The results revealed that in 10 minutes, both spinal ventral and dorsal roots induced a frequency change; however, the frequency change induced by the ventral roots was notably higher than that induced by the dorsal roots. No change was induced by bovine serum albumin or PBS. These results clearly demonstrate that a quartz crystal microbalance sensor can be used as a rapid, highly sensitive and accurate detection tool for the quick identification of spinal nerve roots intraoperatively.
基金the PetroChina for its financial support (Grant number: 2011B-2503-2)
文摘On the basis of thin film lubrication theory, the influence of fluid film(disordered film), ordered film and adsorbed film on tribological behavior of lubricating oil in thin-film lubrication(TFL) regime was studied. The μ-L(friction coefficient versus load) curves of different oil viscosity and additive dosage were obtained by a high frequency reciprocating test rig and the adsorption capacity of additive on steel surface were measured by QCM-D. Based on the Stribeck curve and thin film lubrication theory model, some conclusions can be drawn up, namely:(1) The μ-L curves and the parameters of L0 and μ0, obtained from the high frequency reciprocating test rig with ball-disc contact, can be used to study tribological behaviors of lubricating oil under TFL conditions.(2) In comparison with the high viscosity base fluid, the lower one can enter into TFL regime under lower load and keeps a lower friction coefficient in TFL regime.(3) The polar molecules in additive formulation produce ordered adsorbed layer on steel surface to reduce friction coefficient. And in TFL regime, the molecule's polarity, layer thickness and saturation degree on steel surface probably can influence lubricant's tribological behaviors between the moving interfaces. Moreover, the further study would be focused on the competitive adsorption of different additives, the formation of dual- and/or tri-molecular adsorption layers, and other aspects.
文摘Using the langasite crystal microbalance (LCM), the trends in film thickness produced by means of the chemical vapor deposition using trichlorosilane gas, monomethylsilane gas and their mixed gas were observed at 600?C and evaluated by comparison with the information from a transmission electron microscope (TEM). The crystalline silicon film thickness from trichlorosilane gas was comparable to that of an amorphous silicon carbide film from monomethylsilane gas. The film obtained from the gas mixture was amorphous and was the thinnest in this study. Because the thickness trend obtained by the LCM agreed with that by the TEM, the LCM is shown to be a convenient evaluation tool for the behavior of various film deposition.
基金Funded by the National Natural Science Foundation of China(No.31570958)Science and Technology Support Program of Sichuan Province(No.2016SZ0007)
文摘The effects of surface adsorption of bovine serum albumin(BSA)and human gamma-globulin(HGG)on the tribological performance of a DLC film were investigated using a quartz crystal microbalance with dissipation(QCM-D),a ball-on-disk reciprocating tribometer,and a three-electrode electrochemical cell.The results showed that the wear depth in the BSA solution was higher than that in the HGG solution.In the HGG solution,the HGG-adsorbed layer could act as a lubricating layer and protect the DLC film from wear.The wear volume of DLC film in BSA and HGG mixture solution was higher than that in single HGG solution.This may be because the BSA molecules inhibit the formation of HGG adsorbed layer during sliding.
基金Supported by the Jiangsu High-tech Project(BG2006038)
文摘A quartz crystal microbalance （QCM） is used to determine the phase equilibrium of paclitaxel-carbon dioxide system in the pressure range of 0-11 MPa and at temperatures of 35 °C,40 °C and 45 °C.The experimental results indicated that gaseous CO2 could be absorbed poorly into paclitaxel.The swelling of paclitaxel film in CO2 was observed before paclitaxel dissolved into supercritical carbon dioxide （ScCO2） with the increase of pressure.It was found that ScCO2 was not a good solvent for paclitaxel.The mole fraction of paclitaxel in ScCO2 was in the range of （4.5×10-9）-（7.8×10-9） under all our experimental conditions.Therefore,a much higher pressure than the CO2 supercritical point and/or a cosolvent must be used in any processes wherever paclitaxel dissolution in ScCO2 is required.
文摘A new method of determination of trace CNin water was proposed.A thin film of AgS was electrochemically deposited on both sides of a silver coated piezoelectric crystal.The AgS Ag films can react with CN selectively,which causes the frequency shifts of the piezoelectric crystal.The frequency shifts are proportional to the concentration of CN in the range of 106~10'g/L.XPS experiments indicated the sensing film was AgiS Ag.A coordination complex Ag-CNwas formed when AgiS Ag film contacted with solution containing CNion.A response mechanism was proposed based on the XPS data.
