This paper reports an electrochemical microfluidic paper-based analytical device(EμPAD)for glucose detection,featuring a highly sensitive working electrode(WE)decorated with zinc oxide nanowires(ZnO NWs).In addition ...This paper reports an electrochemical microfluidic paper-based analytical device(EμPAD)for glucose detection,featuring a highly sensitive working electrode(WE)decorated with zinc oxide nanowires(ZnO NWs).In addition to the common features ofμPADs,such as their low costs,high portability/disposability,and ease of operation,the reported EμPAD has three further advantages.(i)It provides higher sensitivity and a lower limit of detection(LOD)than previously reportedμPADs because of the high surface-to-volume ratio and high enzyme-capturing efficiency of the ZnO NWs.(ii)It does not need any light-sensitive electron mediator(as is usually required in enzymatic glucose sensing),which leads to enhanced biosensing stability.(iii)The ZnO NWs are directly synthesized on the paper substrate via low-temperature hydrothermal growth,representing a simple,low-cost,consistent,and mass-producible process.To achieve superior analytical performance,the on-chip stored enzyme(glucose oxidase)dose and the assay incubation time are tuned.More importantly,the critical design parameters of the EμPAD,including the WE area and the ZnO-NW growth level,are adjusted to yield tunable ranges for the assay sensitivity and LOD.The highest sensitivity that we have achieved is 8.24μA·mM^(−1)·cm^(−2),with a corresponding LOD of 59.5μM.By choosing the right combination of design parameters,we constructed EμPADs that cover the range of clinically relevant glucose concentrations(0−15 mM)and fully calibrated these devices using spiked phosphate-buffered saline and human serum.We believe that the reported approach for integrating ZnO NWs on EμPADs could be well utilized in many other designs of EμPADs and provides a facile and inexpensive paradigm for further enhancing the device performance.展开更多
Single zinc oxide nanowires(ZnO NWs)are promising for nanogenerators because of their excellent semiconducting and piezoelectric properties,but characterizing the latter efficiently is challenging.As reported here,an ...Single zinc oxide nanowires(ZnO NWs)are promising for nanogenerators because of their excellent semiconducting and piezoelectric properties,but characterizing the latter efficiently is challenging.As reported here,an electrical breakdown strategy was used to construct single ZnO NWs with a specific length.With the high operability of a nanomanipulator in a scanning electron microscope,ZnO-NW-based twoprobe and three-probe structures were constructed for fabricating AC/DC nanogenerators,respectively.For a ZnO NW,an AC output of between−15.31 mV and 5.82 mV was achieved,while for a DC nanogenerator,an output of24.3 mV was realized.Also,the three-probe structure’s output method was changed to verify the distribution of piezoelectric charges when a single ZnO NW is bent by a probe,and DC outputs of different amplitudes were achieved.This study provides a low-cost,highly convenient,and operational method for studying the AC/DC output characteristics of single NWs,which is beneficial for the further development of nanogenerators.展开更多
Poly(glycidyl methacrylates)(PGMA) was grafted from zinc oxide(ZnO) nanowires via surface-initiated atom transfer radical polymerization(SI-ATRP) technique.Firstly,the ZnO nanowires were synthesized by the one-pot hyd...Poly(glycidyl methacrylates)(PGMA) was grafted from zinc oxide(ZnO) nanowires via surface-initiated atom transfer radical polymerization(SI-ATRP) technique.Firstly,the ZnO nanowires were synthesized by the one-pot hydrothermal technique.Subsequently,the ZnO was functionalized with 3-aminopropyl triethoxysilane,which was converted to macroinitiator by the esterification of them with 2-bromopropionyl bromide.PGMA grafted ZnO nanowires(PGMA-ZnO) were then synthesized in an ATRP of the GMA with CuCl/2,2`-bipyridine as the catalyst system.Kinetics studies revealed an approximate linear increase in weight of polymer with reaction time,indicating that the polymerization process owned some "living" character.The structure and composition of PGMA-ZnO were characterized with scanning electron microscope(SEM),energy-dispersive X-ray(EDX) spectrometer,fourier transform infrared spectroscopy(FT-IR) and thermogravimetric analysis(TGA).展开更多
Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is bas...Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is based on short oligonucleotide DNA probe immobilized onto zinc oxide nanowires (ZnONWs) chemically synthesized onto gold electrode via hydrothermal technique. The morphology studies of the ZnONWs, performed by field emission scanning electron microscopy (FESEM), showed that the ZnO nanowires are uniform, highly dense and oriented perpendicularly to the substrate. Recognition event between the DNA probe and the target was investigated by differential pulse voltammetry (DPV) in 0.1 M acetate buffer solution (ABS), pH 7.00;as a result of the hybridization, an oxidation signal was observed at +0.8 V. The influences of pH, target concentration, and non-complimentary DNA on biosensor performance were examined. The proposed DNA biosensor has the ability to detect the target sequence in the range of concentration between 10.0 and 100.0 μM with a detection limit of 3.32 μM. The experimental results demonstrated that the prepared ZnONWs/Au electrodes are suitable platform for the immobilization of DNA.展开更多
This paper reports fast and efficient chemical decontamination of water within a tree-branched centimeter-scale microfluidic reactor.The microreactor integrates Zinc oxide nanowires(ZnO NWs)in situ grown acting as an ...This paper reports fast and efficient chemical decontamination of water within a tree-branched centimeter-scale microfluidic reactor.The microreactor integrates Zinc oxide nanowires(ZnO NWs)in situ grown acting as an efficient photocatalytic nanomaterial layer.Direct growth of ZnO NWs within the microfluidic chamber brings this photocatalytic medium at the very close vicinity of the water flow path,hence minimizing the required interaction time to produce efficient purification performance.We demonstrate a degradation efficiency of 95%in o5 s of residence time in one-pass only.According to our estimates,it becomes attainable using microfluidic reactors to produce decontamination of merely 1 l of water per day,typical of the human daily drinking water needs.To conduct our experiments,we have chosen a laboratory-scale case study as a seed for addressing the health concern of water contamination by volatile organic compounds(VOCs),which remain difficult to remove using alternative decontamination techniques,especially those involving water evaporation.The contaminated water sample contains mixture of five pollutants:Benzene;Toluene;Ethylbenzene;m–p Xylenes;and o-Xylene(BTEX)diluted in water at 10 p.p.m.concentration of each.Degradation was analytically monitored in a selective manner until it falls below 1 p.p.m.for each of the five pollutants,corresponding to the maximum contaminant level(MCL)established by the US Environmental Protection Agency(EPA).We also report on a preliminary study,investigating the nature of the chemical by-products after the photocatalytic VOCs degradation process.展开更多
CO oxidation is of great importance in both fundamental study and industrial application.Supported noble metal catalysts are highly active for CO oxidation but suffer from the scarcity and high cost.Single-atom cataly...CO oxidation is of great importance in both fundamental study and industrial application.Supported noble metal catalysts are highly active for CO oxidation but suffer from the scarcity and high cost.Single-atom catalysts(SACs)can maximize the metal atom efficiency.Herein,ZnO nanowire(ZnO-nw)supported Rh,Au,and Pt SACs were successfully developed to investigate their CO oxidation performance.Interestingly,it was found that Rh1/ZnO-nw showed much higher activity than the other noble metals which are usually regarded as good candidates for CO oxidation.In addition,the Rh SAC possessed high stability in high-temperature CO oxidation under simulated conditions in the presence of water and hydrocarbons.The high activity and stability make Rh1/ZnO-nw promising for practical applications,especially in the automotive exhaust emission control.Theoretical calculations indicate that the CO oxidation proceeds via the Mars-van Krevelen mechanism and the lowest barrier for the rate-limiting O2 dissociation at a surface oxygen vacancy site is a key factor in determining the observed highest activity of Rh1/ZnO-nw amongst the studied SACs.展开更多
Pencil-like zinc oxide（ZnO） nanowire was synthesized on Si（111） substrate through a simple vapor phase method using a mixture of zinc oxide and graphite as the source material. The source inside a quartz tube crea...Pencil-like zinc oxide（ZnO） nanowire was synthesized on Si（111） substrate through a simple vapor phase method using a mixture of zinc oxide and graphite as the source material. The source inside a quartz tube created a Zn-rich vapor that facilitated the formation and growth of ZnO nanowires. Field emission scanning electron microscopic studies indicated that pencil-like ZnO nanowires had a size of the range from 50 to 150 nm in diameter and several microns in length. X-ray diffraction was used to investigate the crystal structure of ZnO nanowires. Raman scattering and photoluminescence were applied to characterize the optical properties of the pencils. The growth mechanism of the nanopencils was discussed based on the growth conditions.展开更多
文摘This paper reports an electrochemical microfluidic paper-based analytical device(EμPAD)for glucose detection,featuring a highly sensitive working electrode(WE)decorated with zinc oxide nanowires(ZnO NWs).In addition to the common features ofμPADs,such as their low costs,high portability/disposability,and ease of operation,the reported EμPAD has three further advantages.(i)It provides higher sensitivity and a lower limit of detection(LOD)than previously reportedμPADs because of the high surface-to-volume ratio and high enzyme-capturing efficiency of the ZnO NWs.(ii)It does not need any light-sensitive electron mediator(as is usually required in enzymatic glucose sensing),which leads to enhanced biosensing stability.(iii)The ZnO NWs are directly synthesized on the paper substrate via low-temperature hydrothermal growth,representing a simple,low-cost,consistent,and mass-producible process.To achieve superior analytical performance,the on-chip stored enzyme(glucose oxidase)dose and the assay incubation time are tuned.More importantly,the critical design parameters of the EμPAD,including the WE area and the ZnO-NW growth level,are adjusted to yield tunable ranges for the assay sensitivity and LOD.The highest sensitivity that we have achieved is 8.24μA·mM^(−1)·cm^(−2),with a corresponding LOD of 59.5μM.By choosing the right combination of design parameters,we constructed EμPADs that cover the range of clinically relevant glucose concentrations(0−15 mM)and fully calibrated these devices using spiked phosphate-buffered saline and human serum.We believe that the reported approach for integrating ZnO NWs on EμPADs could be well utilized in many other designs of EμPADs and provides a facile and inexpensive paradigm for further enhancing the device performance.
基金supported by the Research Fund Program of the Guangdong Provincial Key Laboratory of Fuel Cell Technology (Grant No.FC202204).
文摘Single zinc oxide nanowires(ZnO NWs)are promising for nanogenerators because of their excellent semiconducting and piezoelectric properties,but characterizing the latter efficiently is challenging.As reported here,an electrical breakdown strategy was used to construct single ZnO NWs with a specific length.With the high operability of a nanomanipulator in a scanning electron microscope,ZnO-NW-based twoprobe and three-probe structures were constructed for fabricating AC/DC nanogenerators,respectively.For a ZnO NW,an AC output of between−15.31 mV and 5.82 mV was achieved,while for a DC nanogenerator,an output of24.3 mV was realized.Also,the three-probe structure’s output method was changed to verify the distribution of piezoelectric charges when a single ZnO NW is bent by a probe,and DC outputs of different amplitudes were achieved.This study provides a low-cost,highly convenient,and operational method for studying the AC/DC output characteristics of single NWs,which is beneficial for the further development of nanogenerators.
基金the National Natural Science Foundation of China (No.50730008 and 30772434)Shanghai Science & Technology Committee (No.09JC1407400 and 1052nm02000)
文摘Poly(glycidyl methacrylates)(PGMA) was grafted from zinc oxide(ZnO) nanowires via surface-initiated atom transfer radical polymerization(SI-ATRP) technique.Firstly,the ZnO nanowires were synthesized by the one-pot hydrothermal technique.Subsequently,the ZnO was functionalized with 3-aminopropyl triethoxysilane,which was converted to macroinitiator by the esterification of them with 2-bromopropionyl bromide.PGMA grafted ZnO nanowires(PGMA-ZnO) were then synthesized in an ATRP of the GMA with CuCl/2,2`-bipyridine as the catalyst system.Kinetics studies revealed an approximate linear increase in weight of polymer with reaction time,indicating that the polymerization process owned some "living" character.The structure and composition of PGMA-ZnO were characterized with scanning electron microscope(SEM),energy-dispersive X-ray(EDX) spectrometer,fourier transform infrared spectroscopy(FT-IR) and thermogravimetric analysis(TGA).
基金the Ministry of Higher Education Malaysia for the ERGS grant(600/RMI/st/ERGS/5/3/fst12/2011)Universiti Teknologi MARA for financial support via postgraduate teaching assistant scheme(UPTA)to Nur Azimah Mansor for conducting this research.
文摘Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is based on short oligonucleotide DNA probe immobilized onto zinc oxide nanowires (ZnONWs) chemically synthesized onto gold electrode via hydrothermal technique. The morphology studies of the ZnONWs, performed by field emission scanning electron microscopy (FESEM), showed that the ZnO nanowires are uniform, highly dense and oriented perpendicularly to the substrate. Recognition event between the DNA probe and the target was investigated by differential pulse voltammetry (DPV) in 0.1 M acetate buffer solution (ABS), pH 7.00;as a result of the hybridization, an oxidation signal was observed at +0.8 V. The influences of pH, target concentration, and non-complimentary DNA on biosensor performance were examined. The proposed DNA biosensor has the ability to detect the target sequence in the range of concentration between 10.0 and 100.0 μM with a detection limit of 3.32 μM. The experimental results demonstrated that the prepared ZnONWs/Au electrodes are suitable platform for the immobilization of DNA.
基金This work has received funding from the ANR EquipEx SENSECITY projectthe FUI 18 MIMESYS funded by Region Ile-de-France and the European Union’s H2020 Programme for research,technological development and demonstration under grant agreement No 644852.
文摘This paper reports fast and efficient chemical decontamination of water within a tree-branched centimeter-scale microfluidic reactor.The microreactor integrates Zinc oxide nanowires(ZnO NWs)in situ grown acting as an efficient photocatalytic nanomaterial layer.Direct growth of ZnO NWs within the microfluidic chamber brings this photocatalytic medium at the very close vicinity of the water flow path,hence minimizing the required interaction time to produce efficient purification performance.We demonstrate a degradation efficiency of 95%in o5 s of residence time in one-pass only.According to our estimates,it becomes attainable using microfluidic reactors to produce decontamination of merely 1 l of water per day,typical of the human daily drinking water needs.To conduct our experiments,we have chosen a laboratory-scale case study as a seed for addressing the health concern of water contamination by volatile organic compounds(VOCs),which remain difficult to remove using alternative decontamination techniques,especially those involving water evaporation.The contaminated water sample contains mixture of five pollutants:Benzene;Toluene;Ethylbenzene;m–p Xylenes;and o-Xylene(BTEX)diluted in water at 10 p.p.m.concentration of each.Degradation was analytically monitored in a selective manner until it falls below 1 p.p.m.for each of the five pollutants,corresponding to the maximum contaminant level(MCL)established by the US Environmental Protection Agency(EPA).We also report on a preliminary study,investigating the nature of the chemical by-products after the photocatalytic VOCs degradation process.
基金supported by the National Natural Science Foundation of China(21606222,21776270)Liaoning Revitalization Talents Program(XLYC1807068)+1 种基金DNL Cooperation Fund,CAS(180403)US National Science Foundation under CHE-1465057~~
文摘CO oxidation is of great importance in both fundamental study and industrial application.Supported noble metal catalysts are highly active for CO oxidation but suffer from the scarcity and high cost.Single-atom catalysts(SACs)can maximize the metal atom efficiency.Herein,ZnO nanowire(ZnO-nw)supported Rh,Au,and Pt SACs were successfully developed to investigate their CO oxidation performance.Interestingly,it was found that Rh1/ZnO-nw showed much higher activity than the other noble metals which are usually regarded as good candidates for CO oxidation.In addition,the Rh SAC possessed high stability in high-temperature CO oxidation under simulated conditions in the presence of water and hydrocarbons.The high activity and stability make Rh1/ZnO-nw promising for practical applications,especially in the automotive exhaust emission control.Theoretical calculations indicate that the CO oxidation proceeds via the Mars-van Krevelen mechanism and the lowest barrier for the rate-limiting O2 dissociation at a surface oxygen vacancy site is a key factor in determining the observed highest activity of Rh1/ZnO-nw amongst the studied SACs.
基金supported by the Universiti Putra Malaysia through Grant Nos
文摘Pencil-like zinc oxide（ZnO） nanowire was synthesized on Si（111） substrate through a simple vapor phase method using a mixture of zinc oxide and graphite as the source material. The source inside a quartz tube created a Zn-rich vapor that facilitated the formation and growth of ZnO nanowires. Field emission scanning electron microscopic studies indicated that pencil-like ZnO nanowires had a size of the range from 50 to 150 nm in diameter and several microns in length. X-ray diffraction was used to investigate the crystal structure of ZnO nanowires. Raman scattering and photoluminescence were applied to characterize the optical properties of the pencils. The growth mechanism of the nanopencils was discussed based on the growth conditions.
