This paper describes severe plastic deformation(SPD)procedures,which are utilized to form an ultrafine-grained structure in metallic biomaterials.During the SPD process,a solid material sample is subjected to very hig...This paper describes severe plastic deformation(SPD)procedures,which are utilized to form an ultrafine-grained structure in metallic biomaterials.During the SPD process,a solid material sample is subjected to very high loads without a significant change in sample dimensions.In the present work,the high-pressure torsion(HPT)process,as one of the SPD techniques,which achieves a high degree of deformation and ensures refinement of the microstructure,will be discussed in more detail.Considering that grain size control is accepted as a method to obtain materials with desired characteristics,an overview of the properties of ultrafine-grained titanium-based biomaterials to be used in medicine is given.Moreover,particular attention is dedicated to the influences of HPT process parameters,primarily hydrostatic pressure,and number of revolutions during torsion,on the grain size and physical and mechanical characteristics(modulus of elasticity,microhardness,and tensile properties),corrosion resistance,and biocompatibility of the titanium-based biomaterials.A review of the literature indicates that titanium-based materials obtained by the SPD process show improved mechanical and physical properties without losing biocompatibility and corrosion resistance,which suggests that these methods of obtaining implants are something that should be further developed in the future.展开更多
Efficient and innovative nano-catalytic oxidation technologies offer a breakthrough in removing emerging contaminants(ECs)from water,surpassing the limitations of traditional methods.Environmental functional materials...Efficient and innovative nano-catalytic oxidation technologies offer a breakthrough in removing emerging contaminants(ECs)from water,surpassing the limitations of traditional methods.Environmental functional materials(EFMs),particularly high-end oxidation systems using eco-friendly nanomaterials,show promise for absorbing and degrading ECs.This literature review presents a comprehensive analysis of diverse traditional restoration techniques-biological,physical,and chemical-assessing their respective applications and limitations in pesticide-contaminated water purification.Through meticulous comparison,we unequivocally advocate for the imperative integration of environmentally benign nanomaterials,notably titanium-based variants,in forthcoming methodologies.Our in-depth exploration scrutinizes the catalytic efficacy,underlying mechanisms,and adaptability of pioneering titanium-based nanomaterials across a spectrum of environmental contexts.Additionally,strategic recommendations are furnished to surmount challenges and propel the frontiers of implementing eco-friendly nanomaterials in practical water treatment scenarios.展开更多
The mechanical behaviour of Titanium-based Fiber Metal Laminates(FMLs)reinforced with Kevlar,Jute and the novel woven(Kevlar+Jute)fiber mat were evaluated through tensile,flexural,Charpy impact,and drop-weight tests.T...The mechanical behaviour of Titanium-based Fiber Metal Laminates(FMLs)reinforced with Kevlar,Jute and the novel woven(Kevlar+Jute)fiber mat were evaluated through tensile,flexural,Charpy impact,and drop-weight tests.The FMLs were fabricated with various stacking configurations(2/1,3/2,4/3,and 5/4)to examine their influence on mechanical properties.Kevlar-reinforced laminates consistently demonstrated superior tensile and flexural strengths,with the highest tensile strength of 772 MPa observed in the 3/2 configuration,attributed to Kevlar's excellent load-bearing capacity.Jute-reinforced laminates exhibited lower performance due to poor bonding and early delamination,while the FMLs reinforced with woven(Kevlar+Jute)fiber mat achieved a balance between mechanical strength and cost-effectiveness by attaining a tensile strength of 718 MPa in the 3/2 configuration.Impact energy absorption results revealed that Kevlar-reinforced FMLs provided the highest energy absorption under Charpy tests,reaching 13.5 J in the 3/2 configuration.The 4/3 configu ration exhibited superior resistance under drop-weight impacts,absorbing 104.7 J of energy.Failure analysis using SEM revealed key mechanisms such as fiber debonding,delamination,and fiber pull-out,with increased severity observed in laminates with a higher number of fiber-epoxy layers,especially in the 5/4 configuration.This study highlights the potential of Kevlar-Jute hybrid fiber-reinforced FMLs for applications requiring high mechanical performance and impact resistance.Future research should explore advanced surface treatments and the environmental durability of these laminates for aerospace and automotive applications.展开更多
A novel method for preparing silver nanoelectrode ensembles (SNEEs) and gold nanoelectrode ensembles (GNEEs) has been developed. Silver colloid particles were first absorbed to the gold electrode surface to form a mo...A novel method for preparing silver nanoelectrode ensembles (SNEEs) and gold nanoelectrode ensembles (GNEEs) has been developed. Silver colloid particles were first absorbed to the gold electrode surface to form a monolayer silver colloid. N-hexadecyl mercaptan was then assembled on the electrode to form a thiol monolayer on which hydrophilic ions cannot be transfered. The SNEEs was prepared by removing thiol from silver colloid surface through applying an AC voltage with increasing frequency at 0.20 V (vs. SCE). Finally, GNEEs was obtained by immersing a SNEEs into 6 mol/L HNO3 to remove the silver colloid particles. By comparison with other methods such as template method etc., this method enjoys some advantages of lower resistance, same diameter, easy preparation, controllable size and density.展开更多
The coupling of bipolar electrode(BPE)arrays and electrofluorochromic(EFC)imaging has exhibited great abilities in bioanalysis.However,the imaging resolution and analytical performance are hampered by the large size o...The coupling of bipolar electrode(BPE)arrays and electrofluorochromic(EFC)imaging has exhibited great abilities in bioanalysis.However,the imaging resolution and analytical performance are hampered by the large size of the electrode and the rapid diffusion of EFC molecules on the electrode surface.Here,to address the challenges,bipolar nanoelectrodes(BPn E)array and in situ immobilization strategy of EFC molecules were proposed.Anodized aluminum oxide(AAO)template-assisted Au nanoelectrodes array with high density was fabricated as BPn E array for high spatial imaging resolution.By electrically polymerizing EFC molecules on the surface of single Au nanoelectrode,the rapid diffusion of EFC molecules on the electrode surface was not only avoided,but also realizing electrofluorescent imaging on an individual nanoelectrode.Using dopamine(DA)released from living PC12 cells as a model,the proposed strategy exhibited an ultra-high sensitivity for DA analysis with a detection limit of 0.45 nmol/L and the DA release amount from a single cell was calculated to be 0.13 pmol/L.Moreover,the dynamic change of DA release under the drug stimulation from living PC12 cells could also be monitored.展开更多
A novel strategy has been developed for construction of nanoparticle chains between nanoelectrodes with bifunctional molecules by taking advantage of linear aggregation of colloidal particles in organis solvents. As c...A novel strategy has been developed for construction of nanoparticle chains between nanoelectrodes with bifunctional molecules by taking advantage of linear aggregation of colloidal particles in organis solvents. As confirmed by scanning electron microscopy （SEM）,an individual nanoparticle chain bridged the electrode pair. The present approach makes this technique to be cheap and may be applicable in microelectronic industry.展开更多
A facile method has been developed for the fabrication of Au nanoelecrodes (Au NEs). The tip of Au NEs can be controlled within the range from dozens to hundreds of nanometer.
Here we demonstrate the fabrication of nanometer-sized gaps by assembling single coreshell nanoparticles between metallic nanoelectrodes. Protein coated SiO2@Au coreshell nanopar- tides arc synthesized and positioned ...Here we demonstrate the fabrication of nanometer-sized gaps by assembling single coreshell nanoparticles between metallic nanoelectrodes. Protein coated SiO2@Au coreshell nanopar- tides arc synthesized and positioned between fluorescent molecules-covered electrodes in a controllable way using dielectrophoretic trapping, forming nanogaps sandwiched between nanoparticle and manoelectrodes. Preliminary photoluminescence measurements show that enhanced molecular fluorescence could be detected from the fluorescent molecules inside the nanogaps. These results pave the way for realizing electrically driven molecular fluorescence based on nanogap electrodes.展开更多
Taking advantage of the extremely small size of the gold nanodisk electrode,the single hydrogen nanobubble generated on the surface of the nanoelectrode was studied to evaluate its hydrogen evolution performance.It wa...Taking advantage of the extremely small size of the gold nanodisk electrode,the single hydrogen nanobubble generated on the surface of the nanoelectrode was studied to evaluate its hydrogen evolution performance.It was found that compared with the bare gold nanodisk electrode,the bubble formation potential of the gold nanodisk electrode modified with tungsten disulfide quantum dots(WS_(2)QDs)on the surface was more positive,indicating that its hydrogen evolution activity was higher.Microdynamic model analysis shows that the average standard rate constant of the rate-determining step of the hydrogen evolution reaction of gold nanoelectrodes modified with WS_(2)QDs is approximately 12 times larger than that of gold nanoelectrodes.This work based on the formation of nanobubbles provides new ideas for the design and performance evaluation of hydrogen evolution reaction catalysts.展开更多
The long-lasting expectation“the hotter the engine,the better”calls for the development of high-temperature metallic alloys.Although the high specific strengths of titanium alloys are compelling for such application...The long-lasting expectation“the hotter the engine,the better”calls for the development of high-temperature metallic alloys.Although the high specific strengths of titanium alloys are compelling for such applications,their deleterious softening beyond 600℃ imposes serious limitations.Much has been known for decades regarding the phase metallurgy for precipitation strengthening design in titanium alloys,however,the other facile strength promotion mechanism,dispersion strengthening,remains comparatively less-explored and unutilized.The present research concerns the multi-scale dispersion strengthening in titanium alloys,with mechanistic emphases on the critical plasticity micro-events that affect strength preservation.Due to the simultaneous introduction of intragranular dispersoids and intergranular reinforcers,the current titanium alloys present superior engineering tensile strength of 519 MPa at 700℃.Throughout the examined 25-800℃ temperature range,noticeable softening induced by the thermal activation occurs above 600℃,accompanied by evident strength loss.The temperature-dependence transition of dominated softening mechanisms from dynamic recovery to dynamic recrystallization has been clarified by theoretical calculations.Furthermore,the strengthening effect of multi-scale architectures is underpinned as the enhanced dislocation strengthening owing to the introduction of thermally-stable heterointerfaces,which could generically guide the design of similar heat-resistant titanium alloys.展开更多
Ti-Gd alloys with Gd contents of 2 wt%-8 wt% were prepared,and the influence of Gd content on the microstructure,mechanical properties,corrosion behavior,neutron absorption property and density of the alloy weas inves...Ti-Gd alloys with Gd contents of 2 wt%-8 wt% were prepared,and the influence of Gd content on the microstructure,mechanical properties,corrosion behavior,neutron absorption property and density of the alloy weas investigated.The micro structure changes from full lamellar α phase to fine equiaxed crystals,and the area fraction of Gd-rich phase decreases from 3.2% to 1.8% and then increases to 9.1%.Gd has three existing forms:pure Gd,compound oxide of Gd_(2)TiO_(5)and/or Gd_(2)O_(3)and solidifies in the Ti matrix.Ti-4Gd exhibits the best mechanical properties,its tensile strength and elongation is 102 MPa and 49%,respectively.The neutron transmittancy of Ti-8Gd alloy in water is the lowest,which is 3.75%.The corrosion rate of Ti-Gd alloy is 0.00097-0.00238 mm/a,which meets the corrosion standard of small-scale nuclear reactors and containers for spent fuel.展开更多
For nano-collision, regulating the interaction between nanoparticles(NPs) and electrode interfaces is crucial for the precise analysis of individual NPs. However, existing ultramicroelectrodes(UMEs) suffer from narrow...For nano-collision, regulating the interaction between nanoparticles(NPs) and electrode interfaces is crucial for the precise analysis of individual NPs. However, existing ultramicroelectrodes(UMEs) suffer from narrow electrochemical window and poor electrode interface adhesion, severely hindering the application of precise single NP analysis. Here, we propose a simple and effective interface modification strategy. By electrochemically self-assembling poly(diallyldimethylammonium chloride)(PC) on the surface of carbon nanocone electrodes(CNCEs), we successfully prepared PC-modified CNCEs(PC–CNCEs). These electrodes not only possess sufficiently wide electrochemical window but also exhibit strong adhesion to negatively charged Ag NPs on their surfaces. Surface physical analysis and electrochemical molecule detection validated the high-density loading of PC on the modified electrodes. Furthermore, the working principle of PC–CNCEs for single Ag NP collision detection was further verified through the techniques of nanocollision and double-potential steps. Leveraging these significant advantages, PC–CNCEs not only achieved precise measurements of single or mixed-sized Ag NPs but also detected Ag NP solutions at concentrations as low as fmol/L levels. This advancement offers a new strategy for the rapid and precise analysis of NP colloids.展开更多
Carbon fiber nanoelectrodes(200-300 nm) were firstly used to amperometricaly monitor the dopamine release from single PC12 cells with temporal resolution and especially more higher spatial resolution than those obtain...Carbon fiber nanoelectrodes(200-300 nm) were firstly used to amperometricaly monitor the dopamine release from single PC12 cells with temporal resolution and especially more higher spatial resolution than those obtained by using microelectrodes. When the nanoelectrode was in a distance 1 μm above the PC12 cell, only one peak signal corresponding to a single vesicle exocytotic event was detected caused from the stimulation with 1 mmol/L nicotine. The spatial difference of exocytosis was also detected by placing the electrode onto the different locations of the cell body, the results have demostrated that the spatial distribution of dopamine in cells is not uniform and the time for stimulating secretion is very different. Nanoelectrodes electrochemical method can provide a powerful tool for observing the temporal and spatial characteristics of the secretion from single cells directly.展开更多
基金Funded by the Ministry of Science,Technological Development and Innovation of the Republic of Serbia(Nos.451-03-47/2023-01/200135,451-03-47/2023-01/200017 and 451-03-47/2023-01/200287)。
文摘This paper describes severe plastic deformation(SPD)procedures,which are utilized to form an ultrafine-grained structure in metallic biomaterials.During the SPD process,a solid material sample is subjected to very high loads without a significant change in sample dimensions.In the present work,the high-pressure torsion(HPT)process,as one of the SPD techniques,which achieves a high degree of deformation and ensures refinement of the microstructure,will be discussed in more detail.Considering that grain size control is accepted as a method to obtain materials with desired characteristics,an overview of the properties of ultrafine-grained titanium-based biomaterials to be used in medicine is given.Moreover,particular attention is dedicated to the influences of HPT process parameters,primarily hydrostatic pressure,and number of revolutions during torsion,on the grain size and physical and mechanical characteristics(modulus of elasticity,microhardness,and tensile properties),corrosion resistance,and biocompatibility of the titanium-based biomaterials.A review of the literature indicates that titanium-based materials obtained by the SPD process show improved mechanical and physical properties without losing biocompatibility and corrosion resistance,which suggests that these methods of obtaining implants are something that should be further developed in the future.
基金supported by the Research Platform Open Fund Project of Zhejiang Industry and Trade Vocation College(No.Kf202203)the Scientific Research Project of CCCC First Harbor Engineering Company Ltd.(No.2022-7-2)+3 种基金the National Natural Science Foundation of China(No.22406142)the Fellowship of China National Postdoctoral Program for Innovative Talents(No.BX20230262)the Fellowship of China Postdoctoral Science Foundation(No.2023M732636)the Shanghai Post-doctoral Excellence Program(No.2023755).
文摘Efficient and innovative nano-catalytic oxidation technologies offer a breakthrough in removing emerging contaminants(ECs)from water,surpassing the limitations of traditional methods.Environmental functional materials(EFMs),particularly high-end oxidation systems using eco-friendly nanomaterials,show promise for absorbing and degrading ECs.This literature review presents a comprehensive analysis of diverse traditional restoration techniques-biological,physical,and chemical-assessing their respective applications and limitations in pesticide-contaminated water purification.Through meticulous comparison,we unequivocally advocate for the imperative integration of environmentally benign nanomaterials,notably titanium-based variants,in forthcoming methodologies.Our in-depth exploration scrutinizes the catalytic efficacy,underlying mechanisms,and adaptability of pioneering titanium-based nanomaterials across a spectrum of environmental contexts.Additionally,strategic recommendations are furnished to surmount challenges and propel the frontiers of implementing eco-friendly nanomaterials in practical water treatment scenarios.
基金the aid of Research and Development Fund-Seed Money provided by Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and Technology。
文摘The mechanical behaviour of Titanium-based Fiber Metal Laminates(FMLs)reinforced with Kevlar,Jute and the novel woven(Kevlar+Jute)fiber mat were evaluated through tensile,flexural,Charpy impact,and drop-weight tests.The FMLs were fabricated with various stacking configurations(2/1,3/2,4/3,and 5/4)to examine their influence on mechanical properties.Kevlar-reinforced laminates consistently demonstrated superior tensile and flexural strengths,with the highest tensile strength of 772 MPa observed in the 3/2 configuration,attributed to Kevlar's excellent load-bearing capacity.Jute-reinforced laminates exhibited lower performance due to poor bonding and early delamination,while the FMLs reinforced with woven(Kevlar+Jute)fiber mat achieved a balance between mechanical strength and cost-effectiveness by attaining a tensile strength of 718 MPa in the 3/2 configuration.Impact energy absorption results revealed that Kevlar-reinforced FMLs provided the highest energy absorption under Charpy tests,reaching 13.5 J in the 3/2 configuration.The 4/3 configu ration exhibited superior resistance under drop-weight impacts,absorbing 104.7 J of energy.Failure analysis using SEM revealed key mechanisms such as fiber debonding,delamination,and fiber pull-out,with increased severity observed in laminates with a higher number of fiber-epoxy layers,especially in the 5/4 configuration.This study highlights the potential of Kevlar-Jute hybrid fiber-reinforced FMLs for applications requiring high mechanical performance and impact resistance.Future research should explore advanced surface treatments and the environmental durability of these laminates for aerospace and automotive applications.
文摘A novel method for preparing silver nanoelectrode ensembles (SNEEs) and gold nanoelectrode ensembles (GNEEs) has been developed. Silver colloid particles were first absorbed to the gold electrode surface to form a monolayer silver colloid. N-hexadecyl mercaptan was then assembled on the electrode to form a thiol monolayer on which hydrophilic ions cannot be transfered. The SNEEs was prepared by removing thiol from silver colloid surface through applying an AC voltage with increasing frequency at 0.20 V (vs. SCE). Finally, GNEEs was obtained by immersing a SNEEs into 6 mol/L HNO3 to remove the silver colloid particles. By comparison with other methods such as template method etc., this method enjoys some advantages of lower resistance, same diameter, easy preparation, controllable size and density.
基金supported by the National Natural Science Foundation of China(Nos.22174016,21874018,21627806,21635004)Fundamental Research Funds for the Central Universities(No.2242022K40018)。
文摘The coupling of bipolar electrode(BPE)arrays and electrofluorochromic(EFC)imaging has exhibited great abilities in bioanalysis.However,the imaging resolution and analytical performance are hampered by the large size of the electrode and the rapid diffusion of EFC molecules on the electrode surface.Here,to address the challenges,bipolar nanoelectrodes(BPn E)array and in situ immobilization strategy of EFC molecules were proposed.Anodized aluminum oxide(AAO)template-assisted Au nanoelectrodes array with high density was fabricated as BPn E array for high spatial imaging resolution.By electrically polymerizing EFC molecules on the surface of single Au nanoelectrode,the rapid diffusion of EFC molecules on the electrode surface was not only avoided,but also realizing electrofluorescent imaging on an individual nanoelectrode.Using dopamine(DA)released from living PC12 cells as a model,the proposed strategy exhibited an ultra-high sensitivity for DA analysis with a detection limit of 0.45 nmol/L and the DA release amount from a single cell was calculated to be 0.13 pmol/L.Moreover,the dynamic change of DA release under the drug stimulation from living PC12 cells could also be monitored.
基金The authors thank the support by the National Natural Science Foundation of China （No.60171005, No.6037107 and No.90406023）Promotional Foundation of Ministry of Education of China for excellent youth teachers （2000） Grant-in-aid for Returnee in City of Nanjing, China.
文摘A novel strategy has been developed for construction of nanoparticle chains between nanoelectrodes with bifunctional molecules by taking advantage of linear aggregation of colloidal particles in organis solvents. As confirmed by scanning electron microscopy （SEM）,an individual nanoparticle chain bridged the electrode pair. The present approach makes this technique to be cheap and may be applicable in microelectronic industry.
基金This work was supported by the National Natural Science Foundation of China.
文摘A facile method has been developed for the fabrication of Au nanoelecrodes (Au NEs). The tip of Au NEs can be controlled within the range from dozens to hundreds of nanometer.
文摘Here we demonstrate the fabrication of nanometer-sized gaps by assembling single coreshell nanoparticles between metallic nanoelectrodes. Protein coated SiO2@Au coreshell nanopar- tides arc synthesized and positioned between fluorescent molecules-covered electrodes in a controllable way using dielectrophoretic trapping, forming nanogaps sandwiched between nanoparticle and manoelectrodes. Preliminary photoluminescence measurements show that enhanced molecular fluorescence could be detected from the fluorescent molecules inside the nanogaps. These results pave the way for realizing electrically driven molecular fluorescence based on nanogap electrodes.
基金financial support from the National Natural Science Foundation of China(No.21775003)Anhui Provincial Natural Science Foundation(No.2308085MB56)the Key Project of Anhui Provincial Department of Education Scientific Research Project(No.2023AH040032).
文摘Taking advantage of the extremely small size of the gold nanodisk electrode,the single hydrogen nanobubble generated on the surface of the nanoelectrode was studied to evaluate its hydrogen evolution performance.It was found that compared with the bare gold nanodisk electrode,the bubble formation potential of the gold nanodisk electrode modified with tungsten disulfide quantum dots(WS_(2)QDs)on the surface was more positive,indicating that its hydrogen evolution activity was higher.Microdynamic model analysis shows that the average standard rate constant of the rate-determining step of the hydrogen evolution reaction of gold nanoelectrodes modified with WS_(2)QDs is approximately 12 times larger than that of gold nanoelectrodes.This work based on the formation of nanobubbles provides new ideas for the design and performance evaluation of hydrogen evolution reaction catalysts.
基金financially supported by the National Key R&D Program of China(No.2021YFB3701203)the National Natural Science Foundation of China(Nos.U22A20113,52261135543,52171137 and 52071116)the Heilongjiang Touyan Team Program,Heilongjiang Provincial Natural Science Foundation of China(No.TD2020E001).
文摘The long-lasting expectation“the hotter the engine,the better”calls for the development of high-temperature metallic alloys.Although the high specific strengths of titanium alloys are compelling for such applications,their deleterious softening beyond 600℃ imposes serious limitations.Much has been known for decades regarding the phase metallurgy for precipitation strengthening design in titanium alloys,however,the other facile strength promotion mechanism,dispersion strengthening,remains comparatively less-explored and unutilized.The present research concerns the multi-scale dispersion strengthening in titanium alloys,with mechanistic emphases on the critical plasticity micro-events that affect strength preservation.Due to the simultaneous introduction of intragranular dispersoids and intergranular reinforcers,the current titanium alloys present superior engineering tensile strength of 519 MPa at 700℃.Throughout the examined 25-800℃ temperature range,noticeable softening induced by the thermal activation occurs above 600℃,accompanied by evident strength loss.The temperature-dependence transition of dominated softening mechanisms from dynamic recovery to dynamic recrystallization has been clarified by theoretical calculations.Furthermore,the strengthening effect of multi-scale architectures is underpinned as the enhanced dislocation strengthening owing to the introduction of thermally-stable heterointerfaces,which could generically guide the design of similar heat-resistant titanium alloys.
基金Project supported by the National Key R&D Program of China (2023YFB3506703)。
文摘Ti-Gd alloys with Gd contents of 2 wt%-8 wt% were prepared,and the influence of Gd content on the microstructure,mechanical properties,corrosion behavior,neutron absorption property and density of the alloy weas investigated.The micro structure changes from full lamellar α phase to fine equiaxed crystals,and the area fraction of Gd-rich phase decreases from 3.2% to 1.8% and then increases to 9.1%.Gd has three existing forms:pure Gd,compound oxide of Gd_(2)TiO_(5)and/or Gd_(2)O_(3)and solidifies in the Ti matrix.Ti-4Gd exhibits the best mechanical properties,its tensile strength and elongation is 102 MPa and 49%,respectively.The neutron transmittancy of Ti-8Gd alloy in water is the lowest,which is 3.75%.The corrosion rate of Ti-Gd alloy is 0.00097-0.00238 mm/a,which meets the corrosion standard of small-scale nuclear reactors and containers for spent fuel.
基金support from the Instrument Developing Project of the Chinese Academy of Sciences (No.YJKYYQ20210003)Natural Science Foundation of Jilin Province (No. 20210101402JC)support from the National Natural Science Foundation of China (No. 22204159)。
文摘For nano-collision, regulating the interaction between nanoparticles(NPs) and electrode interfaces is crucial for the precise analysis of individual NPs. However, existing ultramicroelectrodes(UMEs) suffer from narrow electrochemical window and poor electrode interface adhesion, severely hindering the application of precise single NP analysis. Here, we propose a simple and effective interface modification strategy. By electrochemically self-assembling poly(diallyldimethylammonium chloride)(PC) on the surface of carbon nanocone electrodes(CNCEs), we successfully prepared PC-modified CNCEs(PC–CNCEs). These electrodes not only possess sufficiently wide electrochemical window but also exhibit strong adhesion to negatively charged Ag NPs on their surfaces. Surface physical analysis and electrochemical molecule detection validated the high-density loading of PC on the modified electrodes. Furthermore, the working principle of PC–CNCEs for single Ag NP collision detection was further verified through the techniques of nanocollision and double-potential steps. Leveraging these significant advantages, PC–CNCEs not only achieved precise measurements of single or mixed-sized Ag NPs but also detected Ag NP solutions at concentrations as low as fmol/L levels. This advancement offers a new strategy for the rapid and precise analysis of NP colloids.
文摘Carbon fiber nanoelectrodes(200-300 nm) were firstly used to amperometricaly monitor the dopamine release from single PC12 cells with temporal resolution and especially more higher spatial resolution than those obtained by using microelectrodes. When the nanoelectrode was in a distance 1 μm above the PC12 cell, only one peak signal corresponding to a single vesicle exocytotic event was detected caused from the stimulation with 1 mmol/L nicotine. The spatial difference of exocytosis was also detected by placing the electrode onto the different locations of the cell body, the results have demostrated that the spatial distribution of dopamine in cells is not uniform and the time for stimulating secretion is very different. Nanoelectrodes electrochemical method can provide a powerful tool for observing the temporal and spatial characteristics of the secretion from single cells directly.
