The hydroxyl-terminated self-assembled monolayer(OH-SAM),as a surface resistant to protein adsorption,exhibits substantial potential in applications such as ship navigation and medical implants,and the appropriate str...The hydroxyl-terminated self-assembled monolayer(OH-SAM),as a surface resistant to protein adsorption,exhibits substantial potential in applications such as ship navigation and medical implants,and the appropriate strategies for designing anti-fouling surfaces are crucial.Here,we employ molecular dynamics simulations and alchemical free energy calculations to systematically analyze the factors influencing resistance to protein adsorption on the SAMs terminated with single or double OH groups at three packing densities(∑=2.0 nm^(-2),4.5 nm^(-2),and 6.5 nm^(-2)),respectively.For the first time,we observed that the compactness and order of interfacial water enhance its physical barrier effect,subsequently enhancing the resistance of SAM to protein adsorption.Notably,the spatial hindrance effect of SAM leads to the embedding of protein into SAM,resulting in a lack of resistance of SAM towards protein.Furthermore,the number of hydroxyl groups per unit area of double OH-terminated SAM at ∑=6.5 nm^(-2) is approximately 2 to 3 times that of single OH-terminated SAM at ∑=6.5 nm^(-2) and 4.5 nm^(-2),consequently yielding a weaker resistance of double OH-terminated SAM towards protein.Meanwhile,due to the structure of SAM itself,i.e.,the formation of a nearly perfect ice-like hydrogen bond structure,the SAM exhibits the weakest resistance towards protein.This study will complement and improve the mechanism of OH-SAM resistance to protein adsorption,especially the traditional barrier effect of interfacial water.展开更多
Bio-based cyclodextrins(CDs)are a common research object in supramolecular chemistry.The special cavity structure of CDs can form supramolecular self-assemblies such as vesicles and microcrystals through weak interact...Bio-based cyclodextrins(CDs)are a common research object in supramolecular chemistry.The special cavity structure of CDs can form supramolecular self-assemblies such as vesicles and microcrystals through weak interaction with guest molecules.The different forms of supramolecular self-assemblies can be transformed into each other under certain conditions.The regulation of supramolecular self-assembly is not only helpful to understand the self-assembly principle,but also beneficial to its application.In the present study,the self-assembly behavior of epoxy-β-cyclodextrin(EP-β-CD)and mixed anionic and cationic surfactant system(sodium dodecyl sulfate/dodecyltrimethylammonium bromide,SDS/DTAB)in aqueous solution was studied.Morphological and particle size characterization found that the SDS/DTAB@EP-β-CD complex,as the basic building unit,self-assembled into worm-like micelles at lower temperatures and vesicles at higher temperatures.Nuclear magnetic resonance(NMR)and Fourier transform infrared spectroscopy(FT-IR)analysis revealed that the driving force for the formation of vesicles and worm-like micelles was the hydrogen bonds between EP-β-CD molecules,while water molecules played an important role in promoting vesicle formation between SDS/DTAB@EP-β-CD units.Herein,the mechanism of the morphologic transformation of SDS/DTAB@EP-β-CD supramolecular aggregates induced by temperature was elucidated by exploring the self-assembly process,which may provide an excellent basis for the development of delivery carriers.展开更多
Generating sufficient strains on metal surfaces are highly challenging owing to that most metals can deform plastically to relax the strains on the surfaces.In this work,we developed a facile but highly efficient stac...Generating sufficient strains on metal surfaces are highly challenging owing to that most metals can deform plastically to relax the strains on the surfaces.In this work,we developed a facile but highly efficient stacked deposition strategy to in situ activation and reconstruction of NiO/NiOOH on Ni matrix,following with the migration of Fe ions to NiOOH.The Fe sites on the Ni/NiO/NiOOH facilitate the formation of the stable*OH oxygenated intermediates,and the Ni matrix in the catalyst provides the catalyst excellent stability.The oxygen evolution reaction(OER)performance of the stacked NiFe-5 with compressive strain displays the strengthened binding to oxygenated intermediates and superior OER activity,the ultralow overpotentials of 162 versus reversible hydrogen electrode at 10 mA cm^(-2).On the other hand,the Ni-5 without the incorporation of Fe has shown an outstanding hydrogen evolution reaction(HER)activity,affording an overpotential of 47 mV at 10 mA cm^(-2).The NiFe-5‖Ni-5 enables the overall water splitting at a voltage of 1.508 V to achieve 20 mA cm^(-2) with remarkable durability.The stacked deposition strategy improves binding strength of Ni-based catalysts to oxygenated intermediates via generating compressive strain,causing high catalytic activities on OER and HER.展开更多
We demonstrated a chemical process in the fabrication of a SERS fiber probe with an ultrahigh sensitivity.The synthesis was carried out by preparing Au@Ag core-shell nanorods (Au@Ag-NRs) selfassembled on polyelectroly...We demonstrated a chemical process in the fabrication of a SERS fiber probe with an ultrahigh sensitivity.The synthesis was carried out by preparing Au@Ag core-shell nanorods (Au@Ag-NRs) selfassembled on polyelectrolyte (PE) multilayers,for which Au@Ag-NRs were controlled by adjusting the silver layer thickness.The effect of silver layer thickness of Au@Ag-NRs on the SERS performance of the fiber probe was investigated.The SERS fiber probe shows the best performance when the silver layer thickness is controlled at 8.57 nm.Under the condition of optimizing silver layer thickness,the fiber probe exhibits ultra-high sensitivity (i e,10^(-10) M crystalline violet,CV),good reproducibility (i e,RSD of 3.5%) and stability.Besides,electromagnetic field distribution of the SERS fiber probe was also investigated.The strongest enhancement is found within the core of fiber,whereas a weakened electromagnetic field exists in the fiber cladding layer.The SERS fiber probe can be a good candidate in ultra-trace detection for biomedical and environmental areas.展开更多
Silane coupling reagent (3-aminopropyltriethoxysilane (APTES)) was prepared on single-crystal silicon substrates to form two-dimensional self-assembled monolayer (SAM). The terminal-NH2 groups in the film were in situ...Silane coupling reagent (3-aminopropyltriethoxysilane (APTES)) was prepared on single-crystal silicon substrates to form two-dimensional self-assembled monolayer (SAM). The terminal-NH2 groups in the film were in situ phosphorylated to -PO(OH)2 group to endow the film with good chemisorption ability. Then La-based thin films were deposited on phosphorylated APTES-SAM in order to make good use of the chemisorption ability of -PO(OH)2 groups. The thickness of the film was determined with ellipsometer, while phase transformation and surface morphology, surface energy, phase composition were analyzed by means of atomic force microscope (AFM), contact angle measurements and X-ray photoelectron spectroscopy (XPS). The results indicated that the terminal-NH2 groups could be completely transformed into desirable-PO(OH)2 groups after phosphorylation of APTES-SAM. Detailed XPS analysis of the La3+ peaks revealed that lanthanum element existed in the films in different states. As a result, conclusion could be made that lanthanum reacted with -PO(OH)2 groups on the surface of the substrate by chemical bond which would improve the bonding strength between the film and silicon substrate. Since the La-based thin films were well adhered to the silicon substrate, it might find promising application in the surface-modification of single-crystal Si and SiC in microelectromechanical systems (MEMS).展开更多
Light confinement induced by spontaneous near-surface resonance is inherently determined by the location and geometry of metallic nanostructures(NSs),offering a facile and effective approach to break through the limit...Light confinement induced by spontaneous near-surface resonance is inherently determined by the location and geometry of metallic nanostructures(NSs),offering a facile and effective approach to break through the limitation of the light-mater interaction within the photoactive layers.Here,we demonstrate high-performance Al NS/ZnO quantum dots(Al/ZnO) heterostructure UV photodetectors with controllable morphologies of the self-assembled Al NSs.The Al/ZnO heterostructures exhibit a superior light utilization than the ZnO/Al heterostructures,and a strong morphological dependence of the Al NSs on the optical properties of the heterostructures.The inter-diffusion of Al atoms into ZnO matrixes is of a great benefit for the carrier transportation.Consequently,the optimal photocurrent of the Al/ZnO heterostructure photodetectors is significantly increased by 275 times to ~1.065 mA compared to that of the pristine ZnO device,and an outstanding photoresponsivity of 11.98 A W-1 is correspondingly achieved under 6.9 MW cm-2 UV light illumination at 10 V bias.In addition,a relatively fast response is similarly witnessed with the Al/ZnO devices,paving a path to fabricate the high-performance UV photodetectors for applications.展开更多
Trimethoxysilyl-functionalized PPEK(PKGS) films had been designed to serve as wear resistant coatings for silicon surfaces. These surface films were formed by a dip-coating technique applied to self-assembled monola...Trimethoxysilyl-functionalized PPEK(PKGS) films had been designed to serve as wear resistant coatings for silicon surfaces. These surface films were formed by a dip-coating technique applied to self-assembled monolayers(SAMs).The formation and wetting behavior of PKGS films were characterized by means of contact angle measurement.The friction coefficient of the film prepared is very low(about 0.1),and the anti-wear behavior is good,with a lack of failure after sliding over 1800 s.展开更多
The development of natural biomaterials applied for hard tissue repair and regeneration is of great importance,especially in societies with a large elderly population.Self-assembled peptide hydrogels are a new generat...The development of natural biomaterials applied for hard tissue repair and regeneration is of great importance,especially in societies with a large elderly population.Self-assembled peptide hydrogels are a new generation of biomaterials that provide excellent biocompatibility,tunable mechanical stability,injectability,trigger capability,lack of immunogenic reactions,and the ability to load cells and active pharmaceutical agents for tissue regeneration.Peptide-based hydrogels are ideal templates for the deposition of hydroxyapatite crystals,which can mimic the extracellular matrix.Thus,peptide-based hydrogels enhance hard tissue repair and regeneration compared to conventional methods.This review presents three major self-assembled peptide hydrogels with potential application for bone and dental tissue regeneration,including ionic self-complementary peptides,amphiphilic(surfactant-like)peptides,and triple-helix(collagen-like)peptides.Special attention is given to the main bioactive peptides,the role and importance of self-assembled peptide hydrogels,and a brief overview on molecular simulation of self-assembled peptide hydrogels applied for bone and dental tissue engineering and regeneration.展开更多
γ-mercapto-propyl trimethoxysilane (MPTS) and γ-methacryloxy propyltrimethoxysilane (MPTES) were self-assembled on a hy- droxylated glass substrate to form a two-dimensional organic monolayer (MPTS-MPTES SAM)....γ-mercapto-propyl trimethoxysilane (MPTS) and γ-methacryloxy propyltrimethoxysilane (MPTES) were self-assembled on a hy- droxylated glass substrate to form a two-dimensional organic monolayer (MPTS-MPTES SAM). The terminal thiol groups (-SH) in the MPTS-MPTES SAM were in-situ oxidized into sulfonic acid groups (-SO3H) to endow the film with good chemisorption ability. Then rare earth (RE) (lanthanum-based) composite thin films were prepared by self-assembly technique based on the as-prepared SAM, taking advantage of the chemisorption ability of the sulfonic acid groups. Automatic force microscope (AFM), X-ray photoelectron spectrometry (XPS), contact angle measurement and ellipsometer were used to characterize MPTS-MPTES/RE composite films. The macrofriction and wear behaviors of the films sliding against an AISI-52100 steel ball were examined on a unidirectional friction and wear tester, and the worn surface morphologies were observed on an AFM. The results showed that MPTS-MPTES/RE films had a low friction coefficient (0.09) and a long wear life (5980 sliding pass) at a light load (50 mN). It indicated that the superior tribological properties of the MPTS-MPTES/RE composite films were attributed to the special characteristic of RE elements, the mobility of the films and good bonding strength.展开更多
The electrochemical quartz crystal microbalance (EQCM) is used to investigate the characteristics of the thiolated self-assembled monolayer(SAM) on gold surface.A 5MHz QCM element serves as both the mass-sensitive sen...The electrochemical quartz crystal microbalance (EQCM) is used to investigate the characteristics of the thiolated self-assembled monolayer(SAM) on gold surface.A 5MHz QCM element serves as both the mass-sensitive sensor and the working electrode of the electrochemical system.The 6-mecapto-1-hexanol and and the 16-mer oligonucleotide with a mercaptohexyl group at the 5'-phosphate end are utilized to form the SAM on the gold electrode.The frequency response of the QCM during cyclic voltammetry (CV) scanning and cbronoamperometry are recorded together with the electrochemical current.The experimental results indicates that the frequency response is more sensitive to the surface coverage.Therefore,the response of the EQCM reveals more details of the SAM on gold electrode.It is especially useful for analysing the immobilization quality,such as probe orientation and coverage,of the SAM.展开更多
The electrochemical behavior of trifluoperazine at decanethiol self-assembledmonolayer (SAM) modified gold electrodes (i. e. C_(10) H_(21) SH/Au) has been studied,Trifluoperazine can effectively accumulate on C_(10) H...The electrochemical behavior of trifluoperazine at decanethiol self-assembledmonolayer (SAM) modified gold electrodes (i. e. C_(10) H_(21) SH/Au) has been studied,Trifluoperazine can effectively accumulate on C_(10) H_(21) SH/Au electrodes and generate asensitive anodic peak at about 0.63 V (vs. SCE) in 0.05 mol/L pH 9.4 Na_2 B_4 O_7 buffer solution.Under the selected conditions, the anodic peak current was linear to trifluoperazine concentrationin the range of 5.0 X 10^(-7)-3.O X 10^(-3) mol/Lwith correlation coefficient of 0.997, thedetection limit was 3.0 X 10^(-5) mol/L. This method was applied to the determination oftrifluoperazine in drug samples and the recovery was 97.3%-104.0% It was found that sodium dodecylsulfate (SDS) could make the anodic peak current increase. In the presence of SDS, the peak at about0.63 V turned into two peaks, resulting from the change of the electrochemical mechanism.展开更多
SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers(SAMs) by the Liquid Phase Deposition(LPD) method.The as-prepared samples were characterized by X-ray diffraction(...SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers(SAMs) by the Liquid Phase Deposition(LPD) method.The as-prepared samples were characterized by X-ray diffraction(XRD),atomic force microscope(AFM),scanning electron microscopy(SEM) and metallographic microscope.Measurement of contact angle showed that the hydrophobe substrate was changed into hydrophile by UV irradiation.AFM photographs of octadecyl-trichloro-silane self-assembled monolayer(OTS-SAM) surface approved that UV irradiation did change the morphology of OTS monolayer and provided evidence for the conversion of hydrophilic characteristic.Photographs of Metallographic Microscope showed that OTS-SAM had an active effect on the deposition of SrTiO3 thin film.XRD and SEM indicated that the thin film was of pure cubic phase SrTiO3 and composed of nanosized grains with a size in the range of 100-500 nm.The formation mechanism of the SrTiO3 film was proposed.展开更多
Self assembled monolayers (SAMs) of to-mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic ac...Self assembled monolayers (SAMs) of to-mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic acid (AA) was repelled from the SAMs. TheMPEG film is a biocompatible film, there was no adsorption of biosample and no inactivation atelectrode surface when it was used to detect DA in biosamples.展开更多
Hybrid self-assembled multilayer films were prepared by alternate adsorption of 1,10-diaminodecane (1,10-DAD) and Keggin polyoxometalates of SiW12O404-, SiW11VO405-, and PMo12O403-, respectively. The films were repro...Hybrid self-assembled multilayer films were prepared by alternate adsorption of 1,10-diaminodecane (1,10-DAD) and Keggin polyoxometalates of SiW12O404-, SiW11VO405-, and PMo12O403-, respectively. The films were reproducibly grown at each adsorption cycle as monitored by UV spectroscopy.展开更多
By three-dimensional kinetic Monte Carlo simulations, the effects of the temperature, the flux rate, the total coverage and the interruption time on the distribution and the number of self-assembled InAs/GaAs (001) ...By three-dimensional kinetic Monte Carlo simulations, the effects of the temperature, the flux rate, the total coverage and the interruption time on the distribution and the number of self-assembled InAs/GaAs (001) quantum dot (QD) islands are studied, which shows that a higher temperature, a lower flux rate and a longer growth time correspond to a better island distribution. The relations between the number of islands and the temperature and the flux rate are also successfully simulated. It is observed that for the total coverage lower than 0.5 ML, the number of islands decreases with the temperature increasing and other growth parameters fixed and the number of islands increases with the flux rate increasing when the deposition is lower than 0.6 ML and the other parameters are fixed.展开更多
By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum ...By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum dots. It is found that this system can exhibit the transparency, and the width of the transparency window becomes wider with the increase of control light field. Interestingly, a weak probe light beam can form spatial weak-light dark solitons. When it propagates along the axial direction, the soliton will transform into a steady spatial weak-light ring dark soltion. In addition, the stability of two-dimensional spatial optical solitons is testified numerically.展开更多
The orientation of the biological molecule immobi-lized on a solid surface has been critical in devel-opment of various applications. In this study, ori-entation of antibody was retained by protecting the antigen-bind...The orientation of the biological molecule immobi-lized on a solid surface has been critical in devel-opment of various applications. In this study, ori-entation of antibody was retained by protecting the antigen-binding site of the antibody prior to immo-bilization to -functionalized mixed self-assembled monolayer (SAM) of 12-mercaptododecanoic acid and 1-heptanethiol. More importantly, the number of immobilization bonds formed between each an-tigen-binding site protected antibody molecule and the solid surface was controlled by optimizing the mole fraction of the activated carboxyl group of the linker molecules in the mixed SAM. The amount of antibody used in this study was approximately equivalent to the amount for one monolayer surface coverage. The resulting activity of protected immo-bilized antibody was about 10 fold higher than that of random immobilized展开更多
The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In...The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In the first, cyclic voltammetry (CV) was used to inspect the functional groups of the film and the same time hydroquinone was chosen to be a probe molecule in the based solution;secondly, based on analytical technology of scanning electrochemical microscopy (SECM), the heterogeneous rate constant (keff) between solid phase (the modified electrode) and liquid phase (K3Fe(CN)6) was obtained. As a result, the better binary catalysis of hydroquinone was demonstrated and the heterogeneous rate constant (keff) is the greater at 8 h for L-cysteine self-assembled monolayers (SAMs).展开更多
基金Project supported by the National Natural Science Foundation of China (Grants No. 12075201)the Science and Technology Planning Project of Jiangsu Province, China (Grant No. BK20201428)+1 种基金the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (Grant No. KYCX21 3193)the Special Program for Applied Research on Supercomputation of the NSFC–Guangdong Joint Fund (the second phase)。
文摘The hydroxyl-terminated self-assembled monolayer(OH-SAM),as a surface resistant to protein adsorption,exhibits substantial potential in applications such as ship navigation and medical implants,and the appropriate strategies for designing anti-fouling surfaces are crucial.Here,we employ molecular dynamics simulations and alchemical free energy calculations to systematically analyze the factors influencing resistance to protein adsorption on the SAMs terminated with single or double OH groups at three packing densities(∑=2.0 nm^(-2),4.5 nm^(-2),and 6.5 nm^(-2)),respectively.For the first time,we observed that the compactness and order of interfacial water enhance its physical barrier effect,subsequently enhancing the resistance of SAM to protein adsorption.Notably,the spatial hindrance effect of SAM leads to the embedding of protein into SAM,resulting in a lack of resistance of SAM towards protein.Furthermore,the number of hydroxyl groups per unit area of double OH-terminated SAM at ∑=6.5 nm^(-2) is approximately 2 to 3 times that of single OH-terminated SAM at ∑=6.5 nm^(-2) and 4.5 nm^(-2),consequently yielding a weaker resistance of double OH-terminated SAM towards protein.Meanwhile,due to the structure of SAM itself,i.e.,the formation of a nearly perfect ice-like hydrogen bond structure,the SAM exhibits the weakest resistance towards protein.This study will complement and improve the mechanism of OH-SAM resistance to protein adsorption,especially the traditional barrier effect of interfacial water.
基金China Postdoctoral Science Foundation(2020M681125)National Natural Science Foundation of China(32272254,31901618)Collaborative Innovation Center of Fragrance Flavour and Cosmetics.
文摘Bio-based cyclodextrins(CDs)are a common research object in supramolecular chemistry.The special cavity structure of CDs can form supramolecular self-assemblies such as vesicles and microcrystals through weak interaction with guest molecules.The different forms of supramolecular self-assemblies can be transformed into each other under certain conditions.The regulation of supramolecular self-assembly is not only helpful to understand the self-assembly principle,but also beneficial to its application.In the present study,the self-assembly behavior of epoxy-β-cyclodextrin(EP-β-CD)and mixed anionic and cationic surfactant system(sodium dodecyl sulfate/dodecyltrimethylammonium bromide,SDS/DTAB)in aqueous solution was studied.Morphological and particle size characterization found that the SDS/DTAB@EP-β-CD complex,as the basic building unit,self-assembled into worm-like micelles at lower temperatures and vesicles at higher temperatures.Nuclear magnetic resonance(NMR)and Fourier transform infrared spectroscopy(FT-IR)analysis revealed that the driving force for the formation of vesicles and worm-like micelles was the hydrogen bonds between EP-β-CD molecules,while water molecules played an important role in promoting vesicle formation between SDS/DTAB@EP-β-CD units.Herein,the mechanism of the morphologic transformation of SDS/DTAB@EP-β-CD supramolecular aggregates induced by temperature was elucidated by exploring the self-assembly process,which may provide an excellent basis for the development of delivery carriers.
基金supported by the National Natural Science Foundations of China(21965024,22269016,51721002)the Inner Mongolia funding(2020JQ01,21300-5223601)the funding of Inner Mongolia University(10000-21311201/137,213005223601/003,21300-5223707)。
文摘Generating sufficient strains on metal surfaces are highly challenging owing to that most metals can deform plastically to relax the strains on the surfaces.In this work,we developed a facile but highly efficient stacked deposition strategy to in situ activation and reconstruction of NiO/NiOOH on Ni matrix,following with the migration of Fe ions to NiOOH.The Fe sites on the Ni/NiO/NiOOH facilitate the formation of the stable*OH oxygenated intermediates,and the Ni matrix in the catalyst provides the catalyst excellent stability.The oxygen evolution reaction(OER)performance of the stacked NiFe-5 with compressive strain displays the strengthened binding to oxygenated intermediates and superior OER activity,the ultralow overpotentials of 162 versus reversible hydrogen electrode at 10 mA cm^(-2).On the other hand,the Ni-5 without the incorporation of Fe has shown an outstanding hydrogen evolution reaction(HER)activity,affording an overpotential of 47 mV at 10 mA cm^(-2).The NiFe-5‖Ni-5 enables the overall water splitting at a voltage of 1.508 V to achieve 20 mA cm^(-2) with remarkable durability.The stacked deposition strategy improves binding strength of Ni-based catalysts to oxygenated intermediates via generating compressive strain,causing high catalytic activities on OER and HER.
基金Funded by National Natural Science Foundation of China (Nos.51372179, 51772224)the Open Projects Foundation of Yangtze Optical Fiber and Cable Joint Stock Limited Company (YOFC)(No.SKLD1705)。
文摘We demonstrated a chemical process in the fabrication of a SERS fiber probe with an ultrahigh sensitivity.The synthesis was carried out by preparing Au@Ag core-shell nanorods (Au@Ag-NRs) selfassembled on polyelectrolyte (PE) multilayers,for which Au@Ag-NRs were controlled by adjusting the silver layer thickness.The effect of silver layer thickness of Au@Ag-NRs on the SERS performance of the fiber probe was investigated.The SERS fiber probe shows the best performance when the silver layer thickness is controlled at 8.57 nm.Under the condition of optimizing silver layer thickness,the fiber probe exhibits ultra-high sensitivity (i e,10^(-10) M crystalline violet,CV),good reproducibility (i e,RSD of 3.5%) and stability.Besides,electromagnetic field distribution of the SERS fiber probe was also investigated.The strongest enhancement is found within the core of fiber,whereas a weakened electromagnetic field exists in the fiber cladding layer.The SERS fiber probe can be a good candidate in ultra-trace detection for biomedical and environmental areas.
基金Project supported by the National Natural Science Foundation of China (50475023)
文摘Silane coupling reagent (3-aminopropyltriethoxysilane (APTES)) was prepared on single-crystal silicon substrates to form two-dimensional self-assembled monolayer (SAM). The terminal-NH2 groups in the film were in situ phosphorylated to -PO(OH)2 group to endow the film with good chemisorption ability. Then La-based thin films were deposited on phosphorylated APTES-SAM in order to make good use of the chemisorption ability of -PO(OH)2 groups. The thickness of the film was determined with ellipsometer, while phase transformation and surface morphology, surface energy, phase composition were analyzed by means of atomic force microscope (AFM), contact angle measurements and X-ray photoelectron spectroscopy (XPS). The results indicated that the terminal-NH2 groups could be completely transformed into desirable-PO(OH)2 groups after phosphorylation of APTES-SAM. Detailed XPS analysis of the La3+ peaks revealed that lanthanum element existed in the films in different states. As a result, conclusion could be made that lanthanum reacted with -PO(OH)2 groups on the surface of the substrate by chemical bond which would improve the bonding strength between the film and silicon substrate. Since the La-based thin films were well adhered to the silicon substrate, it might find promising application in the surface-modification of single-crystal Si and SiC in microelectromechanical systems (MEMS).
基金the National Natural Science Foundation of China(Grant Nos.61705070 and 61974052)China Postdoctoral Science Foundation(Grant Nos.2019M662594)National Research Foundation of Korea(NRF)Grant funded by the Korean Government(MSIP)(Nos.NRF2019R1A2C4069438 and NRF2018R1A6A1A03025242)。
文摘Light confinement induced by spontaneous near-surface resonance is inherently determined by the location and geometry of metallic nanostructures(NSs),offering a facile and effective approach to break through the limitation of the light-mater interaction within the photoactive layers.Here,we demonstrate high-performance Al NS/ZnO quantum dots(Al/ZnO) heterostructure UV photodetectors with controllable morphologies of the self-assembled Al NSs.The Al/ZnO heterostructures exhibit a superior light utilization than the ZnO/Al heterostructures,and a strong morphological dependence of the Al NSs on the optical properties of the heterostructures.The inter-diffusion of Al atoms into ZnO matrixes is of a great benefit for the carrier transportation.Consequently,the optimal photocurrent of the Al/ZnO heterostructure photodetectors is significantly increased by 275 times to ~1.065 mA compared to that of the pristine ZnO device,and an outstanding photoresponsivity of 11.98 A W-1 is correspondingly achieved under 6.9 MW cm-2 UV light illumination at 10 V bias.In addition,a relatively fast response is similarly witnessed with the Al/ZnO devices,paving a path to fabricate the high-performance UV photodetectors for applications.
基金This project was financially supported by National High Technology and Development Program of China(863 Program)(No.2003AA33G030)
文摘Trimethoxysilyl-functionalized PPEK(PKGS) films had been designed to serve as wear resistant coatings for silicon surfaces. These surface films were formed by a dip-coating technique applied to self-assembled monolayers(SAMs).The formation and wetting behavior of PKGS films were characterized by means of contact angle measurement.The friction coefficient of the film prepared is very low(about 0.1),and the anti-wear behavior is good,with a lack of failure after sliding over 1800 s.
文摘The development of natural biomaterials applied for hard tissue repair and regeneration is of great importance,especially in societies with a large elderly population.Self-assembled peptide hydrogels are a new generation of biomaterials that provide excellent biocompatibility,tunable mechanical stability,injectability,trigger capability,lack of immunogenic reactions,and the ability to load cells and active pharmaceutical agents for tissue regeneration.Peptide-based hydrogels are ideal templates for the deposition of hydroxyapatite crystals,which can mimic the extracellular matrix.Thus,peptide-based hydrogels enhance hard tissue repair and regeneration compared to conventional methods.This review presents three major self-assembled peptide hydrogels with potential application for bone and dental tissue regeneration,including ionic self-complementary peptides,amphiphilic(surfactant-like)peptides,and triple-helix(collagen-like)peptides.Special attention is given to the main bioactive peptides,the role and importance of self-assembled peptide hydrogels,and a brief overview on molecular simulation of self-assembled peptide hydrogels applied for bone and dental tissue engineering and regeneration.
基金supported by the National Natural Science Foundation of China (50475023)
文摘γ-mercapto-propyl trimethoxysilane (MPTS) and γ-methacryloxy propyltrimethoxysilane (MPTES) were self-assembled on a hy- droxylated glass substrate to form a two-dimensional organic monolayer (MPTS-MPTES SAM). The terminal thiol groups (-SH) in the MPTS-MPTES SAM were in-situ oxidized into sulfonic acid groups (-SO3H) to endow the film with good chemisorption ability. Then rare earth (RE) (lanthanum-based) composite thin films were prepared by self-assembly technique based on the as-prepared SAM, taking advantage of the chemisorption ability of the sulfonic acid groups. Automatic force microscope (AFM), X-ray photoelectron spectrometry (XPS), contact angle measurement and ellipsometer were used to characterize MPTS-MPTES/RE composite films. The macrofriction and wear behaviors of the films sliding against an AISI-52100 steel ball were examined on a unidirectional friction and wear tester, and the worn surface morphologies were observed on an AFM. The results showed that MPTS-MPTES/RE films had a low friction coefficient (0.09) and a long wear life (5980 sliding pass) at a light load (50 mN). It indicated that the superior tribological properties of the MPTS-MPTES/RE composite films were attributed to the special characteristic of RE elements, the mobility of the films and good bonding strength.
文摘The electrochemical quartz crystal microbalance (EQCM) is used to investigate the characteristics of the thiolated self-assembled monolayer(SAM) on gold surface.A 5MHz QCM element serves as both the mass-sensitive sensor and the working electrode of the electrochemical system.The 6-mecapto-1-hexanol and and the 16-mer oligonucleotide with a mercaptohexyl group at the 5'-phosphate end are utilized to form the SAM on the gold electrode.The frequency response of the QCM during cyclic voltammetry (CV) scanning and cbronoamperometry are recorded together with the electrochemical current.The experimental results indicates that the frequency response is more sensitive to the surface coverage.Therefore,the response of the EQCM reveals more details of the SAM on gold electrode.It is especially useful for analysing the immobilization quality,such as probe orientation and coverage,of the SAM.
基金Supported by the National Natural Science Foundation of China (20173040)
文摘The electrochemical behavior of trifluoperazine at decanethiol self-assembledmonolayer (SAM) modified gold electrodes (i. e. C_(10) H_(21) SH/Au) has been studied,Trifluoperazine can effectively accumulate on C_(10) H_(21) SH/Au electrodes and generate asensitive anodic peak at about 0.63 V (vs. SCE) in 0.05 mol/L pH 9.4 Na_2 B_4 O_7 buffer solution.Under the selected conditions, the anodic peak current was linear to trifluoperazine concentrationin the range of 5.0 X 10^(-7)-3.O X 10^(-3) mol/Lwith correlation coefficient of 0.997, thedetection limit was 3.0 X 10^(-5) mol/L. This method was applied to the determination oftrifluoperazine in drug samples and the recovery was 97.3%-104.0% It was found that sodium dodecylsulfate (SDS) could make the anodic peak current increase. In the presence of SDS, the peak at about0.63 V turned into two peaks, resulting from the change of the electrochemical mechanism.
基金Funded by National Natural Science Foundation of China (No. 50672055,50872077)National Key Technology R&D Program (No. 2006BAF02A28)the Graduate Innovation Fund of Shaanxi University of Science and Technology
文摘SrTiO3 thin film was successfully prepared on the functionalized organic self-assembled monolayers(SAMs) by the Liquid Phase Deposition(LPD) method.The as-prepared samples were characterized by X-ray diffraction(XRD),atomic force microscope(AFM),scanning electron microscopy(SEM) and metallographic microscope.Measurement of contact angle showed that the hydrophobe substrate was changed into hydrophile by UV irradiation.AFM photographs of octadecyl-trichloro-silane self-assembled monolayer(OTS-SAM) surface approved that UV irradiation did change the morphology of OTS monolayer and provided evidence for the conversion of hydrophilic characteristic.Photographs of Metallographic Microscope showed that OTS-SAM had an active effect on the deposition of SrTiO3 thin film.XRD and SEM indicated that the thin film was of pure cubic phase SrTiO3 and composed of nanosized grains with a size in the range of 100-500 nm.The formation mechanism of the SrTiO3 film was proposed.
文摘Self assembled monolayers (SAMs) of to-mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic acid (AA) was repelled from the SAMs. TheMPEG film is a biocompatible film, there was no adsorption of biosample and no inactivation atelectrode surface when it was used to detect DA in biosamples.
基金This project was supported by the National Natural Science Foundation of China(20071004)Beijing Natural Science Foundation(2002007)Scientific Research Foundation for the Retumed Overseas Chinese Scholars,State Education Ministry,to KZW.
文摘Hybrid self-assembled multilayer films were prepared by alternate adsorption of 1,10-diaminodecane (1,10-DAD) and Keggin polyoxometalates of SiW12O404-, SiW11VO405-, and PMo12O403-, respectively. The films were reproducibly grown at each adsorption cycle as monitored by UV spectroscopy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60908028,60971068,and 10979065)the Fundamental Research Funds for the Central Universities,China(Grant No.2011RC0402)the Program for New Century Excellent Talents in University,China(Grant No.NCET-10-0261)
文摘By three-dimensional kinetic Monte Carlo simulations, the effects of the temperature, the flux rate, the total coverage and the interruption time on the distribution and the number of self-assembled InAs/GaAs (001) quantum dot (QD) islands are studied, which shows that a higher temperature, a lower flux rate and a longer growth time correspond to a better island distribution. The relations between the number of islands and the temperature and the flux rate are also successfully simulated. It is observed that for the total coverage lower than 0.5 ML, the number of islands decreases with the temperature increasing and other growth parameters fixed and the number of islands increases with the flux rate increasing when the deposition is lower than 0.6 ML and the other parameters are fixed.
基金Project supported by the Special Funds of the National Natural Science Foundation of China(Grant No.11247313)
文摘By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum dots. It is found that this system can exhibit the transparency, and the width of the transparency window becomes wider with the increase of control light field. Interestingly, a weak probe light beam can form spatial weak-light dark solitons. When it propagates along the axial direction, the soliton will transform into a steady spatial weak-light ring dark soltion. In addition, the stability of two-dimensional spatial optical solitons is testified numerically.
文摘The orientation of the biological molecule immobi-lized on a solid surface has been critical in devel-opment of various applications. In this study, ori-entation of antibody was retained by protecting the antigen-binding site of the antibody prior to immo-bilization to -functionalized mixed self-assembled monolayer (SAM) of 12-mercaptododecanoic acid and 1-heptanethiol. More importantly, the number of immobilization bonds formed between each an-tigen-binding site protected antibody molecule and the solid surface was controlled by optimizing the mole fraction of the activated carboxyl group of the linker molecules in the mixed SAM. The amount of antibody used in this study was approximately equivalent to the amount for one monolayer surface coverage. The resulting activity of protected immo-bilized antibody was about 10 fold higher than that of random immobilized
文摘The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In the first, cyclic voltammetry (CV) was used to inspect the functional groups of the film and the same time hydroquinone was chosen to be a probe molecule in the based solution;secondly, based on analytical technology of scanning electrochemical microscopy (SECM), the heterogeneous rate constant (keff) between solid phase (the modified electrode) and liquid phase (K3Fe(CN)6) was obtained. As a result, the better binary catalysis of hydroquinone was demonstrated and the heterogeneous rate constant (keff) is the greater at 8 h for L-cysteine self-assembled monolayers (SAMs).