A novel capacitive sensor for pazufloxacin mesilate (pazufloxacin) determination was developed by electropolymerizing p-aminobenzene sulfonic (p-ABSA) and molecularly imprinted polymers (MPs), which was synthesized th...A novel capacitive sensor for pazufloxacin mesilate (pazufloxacin) determination was developed by electropolymerizing p-aminobenzene sulfonic (p-ABSA) and molecularly imprinted polymers (MPs), which was synthesized through thermal radical copolymerization of metharylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of pazufloxacin template molecules, on the gold electrode surface. Furthermore, 1-dedecanethiol was used to insulate the modified electrode. Alternating current (ac) impedance experiments were carried out with a Model IM6e to obtain the capacitance responses. Under the optimum conditions, the sensor showed linear capacitance response to pazufloxacin in the range of 5 ng·mL?1 to 5 μg·mL?1 with a relative standard deviation (RSD) 5.3% (n=7) and a detection limit of 1.8 ng·mL?1. The recoveries for different concentration levels of pazufloxacin samples varied from 94.0% to 102.0%. Electrochemical experiments indicated the capacitive sensor exhibited good sensitivity and selectivity and showed excellent parameters of regeneration and stability.展开更多
Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and elect...Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and electrostatic interactions onto a self-assembled monolayer configuration is de- scribed in this paper.The enzyme,horseradish peroxidase(HRP),was employed to block the possible remaining active sites of the nano-Au monolayer,avoid the non-specific adsorption,instead of bovine serum albumin(BSA),and amplify the response of the antigen-antibody reaction.Electrochemical ex- periments indicated highly efficient electron transfer by the imbedded Thi mediator and adsorbed nano-Au.The HRP kept its activity after immobilization,and the studied electrode showed sensitive response to CEA and high stability during a long period of storage.The working range for the system was 2.5 to 80.0 ng/mL with a detection limit of 0.90 ng/mL.The model membrane system in this work is a potential biosensor for mimicking the other immunosensor and enzyme sensor.展开更多
An effective electrochemical signal amplification strategy based on enzyme membrane modification and redox probe immobilization was proposed to construct an amperometric immunosensor.L-cysteine@ferrocene functionalize...An effective electrochemical signal amplification strategy based on enzyme membrane modification and redox probe immobilization was proposed to construct an amperometric immunosensor.L-cysteine@ferrocene functionalized chitosan,which possessed not only efficient redox-activity but also excellent film-forming ability,was coated on the bare glass carbon electrode. Moreover,the thiol groups(SH)in the ferrocenyl compound were used for gold nanoparticles immobilization via the strong bonding interaction,which could further be utilized for the immobilization of antibody biomolecules with well-retained bioactivities.Finally,glucose oxidase(GOD)as the enzyme membrane was employed to block the possible remaining active sites and avoid the nonspecific adsorption.With the excellent electrocatalytic properties of GOD towards glucose,the amplification of antigen-antibody interaction and the enhanced sensitivity could be achieved.Under the optimal conditions,the linear range of the proposed immunosensor for the determination of carcinoembryonic antigen(CEA)was from 0.05 to 100 ng/mL with a detection limit of 0.02 ng/mL(S/N=3).Moreover,the immunosensor exhibited good selectivity,stability and reproducibility, which provided a promising potential for clinical immunoassay.展开更多
A highly sensitive potentiometric immunosensor for the diagnoses of epidemic dis-eases has been developed by means of self-assembly to immobilize hepatitis B surface antibody(HBsAb)for the detection of hepatitis B sur...A highly sensitive potentiometric immunosensor for the diagnoses of epidemic dis-eases has been developed by means of self-assembly to immobilize hepatitis B surface antibody(HBsAb)for the detection of hepatitis B surface antigen(HBsAg)as a model.At first,the Nafion containing-SO^(-)_(3)groups was immobilized on a platinum electrode surface to absorb the-NH^(+)_(3)groups of antibody molecules via the opposite-charged adsorption technique,in the meantime,hepatitis B surface antibodies were adsorbed onto the surface of Au nanoparticles,then hepatitis B surface antibodies and Au nanopartilces were entrapped into polyvinyl butyral on the surface of Nafion film.The modified procedure was further characterized by electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).The influence and factors influencing the per-formance of resulting immunosensor were studied in detail.The resulting immunosensor exhib-ited sigmoid curve with log HBsAg concentrations,high sensitivity,wide linear range from 26 to 1280 ng·mL^(-1)with a detection limit of 3.1 ng·mL^(-1),rapid potentiometric response(<3 min)and long-term stability(>4 months).Analytical results of clinical samples show that the developed immunoassay is comparable with the enzyme-linked immunosorbent assays(ELISAs)method,implying a promising alternative approach for detecting HBsAg in the clinical diagnosis.展开更多
Alternate adsorption of positively charged colloid-Au nanoparticles(nano-Au^(⊕))and negatively charged hemoglobin(Hb)on L-cysteine(L-cys)modified gold electrode resulted in the assembly of{Hb/nano-Au^(⊕)}n layer-by-...Alternate adsorption of positively charged colloid-Au nanoparticles(nano-Au^(⊕))and negatively charged hemoglobin(Hb)on L-cysteine(L-cys)modified gold electrode resulted in the assembly of{Hb/nano-Au^(⊕)}n layer-by-layer films/L-cys modified gold electrode.The nano-Au^(⊕)was characterized by transmission electron micrograph(TEM)and microelectrophoresis.The modified electrode interface morphology was characterized by electrochemical impedance spectroscopy(EIS),atomic force mi-croscopy(AFM),cyclic voltammograms(CV)and chronoamperometry.Direct electron transfer between hemoglobin and gold electrodes was studied,and the apparent Michaelis-Menten constant(k_(m)^(app))of the modified electrode was evaluated to be 0.10 mmol·L^(-1).Moreover,the higher activity of proteins in the nano-Au^(⊕)films could be retained compared with the electropolymerization membrane,since the pro-teins in nano-Au^(⊕)films retained their near-native structure.Direct electron transfer between hemoglo-bin and electrode and electrochemically catalyzed reduction of hydrogen peroxide on a modified elec-trode was studied,and the linear range was from 2.1×10^(-8)to 1.2×10^(-3)mol·L^(-1)(r=0.994)with a detection limit of 1.1×10^(-8)mol·L^(-1)H_(2)O_(2).展开更多
A sensitive electrochemical immunoassay system for the detection of a protein tumor biomarker through a dual amplified strategy was reported. Firstly, this protocol involves in the electropolymerization of o-aminobenz...A sensitive electrochemical immunoassay system for the detection of a protein tumor biomarker through a dual amplified strategy was reported. Firstly, this protocol involves in the electropolymerization of o-aminobenzoic acid (o-ABA) on a glass carbon electrode (GCE). Subsequently, capture anti-CEA (Abl) is covalently linked to poly(o-ABA) (PAB) film, via N-(3-dimethylamminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), and N-hydroxysulfosuccinimid sodium salt (NHS) activation of the carboxyl groups and surface blocking with ethanolamine. Later, the target, carcinoembryonic antigen (CEA), is sandwiched between an electrode surface confined Ab1 and the alkaline phosphatase-labeled signal anti-CEA antibodies conjugated with gold nanoparticles (Ab2-ALP-AuNP bioconjugates). The dual biocatalytic signal amplification for CEA monitoring is achieved by coupling the numerous enzymes loaded on the AuNPs with redox-recycling of the enzymatic products in the presence of the secondary enzyme and the corresponding substrate. The novel dramatic signal amplification strategy, exhibits a good linearity at the studied concentration range from 0.005 to 50 ng mL-1 towards CEA with a detection limit of 2 pg mL-1 (S/N=3). There is a 5-100-fold improvement in detection limit compared to other similar studies. The developed dual signal amplified strategy shows good selectivity, regeneration, stability and acceptable reproducibility. Therefore, the signal amplification approach holds great potential applications in detection of ultra-trace protein biomarkers.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 20675064)the Natural Science Foundation of Chongqing City (Grant No. CSTC-2004BB4149 and 2005BB4100)High Technology Project Foundation of Southwest University (Grant No. XSGX02).
文摘A novel capacitive sensor for pazufloxacin mesilate (pazufloxacin) determination was developed by electropolymerizing p-aminobenzene sulfonic (p-ABSA) and molecularly imprinted polymers (MPs), which was synthesized through thermal radical copolymerization of metharylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of pazufloxacin template molecules, on the gold electrode surface. Furthermore, 1-dedecanethiol was used to insulate the modified electrode. Alternating current (ac) impedance experiments were carried out with a Model IM6e to obtain the capacitance responses. Under the optimum conditions, the sensor showed linear capacitance response to pazufloxacin in the range of 5 ng·mL?1 to 5 μg·mL?1 with a relative standard deviation (RSD) 5.3% (n=7) and a detection limit of 1.8 ng·mL?1. The recoveries for different concentration levels of pazufloxacin samples varied from 94.0% to 102.0%. Electrochemical experiments indicated the capacitive sensor exhibited good sensitivity and selectivity and showed excellent parameters of regeneration and stability.
基金the National Natural Science Foundation of China(Grant No.20675064)Natural Science Foundation of Chongqing City(Grant Nos.CSTC-2004BB4149 and 2005BB4100)the High Technology Project Foundation ofSouthwest University(XSGX02),China
文摘Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and electrostatic interactions onto a self-assembled monolayer configuration is de- scribed in this paper.The enzyme,horseradish peroxidase(HRP),was employed to block the possible remaining active sites of the nano-Au monolayer,avoid the non-specific adsorption,instead of bovine serum albumin(BSA),and amplify the response of the antigen-antibody reaction.Electrochemical ex- periments indicated highly efficient electron transfer by the imbedded Thi mediator and adsorbed nano-Au.The HRP kept its activity after immobilization,and the studied electrode showed sensitive response to CEA and high stability during a long period of storage.The working range for the system was 2.5 to 80.0 ng/mL with a detection limit of 0.90 ng/mL.The model membrane system in this work is a potential biosensor for mimicking the other immunosensor and enzyme sensor.
基金financially supported by the National Natural Science Foundation of China(20675064)the Ministry of Education of China(708073)+1 种基金the Natural Science Foundation of Chongqing City (CSTC-2009BA1003)High Technology Project Foundation of Southwest University(XSGX 02)
文摘An effective electrochemical signal amplification strategy based on enzyme membrane modification and redox probe immobilization was proposed to construct an amperometric immunosensor.L-cysteine@ferrocene functionalized chitosan,which possessed not only efficient redox-activity but also excellent film-forming ability,was coated on the bare glass carbon electrode. Moreover,the thiol groups(SH)in the ferrocenyl compound were used for gold nanoparticles immobilization via the strong bonding interaction,which could further be utilized for the immobilization of antibody biomolecules with well-retained bioactivities.Finally,glucose oxidase(GOD)as the enzyme membrane was employed to block the possible remaining active sites and avoid the nonspecific adsorption.With the excellent electrocatalytic properties of GOD towards glucose,the amplification of antigen-antibody interaction and the enhanced sensitivity could be achieved.Under the optimal conditions,the linear range of the proposed immunosensor for the determination of carcinoembryonic antigen(CEA)was from 0.05 to 100 ng/mL with a detection limit of 0.02 ng/mL(S/N=3).Moreover,the immunosensor exhibited good selectivity,stability and reproducibility, which provided a promising potential for clinical immunoassay.
基金the National Natural Science Foundation of China(Grant No.29705001)the Chinese Education Ministry Foundation for Excellent Young Teachersthe Natural Science Foundation of Chongqing City,China.
文摘A highly sensitive potentiometric immunosensor for the diagnoses of epidemic dis-eases has been developed by means of self-assembly to immobilize hepatitis B surface antibody(HBsAb)for the detection of hepatitis B surface antigen(HBsAg)as a model.At first,the Nafion containing-SO^(-)_(3)groups was immobilized on a platinum electrode surface to absorb the-NH^(+)_(3)groups of antibody molecules via the opposite-charged adsorption technique,in the meantime,hepatitis B surface antibodies were adsorbed onto the surface of Au nanoparticles,then hepatitis B surface antibodies and Au nanopartilces were entrapped into polyvinyl butyral on the surface of Nafion film.The modified procedure was further characterized by electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).The influence and factors influencing the per-formance of resulting immunosensor were studied in detail.The resulting immunosensor exhib-ited sigmoid curve with log HBsAg concentrations,high sensitivity,wide linear range from 26 to 1280 ng·mL^(-1)with a detection limit of 3.1 ng·mL^(-1),rapid potentiometric response(<3 min)and long-term stability(>4 months).Analytical results of clinical samples show that the developed immunoassay is comparable with the enzyme-linked immunosorbent assays(ELISAs)method,implying a promising alternative approach for detecting HBsAg in the clinical diagnosis.
基金Supported by the National Natural Science Foundation of China(Grant No.20675064)the Natural Science Foundation of Chongqing City,China(Grant Nos.CSTC-2004 BB4149,2005 BB4100)High Technology Project Foundation of Southwest University(Grant No.XSGX02)
文摘Alternate adsorption of positively charged colloid-Au nanoparticles(nano-Au^(⊕))and negatively charged hemoglobin(Hb)on L-cysteine(L-cys)modified gold electrode resulted in the assembly of{Hb/nano-Au^(⊕)}n layer-by-layer films/L-cys modified gold electrode.The nano-Au^(⊕)was characterized by transmission electron micrograph(TEM)and microelectrophoresis.The modified electrode interface morphology was characterized by electrochemical impedance spectroscopy(EIS),atomic force mi-croscopy(AFM),cyclic voltammograms(CV)and chronoamperometry.Direct electron transfer between hemoglobin and gold electrodes was studied,and the apparent Michaelis-Menten constant(k_(m)^(app))of the modified electrode was evaluated to be 0.10 mmol·L^(-1).Moreover,the higher activity of proteins in the nano-Au^(⊕)films could be retained compared with the electropolymerization membrane,since the pro-teins in nano-Au^(⊕)films retained their near-native structure.Direct electron transfer between hemoglo-bin and electrode and electrochemically catalyzed reduction of hydrogen peroxide on a modified elec-trode was studied,and the linear range was from 2.1×10^(-8)to 1.2×10^(-3)mol·L^(-1)(r=0.994)with a detection limit of 1.1×10^(-8)mol·L^(-1)H_(2)O_(2).
基金supported by the National Natural Science Foundation of China (20905062 & 20675064)the Natural Science Foundation Project of Chongqing City (CSTC-2009BB5003 & CSTC-2009BA1003)+1 种基金China Post-doctoral Science Foundation (20090460715)research funds from Southwest University (SWUB2008078 & XDJK2009B013)
文摘A sensitive electrochemical immunoassay system for the detection of a protein tumor biomarker through a dual amplified strategy was reported. Firstly, this protocol involves in the electropolymerization of o-aminobenzoic acid (o-ABA) on a glass carbon electrode (GCE). Subsequently, capture anti-CEA (Abl) is covalently linked to poly(o-ABA) (PAB) film, via N-(3-dimethylamminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), and N-hydroxysulfosuccinimid sodium salt (NHS) activation of the carboxyl groups and surface blocking with ethanolamine. Later, the target, carcinoembryonic antigen (CEA), is sandwiched between an electrode surface confined Ab1 and the alkaline phosphatase-labeled signal anti-CEA antibodies conjugated with gold nanoparticles (Ab2-ALP-AuNP bioconjugates). The dual biocatalytic signal amplification for CEA monitoring is achieved by coupling the numerous enzymes loaded on the AuNPs with redox-recycling of the enzymatic products in the presence of the secondary enzyme and the corresponding substrate. The novel dramatic signal amplification strategy, exhibits a good linearity at the studied concentration range from 0.005 to 50 ng mL-1 towards CEA with a detection limit of 2 pg mL-1 (S/N=3). There is a 5-100-fold improvement in detection limit compared to other similar studies. The developed dual signal amplified strategy shows good selectivity, regeneration, stability and acceptable reproducibility. Therefore, the signal amplification approach holds great potential applications in detection of ultra-trace protein biomarkers.
