Showing papers by "Shouzhuo Yao published in 2009"
TL;DR: Enlargement of Apt-AuNPs integrated with negatively charged surfactant (SDS) capping could not only improve the detection sensitivity of the impedimetric aptasensor for thrombin but also present a simple and general signal-amplification model for impedIMetric sensor.
Abstract: A simple and ultrasensitive label-free electrochemical impedimetric aptasensor for thrombin based on the cascaded signal amplification was reported. The sandwich system of aptamer/thrombin/aptamer-functionalized Au nanoparticles (Apt-AuNPs) was fabricated as the sensing platform. The change of the interfacial feature of the electrode was characterized by electrochemical impedance analysis with the redox probe [Fe(CN)6]3−/4−. For improving detection sensitivity, the three-level cascaded impedimetric signal amplification was developed: (1) Apt-AuNPs as the first-level signal enhancer; (2) the steric-hindrance between the enlarged Apt-AuNPs as the second-level signal amplification; (3) the electrostatic-repulsion between sodium dodecylsulfate (SDS) stabilized Apt-AuNPs and the redox probe [Fe(CN)6]3−/4− as the third-level signal amplification. Enlargement of Apt-AuNPs integrated with negatively charged surfactant (SDS) capping could not only improve the detection sensitivity of the impedimetric aptasensor fo...
165 citations
TL;DR: The assembly of two aptamer-contained DNA strands integrated with the DNA-AuNPs amplification not only improves the sensitivity of the electrochemical aptas sensor but also presents a simple and general model for bifunctional aptasensor.
Abstract: In this paper, a bifunctional electrochemical biosensor for highly sensitive detection of small molecule (adenosine) or protein (lysozyme) was developed. Two aptamer units for adenosine and lysozyme were immobilized on the gold electrode by the formation of DNA/DNA duplex. The detection of adenosine or lysozyme could be carried out by virtue of switching structures of aptamers from DNA/DNA duplex to DNA/target complex. The change of the interfacial feature of the electrode was characterized by cyclic voltammertic (CV) response of surface-bound [Ru(NH3)6]3+. On the other hand, DNA functionalized Au nanoparticles (DNA-AuNPs) were used to enhance the sensitivity of the aptasensor because DNA-AuNPs modified interface could load more [Ru(NH3)6]3+ cations. Thus, the assembly of two aptamer-contained DNA strands integrated with the DNA−AuNPs amplification not only improves the sensitivity of the electrochemical aptasensor but also presents a simple and general model for bifunctional aptasensor. The proposed apta...
104 citations
TL;DR: In this paper, a boron-doped carbon nanotube (BCNT)-modified glassy carbon (GC) electrode was constructed for the detection of l -cysteine (L-CySH).
99 citations
TL;DR: An electrochemical biosensor was developed for the label-free and selective detection of leukemia cells based on aptamer-modified gold electrode using electrochemical impedance spectroscopy (EIS) technique as discussed by the authors.
Abstract: An electrochemical biosensor was developed for the label-free and selective detection of leukemia cells based on aptamer-modified gold electrode using electrochemical impedance spectroscopy (EIS) technique. The thiol-terminated aptamer (sgc8c) selected for CCRF-CEM acute leukemia cells was self-assembled onto the gold electrode surface as recognition probe, which was characterized by cyclic voltammetry (CV) and EIS using Fe(CN)63−/4− as a redox probe. The surface density of aptamers was determined by chronocoulometric method using a redox cation of Ru(NH3)63+. Upon incubation of the aptamer-modified electrode with CCRF-CEM cells, the electron-transfer resistance (Ret) of Fe(CN)63−/4− on the sensor surface increased substantially. Only a small Ret change of the sensor to the control negative cell line RAJI was observed, indicating the excellent selectivity of the sensor. The selective capture of CCRF-CEM cells on the sensor surface was also confirmed by fluorescence microscopy. A linear relationship between Ret and the logarithmic value of CCRF-CEM cells concentration was found in the range of 1×104 to 1×107 cells/mL, with a detection limit of 6×103 cells/mL. This work provided a simple, convenient, low-cost and label-free method for early leukemia diagnosis.
87 citations
TL;DR: A novel extracting system based on the use of IL surfactants in ultrasonic-assisted extraction followed by HPLC analysis is demonstrated, showing a promising prospect of the IL surfacts in the extraction of active ingredients from herbs.
Abstract: Ionic liquid surfactants are a class of ionic liquids (ILs), which can form micelles in the aqueous solution. In this paper, we demonstrate a novel extracting system based on the use of IL surfactants in ultrasonic-assisted extraction followed by HPLC analysis. No organic solvents were used in the extraction, making this method environmentally friendly and more attractive than the conventional organic solvent-based extraction methods. As an example, this method was applied to determine tanshinones in Chinese herbal medicine Salvia miltiorrhiza bunge. The effect of the carbon chain length of the IL cation, as well as other influencing factors on ultrasonic-assisted extraction, was investigated in detail. Under the optimized conditions, satisfactory extraction efficiency was achieved with the recoveries ranging from 87.5 to 107.6%, and the RSDs were lower than 6%. This work shows a promising prospect of the IL surfactants in the extraction of active ingredients from herbs.
84 citations
TL;DR: The combined treatment with ADM and Se NPs was more effective in inhibiting cell growth than each of the two drugs alone and the drug combination with lower concentrations still exhibited synergism after 24h, suggesting a potential application in cancer therapy.
80 citations
TL;DR: The Boron-doped carbon nanotubes (BCNTs) modified glassy carbon (GC) electrode was obtained simply and used for highly selective and sensitive determination of dopamine (DA) and the selective determination of DA was carried out successfully in the presence of AA.
79 citations
TL;DR: The results demonstrate that the nanoparticles-based amplification strategy is feasible for ATP assay and presents a potential universal method for other small molecular aptasensors.
75 citations
TL;DR: The sequence-length-dependent adsorption of single-stranded DNA on unmodified gold nanoparticles is exploited as a new mechanism for colorimetric nuclease assay and measurement of oxidative DNA damage.
75 citations
TL;DR: A novel label-free electrochemical strategy for monitoring the activity and inhibition of protein kinase is developed, based on the linkage between the phosphorylated peptide and DNA functionalized Au nanoparticles (DNA-AuNPs) by Zr(4+) and the chronocoulometric response of [Ru(NH(3))(6)](3+) absorbed on the DNA-AeNPs.
71 citations
TL;DR: A bienzyme layered assembly on magnetoelastic sensor is used to sense glucose by the horseradish peroxidase-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine, and the formation of the insoluble product on the sensor surface, resulting in shifts of the sensor resonance frequency which are correlated with the amount of H 2 O 2 or glucose.
Abstract: A bienzyme layered assembly on magnetoelastic sensor, consisting of horseradish peroxidase and glucose oxidase is used to sense glucose by the horseradish peroxidase-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine, by H 2 O 2 , and the formation of the insoluble product on the sensor surface. A horseradish peroxidase is used to analyze hydrogen peroxide (H 2 O 2 ) via the biocatalyzed oxidation of tetramethylbenzidine and the precipitation of the insoluble product. The glucose oxidase catalyzed oxidation of glucose produces gluconic acid and H 2 O 2 , and the generated H 2 O 2 effects the formation of the insoluble product in the presence of horseradish peroxidase. The insoluble product accumulated on the sensor surface resulting in shifts of the sensor resonance frequency which are correlated with the amount of H 2 O 2 or glucose. The biosensor response is linear in the range of glucose concentrations of 5–50 mM, with a detection limit of 2 mM at a noise level of ∼10 Hz. The biosensor is applied to determine glucose concentration in urine sample.
TL;DR: It was found that the smoother surface gave a higher surface stress during cell attachment and less cell population on it than the rougher surface, suggesting that the surface-stress measurement can exhibit the difference of adhesion-performance between the healthy and ill-behaved cells.
TL;DR: In this article, a core-shell molecularly imprinting microspheres (MIMs) with trans-resveratrol as the template molecule; acrylamide (AA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, was prepared based on SiO2 micros with surface imprinting technique.
TL;DR: Both the TiO2 NTs and the carbon-modified TiO1 NTs have good biocompatibility supporting the normal growth and adhesion of MG-63 cells with no need of extracellular matrix protein coating, working as an efficient drug delivery vehicle.
Abstract: TiO2 nanotube (NT) arrays have been prepared by anodic oxidation of a Ti sheet, and carbon-deposited TiO2 NT arrays have been prepared by annealing TiO2 NT arrays in carbon atmosphere. The biocompatibility of the as-prepared NT arrays was investigated by observing the growth of osteosarcoma (MG-63) cells on the NT arrays. The application of the TiO2 NT arrays as a drug delivery vehicle was investigated. Both the TiO2 NTs and the carbon-modified TiO2 NTs have good biocompatibility supporting the normal growth and adhesion of MG-63 cells with no need of extracellular matrix protein coating. The one end-opened TiO2 NTs can be easily filled with drugs, working as an efficient drug delivery vehicle.
TL;DR: In this article, a green micellar liquid chromatography (MLC) method was proposed, and the use of a mousellar mobile phase was used to give a more sensitive and rapid separation than in conventional high-performance liquid chromation (HPLC).
TL;DR: A simple, rapid and sensitive high-performance liquid chromatography-diode array detection-fluorescence detection (HPLC-DAD-FLD) method was developed and validated for the analysis of AA I and its metabolites in cell culture medium for the first time and appears to be a suitable tool for the cellular toxicokinetic study with acceptable precisions and recoveries.
TL;DR: This paper proposes a new method for CE separation of inorganic anions based on the use of gemini surfactants as capillary coatings in mixed aqueous-organic solvents with good tolerance of methanol (MeOH) or ACN.
Abstract: This paper proposes a new method for CE separation of inorganic anions based on the use of gemini surfactants as capillary coatings in mixed aqueous-organic solvents. The semipermanent gemini surfactant coatings were facilely prepared by rinsing the capillary with 18-s-18 solutions; they can keep be stable during the electrophoretic runs without surfactants in buffer. The coatings showed a good tolerance of methanol (MeOH) or ACN, e.g. at pH 8.0 and with 40% v/v MeOH or ACN, the EOF magnitude after 60 min of continuous electrokinetic rinsing only decreased by 2.9 or 6.0%, respectively. The coatings were successfully applied to the separation of inorganic anions. Adding organic solvents in buffer can effectively improve the resolution and efficiencies; however, it remarkably prolonged the analysis time due to the suppression of EOF. Interestingly, varying the spacer length of the gemini surfactants can also modulate (improve) the resolution but without any sacrifice of analysis time. This benefit was resulted from the unique chemical structures of gemini surfactants because it introduced a new variable, i.e. the spacer length, to the separation mechanism.
TL;DR: In this article, the authors demonstrated simultaneous separation of acidic and basic proteins using cationic gemini surfactants as buffer additives in capillary electrophoresis, and showed that even at a low concentration (0.1 mmol·L−1) of alkanediyl-α,ω-bis(dimethyl-decadecylammonium bromide) (18-s-18), the wall adsorption of both acidic and Basic proteins could be effectively suppressed under acidic conditions.
Abstract: This paper demonstrated simultaneous separation of acidic and basic proteins using cationic gemini surfactants as buffer additives in capillary electrophoresis. We showed that even at a low concentration (0.1 mmol·L−1) of alkanediyl-α,ω-bis(dimethyloctadecylammonium bromide) (18-s-18), the wall adsorption of both acidic and basic proteins could be effectively suppressed under acidic conditions. Smaller micelle size (e.g., s = 5–8) is more effective for the separation of acidic proteins than larger micelle size (e.g., s 10). Varying the spacer length of gemini surfactants can influence the electrophoretic mobility and selectivity of proteins to achieve the desired separation. Under the optimized conditions, RSDs of the migration time were less than 0.8% and 2.2% for run-to-run and day-to-day assays, respectively, and protein recoveries ranged from 79% to 100.4%. Furthermore, we also investigated the use of gemini surfactant-capped gold nanoparticles (gemini@AuNPs) as buffer additives in protein separation. Introduction of AuNPs into the buffer shortened the analysis time and slightly improved the separation efficiencies. Finally, we presented the applications of this method in the analysis of biological samples, including plasma, red blood cells and egg white.
TL;DR: Amino acid ionic liquids (AAILs) have attracted much attention due to their special chemical and physical properties, especially their outstanding biocompatibility and truly green aspect as mentioned in this paper.
Abstract: Amino acid ionic liquids (AAILs) have attracted much attention due to their special chemical and physical properties, especially their outstanding biocompatibility and truly green aspect In this work, a novel electrochemical biosensing platform based on AAILs/carbon nanotubes (CNTs) composite was fabricated AAILs were used as a novel solvent for glucose oxidase (GOD) and the GOD-AAILs/CNTs/GC electrode was conveniently prepared by immersing the carbon nanotubes (CNTs) modified glassy carbon (GC) electrode into AAILs containing GOD The direct electrochemistry of GOD on the GOD-AAILs/CNTs/GC electrode has been investigated and a pair of reversible peaks was obtained by cyclic voltammetry The immobilized glucose oxidase could retain bioactivity and catalyze the reduction of dissolved oxygen Due to the synergic effect of AAILs and CNTs, the GOD-AAILs/CNTs/GC electrode shows excellent electrocatalytic activity towards glucose with a linear range from 005 to 08 mM and a detection limit of 55 µM (S/N = 3) Furthermore, the biosensor exhibits good stability and ability to exclude the interference of commonly coexisting uric and ascorbic acid Therefore, AAILs/CNTs composite can be a good candidate biocompatible material for the direct electrochemistry of the redox-active enzyme and the construction of third- generation enzyme sensors