Biomedical subjects

Fengli Qu

Publications and source records attributed to Fengli Qu.

4 recordsLinked to original sources

PubMed2006

Electrochemical biosensing utilizing synergic action of carbon nanotubes and platinum nanowires prepared by template synthesis.

Platinum nanowires (PtNWs) prepared by electrodeposition method with the help of porous anodic aluminum oxide (AAO) templates have been solubilized in chitosan (CHIT) together with carbon nantubes (CNTs) to form a PtNW-CNT-CHIT organic-inorganic system. The resulting PtNW-CNT-CHIT material brings capabilities for utilizing synergic action of PtNWs and CNTs to facilitate electron-transfer process in electrochemical sensor design. The PtNW-CNT-CHIT film modified electrode offered a significant decrease in the overvoltage for the hydrogen peroxide and showed to be excellent amperometric sensors for hydrogen peroxide at -0.1 V over a wide range of concentrations, and the sensitivity is 260 microAmM-1cm-2. As an application example, by linking glucose oxidase (GOx), an amplified biosensor toward glucose was prepared. The glucose biosensor exhibits a selective determination of glucose at -0.1 V with a linear response range of 5 x 10(-6) to 1.5 x 10(-2)M with a correlation coefficient of 0.997, and response time <10s. The high sensitivity of the glucose biosensor is up to 30 microAmM-1cm-2 and the detection limit was 3 microM. The biosensor displays rapid response and expanded linear response range, and excellent repeatability and stability.

Biosensing Techniques↗

PubMed2006

Platinum nanowire nanoelectrode array for the fabrication of biosensors.

Platinum nanowire arrays can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm and the height about 2 microm. The nanowire array prepared by the proposed method can be considered as nanoelectrode array (NEA) with nanoelectrode density of 5 x 10(8)cm(-2). While the NEA can improve the signal-to-noise ratio and decrease the detection limit, the high surface area of the platinum NEA circumvents the problem of conventional platinum electrodes associated with the limited electroactive site. The platinum NEA can direct response to hydrogen peroxide at low potential of 0 V with wide linear range (1 x 10(-7)-6 x 10(-2)M) and sensitivity 50 times larger than that of the conventional platinum electrode. With the absorption of glucose oxidase onto the ordered NEA surface, the spatially patterned glucose oxidase improves greatly the resulting biosensor. The biosensor can achieve interference free determination of glucose with wide linear range (10(-6)-3 x 10(-2)M). The sensitivity of the glucose biosensor is one-fifth of the sensitivity toward hydrogen peroxide, indicating high efficiency of signal transduction. The biosensor was used to determine glucose in real blood samples, and the glucose contents determined by the present biosensor were in agreement with the results of existing method.

Biosensing Techniques↗

PubMed2006

Amperometric determination of bovine insulin based on synergic action of carbon nanotubes and cobalt hexacyanoferrate nanoparticles stabilized by EDTA.

A simple approach is proposed for the synthesis of cobalt hexacyanoferrate nanoparticles (CoNPs) with uniform shape and size controlled by ethylene diamine tetraacetic acid (EDTA) as a stabilizer. A sensitive amperometric biosensor for insulin has been prepared using glassy carbon electrodes by solubilization of carbon nanotubes (CNTs) in chitosan (CHIT) together with CoNPs synthesized by the new methodology. The CoNP-CNT-CHIT organic-inorganic system exerts a synergistic effect, resulting in the remarkably enhanced insulin currents owing to the superior electron-transfer ability of CNTs and the excellent reversible redox centers of CoNPs. High-resolution transmission electron microscopy (HRTEM) was used to provide closer inspection of the CoNPs. The effects of alkali metal cations and the concentrations of CNTs and CoNPs on the voltammetric behavior of the film-modified electrode were also investigated. In pH 6.98 phosphate buffer (PB) at +0.7 V (vs. SCE) the insulin biosensor exhibits a linear response range of 0.1-3 microM with a correlation coefficient of 0.98, and the detection limit (S/N=3) is determined to be 40 nM, the stability of the biosensor was tested and found satisfactory. There is great promise for in vivo measurements of this important hormone.

Amino Acid Sequence↗

PubMed2005

Amperometric biosensor for choline based on layer-by-layer assembled functionalized carbon nanotube and polyaniline multilayer film.

Conducting polymer film was prepared by electrochemical polymerization of aniline. Multiwalled carbon nanotubes (MWNTs) were treated with a mixture of concentrated sulfuric and nitric acid to introduce carboxylic acid groups to the nanotubes. By using the layer-by-layer method, homogeneous and stable MWNTs and polyaniline (PANI) multilayer films were alternately assembled on glassy carbon (GC) electrodes. Conducting polymer of PANI had three main functions: (i) excellent antiinterference ability, (ii) protection ability in favor of increasing the amount of the MWNTs immobilized on GC electrodes, and (iii) superior transducing ability. The protection effect of PANI film and the electrostatic interaction between positively charged PANI and negatively charged MWNTs both attributed to immobilizing abundant MWNTs stably, thereby enhancing the catalytic activity. The layer-by-layer assembled MWNTs and PANI-modified GC electrodes offered a significant decrease in the overvoltage for the H2O2 and were shown to be excellent amperometric sensors for H2O2 from +0.2V over a wide range of concentrations. As an application example, by linking choline oxidase (CHOD), an amplified biosensor toward choline was prepared. The choline biosensor exhibited a linear response range of 1x10(-6) to 2x10(-3) M with a correlation coefficient of 0.997, and the response time and detection limit (S/N=3) were determined to be 3 s and 0.3 microM, respectively. The antiinterference biosensor displays a rapid response and an expanded linear response range as well as excellent reproducibility and stability.

Alcohol Oxidoreductases↗