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Wang X.,Qingdao University of Science and Technology | Wang H.,Qingdao University of Science and Technology | Ge T.,Huangdao Entry Exit Inspection and Quarantine Bureau | Yang T.,Qingdao University of Science and Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2015

Recently, functional composites based on chemically modified graphenes (CMGs) and nanostructured conducting polymers have attracted wide interest in the field of electrochemical biosensing. However, comprehensive studies of the effects of various CMGs on the electrochemical properties and biosensing performance of the resulting composites are scarce. In this work, for the first time, we fabricated and deeply evaluated three composites composed of CMGs and sulfonic acid-doped polyaniline nanofiber (namely, CMG-SPAN composites). The CMGs (involving the unreduced form and reduced forms prepared by different reduction routes) were chosen to show the effects of reduction and different preparation routes on the morphologies, electrochemical properties, and DNA biosensing performances of the composites. Notably, the self-redox signals of SPAN in these composites were significantly enhanced and were used for rapid, direct, and label-free DNA detection. Moreover, a preliminary study of the capacitive characteristics of the thermally reduced graphene oxide-SPAN composite was conducted at the end of this work, owing to the potential benefits of the composite in a supercapacitor that were surprisingly observed in this research. The findings of this work will provide useful guides for better understanding of the interaction between CMG and SPAN and for the future development of high-performance functional materials for electrochemical sensors/biosensors and supercapacitors. © 2015 American Chemical Society. Source


Wang X.,Qingdao University of Science and Technology | Nan F.,Qingdao University of Science and Technology | Zhao J.,Qingdao University of Science and Technology | Yang T.,Qingdao University of Science and Technology | And 2 more authors.
Biosensors and Bioelectronics | Year: 2014

A label-free and ultrasensitive electrochemical DNA biosensor, based on thin-layer molybdenum disulfide (MoS2) nanosheets sensing platform and differential pulse voltammetry detection, is constructed in this paper. The thin-layer MoS2 nanosheets were prepared via a simple ultrasound exfoliation method from bulk MoS2, which is simpler and no distortion compared with mechanical cleavage and lithium intercalation. Most importantly, this procedure allows the formation of MoS2 with enhanced electrochemical activity. Based on the high electrochemical activity and different affinity toward ssDNA versus dsDNA of the thin-layer MoS2 nanosheets sensing platform, the tlh gene sequence assay can be performed label-freely from 1.0×10-16M to 1.0×10-10M with a detection limit of 1.9×10-17M. Without labeling and the use of amplifiers, the detection method described here not only expands the application of MoS2, but also offers a viable alternative for DNA analysis, which has the priority in sensitivity, simplicity, and costs. Moreover, the proposed sensing platform has good electrocatalytic activity, and can be extended to detect more targets, such as guanine and adenine, which further expands the application of MoS2. © 2014 Elsevier B.V. Source


Meng L.,Qingdao Technological University | Chen H.,Qingdao Technological University | Ge T.,Huangdao Entry Exit Inspection and Quarantine Bureau | Yang T.,Qingdao Technological University | Jiao K.,Qingdao Technological University
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2016

A variety of sulfonated polyaniline-graphene oxide (SPAN-GNO) nanocomposites based on GNO, aniline (ANI) and m-aminobenzenesulfonic acid (ABSA) are prepared via changing the mole ratio of ANI to ABSA for the comparison of DNA sensing behavior. Self-signals of SPAN-GNO are employed for estimating the effect of preparation conditions [component, monomer composition (mole ratio of ANI to ABSA), and reaction time] on DNA immobilization and hybridization detection. Then, we find herein that the mole ratio of ANI to ABSA plays a lead role over other factors on hybridization efficiency. Meanwhile, the parallel experiments using methylene blue as the classic indicator verifies this conclusion. The results show that, by comparison with other mole ratio SPAN-GNO nanocomposites-modified electrodes, the mole ratio (2:3) exhibits the widest dynamic detection range from 1.0 × 10-14 to 1.0 × 10-6 M, as well as the lowest detection limit (3.06 × 10-15 M). © 2016 Wiley Periodicals, Inc. Source


Zhang Q.,Qingdao Agricultural University | Zhang G.,Qingdao Agricultural University | Yin P.,Huangdao Entry Exit Inspection and Quarantine Bureau | Lv Y.,Qingdao Agricultural University | And 4 more authors.
Chemosphere | Year: 2015

The aim of this study was to evaluate the potential toxicity of spirotetramat to the earthworm Eisenia fetida in a natural soil environment. Many biochemical markers, viz., superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione S-transferase (GST), cellulase, and malondialdehyde (MDA) contents were measured after exposure to 0.25, 1.25, and 2.5mgkg-1 for 2, 7, 14, 21, and 28days. In addition, the comet assay was performed on earthworm coelomocytes to assess the level of genetic damage. The results demonstrate that the SOD activity and MDA content were significantly stimulated by the highest dose (2.5mgkg-1) of spirotetramat for the entire period of exposure. The activities of CAT and POD increased significantly by 2d and 21d, respectively, but the activities of both were significantly inhibited after prolonged exposure (28d). After an initial increase on the 2nd day, the cellulase activity in the high-dose treatment group was significantly inhibited for the entire remaining exposure period. The comet assay results demonstrate that spirotetramat (≤2.5mgkg-1) can induce low and intermediate degrees of DNA damage in earthworm coelomocytes. The results indicate that spirotetramat may pose potential biochemical and genetic toxicity to earthworms (E. fetida), and this information is helpful for understanding the ecological toxicity of spirotetramat on soil invertebrate organisms. © 2015 Elsevier Ltd. Source


Yang T.,Qingdao Technological University | Chen H.,Qingdao Technological University | Ge T.,Huangdao Entry Exit Inspection and Quarantine Bureau | Wang J.,Qingdao Technological University | And 2 more authors.
Talanta | Year: 2015

The nanocomposite of molybdenum disulfide (MoS2) and polyaniline (PANI) was prepared through in situ polymerization of aniline on the surface and interlayer of thin-layered MoS2. Owing to the physisorption of aromatic aniline onto the basal plane of MoS2, the electrochemical properties of MoS2/PANI nanocomposite were improved. And a novel electrochemical sensor based on MoS2/PANI nanocomposite was used to determine chloramphenicol by differential pulse voltammetry, exhibiting excellent performance. The detection range was from 1×10-7 mol L-1 to 1×10-4 mol L-1, with a high sensitivity and a low detection limit of 6.9×10-8 mol L-1. In addition, this sensor can be used for the determination of chloramphenicol in real samples. © 2015 Elsevier B.V. Source

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