Design And Application Of Novel Micro-and Nano-Interface For Environment And Life Analysis

The deeply development of science and technology has brought up the most important tools for discovering the natural world at macro, micro and nano level. As we known, many chemical and physical changes main occurred on the interface of two-phase separation. As particle size of the micro-nano interface decreases, the specific surface area and the chemical reaction rates will greatly increase. Study on interface chemistry by using novel nano materials, can effectively increase the contact area of reactants and the reaction rates. Therefore, building novel functional micro-nano interface will play a pivotal role in the field of biology, chemistry, physics and interdisciplinary.SPCE can be used for in-situ, rapid determination in environment monitoring, especially for the determination of heavy metal ions, pesticide and organic infectant, due to its particular advantage, such as disposable, low-cost, easy-to-use. Herein, a novel in-situ catechol biosensor with rapidly responsibility was designed based on multi-walled carbon nanotube modified SPCE. The sensor response current linear with the catechol concentration in a wide range of 1～84μM, and a low determination limit of 0.45μM.A portable analysis system has been successfully developed for on-site heavy metal ion detection, which can be used in the determination of Cd2+ in the tap water and river water samples. The AuASEs exhibit a possible alternative to the hanging mercury drop electrode due to their excellent characters in mechanical stability, repeatability and electrochemical response. The disposable AuASEs represent a reliable and simple electrochemical sensor design, which has high sensitivity and selectivity towards Cd2+. A linear relationship between the reduction current and Cd2+concentration is obtained ranging from 8.4 ppb to 500 ppm with a low detection limit of 2.6 ppb in PBS (pH=5.5). Furthermore, the AuASEs shows sensibly electrochemical response in environmental water samples containing Cd2+. As a new USB electrochemical device, the analysis system with AuASEs will bring more comprehensive approach to the on-site, rapid, low-cost and environmental monitoring, especially for heavy metal ion monitoring of sudden environmental pollution accident in China. By constant potential voltammetry and cyclic voltammetry were prepared by electrodeposition in two steps based on hydrophobic nano screen-printed electrodes modified Golden interface that has good hydrophobic properties, while showing good electrochemical response can be developed based on the results of this study performance of electrochemical sensors. In addition, the study of the nano-modified screen-printed electrodes Golden interface's performance in the SERS, the results show that the red excitation SERS enhancement for its significant effect, presumed to be modified gold nanoparticle interface between stacked together after due to the coupling. In addition to using this interface, a quantitative analysis of pyridine, in a certain range, pyridine concentration and Raman peak intensity of a significant linear relationship.A novel H2O2 biosensor is fabricated to perform a direct electrochemistry between Mb and the modified electrode. The Mb immobilized in SF/MWCNTs matrix can retain its catalytic activity toward H2O2. The biosensor exhibits a rapid response time, a high sensitivity and a good linear range with a low detection limit of 0.36μM. These results indicated the SF/MWCNTs matrix can provide a favorable microenvironment for direct electron transfer between the Mb and the interface of pSPCE.The present investigation reveals that the GO/SPCEs shows excellent electrocatalytic oxidation activity towards NADH with a remarkable decrease in overpotential and enhanced stability compared to the performance observed at a bare SPCEs and rGO/SPCEs. This could be attributed to the oxygen-containing functional groups on the surface of SPCEs, rGO/SPCEs and GO/SPCEs. The results of XPS provide a solid support to the oxygen-containing groups of edge plane sites on the surface of SPCEs, rGO/SPCEs and GO/SPCEs. The disposable SPCEs could act as the edge plane graphite electrode in the electrocatalytic oxidation of NADH. The detection range of GO/SPCEs is 0.8 to 500μM with a lower detection limit of 0.10μM. These facts offer a boarder application in the disposable amperometric NADH biosensors with immobilizing GO on the SPCEs surface.A novel method based on dark field microscopy was used to detect the NADH cofactor or to follow NAD+-dependent biocatalyzed transformations. The method involves the NADH-mediated reduction of Cu2+ onto GNPs acting as catalysts for the formation of Au@Cu core-shell nanoparticles. We find that the PRRS spectra of the Au@Cu nanoparticles are red-shifted as the concentration of NADH increases or as the concentration of the substrate generative NADH, in the presence of NAD+ and the cofactor-dependent enzyme, increases. The fact the each individual GNP acts as a probe for the local quantified detection of NADH enable the miniaturization of the sensor system, and the use of microscale droplets as analysis volumes. Furthermore, our studies demonstrated the ability to use DFM and scattering spectra to monitor in vitro the metabolism in HeLa cancer cells, and particularly to probe the effect of an anti-cancer drug (taxol) on the cell metabolism. We anticipate that these discoveries add important tools for the imaging of cells, mapping the distribution of NADH in cells, to follow in vitro intracellular metabolic pathways, and to screen drugs affecting cell metabolism.