The Research And Application Of Nobel Metal Nanoparticles In Molecular Logic Gate And Biochemistry Sensor

In modern science, combined with chemical, biological, physical and medical science constantly, nano techno logy has become one of the most promising frontier fields in analytical chemistry and life science. The nobel metallic nanoparticles can be not only used to build and improve the innovative sensor devices, but also play an important role in electrochemical sensors and biosensors. Using the metal nanoparticles can improve the sensitivity, lower the detection limit of the sensor, and may complete the work that other materials can not accomplish. In addition, the difference of distance between the nanoparticles may lead to its plasmonic change, and the color of the solution may also be changed, hence, metal nanomaterials have potential significance and broad application prospects in colorimetric analysis.The logic gate is not only the basic element of logic operation, but also the core component of the traditional silicon-based computer. Molecular logic gates can be employed in the development of automatic chemical control systems and computer. Molecular logic device has various advantages of small size, large storage capacity, fast response and easy design, and is one of most important cross-disciplinary fields in chemistry, biology and material science. Gold nanoparticles (AuNPs) presented its unique value in the field of nano-devices and biosensors with its unique optical properties, smallsize effect, surface effect and excellent bio compatibility. The main research work of this thesis is as follows:1. A novel chemical colorimetric square wave was named based on plasmonic change during the formation of H2O2-mediated AuNPs. After reasonable definition, the color change of AuNPs solutions can exhibit OFF-ON-OFF mode, which is similar to square wave in the electronics, and the Ag+concentration and pH-dependent chemical colorimetric square wave were successfully exhibited. The Ag+concentration chemical colorimetric square wave can be employed to detect Ag+with its good selectivity. The new concept opens up a new possibility for sensing and may have a potential value and wide use in the analysis and materials chemistry.2. A series of novel logic gates were constructed based on the reasonably integration of the chemical colorimetric square wave with the characteristic discontinuity. The concentration of Ag+and pH value of the solution were defined as inputs of the logic gates, and the AuNPs solution color was defined as output of logic gates to achieve AND, INHIBIT and OR gates. These logic gates are facile, fast and cost-efficient, which tremendously avoided the tedious modification process to prepare AuNPs probe and the complicated operations in common AuNPs crosslinking-based logic gates. We present an instance of nanoscale logic gates based on AuNPs generation-induced plsmonic change, which expands the application of colorimetric logic gates.3. A simple method for detection of mercury ions was established based on the fluorescence quencing of DNA-AgNCs. In this assay, the cytosine-rich DNA was used to synthesize single-stranded DNA-AgNCs with fluorescence. The synthesed DNA-AgNCs with fluorescence was used as sensitive and selective probe for label-free Hg2+detection based on the fluorescence quenching due to the5d10(Hg2+)-4d10(Ag+) metallophilic interaction. This method has the advantage of fast response, low detection limits, and excellent selectivity.