The Preparation Of Functional Metal Nanomaterials And Its Application In The Field Of Pharmaciuctic Analysis

Noble metal nanoclusters（NCs） usually consist of several to dozens of atoms with properties regulated by their subnanometer dimensions. It has large specific surface area, high surface activity and fantastic characteristics, including satisfactory water solubility, high quantum-yield, biocompatibility, excellent stability, and outstanding catalytic properties that traditional materials cannot match. It has recently attracted extensive attentions, potentiating it as a novel candidate for biosensing, biolabeling and catalysis. Thus, numerous methods have been developed for synthesizing NCs during the past decades, especially Au and Ag nanoclusters. Au、Ag or Pt with chemical inertness have excellent biocompatibility. Commonly, the size of NCs is about 2 nm between atoms and nanoparticles. Recently, more and more certain research results have been made about metal clusters by nanotechnology applications, such as catalytic oxidation, biological imaging. This article mainly introduced some physical, chemical properties on the basis of gold, silver, copper nanoclusters, and other advantages, including applications of some special areas, the special properties and the prospect for application of nanomaterials. The nanomaterials（Ag、Au、Cu） were synthesized here with the residues of heavy metals in the human body and drug residues as target around environment. According to the fluorescence properties of metal nano clusters and fluorescence quenching effect, the synthesis of the three kinds of gold, silver, copper has the function of fluorescent active nano clusters. Its surface structure characteristics, fluorescence characteristics are studied and the fluorescence quenching and surface fluorescence enhancement effect, also discusses their application on the analysis of the sensor.1. Copper, one of the most abundant excessive element, is very important to human body as necessary trace elements. However, too much copper intruducing can destroy the protein, nucleic acid and lipid, oxygen free radicals. At the same time, increasing serious pollution was caused by the excessive copper ions on the surrounding ecological environment. At present, there are some existing traditional methods for the detection of trace concentrations of Cu²⁺, such as Atomic absorption analysis, Matrix-assisted laser desorption/ionization time-of-flight mass spectrum and so on. But these methods are usually complex, time-consuming and expensive. So the development of high sensitivity, high selectivity, cheap, easy to analysis the copper ion methods are still being valueable. Doxycycline（DC）, one class of tetracycline antibiotics, is widely used in various types of the treatment, such as respiratory and urinary tract infection. It is a broad-spectrum antibacterial compounds. However, excessive intake of DC can cause serious damage to human body health, such as allergic reactions, liver function damage, teeth yellow, gastrointestinal disorders, etc. Complicated sample preparation and operation needed for traditional analysizing DC. Therefore, the simple, sensitive method of detection DC has a certain application prospect.2. Numerous nanomaterials have been reported for synthesizing NCs during the past decades, especially Au and Ag nanoclusters. Nevertheless, scarce approaches have been reported towards synthesizing Cu nanoclusters（Cu NCs）, although copper has been widely playing critical roles in various fields as a member of transition metals. Hg2+, as one of highly toxic metal ions, has exhibited manifold damage on human health by invading respiratory passage, skin, or digestive system. Recently, fluorescent probes have provided new ways for detections of Hg2+. We have creatively synthesized Cu NCs stabilized with L-Cysteine via a simple method for the first time. Subsequently, the Cu NCs was employed to selectively detect Hg2+ on the basis of interactions between Hg2+ and L-Cysteine, thus facilitating to quench their fluorescence. Furthermore, the fluorescent intensity decrease（F0-F） versus the logarithmic plot of Hg2+ concentrations displayed a linear range from 1.0×10-7 mol/L to 1.0×10-3 mol/L with a correlation coefficient of 0.9598, demonstrating an excellent precision of the fluorescent probe. The detection limit of Hg2+ was 2.4×10-8 mol/L at a signal-to-noise ratio of 3. Significantly, this new Cu NCs described here were applied for coding and fluorescent staining, demonstrating may widen potential roads for biosensing and commercial purpose.3. Surface-enhanced fluorescence（SEF） on metal nanostructure, usually happens while a fluorophore locating near the surface of metallic nanoparticles. SEF is believed to occur through the coupling of the fluorophores with radiating plasmons from the metallic particles. Nevertheless, fluorescence is also quenched once the fluorophore is excessively close to the metal core, and maximum enhancement occurs at about 10 nm away from the metal surface. Additionally, the size of the metal core has also been considered as a critical factor affecting enhancement of the fuorophore on nanoparticles. Fortunately, gold nanoparticles functions as one major member of metallic particles for fluorescence enhancement as well as silver nanoclusters playing the role as the fluorophore. Here, we successfully built up a creative SEF system by employing Au NPs to enhance the fluorescence intensity of Ag NCs on the basis of complementary DNA hybridization, and further applied this system for assaying CEA due to its more competitive interactions with CEA-aptamer by comparison to hybridization between complementary DNA sequences. In particular, the fluorescence signals of Ag NCs were first effectively enhanced by Au NPs, and introductions of CEA subsequently competed with the complementary DNA for interacting with CEA-aptamer, leading to SEF destroyed and the enhanced-fluorescence decreased. Importantly, the decrease of fluorescence intensity permitted detecting CEA in a linear range of 0.01 ng/m L-1 to 0.1 ng/m L-1 together with a detection limit of 3 pg/m L-1 at a signal-to-noise ratio of 3, indicating that the sensitivity of this proposed strategy.