| The abuse and spread of drugs have become an increasingly serious problem in the world, such as methamphetamine (MA),3,4-methylenedioxy-methamphetamine (MDMA).The popularity of drugs not only destroy the family but also lead to the spread of diseases. Therefore, the rapid detection of drugs would possess great value in applications of medical treatment and law enforcement. The commonly used methods of detecting drugs include Gas Chromatography (GC), High Performance Liquid Chromatography (HPLC), Gas chromatography-Mass spectrometer (GC-MS), enzyme linked immunosorbent assay (ELISA), and immuno-colloidal gold technique (ICGT). In view of fingerprint characteristics, non-destructive examination, high sensitivity, and repeatability of advantages for Surface-enhanced Raman Scattering (SERS) detection, it has been applied in the detection of drugs. The addicted drugs is typically detected in human body fluids, for example urine, blood, saliva, and hair. Here, we choose human urine for test system, which is easy to collected in a non-destructive examination. However, a urine is a complex system, and the complicated composition in urine can interference the detection of drugs seriously. In addition, the simple SERS substrates have cannot satisfied SERS sensitive and repeatable detection of drugs.First of all, we review the history of SERS and its widely applications inbioscience, cultural relics and public security. Simultaneously, we will focus on the latest progress of one-dimensional, two-dimensional and three-dimensional SERS substrates prepared-through self-assembly method and the-commonly used method for drug testing.In chapter 2, an oil-in-water emulsion method is used to assemble monodisperse Ag nanoparticles in cyclohexane into spherical colloidal superstructures in water phase, which create three-dimensional SERS hotspots, extend the hotspots into the third dimension along the z-axis, and take full advantage of this active volume. Simultaneously, we develop a rapid separation and purification of amphetamines in real human urine samples by utilizing cyclohexane as extraction solvent.The whole process can be completed in 5 mins. The extraction rates are larger than 80%, which was examined by UPLC. The identical transmission medium, CYH, in both the self-assembly and purification processes provided a high acceptance of the target analytes in the highly-active 3D SERS hotspots. The results revealed that 3D SERS hotspots of colloidal superstructures realized the highly sensitive and reproducible identification and detection of chemical molecules in both aqueous and organic phases, certainly including the purified amphetamines from various human urine samples. By virtue of a modified mathematical procedure identification algorithm, we could rapidly and accurately recognize weak Raman signals of different drugs at ultratrace level of 10 ppb in human urine sample and clearly distinguish different kinds of drugs.In chapter 3, the two-dimensional gold nanorods in different dimensions were assembled by the use of methoxy-mercaptopoly (ethylene glycol) (mPEG-SH) to detect the amphetamines in human urine, which can create a large number of homogeneous hotspots in two-dimensional space. The amphetamines in thirty experimenter urine samples from Hefei cancer hospital of Chinese academy of sciences, were rapidly separated and purified. The self-assembled gold nanorod realized the highly reproducible identification and detection of amphetamines, improved the precision of detection, and reduced the occurrence of a raise positive.In chapter 4, the self-assembled gold nanorod was used as the basement to detect the drugs in real human urine combined with a portable Raman spectrometer, which realized the practicability of drugs SERS detectioa Our platform for detecting drugs promises a great prospective towards a rapid, reliable and on-spot analyzer.Finally, we summarized the past work and proposed the outlook for the further research. |
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