Application Of Quantum Dots And Gold Nanoparticles In Pharmaceutical And Protein Analysis

Nanomaterials have attracted increasing interest in several studies owing to their novel optic and electric properties. Recently, the use of quantum dots(QDs) and gold nanoparticles(Au NPs) to develop optical sensors is one of the fastest moving fields. In this dissertation, two new optical sensing systems have been designed for the determination of pharmaceuticals as well as protein. The one method was based on the fluorescence of thioglycolic acid-capped Cd Te QDs could be efficiently quenched or enhanced by targets. While the other was a simple colorimetric sensing platform for trace pharmaceuticals based on the aggregation of Au NPs. The main contents are as follows:(1) Two new optical methods for the sensitive detection of tigecycline based on the fluorescent quenching of Cd Te QDs and the aggregation of Au NPs have been developed. Under optimum conditions, the fluorescence intensity of Cd Te QDs decreased linearly with the increasing concentration of tigecycline in the range of 0.11-35.56 μg m L-1 with a detection limit of 3.93×10-2 μg m L-1. The colorimetric platform is capable of determining tigecycline in ranges from 5.98×10-3 to 1.44×10-1 μg m L-1 and from 0.30 to 2.99 μg m L-1 with a detection limit of 1.07×10-3 μg m L-1. Both methods were validated to the application for the analyses of tigecycline in real samples with recoveries of 94.60%-104.44%.(2) Two new optical methods for the sensitive determination of lincomycin(LCM) have been developed based on the fluorescent enhancement of Cd Te QDs and the aggregation of Au NPs, respectively. Under optimal conditions, the enhanced fluorescence intensity of Cd Te QDs was linearly proportional to LCM concentration in the range of 1-240 μg m L-1 with a detection limit of 2.63×10-1 μg m L-1. For the second method, the absorbance ratios(A650/A519) nm exhibited a good linear correlation to the concentration of LCM in the range of 1.00×10-3-2.00×10-2 μg m L-1 and 3.00×10-2-1.20×10-1 μg m L-1 respectively. The detection limit is 1.27×10-4 ug m L-1. Both methods were used for rapid detection of LCM in real samples with satisfactory results.(3) Two simple and sensitive methods for the determination of etimicin(ETM) have been developed based on the fluorescent enhancement of Cd Te QDs and the aggregation of Au NPs, respectively. Under optimal conditions, the relative fluorescence intensity of TGA-Cd Te QDs was linearly proportional to the ETM concentration in the range of 5.55-266.40 ng m L-1 with a detection limit of 1.28 ng m L-1. While the second platform is capable of determining ETM in ranges from 1.00 to 20.00 ng m L-1 and from 28.00 to 84.00 ng m L-1 with a detection limit of 0.26 ng m L-1. Both the proposed methods were successfully applied for the analyses of ETM in real samples and the recoveries vary from 95.0% to 104.9%.(4) The interaction between TGA-Cd Te QDs with fat mass and obesity-associated(FTO) protein was investigated by fluorescence, UV-visible absorption, synchronous fluorescence and three-dimensional fluorescence spectroscopy. Results revealed that TGA-Cd Te QDs could strongly quench the intrinsic fluorescence of FTO protein with a static quenching procedure. The binding constant and thermodynamic parameters at different temperatures were obtained. In addition, based on the fluorescence enhancement of TGA-Cd Te QDs by FTO protein, a sensitive method for detecting FTO protein was obtained at the linear range of 5.52×10-9-6.62×10-7 mol L-1 with the detection limit of 1.14×10-9 mol L-1. The proposed method were applied to the analysis of FTO protein in synthetic samples with satisfactory results.