| Serum albumins(SA) is extremely rich in plasma, which to maintained the main plasma osmotic pressure. It can reversibly combine with most of the substances in the blood, which enable the storag, transportation and metabolism of drugs in the body.Therefore, from a different perspective studying the interaction of proteins and drug molecules for drug storage and transportation is of great importance. Recently, the interactions of bovine serum albumin(BSA) as a carrier protein with a lot of drugs have been reported. However, using endogenous fluorescence changes of biological macromolecules as a fluorescent probe for quantitative analysis of drugs are less reported.Carbon quantum dots(CDs) are as a new type of fluorescence probe, which have been widely used for biological imaging and biomarkers research fields. Because it not only has a similar traditional luminescent properties of semiconductor quantum dots, but also owns the characteristics of small size, high photostability and low cytotoxicity. CDs have become the research hotspot in recognition and detection of metal ion, except for analysis of drugs. This research obtained the high quantum yield CDs by employing the cheap carbon source, studied the interactions with drugs by using BSA and CDs as fluorescent probes, and analyzed its performance to realize the quantitative detection of drugs. There are two parts in the paper: one is literature review, the other is research report, which including the following five contents:1. In p H 7.40 Tris-HCl buffer solution, a novel method for detection of phenolphthalein has been developed by using BSA as a fluorescence probe, based on the phenolphthalein could quench the intrinsic fluorescence of BSA remarkably, and phenolphthalein showed a good linear relationship with ΔF in8.0×10-9mol/L~2.8×10-7mol/L(0.9955) range. The detection limit was 5.4×10-9mol/L, therelative standard deviation was 0.86%(n=5, c=2.0×10-7mol/L). The method has been used for the determination of phenolphthalein in samples with satisfactory results. At the same time, the interaction mechanism of phenolphthalein and BSA was investigated by fluorescence lifetime, the temperature effect on the quenching constants and UV-Vis absorption spectrometry, the mechanism of fluorescence quenching was confirmed combining by both static quenching and non-radiation energy transferring. The binding site number and apparent binding constant were measured according to Stern-Volmer equation. The distance between BSA and phenolphthalein was obtained based on the F?rster nonradiative energy transfer theory. The main sorts of binding force between phenolphthalein and BSA was electrostatic force. Mean while, the effect of phenolphthalein on the conformation of BSA was also analyzed by using synchronous fluorescence spectroscopy.2. In p H=6.60 B-R buffer solution, the cefdinir could quench the intrinsic fluorescence of BSA, and in the presence of Cu2+ the fluorescence intensity of BSA decreased remarkably by cefdinir. Under the optimum experimental conditions, cefdinir showed a good linear relationship with ΔF in 6.0×10-9mol/L~3.6×10-7mol/L(0.9997)range. The detection limit was 3.3×10-9mol/L, the relative standard deviation was 0.35%(n=5, c=8.0×10-8 mol/L). The method has been used for the determination of cefdinir in samples with satisfactory results. The interaction mechanism was investigated by fluorescence lifetime,quenching constants and UV-Vis absorption spectrometry under imitated physiological conditions. The mechanism of fluorescence quenching was a static quenching process, the binding site number n was 1, the mainly force between cefdinir and BSA was Van der Waars. Mean while, the effect of cefdinir on tyrosine residues was also analyzed by using synchronous fluorescence spectroscopy.3. Under the condition of acid, a novel method for determination of aceclofenac has been developed using BSA as a fluorescence probe, based on the fluorescence intensity of BSA decreased remarkably by aceclofenac. Under the optimum experimental conditions, aceclofenac showed a good linear relationship with ΔF in 4.0×10-8mol/L~2.8×10-6 mol/L(0.9963) range. The detection limit was 3.1×10-8 mol/L, the relative standard deviation was 0.43%(n=5, c=8.0×10-7mol/L). The method has been used for the determination of aceclofenac in samples with satisfactory results. The interaction mechanism between BSA and aceclofenac was investigated by quenching constants and UV-Vis absorption spectrometry under imitated physiological conditions. The binding site number, binding constant, the combination of the specific position and the main sorts of binding force between BSA and aceclofenac was obtained based on the Stern-Volmer equation. Mean while, the effect of aceclofenacthe on the conformation of BSA was also analyzed.4. Graphene quantum dot(GQDs) were synthesized by the pyrolysis of citric acid,its fluorescent quantum yield was remarkly increased by PEG2000 modified.Luminescence characteristics of GQDs were studied by fluorescence spectroscopy,ultraviolet-visible spectroscopy, infrared spectroscopy. A novel method for quantitative determination of trace carbazochrome(CBZC) has been developed using GQDs as a fluorescence probe, based on the fluorescence quenching of GQDs in Tris-HCl buffer solution. A wide range of reaction parameters such as concentration of GQDs, reaction time, surfactant, sorts and amount of buffer were examined. The screening results showed that the ΔF was linearly related with the carbazochrome concentration from4.0×10-7mol/L to 1.2×10-5mol/L(0.9956) with the detection limit of 1.5×10-7 mol/L. The relative standard deviation was 0.15%(n=5, c=4.0×10-6mol/L), when the concentration of GQDs was 2.3×10-3mol/L. The method has been used for determination of carbazochrome in drugs with the recoveries of 97.46%~101.6%. The interaction mechanism and main sorts of binding force between GQDs and carbazochrome were investigated by the temperature effect on the quenching constants and UV-visible absorption spectrometry.5. A new N-doped carbon dots(NCDs) has been prepared by using the microwave-assisted technique with triethanolamine(TEA). Herein, TEA can serve as both a carbon source and a nitrogen source. Luminescence characteristics of NCDs werestudied by UV-Vis spectroscopy and the fluorescence lifetime, as well as the different excitation wavelengths on the influence of the fluorescence intensity of NCDs were investigated. A novel method for quantitative determination of sulfasalazine(SSZ) has been developed using NCDs as a fluorescence probe, based on the fluorescence quenching of NCDs in p H 6.37 B-R buffer solution. The ΔF was linearly related with the sulfasalazine concentration from 4.0×10-7mol/L~1.0×10-5mol/L(0.9971) with the detection limit of 1.1×10-7 mol/L, and the relative standard deviation was 0.25%(n=5,c=8.0×10-6mol/L). When the concentration of NCDs was fixed value, the method has been used for the determination of sulfasalazine in samples with the recoveries of97.50%~103.1%. The interaction mechanism between NCDs and sulfasalazine were investigated, which revealed a dynamic quenching behavior, and the main sorts of binding force was hydrophobic force according to the thermodynamic parameters. |
