The Interaction Between Hemoglobin And Ag,CdS And CdSe Nanoparticles And Its Biological Application

Chapter one: In this chapter, the application of nanoparticles for biological technology is summarized, including the application for the clinical diagnostics, DNA array technology, and directed delivery of drugs. The progress in hemoglobin and its interaction with nanoparticles, such as Ag,CdS,and CdSe nanoparticles, are reviewed. Lastly, we introduce the research success of our team and the significance of this article.Chapter two: In this paper, the interaction between bovine hemoglobin (BHb) and Ag nanoparticles (Ag NPs) has been investigated by ultraviolet-visible (UV-Vis), fluorescence, synchronous fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopies. The decrease and red-shift of 415-nm surface plamon band of Ag NPs indicates that the BHb can be adsorbed on the surface of Ag NPs. The Soret band decreases gradually with the increasing amount of Ag NPs, suggesting that the detachment of some heme chromophores from their matrixes in BHb. The fluorescence intensity of BHb is quenched by Ag NPs, and the analysis of Stern-Volmer equation reveals that the mechanism is a static quenching procedure. The binding constant K was obtained with calculation of the spectra data, and the order of magnitude of K is found to be 109~1010. The blue-shift of synchronous fluorescence spectral reveals that the microenvironments around tryptophan and tyrosine residues are disturbed by Ag NPs, which induced to be buried inside the hydrophobic cavities. The calculation of far-UV CD data show that the secondary structure of BHb has slight changes, and theα-helical content decreases. In addition, the FT-IR spectra provide the evidence that the sulphur atoms in cysteine residues, carboxyl oxygen, and nitrogen atoms in peptide or residues probably have the direct chemical bonds on surface of Ag NPs.Chapter three: In this paper, the interaction between Human hemoglobin (HHb) and CdS quantum dots (CdS QDs) has been investigated by ultraviolet-visible (UV-Vis), fluorescence, synchronous fluorescence and Fourier transform infrared (FT-IR) spectroscopies. The Soret band decreases gradually with the increasing amount of CdS QDs, suggesting that the detachment of some heme chromophores from their matrixes in BHb. The fluorescence intensity of amino residues in Hb is quenched by CdS QDs, and the analysis of Stern-Volmer equation reveals that the mechanism is a static quenching procedure when the concentration of CdS QDs below 9.57×10?7 mol·L?1; if the concentration of CdS QDs continues to increase, the quenching mechanism will be dynamic. The level of binding constants is determined to be 106 by UV-Vis and Fluorescence data. By analyzing the thermodynamic parameters, standard enthalpy change (?H0), standard entropy change (?S0) and Gibbz free energy change (?G0), we conclude that electrostatic force and hydrophobic interaction are involved in the binding process. The environment of tryptophan is altered by CdS QDs. In addition, the results of FT-IR spectra provide the evidence that carboxyl oxygen and nitrogen atoms in peptide or residues probably have the direct chemical bonds on surface of CdS QDs.Chapter four: A novel method for the determination of trace human hemoglobin (HHb) using the fluorescence enhancement of CdSe quantum dots (QDs) is described. The CdSe QDs have been prepared and characterized, which have uniform size and high photostability. Under the optimum conditions, the fluorescence enhancement is linearly proportional to the concentration of Hb over the range of 0.375～105 ng·ml?1. Detection limit was 0.18 ng·ml?1, and the relative standard deviation is 0.41% (9 determinations) for 30 ng·ml?1 of Hb. Most of metal ions and amino acids do not significantly influence this method. Human serum albumin (HSA) has some influence but is permitted at 20 times of Hb within±5% error. The proposed method is applied to the determination of Hb in human blood with satisfactory results.