Nanoparticles Co-operation With The Research, Protein Interactions And The Package Of Cyclodextrins And Amino Acids

1. Interaction between bovine hemoglobin and Au nanoparticlesThe interaction between Au nanoparticles (Au NPs) has been investigated by ultraviolet-visible, fluorescence; synchronous fluorescence, circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy. The decrease and red shift of 520nm surface plamon band of Au NPs indicate that the BHb can be adsorbed on the surface of Au NPs. The Soret band was decreased gradually with the increased amount of Au NPs, suggesting the detachment of some heme chromophores from their matrixes in BHb. The fluorescence intensity of BHb was quenched by Au NPs, and the analysis of Stern-Volmer equation reveals that the mechanism may be a static quenching procedure. The binding constant K was obtained with calculation of the spectral data. The red shift of synchronous fluorescence spectra reveals that the microenvironments around tryptophan and tyrosine residues were disturbed by Au NPs. The calculation of far UV CD data showed that the secondary structure of BHb had changes, and theα-helical content was decreased. In addition, the FTIR spectra could provide the evidence that the sulphur atoms of cysteine residues, carboxyl oxygen, and nitrogen atoms of peptide or residues probably have the direct chemical bonds to surface of Au NPs.2. Interaction between bovine Serum Albumin and Au nanoparticlesThe interaction between Au nanoparticles (Au NPs) and bovine Serum Albumin (BSA) was investigated using fluorescence and UV-Vis. The experimental results show that the fluorescence quenching of BSA by Au NPs are results of the formation of AuNP-BSA complex; and the quenching mechanism is mainly static quenching. Electrostatic interaction plays a major role in stabilizing the complex. The effect of Au NPs on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy and circular dichroism (CD).3. Interaction between hydroxypropyl cyclodextrin and L-tyrosineIn order to investigate the complexation reaction of L-tyrosine and hydroxypropyl -cyclodextrin (HP-β-CD), the spectroscopy and thermodynamics methods were used as direct methods. However, when more HP-β-CD is added, an increase in the fluorescence signal is observed, attesting the formation of a non-covalent inclusion complex between L-tyrosine and HP-β-CD. In this work, the corresponding constant (KD = 1.3x10^-4 mol ^-1 . L) has been determined from fluorescence data by Benesi-Hildebrand's method. The result indicated that inclusion complexes of HP-β-CD with aromatic amino acids could be formed and the inclusion behaviors were affected by the amount of HP-β-CD, temperature, and pH value. The formation mechanism of the supramolecular systems between the host and the guest was discussed.