| Nano biological effects have become a hot point in the research of nano science and technology in the current, the research of interactions between nano particles and biomolecules could help us reveal the effects mechanism at molecular level. Numerous studies indicate that nano particles and proteins form nano-protein crown complexes, such complexes have good biocompatibility, molecular recognition and other function, they have broad application prospects in health care, drug, gene delivery and so on, which has aroused widespread concern in materials science, nanoscience and biotechnology researchers. In the reaction, proteins have surface modification to nano particle, nano particles have impact on the structure and physiological functions of the proteins at the same time. However, it’s very rare that studying the thermodynamics and kinetics of the reaction between nano particles and gelatin, This paper had systematically researched the reaction by a variety of testing method, the results not only provide guidance for synthesis of such bionanocomposites but also provide data accumulation for nano medicine and nano-toxicology. The main researchs and conclusions are divided into the following four sections:1.The preparation of gelatin/AgI bionanocomposites. The gelatin/Ag I bionanocomposites were prepared by one-pot chemical reaction at physiological pH(p H = 7.4) and strong alkalinity(pH = 12.0) respectively with gelatin、AgNO3 and KI as raw material. Using XRD, TEM, DLS to analyze the gelatin/Ag I bionanocomposites, the results showed that nano-AgI were triangular nanoparticles at pH = 7.4 and spherical at p H = 12.0,they have good dispersibility in gelatin solution. The results of UV–vis absorption spectra showed that gelatin coated AgI nanoparticles and played a role of chemical modification on the AgI surface, thereby the gelatin/AgI bionanocomposites has well dispersibility and certain stability.2. The thermodynamics of the direct bonding reaction between nano Ag I and gelatin. Respectively at 298 K, 303 k, 308 k and 313 k, in pH = 7.4 and pH = 12.0 reaction system, using UV-vis spectroscopy to study the thermodynamic characteristics of the direct bonding reaction and then calculated apparent reaction bonding constant, bonding sites and the thermodynamic parameters, the results showed that the reaction was spontaneous, exothermic, and enthalpy driven, there would be strong static electricity between AgI and gelatin.3.The conformational changes of gelatin and mechanism of the direct bonding reaction between nano AgI and gelatin. Studying the conformational changes of gelatin by UV-vis absorption spectra, synchronous fluorescence spectra and so on at pH = 7.4 and pH = 12.0, the results showed that α-helix structure decreased, peptide chains of gelatin tend to stretch. FT-IR showed that Ag+ bonding with carboxy group in gelatin firstly, then I- combined with gelatin/Ag+ to form gelatin/AgI bionanocomposites, AgI nucleated and growed on the site.4. The kinetics of the direct bonding reaction between nano AgI and gelatin and growing mechanism of nano AgI. Using UV-vis to measure the absorbance intensity of the reaction system varying time, then calculated the reaction order of each reagent, activation energy, pre-exponential factor, and other kinetic parameters(activation entropy, activation Gibbs, activation enthalpy) at p H = 7.4 and p H = 12.0, and then getting the reaction rate equation; the growth mechanism of the gelatin/AgI bionanocomposites was preliminarily concluded bonding and Oriented attachment,the generated bionanocomposites are uniformly at the condition of p H = 12.0. |
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