The Synthesis And Application Studies Based On Cyclodextrins Host-guest Reaction

With the rapid development of supramolecular chemistry, the host-guest supramolecular system was also achieved a higher level. As we know, the cyclodextrin has a lot of advantages such as low toxicity, low price and excellent biological compatibility. In supramolecular system, it not only can improve the solubility of the gest molecules, but also can make the gest molecules more activitively and stability, that makes it becomes the best candidacy for the supramolecular system.In this paper, two kinds of the supramoleculars had prepared by the host-guest reaction. One was 2-hydroxypropyl-β-cyclodextrin- ferrocene derivatives(HP-β-CD/Fc), which was used for drug release. The other one was 2-hydroxypropyl-β-cyclodextrin-10-methylphenothiazine(MPT-HP-β-CD), it was used for detection of reduced glutathione(GSH). In order to improve the catalytic propties of the MPT-HP-β-CD, we also synthesized carboxyl multi-walled carbon nanotube(MWNT) modified MPT-HP-β-CD(MPT-HP-β-CD/MWNT) successfully by the Non-Covalent Interaction between HP-β-CD and MWNT. The main details of this paper is as as follows:(1) A novel hydrophobic ferrocene polymer(P-Fc) was synthesized successfully. Taken the advantage of 2-hydroxypropyl-β-cyclodextrin(HP-β-CD) with hydrophilic outside and hydrophobic inside, The P-Fc was enveloped in the cavity of HP-β-CD successfully to form macromolecular vesicle by a self-assembly process. The structure and morphology of the macromolecular vesicle was characterized by FTIR, 1HNMR, SEM and CV. Rhodamine 6G(R6G) and Doxorubicin hydrochloride(DOX) was used as target drugs and loaded in the vesicles successfully. After added the oxidant, ferrocene was oxidized to dicyclopentadienyl iron, which destroy the vesicles successfully. Thus, the rapid directional release of the drugs was realized. The maximum loading values of R6 G and DOX were 6.89 and 39.06 μg/mg, respectively. And the release rates were 73.7% and 88.2%, respectively. It will increase the utilization level of the drugs and enhance their efficiency.(2)2-hydroxylpropyl-β-cyclodextrin-10-Methylphenothiazine(MPT-HP-β-CD) guest-host compounds were characterized by FTIR, UV-visible absorption spectra, which had excellent interfacial charge transfer ability for the electrochemical detection of GSH in neutral environment. The influence of the scan rates, p H and the temperature for MPT-HP-β-CD modified GC were studied. The activation energy of this reaction is about 38.92KJ/mol. An electrochemical sensor based on MPT-HP-β-CD can be further realized, exhibiting a linear response range from 1.0×10-6mol/L to 5.8×10-4 mol/L for GSH with a low detection limit of 2.87x10-7mol/L, which is a higher values among the non-enzymatic sensors based on MPT. The result demonstrate that the as-prepared MPT-HP-β-CD have a potential application in the development of sensors for enzyme-detection of GSH.(3) 10-Methylphenothiazine/2-hydroxypropyl-β-cyclodextrin guest-host compounds were mixed with multi-walled carbon nanotube to give composite materials MPT-HP-β-CD/MWNT by a two-step method, which were characterized by SEM, FTIR and UV-vis studies. The applications of these composite materials toward the catalytic oxidation of GSH were demonstrated by cyclic voltammetry curve, Ac impedance and the study of the reaction activation energy. These results proved that the presence of MWNT could improve the electrical conductivity and catalytic activity of the composite material. The influences of the p H value, temperature, and scan rate on the catalyst activity were examined. These studies suggest that the MPT-HP-β-CD/MWNT composite materials could be used for the electrochemical detection of GSH with good stability and reproducibility and high sensitivity. The optimal detection concentration is 5 × 10-7~4.95 × 10-5 M and the detection limit is 3.96 × 10-8 M(S/N = 3).