Cyclodextrin Polymers And Nucleic Acid Probes For The Detection Of Small Molecules And DNA

Because of the synergistic effect, crosslinking effect, neighboring group effectand multivalent binding effect, cyclodextrin polymers (CDPs) have shown bettermolecular recognition cabilities than cyclodextrin (CD) monomers. Cyclodextrinpolymers used in analyses and detection can enhance the fluorescence signal ofinclusive guest molecules and thus improve the response sensitivity. In this thesis,cyclodextrin polymer-based nucleic acid fluorescent probes have been developed todetect small molecules and DNA. The contents of this thesis are as follows：1. Four types of cyclodextrin polymers, including linear-β-CDP (L-β-CDP),linear-γ-CDP (L-γ-CDP), pendant-β-CDP (P-β-CDP), pendant-γ-CDP (P-γ-CDP) weresynthesized. Four types of complex probes, which consist of CDPs and dual pyrenelabeled DNA (Py-DNA), were utilized for quantitative detection of amantadine. Theresults showed that P-β-CDP/dPy-DNA complex probe has the highest detectionsensitivity for amantadine. The detection limit was0.1mmol/L. The method alsoshowed good specificity.2. Based on competitive host-guest interaction between P-β-CDP/dPy-DNAprobe and cholesterol, and fluorescence enhancement of P-β-CDP for pyrene, aswitchable fluorescent detection method for cholesterol has been developed.dPy-DNA was included into the cavity of P-β-CDP to form an inclusion complex,resulting in a fluorescence enhancement signal. Upon addition of cholesterol,dPy-DNA presented inside the P-β-CDP host can be selectively substituted bycholesterol, leading to dPy-DNA away from the P-β-CDP and correspondingfluorescence attenuation. Thus, the fluorescence switch-off enables us to quantitatecholesterol in aqueous media. The detection limit of cholesterol is0.1μmol/L.3. Based on fluorescence enhancement of linear β-cyclodextrin polymer(L-β-CDP) for pyrene labeled DNA (dPy-DNA-p53), a new detection method for p53gene fragment has been developed. dPy-DNA-p53was included into the cavity ofL-β-CDP to form an inclusion complex, resulting in a fluorescence enhancementsignal. Upon addition of p53gene fragment, dPy-DNA-p53presented inside theL-β-CDP host can be released, leading to dPy-DNA-p53away from the L-β-CDP andcorresponding fluorescence attenuation. Thus, the fluorescence quenching enables usto quantitate p53gene in aqueous media. The method provided a new approach for thedetection of DNA strands.