A one-step and facile strategy toward the construction of multicolor polymers via supramolecular selfassembly was proposed.Multicolor polymers were simply prepared by the self-assembly of adamantane-labeled fluorescein,adamantane-labeled rhodamine B and β-cyclodextrin polymers via host-guest interaction between β-cyclodextrin and adamantane.Multicolor polymers showed several interesting properties：multiple emission signatures by a single wavelength excitation,easy tunability,intense fluorescence,high photostablility.In addition,the self-assembly approach implied a facile and flexible strategy for constructing functionalized materials,such as multicolor materials for biological labeling and imaging,and sensing materials for the detection of physiological parameters.
Xiao-Hai YangFang ZhaoLei-Liang HeKe-Min WangJin HuangQing WangJian-Bo LiuMeng Yang
Combining the inhibited aptazyme and molecular beacon （MB）, we developed a versatile sensing strategy for amplified detection of adenosine. In this strategy, the adenosine aptamer links to the 8-17 DNAzyme to form an aptazyme. A short sequence, denoted as inhibitor, is designed to form a duplex spanning the aptamer-DNAzyme junction, which blocks the catalytic function of the DNAzyme. Only in the presence of target adenosine, the aptamer binds to adenosine, thus the inhibitor dissociates from the aptamer portion of the aptazyme and can no longer form the stable duplex required to inhibit the catalytic activity of the aptazyme. The released DNAzyme domain will hybridize to the MB and catalyze the cleavage in the presence of Zn2＋, making the fluorophore separate from the quencher and resulting in fluorescence signal. The results showed that the detection method has a dynamic range from 10 nmol/L to 1nmol/L, with a detection limit of 10 nmol/L.
This work develops a fluorescence approach for sensitive detection of DNA methyltransferase activity based on endonuclease and rolling circle amplification （RCA） technique. In the presence of DNA adenine methylation （Dam） MTase, the methylation-responsive sequence of hairpin probe is methylated and cleaved by the methylation-sensitive restriction endonuclease Dpn 1. The products cleaved by restriction endonuclease Dpn I then function as a signal primer to initiate RCA reaction by hybridizing with the circular DNA template. Each RCA product containing thousands of repeated sequences might hybridize with a large number of molecular beacons （detection probes）, resulting in an enhanced fluorescence signal. In the absence of Dam MTase, neither methylation/cleavage nor RCA reaction can be initiated and no fluorescence signal is observed. The proposed method exhibits a dynamic range from 0.5 U/mL to 30 U/mL and a detection limit of 0.18 U/mL. This method can be used for the screening of antimicrobial drugs and has a great potential to be further applied in early clinical diagnosis.
Pei LiuXiao-Hai YangQing WangJing HuangJian-Bo LiuYing ZhuLei-Liang HeKe-Min Wang
