A pH-sensitive controlled release system was proposed in this work, which consists of mesoporous silica nanoparticles(MSNs) functionalized on the pore outlets with poly(4-vinylphenybronic acid-co-2-(dimethylamino)ethyl acrylate) [P(VPBA-DMAEA)]. Four kinds of P(VPBA-DMAEA)-gated MSNs were synthesized and applied for the p H-sensitive controlled release. The results showed that P(VPBADMAEA) can work as a p H-sensitive nanovalve. The release behavior of the hybrid nanoparticles could be adjusted by changing the mole ratio of VPBA and DMAEA. With the increasing of the mole ratio of VPBA,the leakage of the entrapped molecules in the pores of MSNs could be decreased at neutral and alkaline conditions. By altering the p H of buffer from 4.0 to 8.0, the valve could be switched ‘‘on'' and ‘‘off''reversibly. In addition, cells viability results indicated that these P(VPBA-DMAEA)-gated MSNs had good biocompatibility. We believe that these MSNs based p H-sensitive controlled release system will provide a promising nanodevice for sited release of drug delivery.
Yu-Jie ChangXi-Zhen LiuQing ZhaoXiao-Hai YangKe-Min WangQing WangMin LinMeng Yang
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
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 I. 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 to30 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
A novel method for the detection of PDGF-BB has been developed using double-strand DNA-copper nanoparticles(dsDNA-CuNPs) as fluorescent markers. This assay relies on the premise that the aptamerbased probe undergoes a conformational change upon binding with target protein, and subsequently triggers polymerization reaction to generate dsDNA. Then, the resultant dsDNA can be used as a template for the formation of CuNPs with high fluorescence. Under the optimized conditions, the proposed assay allowed sensitive and selective detection of PDGF-BB with a detection limit of 4 nmol/L. This possibly makes it an attractive platform for the detection of a variety of biomolecules whose aptamers undergo similar conformational change.
Xiao-Hai YangShan SunPei liuKe-Min WangQing WangJian-Bo LiuJin HuangLei-Liang He
