6 research outputs found

    Synthesis of Multifunctional Cationic Poly(<i>p</i>‑phenylenevinylene) for Selectively Killing Bacteria and Lysosome-Specific Imaging

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    In this work, a cationic polymer was synthesized to bear quaternized <i>N</i>-methyl-imidazole groups in the side chains. Positively charged PPV-M could selectively bind to Gram-negative and Gram-positive bacteria over fungi and exhibit enhanced antibacterial activity with the aid of white light because PPV-M could sensitize oxygen to generate reactive oxygen species (ROS) that would damage bacteria. In addition, green fluorescent and positively charged PPV-M has the ability to enter mammalian cells and be specifically accumulated in lysosome. Moreover, PPV-M could stay in live cells for a relatively long time, which implies that PPV-M has the potential to be a long-term imaging agent

    DNA Hydrogel by Multicomponent Assembly for Encapsulation and Killing of Cells

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    In this work, a new multifunctional assembled hydrogel was prepared by incorporating gadolinium ions (Gd<sup>3+</sup>) with salmon-sperm DNA and polythiophene derivative (PT-COOH) through chelation interactions. Efficient energy transfer from PT-COOH to Gd<sup>3+</sup> ions takes place followed by sensitization of oxygen molecule to generate reactive oxygen species (ROS) under light irradiation. Cancer cells can be encapsulated into the hydrogel in situ as the formation of hydrogel followed by killing by the ROS. Integration of imaging modality with therapeutic function within a single assembled hydrogel is therefore anticipated to be a new and challenging design element for new hydrogel materials

    Synthesis of a Novel Quinoline Skeleton Introduced Cationic Polyfluorene Derivative for Multimodal Antimicrobial Application

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    A new functional polyfluorene derivative containing quinoline skeleton and quarternary ammonium group (QAG) modified side chains (PFPQ) was synthesized and characterized. The multimodal antimicrobial effect toward Gram-negative E. coli was achieved by the dark toxicity resulting from the quinoline skeleton, QAG, and light toxicity resulting from reactive oxygen species (ROS) produced by the main backbone of PFPQ under white light. The mechanism of interaction between PFPQ and bacteria was also demonstrated. PFPQ bound to E. coli mainly through electrostatic interactions causing nearly 50% bacterial death in the absence of light irradiation, and the huge capability of PFPQ to generate ROS under white light opened another bactericidal mode. The killing efficiency was more than 99% upon relatively mild irradiation under white light (400–800 nm) with a light dose of 18 J·cm<sup>–2</sup>. PFPQ with the incorporation of quinoline into the backbones will provide a new versatile strategy to achieve the multimodal antimicrobial effect to fight against resistant bacteria

    New Conjugated Polymers for Photoinduced Unwinding of DNA Supercoiling and Gene Regulation

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    Three cationic polythiophene derivatives (<b>P1</b>, <b>P2</b>, <b>P3</b>) were synthesized and characterized. Under white light irradiation (400–800 nm), they sensitize oxygen molecule in the surrounding to generate reactive oxygen species (ROS) that can efficiently unwind the supercoiled DNA in vitro. Further study shows that this relaxation of the DNA supercoiling results in the decrease of gene (pCX-EGFP plasmid) expression level. The ability of these conjugated polymers for regulating gene expression will add a new dimension to the function of conjugated polymers

    Chemical Molecule-Induced Light-Activated System for Anticancer and Antifungal Activities

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    Except for chemotherapy, surgery, and radiotherapy, photodynamic therapy (PDT) as new therapy modality is already in wide clinic use for the treatment of various diseases. The major bottleneck of this technique is the requirement of outer light source, which always limits effective application of PDT to the lesions in deeper tissue. Here, we first report a new modality for treating cancer and microbial infections, which is activated by chemical molecules instead of outer light irradiation. In this system, in situ bioluminescence of luminol can be absorbed by a cationic oligo­(<i>p</i>-phenylene vinylene) (<b>OPV</b>) that acts as the photosensitizer through bioluminescence resonance energy transfer (BRET) process. The excited <b>OPV</b> sensitizes oxygen molecule in the surroundings to produce reactive oxygen species (ROS) that kill the adjacent cancer cells in vitro and in vivo, and pathogenic microbes. By avoiding the use of light irradiation, this work opens a new therapy modality to tumor and pathogen infections

    Electrochemiluminescence for Electric-Driven Antibacterial Therapeutics

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    The employment of physical light sources in clinical photodynamic therapy (PDT) system endows it with a crucial defect in the treatment of deeper tissue lesions due to the limited penetration depth of light in biological tissues. In this work, we constructed for the first time an electric driven luminous system based on electrochemiluminescence (ECL) for killing pathogenic bacteria, where ECL is used for the excitation of photosensitizer instead of a physical light source to produce reactive oxygen species (ROS). We named this new strategy as ECL-therapeutics. The mechanism for the ECL-therapeutics is dependent on the perfect spectral overlap and energy transfer from the ECL generated by luminol to photosensitizer, cationic oligo­(<i>p</i>-phenylenevinylene) (OPV), to sensitize the surrounding oxygen molecule into ROS. Furthermore, taking into account the practical application of our ECL-therapeutics, we used flexible hydrogel to replace the liquid system to develop hydrogel antibacterial device. Because the chemical reaction is a slow process in the hydrogel, the luminescence could last for more than 10 min after only electrifying for five seconds. This unique persistent luminescence characteristic with long afterglow life makes them suitable for persistent antibacterial applications. Thus, stretchable and persistent hydrogel devices are designed by integrating stretchable hydrogel, persistent ECL and antibacterial function into hydrogel matrices. This novel strategy avoids the employment of external light source, making it simple, convenient and controllable, which exploits a new field for ECL beyond sensors and also opens up a new model for PDT
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