The cytotoxicity of chemotherapeutic agents to healthy organs and drug resistance of tumor cells are believed to be the main obstacles to the successful cancer chemotherapy in the clinic. To ensure that anticancer drugs could be delivered to the tumor region, are quickly released from carriers in tumor cells and rapidly escape from endo/lysosomes, YPSMA-1-modified pH-sensitive polymeric micelles, which would be advantageous in recognizing the prostate specific membrane antigen (PSMA), were designed and fabricated for targeted delivery of paclitaxel to tumors based on the pH-sensitive diblock copolymer poly(2-ethyl-2-oxazoline)-poly(D,L-lactide) (PEOz-PLA) and YPSMA-1-PEOz-PLA for treating prostate cancer. HOOC-PEOz-PLA with a critical micelle concentration of 5.0 mg L−1 was synthesized and characterized by 1H NMR and gel permeation chromatography. The prepared YPSMA-1-modified micelles, about 30 nm in diameter, exhibited a rapid release behavior at endo/lysosome pH and a favorable ability of fast endo/lysosome escape as observed by confocal microscopy. More importantly, we evidenced for the first time that both endosome and lysosome escape existed for pH-sensitive micelles via real time tracing using confocal microscopy, and the real time endo/lysosome escape process was also presented. The YPSMA-1-modified micelles were very effective in enhancing the cytotoxicity of paclitaxel by increasing the cellular uptake in PSMA-positive 22Rv1 cells, which was verified the correlation with PSMA expression in tumor cells by flow cytometric analysis and confocal microscopy. Moreover, the active targeting and pH-sensitivity endowed YPSMA-1-modified micelles with a higher antitumor efficacy and negligible systemic toxicity in 22Rv1 xenograft-bearing nude mice compared with unmodified micelles and Taxol®. These results suggested that the application of combining YPSMA-1 modification with pH-sensitivity to polymeric micelles may be one approach in the efficient delivery of anticancer drugs for treating PSMA-positive prostate cancers.
Herein, a novel on-off-on fluorescent chemosensor for copper (II) ion (Cu2+), iron (III) ion (Fe3+) and cysteine is developed simply by the nano-precipitation method. The prepared organic dots with AIEgens (AIE dots) are advantageous over other metal ions in detecting Cu2+, Fe3+with high selectivity and sensitivity by forming agglomerations (on-off). The agglomerations formed by AIE dots and Cu2+redistributed and the fluorescence was obviously recovered in the presence of cysteine (off-on). This sensor has a wide linear range for Cu2+, Fe3+and cysteine. The fluorescent detection limits of AIE dots are calculated to be 107 nM for Cu2+, 120 nM for Fe3+and 78 nM for cysteine, respectively. These results indicate that the AIE dots can be used as a potential probe for Cu2+, Fe3+and cysteine detection.Keywords:fluorescent chemosensor;nanoparticle;aggregation-induced emission;ion detection;cysteine detection
As one of the most promising candidates for dynamic information storage, intelligent gels with tunable optical properties under external stimuli have received great attention. The implementation of transparency variation for information display is a favorable and versatile strategy but still faces the challenge of on-demand encryption–decryption. Herein, an optical tunable organohydrogel is prepared, which has interpenetrating heterogeneous networks consisting of hydrophilic poly(N,N-dimethylacrylamide) (PDMA) and hydrophobic polyoctadecyl methacrylate (PSMA). The long alkane side chains of PSMA endow the organohydrogel with the capacity of crystallization–melting transitions under the stimulus of heat, accompanied by transparent–opaque switching. In addition, the variations of transparency can also be achieved by water-induced hydrophobic association and microphase separation, resulting from the unique heterogeneous networks of the organohydrogel. Based on the abovementioned two aggregated structures, various pieces of information can be loaded on the organohydrogel by light writing or water printing with the assistance of masks. The coded information can be encrypted and decrypted by solvent replacement and temperature switching. This elaborately designed organohydrogel can act as an effective communication platform with an improved security level and ignite the sparks of developing novel information storage materials.
危险品化学品经营许可证（带存储）