Nanoparticles with Active Targeting Ability and Acid Responsiveness for an Enhanced Antitumor Effect of Docetaxel.

Docetaxel (DOC) is commonly used in cancer treatment, especially for breast cancer. However, there are severe side effects in clinical application. In order to deliver docetaxel more effectively, a novel, active targeting acid-responsive polymer called cRGD-PAE-PEG-DSPE was developed. The polymer structure incorporated poly(ethylene glycol) (PEG) as the hydrophilic segment, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) as the hydrophobic segment, and poly(ß-amino ester) (PAE) as the acid-responsive group, which was grafted onto the PEG. Furthermore, c(RGDyC) was grafted onto PAE to confer active targeting capability. Through self-assembly, docetaxel was encapsulated in RAED@DOC. Through in vitro experiments, it was confirmed that RAED@DOC had good serum stability and acid responsiveness, as well as enhanced uptake by MDA-MB-231 cells. Additionally, the antitumor efficiency in vivo and histopathological analysis showed that RAED@DOC exhibited higher antitumor activity and lower systemic toxicity in comparison to free docetaxel. These results suggested that RAED@DOC had considerable potential clinical use.

pH/Redox Dual-Responsive Drug Delivery System with on-Demand RGD Exposure for Photochemotherapy of Tumors.

Purpose: Nanotechnology has been widely used in antitumor research. The complex physiological environment has brought significant challenges to the field of antitumor micelles. The ideal micelles must not only have an invisible surface to extend the circulation time but must also enhance the retention of drugs and cellular internalization at the tumor. Methods: A graded response micelle (RPPssD@IR780/DOC) was designed to self-assemble by cRGD-poly(ß-amino esters)-polyethylene glycol-ss-distearoyl phosphatidylethanolamine (cRGD-PBAE-PEG-ss-DSPE) loaded with docetaxel (DOC) and IR-780 iodide (IR780). The micelles were designed to allow the PEG shell to prolong the blood circulation time in the body and effectively accumulate in the tumor. Subsequently, the acidic microenvironment of the tumor could transform the PBAE to hydrophilic, thereby increasing the size of micelles and exposing cyclic Arg-Gly-Asp (cRGD) peptides to increase the retention and cellular internalization of micelles in the tumor. After tumor cells had captured micelles, the high expression of glutathione in the cells prompted the release of DOC and IR780. Subsequently, the IR780 was stimulated by an 808-nm laser to generate local heat and reactive oxygen species (ROS) to synergize with DOC to treat the tumor. Results: In vitro and in vivo experimental results suggested that RPPssD@IR780/DOC was a potential photochemical effective for the treatment of tumors with non-negligible antitumor activity and good biocompatibility. Conclusion: A dual-response pH/redox delivery system with on-demand RGD exposure was designed to achieve photochemotherapy of tumors with good biosafety and antitumor effects.

RGD-targeted redox responsive nano micelle: co-loading docetaxel and indocyanine green to treat the tumor.

Cancer, also known as a malignant tumor, has developed into a type of disease with the highest fatality rate, seriously threatening the lives and health of people. Chemotherapy is one of the most important methods for the treatment of cancer. However, chemotherapy drugs have some problems, such as low solubility and lack of targeting, which severely limit their clinical applications. To solve these problems, we designed a block copolymer that has a disulfide bond response. The polymer uses RGD peptide (arginine-glycine-aspartic acid) as the active targeting group, PEG (polyethylene glycol) as the hydrophilic end, and PCL (polycaprolactone) as the hydrophobic end. Then we utilized the amphiphilic polymer as a carrier to simultaneously deliver DOC (docetaxel) and ICG (indocyanine green), to realize the combined application of chemotherapy and photothermal therapy. The antitumor efficacy in vivo and histology analysis showed that the DOC/ICG-loaded micelle exhibited higher antitumor activity. The drug delivery system improved the solubility of DOC and the stability of ICG, realized NIR-guided photothermal therapy, and achieved an ideal therapeutic effect.

A smartphone-combined ratiometric fluorescence probe for specifically and visibly detecting cephalexin.

A smartphone-combined dual-emission ratiometric fluorescence probe for specifically and visibly detecting cephalexin was first designed. In the probe, blue-emitting fluorescent carbon dots (CDs) was synthesized and covered with a layer of silica spacer. Red-emitting fluorescent CdTe QDs (r-QDs) was grafted onto the silica nanospheres as an analytical probe. Then, the cephalexin antibody was covalent grafted to the ratio sensor to increase the selectivity. The ratio of fluorescence intensity (FL) of r-QDs and CDs was quenched with the increasing concentration of cephalexin. The detection method has good linear response in the range of 1-500 µM and the detection limit was 0.7 µM. Then portable device based on smartphone detection was constructed according to the color change under UV lamp. The detection image was obtained through the smartphone camera, and the color picker APP installed in the smartphone captured the RGB value of the image. In addition, this method was also used to determine the amount of cephalexin in milk samples with recovery of 94.1%-102.2%. These results showed that it was a portable, simple and visible method to detect cephalexin in food analysis and environmental monitoring.