Biocompatible Palladium Nanoparticles Prepared Using Vancomycin for Colorimetric Detection of Hydroquinone.

Hydroquinone poses a major threat to human health and is refractory to degradation, so it is important to establish a convenient detection method. In this paper, we present a novel colorimetric method for the detection of hydroquinone based on a peroxidase-like Pd nanozyme. The vancomycin-stabilized palladium nanoparticles (Van-Pdn NPs, n = 0.5, 1, 2) were prepared using vancomycin as a biological template. The successful synthesis of Van-Pdn NPs (n = 0.5, 1, 2) was demonstrated by UV-vis spectrophotometry, transmission electron microscopy, and X-ray diffraction. The sizes of Pd nanoparticles inside Van-Pd0.5 NPs, Van-Pd1 NPs, and Van-Pd2 NPs were 2.6 ± 0.5 nm, 2.9 ± 0.6 nm, and 4.3 ± 0.5 nm, respectively. Furthermore, Van-Pd2 NPs exhibited excellent biocompatibility based on the MTT assay. More importantly, Van-Pd2 NPs had good peroxidase-like activity. A reliable hydroquinone detection method was established based on the peroxidase-like activity of Van-Pd2 NPs, and the detection limit was as low as 0.323 µM. Therefore, vancomycin improved the peroxidase-like activity and biocompatibility of Van-Pd2 NPs. Van-Pd2 NPs have good application prospects in the colorimetric detection of hydroquinone.

Biomineralized synthesis of palladium nanoflowers for photothermal treatment of cancer and wound healing.

Photothermal therapy uses photothermal agents (PTAs) to convert light energy to heat energy under near-infrared light to kill local tumors in cancer patients or speed up wound healing in diabetic patients. However, it is difficult to achieve high photothermal conversion efficiency for most of PTAs. Herein, daptomycin (Dap) micelles-stabilized palladium nanoflowers (Dap-PdNFs) were prepared for the first time. The palladium nanoflowers (PdNFs) inside of the Dap-PdNFs were 106 nm. The temperature of the Dap-PdNFs solution quickly rose from 26.8 °C to 52.0 °C within 10 min under irradiation with high photothermal conversion efficiency up to 38%. In addition, the cell viability of HeLa cells and HT-29 cells of Dap-PdNFs exceeded 95% in the absence of near-infrared light, indicating that Dap-PdNFs had good biocompatibility. Meanwhile, the inhibition rate of Dap-PdNFs on HeLa cells was as high as 71.2% under irradiation of 808 nm near-infrared light. More importantly, Dap-PdNFs had a good healing effect on wounds of diabetic mice under irradiation of 808 nm near-infrared light. In short, this research provides a facile method for the application of Dap-PdNFs in safe and efficient tumor treatment and wound healing.

The Mn-modified porphyrin metal-organic framework with enhanced oxidase-like activity for sensitively colorimetric detection of glutathione.

The selective detection of glutathione (GSH) has been used as important colorimetric probe for human health. Herein, we used a facile method to synthesize manganese ions modified porphyrin metal-organic framework (PCN-224-Mn) with a size of 125.7 ± 14.2 nm and zeta potential of -3.9 ± 0.5 mV. We showed that PCN-224-Mn catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the absence of H2O2, resulting in a blue-colored oxidized TMB (oxTMB) that exhibits oxidase-like activity. Furthermore, a simple colorimetric detection method for GSH was developed based on the oxidase-like activity of PCN-224-Mn. This method shows wide linear detection range of 0.5-60 µM for GSH with a much lower detection limit of 0.233 µM. Finally, the recovery of colorimetric sensor of PCN-224-Mn suggests its great potential as a biosensor. As the catalytically active site, the manganese porphyrin unit plays a major role in the oxidase-like property and detection ability of PCN-224-Mn. Our data suggest that GSH detection method using PCN-224-Mn has great potential in multiple applications in the future.