In this paper, the luminescent temperature/pH dual-responsive nanoparticles based on lanthanide-polyoxometalates were fabricated as a controllable drug delivery system. In the drug delivery carrier, the mesoporous silica acted as the core, and the poly (N-isopropylacrylamide-co-methacrylic acid) and lanthanide-polyoxometalates served as the dual-responsive shell and luminescent labeling, respectively. Composite hydrogels exhibited red luminescence under UV irradiation, which was visible to the naked eye. The releases of doxorubicin hydrochloride (DOX) from the composites were temperature/pH-dependent. DOX can be quickly released in an acidic environment and at high temperatures. Moreover, the drug delivery carrier showed minimal toxicity to HeLa cells and exhibited good biocompatibility. However, DOX loaded drug-delivery system showed the significant toxicity to HeLa cancer cells in vitro. Cell imaging has shown that lanthanide polyoxometalates composites can be used as bioimaging materials for cell monitoring. As a result, the drug delivery systems based on lanthanide-polyoxometalates have potential applications in the field of biomedical science.
Ning Peng,Jingfang Li,Yumei Hua,Sicong Zhao,Guangming Li
Security printing is of the utmost importance in the information era. However, the excessive use of inks and paper still faces many economic and environmental issues. Thus, developing erasable inkless security printing materials is a remarkable strategy to save resources, protect the environment, and improve information security. To this endeavor, a photoresponsive lanthanide-polyoxometalate-doped gelatin film with high transparency was developed through the solution casting method. Attenuated total reflection Fourier-transform infrared spectroscopy confirmed the electrostatic and hydrogen bond interactions between gelatin and lanthanide-polyoxometalate. Absorption spectra, luminescent spectra, and digital images indicated that the film displayed reversible photochromism behavior and was accompanied by luminescent switching property upon exposure to UV irradiation and oxygen (in the dark) alternately, which allowed its potential application as a reprintable medium for inkless security printing. The printed information can be erased upon exposure to oxygen in the dark, and the film can be reused for printing again. The film exhibited excellent erasability, reprintability, renewability, and low toxicity. In addition, multiple encryption strategies were designed to improve information security. This work offers an attractive alternative strategy for constructing a reprintable film for inkless security printing in terms of simplifying the preparation process, saving resources, and protecting the environment.
Wang Jun,Zhao Weiqian,Zhao Menglan,Chen Si,Li Wuke
The temperature-responsive luminescent nanocomposites were prepared by the combination of poly (N-isopropylacrylamide) (PNIPAM) with lanthanide-polyoxometalates/SiO 2 spheres, exhibiting controlled reversible luminescent behavior with change in temperature. The structures and properties of nanocomposites were characterized by transmission electron microscopy, scanning electron microscope, FT-IR, UV-vis, dynamic light scattering and luminescence spectra. The research shows that the nanocomposites in aqueous solution display “on–off” luminescence by simple temperature stimuli. For example, the hybrid nanocomposites of PNIPAM/Eu-polyoxometalate/SiO 2 in aqueous solution show bright red luminescence under UV light, which could be observed by the naked eye when the temperature is below the lower critical solution temperature (LCST), showing the “on” state. However, the red luminescence of nanocomposites in aqueous solution is significantly decreased when temperature is above LCST, showing the “off” state.
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