RESUMO
Design and engineering of highly efficient emitting materials with assembly-induced luminescence, such as room-temperature phosphorescence (RTP) and aggregation-induced emission (AIE), have stimulated extensive efforts. Here, we propose a new strategy to obtain size-controlled Eu3+-complex nanoparticles (Eu-NPs) with self-assembly-induced luminescence (SAIL) characteristics without encapsulation or hybridization. Compared with previous RTP or AIE materials, the SAIL phenomena of increased luminescence intensity and lifetime in aqueous solution for the proposed Eu-NPs are due to the combined effect of self-assembly in confining the molecular motion and shielding the water quenching. As proof of concept, we also show that this system can be further applied in bioimaging, temperature measurement and HClO sensing. The SAIL activity of the rare-earth (RE) system proposed here offers a further step forward on the roadmap for the development of RE light conversion systems and their integration in bioimaging and therapy applications.
RESUMO
Elaborately designed stimuli-responsive smart systems simultaneously enabling activatable imaging and selective treatment are highly desirable for precise diagnosis and therapy of cancer. Herein, such a smart theranostic nanoprobe composed of hollow gold nanospheres (HAuNs), photosensitizer (PS), matrix metalloproteinase 2 (MMP2) substrate peptide, and model drug doxorubicin (DOX) was designed. In the design, HAuNs served as the acceptor of Förster resonance energy transfer (FRET), photothermal therapy (PTT) reagent, and nanocarrier. The fluorescence and 1O2 generation of PS were inhibited by HAuNs through FRET effect, avoiding phototoxicity to normal tissues during circulation. Meanwhile, owing to the MMP2-triggered peptide cleavage, the PS could be efficiently activated in a tumor for selective fluorescence imaging and photodynamic therapy (PDT). The recovered fluorescence could be applied for detecting MMP2, locating tumor in vivo, and further guiding the local triple-combination therapies including PDT, PTT, and chemotherapy. The synergistic treatments of activated PDT, PTT, and controlled DOX release were achieved with single light, which provided the best therapeutic effects with enhanced stability and remarkably reduced nonspecific toxicity of PS and anticancer drug. This study helps to design novel stimuli-responsive systems for precise molecular sensing and site-specific cancer treatment.
RESUMO
With the rapid development of information science, it is urgent that memory devices possessing high security, density, and desirable storage ability should be developed. In this work, a smart duplicate response of stimuli has been developed and a time-gate nanohybrid based on variable valence Eu2+/Eu3+ coencapsulated has been fabricated and acts as active material in the multilevel and multidimensional memory devices. The luminescence lifetime of Eu3+ in this nanohybrid gave a stimuli response due to which the energy level of the coordinated ligand could be modulated. Furthermore, by a simple sintering procedure, Eu3+ was partially in situ reduced to Eu2+ with a short lifetime in the system. And the in situ reduction ensured both Eu3+ and Eu2+ ions' uniform distribution in the nanohybrid and simultaneous response upon light excitation of variable valence Eu ions. Interestingly, Eu3+ revealed a prolonged lifetime because of the presence of an energy-transfer effect of Eu2+ â Eu3+. Such a nanohybrid had abundant luminescent properties, including the short lifetime of Eu2+, the energy transfer from the Eu2+ to Eu3+ ions, and the stimuli response of the Eu3+ lifetimes when exposed to acidic or basic vapor, thus giving birth to interesting recording and encryption performance in spatial-temporal dimensions. We believe that this research will point out a new direction for the future development of multilevel and multidimensional optical recording and encryption materials.
