Deregulated inflammations induced by various factors are one of the most common diseases in people's daily life, while severe inflammation can even lead to death. Thus, the efficient treatment of inflammation has always been the hot topic in the research of medicine. In the past decades, as a potential biomaterial, stimuli‐responsive hydrogels have been a focus of attention for the inflammation treatment due to their excellent biocompatibility and design flexibility. Recently, thanks to the rapid development of nanotechnology and material science, more and more efforts have been made to develop safer, more personal and more effective hydrogels for the therapy of some frequent but tough inflammations such as sepsis, rheumatoid arthritis, osteoarthritis, periodontitis, and ulcerative colitis. Herein, from recent studies and articles, the conventional and emerging hydrogels in the delivery of anti‐inflammatory drugs and the therapy for various inflammations are summarized. And their prospects of clinical translation and future development are also discussed in further detail.

Concentration quenching of rare-earth doped upconversion nanoparticles severely limits the dopant concentration, and this greatly hinders their potential applications. Therefore, it is necessary to understand the roles of dopant concentration in photon population and luminescence quenching for materials designed with improved upconversion luminescence (UCL). Herein, the excited-state dynamics of well-accepted NaYF₄:Yb³⁺,Er³⁺ nanocrystals were investigated as models based on the Kohlrausch-function. The use of the Kohlrausch-function successfully disentangled the rise and decay of dynamics data and well revealed the kinetics. Photon population and concentration quenching mechanisms depending on the sensitizer concentration are deeply revealed by the regular variations of the fitting parameters. The results indicated that high doping of sensitizers will accelerate the population of both green and red emitting energy levels, but cause significant concentration quenching in green emission and little quenching in red emission. Our work opened up new pathways of kinetics analysis, which is beneficial for further mechanism development, and established detailed photon population and concentration quenching models depending on the doping concentration of the sensitizer.

[Yb(tta)₃DFQZ] exhibits improved two-photon-sensitized NIR-luminescence properties and thermally enhanced Yb³⁺ luminescence, and enables the detection of temperature without O₂ influence.

The doping concentration of lanthanide ions is important for manipulating the luminescence properties of upconversion nanoparticles (UCNPs). However, the serious concentration quenching in highly doped UCNPs remains a vital restriction for further enhanced upconversion luminescence (UCL). Herein, we examined the effect of temperature on the concentration quenching of rare-earth UCNPs, an issue that has been overlooked, and we show that it is significant for biomedical or optical applications of UCNPs. In this work, we prepared a series of UCNPs by doping Er³⁺ luminescent centers at different concentrations in a NaLuF₄:Yb³⁺ matrix. At room temperature (298 K), steady-state photoluminescence (PL) spectroscopy showed substantial concentration quenching of the Er³⁺ emission with increasing doping concentrations. However, the concentration quenching effect was no longer effective at lower temperatures. Kinetic curves obtained from time-resolved PL spectroscopy further showed that the concentration quenching dynamics were vitally altered in the cryogenic temperature region, i.e., below 160 K. Our work on the temperature-switchable concentration quenching mechanism may shed light on improving UCL properties, promoting their practical applications.