The state-of-the-art of fluorescent materials and their sensing mechanism/properties for the detection of explosives in the recent 5 years were systematically reviewed.

The development of high temperature gas sensors for industrial applications such as combustion processes is essential to improve energy efficiency and reduce toxic emissions. However, gas sensors operating at high temperatures up to 1000 °C typically encounter many challenging issues, such as thermal and long-term stability, sensitivity, reproducibility and selectivity. This feature article discusses a variety of solid-state gas sensors that can be operated at high temperatures above 600 °C. The basic working principles for each type of solid-state gas sensor are briefly introduced, including potentiometric, amperometric, resistive and impedancemetric sensors. The key results and discussions of previous studies on high temperature O₂, CO, HCs and NO_x sensors are also presented with emphasis on the development of suitable electrolytes and sensing materials with good thermal stability and sensing performance for such high temperature gas sensing applications. Finally, the challenges and scope for future development are discussed.

Microwave-assisted synthesis of nitrogen and phosphorus co-doped carbon dots with high quantum yield and dual (blue and green) fluorescence emission.

Fluorescent carbon nanoparticles were synthesized from a single precursor and applied for explosives detection.

Because of its good biocompatibility and biodegradability, albumins such as bovine serum albumin (BSA) and human serum albumin (HSA) have found a wide range of biomedical applications. Herein, we report that glutaraldehyde cross-linked BSA (or HSA) forms a novel fluorescent biological hydrogel, exhibiting new green and red autofluorescence in vitro and in vivo without the use of any additional fluorescent labels. UV-vis spectra studies, in conjunction with the fluorescence spectra studies including emission, excitation and synchronous scans, indicated that three classes of fluorescent compounds are presumably formed during the gelation process. SEM, FTIR and mechanical tests were further employed to investigate the morphology, the specific chemical structures and the mechanical strength of the as-prepared autofluorescent hydrogel, respectively. Its biocompatibility and biodegradability were also demonstrated through extensive in vitro and in vivo studies. More interestingly, the strong red autofluorescence of the as-prepared hydrogel allows for conveniently and non-invasively tracking and modeling its in vivo degradation based on the time-dependent fluorescent images of mice. A mathematical model was proposed and was in good agreement with the experimental results. The developed facile strategy to prepare novel biocompatible and biodegradable autofluorescent protein hydrogels could significantly expand the scope of protein hydrogels in biomedical applications.