The development of probes for biomolecular imaging and diagnostics is a very active research area. Among the different imaging modalities, optics emerged since it is a noninvasive and cheap imaging technique allowing real time imaging. In vitro, this technique is very useful however in vivo, fluorescence suffers from low signal-to-noise ratio due to tissue autofluorescence under constant excitation. To address this limitation, novel types of optical nanoprobes are actually being developed and among them, persistent luminescence nanoparticles (PLNPs), with long lasting near-infrared (NIR) luminescence capability, allows doing optical imaging without constant excitation and so without autofluorescence. This review will begin by introducing the physical phenomenon associated to the long luminescence decay of such nanoprobes, from minutes to hours after ceasing the excitation. Then we will show how this property can be used to develop in vivo imaging probes and also more recently nanotheranostic agents. Finally, preliminary data on their biocompatibility will be mentioned and we will conclude by envisioning on the future applications and improvements of such nanomaterials.

Cr 3+ -activated persistent luminescent phosphors with a spinel structure are emerging materials in bio-imaging applications for their distinctive features of deep biotissue penetration and rechargeable nearinfrared persistent emission. To realize the long-term and multicycle imaging purpose, reactivation using in situ external light with deep biotissue penetration is an alternative strategy, apart from the efforts on trap modulations for the host lattice. However, recharging with high-energy ultraviolet /visible photons will result in low activation efficiency because of the absorption by biological tissues. Here, we report a low-energy photonrechargeable near-infrared persistent material, with rechargeable efficiency 400 times higher than that of the ZnGa 2 O 4 :Cr 3+ reference material. The crystal field strength and band gap energies can be tailored by control of cation occupancy, contributing the red shift of both the persistent luminescence excitation and emission spectra of the optimized complex spinel samples. The persistent emission red shift is of interest for improved deep tissue penetration for bioimaging, whereas the persistent excitation red shift facilitates the activation of persistent luminescence by low-energy radiation. Furthermore, it demonstrates that increasing the rate of cation site inversion in the spinel can lead to higher storage capacity of charge trapping.

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In this work, multifunctional B,N codoped carbon dots (B/N−C-dots) were synthesized from a facile hydrothermal treatment of branched polyethylenimine and 4-formylphenylboronic acid. The obtained B/N−C-dots had a very narrow size distribution and showed excitation-wavelength-dependent photoluminescence properties with a high fluorescence quantum yield (QY) of 15.85%. The B/N−C-dots showed temperature and pH (3−13) dual responses. Additionally, the B/N−C-dots showed a good sensitivity and selectivity to Fe 3+ with a detection limit of 1.62 μM. What is more, the as-prepared B/N−C-dots exhibited low toxicity and good biocompatibility and could be used for cell imaging. Considering these good properties, the obtained B/N−Cdots have good potential for temperature, pH, and ion sensors and cellular imaging.

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remains a challenge, especially the perception of ocean waves motion. [1][2][3][4] Ocean wave sensing devices based on additional complex mechanical and hydraulic structures typically transform the multidirectional wave motion into linear reciprocation or rotation of these structures to generate electric signals. However, some such devices are restrained by several drawbacks, including lower accuracy and robustness and expensive maintenance costs. Furthermore, impeller-type sensors increase the risk of collision between marine animals, [5] remote radar sensors impact the lives of marine animals due to the generation of a strong electromagnetic field, [6] and the laying of large sensing equipment generates noises and disturbances to marine animals [7] and changes hydrodynamic conditions. Conventional signal processing strategies have been demonstrated to possibly provide insufficient information to estimate ocean wave cues, resulting in difficulty to meet the requirements of high accuracy (error range in the order of 1 m). [8,9] Moreover, most of these ocean wave sensors need an external power supply, and the high cost of power supply limits their development. Therefore, novel ocean wave sensing techniques are still an open research topic.The design of efficient ocean wave sensors for monitoring the marine environment and revealing dynamic changes has been a major challenge. In this study, a self-powered bionic coral wave sensor (BCWS) based on a triboelectric nanogenerator is proposed. The BCWS captures wave data, which are useful for marine engineering construction, marine resource development, and marine disaster warning. It is mainly composed of triboelectric perceiving units (60 mm in length, 10 mm in width, and 1.5 mm in thickness) encapsulated in coral tentacles, a fixation mechanism, a buoyancy tray, and a counterweight mechanism. With the help of its bio-inspired structural design, the BCWS effectively improves the signal response time and sensitivity in the 3D perception of wave information. In particular, the coral tentacles stimulated by a load cause contact-separation between fluorinated ethylene propylene and conductive ink electrodes, thereby generating electric signals. This analysis of the experimental data reveals that the BCWS perceives wave height, wave frequency, wave period, and wave direction with millimeter accuracy. To demonstrate the applicability and stability of the BCWS, several of its potential functions are illustrated, including controlling light emitting diodes, perceiving wave information in the ocean, and assisting overboard rescue. The results show that the BCWS provides an intelligent solution for modern marine monitoring.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/admt.202101098.

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