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Pure Eu3+ ion doped BaF2 nanoparticles with tunable properties or property combinations are accessible via an ionic liquid-assisted solvothermal method. Structural parameters such as cell parameters, lattice strain, and especially morphology are judiciously tuned with calcination temperatures. For example, tensile strain is observed in samples calcined up to 400 °C; however, compressive strain appears in samples calcined at 600 °C and beyond. Larger surface area up to the sample calcined at 400 °C and observation of layer structure at higher calcinations temperature (650 °C and beyond) have been rationalized based on secondary nucleation. Three-dimensional island-like morphology with step-like layer structure caused by secondary nucleation and self-assembly are visualized and explained by scanning electron microscope analysis. Moreover, emission intensity, decay time, quantum yield, and Judd-Ofelt parameter of the Eu3+ ions increase systematically with calcination temperature to a maximum at 400 °C, above which they decrease and finally vanish at 800 °C. Our results suggest that smaller-sized nanoparticles with 3-dimensional island-like structures, generated due to secondary nucleation at higher calcinations temperature, may cause the increase of surface defects and subsequent luminescence quenching. To the best of our knowledge, the interplay between calcinations and secondary nucleation followed by drastic changes in the luminescence properties is new and previously unreported for the nanopowders. In addition, to improve the dispersibility, as-prepared nanoparticles are coated with silica and solubility of nanoparticles is measured in different solvents so that it can be useful for bioimaging applications also.

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For the assessment of cardiac function, heartbeat represents one key parameter. Current methods of heartbeat measurements in the zebrafish larvae usually require larval immobilization, fluorescent transgenic strains and a confocal microscope, costly commercial software for analysis, or strong programming skills if the software is open-source. Here, we present a simple yet powerful method of heartbeat analysis using untethered, unlabeled zebrafish larva using ImageJ (open-source software), which does not require programming skills. We named it as ZebraPace for Zebrafish Precise Algorithm for Cardiac-rhythm Estimation. ZebraPace works directly with AVI videos and requires no image processing steps. ZebraPace uses pixel intensity change in a grayscale video to count the number of beats. We have validated the ZebraPace method by pharmacological alterations of the heartbeat in zebrafish larvae of 48 and 72 hpf stages. We have also determined beat-to-beat interval, which relates to rhythmicity of heartbeat. The results obtained by using ZebraPace corroborates well with the heartbeat values previously reported for similarly aged larvae as determined by using specialized software. We believe that the ZebraPace method is simple, cost-effective, and easy to grasp as it involves fewer steps. It not only reduces the manual workload but also eliminates sample preparation time and researcher subjectivity.

The nanoparticles with biomedical applications should be evaluated for its biocompatibility. Rare-earth doped nanoparticles with unique spectral properties are superior in-vivo optical probes over quantum dots and organic dyes; however,...

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An ionic liquid (IL)-based solvothermal method is employed to prepare single-phase, luminescent, cubic rare-earth doped and silica-coated BaF 2 nanomaterials. High energy transfer efficiency (∼ 60%) from Ce 3 + to Tb 3 + for BaF 2 :Ce 3 + /Tb 3 + nanoparticles dispersed in DMSO solution is observed. Furthermore, for the first time to the best of our knowledge, as-prepared RE ion/s doped and silica-coated BaF 2 nanoparticles are used for the toxicological assessment on live zebrafish larvae. Interestingly, static exposure of these nanoparticles from 6 hpf till 96 hpf period at high concentration (70 mg/L) do not show any developmental anomalies as judged by bright-field and birefringence optical imaging method which promises its largescale applications in imaging and other biological purposes.However, as a positive control, cypermethrin-based pesticide could induce developmental defects at 0.1 mg/L concentration. It is worth mentioning that the concentration of BaF 2 nanoparticles chosen in present study is much higher than the other nanoparticles reported so far.

Zebrafish is a vertebrate animal model. Their maintenance in large number under laboratory conditions is a daunting task. Commercially available recirculating zebrafish maintenance systems are used to efficiently handle the tasks of automatic sediment cleaning from zebrafish tanks with minimal waste of water. Due to their compact nature, they also ensure the maximal use of available lab space. However, the high costs of commercial systems present a limitation to researchers with limited funds. A cost-effective zebrafish maintenance system with major features offered by commercially available systems is highly desirable. Here, we describe a compact and recirculating zebrafish maintenance system. Our system is composed of cost-effective components, which are available in local markets and/or can be procured via online vendors. Depending on the expertise of end users, the system can be assembled in 2 days. The system is completely customizable as it offers geometry independent zebrafish tanks that are capable of auto-cleaning the sediments. Due to these features, we called our setup as Open-RAC (Open-design, Recirculating and Auto-Cleaning zebrafish maintenance system). Open-RAC is a cost-effective and viable alternative to the currently available zebrafish maintenance systems. Thus, we believe that the use of Open-RAC could promote the zebrafish research by removing the cost barrier for researchers.