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Zebrafish larvae are suitable in vivo models for toxicological and pharmacological screens due to their transparency, small size, ex utero development, and genetic and physiological similarity to humans. Using modern imaging techniques, cells and tissues can be dynamically visualized over several days in multiple zebrafish larvae. However, precise specimen immobilization and maintenance of homeostatic conditions remain a challenge for longitudinal studies. A highly customizable mounting configuration with inbuilt means of controlling temperature and media flow would therefore be a valuable tool to facilitate long-term imaging of a large number of specimens. Using three-dimensional printing, we have developed a millifluidic, modular homeostatic imaging plate (HIP), which consists of a customizable sample insert and a temperature-controlled incubation chamber that is continuously perfused, providing an ideal environment for long-term experiments where homeostatic conditions are desired. The HIP is cheap to produce, has a standard microtiter well plate format, and can be fitted to most microscopes. We used the device to image dynamic regeneration of spinal cord neurons. The flexibility and adaptability of the HIP facilitate long-term in vivo imaging of many samples, and can be easily adapted to suit a broad range of specimens.

Neural Style Transfer has been successfully applied for generating plausible novel 2D images by transferring the style of a painting to an existing content image and has been extended to image, video, motion and animation manipulation. Besides first works on 2D/3D hybrid approaches relying on 2D rendering operations, a consistent end-to-end 3D Neural Style Transfer is missing. For realizing such an end-to-end 3D Neural Style Transfer, we suggested a first 3D voxel-based neural network architecture in previous works. Here, we extend this architecture to a resolution of 2563 voxels to process vastly finer visual features, and we include our recently introduced standardized gram matrix approach, which reduces noise and visually improves style transfer results. We furthermore show that the type of activation function used in the network is crucial for the successful application in 3D Neural Style transfer. In particular, we demonstrate that the recently proposed bipolar exponential linear unit (belu) operator achieves a consistent style reconstruction independent of filter orientation relative to the shape surface. We compare the operator to the commonly used exponential linear units (elu) and provide insights for the shown behavior. In addition to a purely visual inspection, we evaluate the constructed shapes using local 3D shape descriptors and confirm the subjective visual improvements. We conclude that the utilization of belu operators in the deep neural network architecture is a crucial component for realizing high-resolution voxel-based 3D Neural Style Transfer.

Neural Style Transfer based on convolutional neural networks has produced visually appealing results for image and video data in the recent years where e.g. the content of a photo and the style of a painting are merged to a novel piece of digital art. In practical engineering development, we utilize 3D objects as standard for optimizing digital shapes. Since these objects can be represented as binary 3D voxel representation, we propose to extend the Neural Style Transfer method to 3D geometries in analogy to 2D pixel representations. In a series of experiments, we first evaluate traditional Neural Style Transfer on 2D binary monochromatic images. We show that this method produces reasonable results on binary images lacking color information and even improve them by introducing a standardized Gram matrix based loss function for style. For an application of Neural Style Transfer on 3D voxel primitives, we trained several classifier networks demonstrating the importance of a meaningful convolutional network architecture. The standardization of the Gram matrix again strongly contributes to visually improved, less noisy results. We conclude that Neural Style Transfer extended by a standardization of the Gram matrix is a promising approach for generating novel 3D voxelized objects and expect future improvements with increasing graphics memory availability for finer object resolutions.

Gold nanoparticles (AuNPs) have been widely investigated in drug delivery and imaging. However, for such biomedical applications, the modification of AuNPs is necessary to improve their aqueous dispersion stability and biocompatibility, especially in a salt environment. Here, we report a simple and highly efficient method to create a library of polymer-modified gold nanoparticles (PAuNPs) and screen their dispersion stability utilizing high-throughput facilities (in total 1000 experiments). Three types of water soluble polymers with different charge and chain length were prepared using Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization technology. The polymers were then converted into thiol-capped polymers by aminolysis and coated on AuNPs via thiol–gold binding to improve aqueous dispersion stability as well as the biocompatibility of AuNPs. Remarkably, we present the first report of imaging zebrafish embryos injected with a PAuNPs sample (selected from our PAuNPs library) using synchrotron X-ray fluorescence microscopy (XFM) beamline. The selected PAuNPs sample, which has been evaluated to be non-cytotoxic to L929 cells and biocompatible to zebrafish larvae in a wide range of concentrations, was injected into zebrafish larvae via the cardinal vein and could be clearly visualized in the whole circulatory system including both peripheral blood vessels and the head region by XFM. The result indicates that zebrafish larvae could be a potential animal model for probing the ability of AuNPs to cross the blood–brain barrier (BBB) and therefore hold promise for investigating AuNPs in biomedical applications such as detecting cancer and Alzheimer's disease (AD).

In the field of two-dimensional image and video processing, convolutional neural networks have been successfully applied to generate novel images by composing content and style of two different sources, a process called artistic or neural style transfer. However a usage of these methods for three-dimensional objects is not straightforward due to the unstructured mesh representations of typical shape data. Hence efficient geometry representations are required to use neural network based style transfer concepts for three-dimensional shapes and to enable the fast creation of style options for instance in a product ideation process. In this paper an overview of current state-of-the-art shape representations is presented with respect to their applicability of neural style transfer on three-dimensional shape data. Combinations of three-dimensional geometric representations with deep neural network architectures are evaluated towards their capability to store and reproduce content and style information based on previously proposed reconstruction tests.

Die Rettungsdienstausbildung in Deutschland hat sich uber die letzten Jahrzehnte stark verandert. Mit der aktuellen Neuausrichtung der Ausbildung vom Rettungsassistenten zum Notfallsanitater scheint es nun an der Zeit, uber neue Ausbildungskonzepte nachzudenken und diese in die Curricula einfliesen zu lassen. Geleitet durch diesen Gedanken, gehen die Autoren folgenden Fragen nach: Welchen Stellenwert hat heute die „Simulation“ als Lehr-Lern-Methode in der deutschen Notfallsanitaterausbildung? Welche offiziellen Aussagen zur Implementierung von Simulation in den Ausbildungsgang gibt es bislang? Warum kann es mit Blick auf den Berufsalltag eines Notfallsanitaters gewinnbringend sein, Teilschritte der Ausbildung in einen Simulator zu verlegen? Inwiefern kann Simulation als sog. dritter Lernort die Transferleistungen der Auszubildenden unterstutzen? Der Text soll zum tieferen Nachdenken uber die didaktische Ausrichtung in der Notfallsanitaterausbildung und zur Diskussion anregen.

Unser Korper stillt Blutungen uber ein ausgeklugeltes System. Nicht immer funktioniert das einwandfrei: Ist die Gerinnung vermindert, drohen grosere Blutverluste. Im Notfall ist es dann wichtig, dass Sie Risikopatienten erkennen und die richtigen Schritte einleiten.

Zebrafish larvae are ideal for toxicology and drug screens due to their transparency, small size and similarity to humans on the genetic level. Using modern imaging techniques, cells and tissues can be dynamically visualised and followed over days in multiple zebrafish. Yet continued imaging experiments require specialized conditions such as: moisture and heat control to maintain specimen homeostasis. Chambers that control the environment are generally very expensive and are not always available for all imaging platforms. A highly customizable mounting configuration with built-in means of controlling temperature and media flow would therefore be a valuable tool for long term imaging experiments. Rapid prototyping using 3D printing is particularly suitable as a production method as it offers high flexibility in design, is widely available and allows a high degree of customizing. We study neural regeneration in zebrafish. Regeneration is limited in humans, but zebrafish recover from neural damage within days. Yet, the underlying regenerative mechanisms remain unclear. We developed an agarose based mounting system that holds the embryos in defined positions along removable strips. Homeostasis and temperature control is ensured by channels circulating buffer and heated water. This allows to image up to 120 larvae simultaneously for more than two days. Its flexibility and the low-volume, high larvae ratio will allow screening of small compound libraries. Taken together, we offer a low cost, highly adaptable solution for long term in-vivo imaging.

A recent revolution in additive manufacturing technologies and access to 3D Computer Assisted Design (CAD) software has spurred an explosive growth of new technologies in biomedical engineering. This includes biomodels for diagnosis, surgical training, hard and soft tissue replacement, biodevices and tissue engineering. Moreover, recent developments in high-definition additive manufacturing systems such as Multi-Jet Modelling (MJM) and Stereolithography (SLA), capable of reproducing feature sizes close to 100 μm, promise brand new capabilities in fabrication of optical-grade biomicrofluidic Lab-on-a-Chip and MEMS devices. Compared with other rapid prototyping technologies such as soft lithography and infrared laser micromachining in PMMA, SLA and MJM systems can enable user-friendly production of prototypes, superior feature reproduction quality and comparable levels of optical transparency. Prospectively they can revolutionize fabrication of microfluidic devices with complex geometric features and eliminate the need to use clean room environment and conventional microfabrication techniques. In this work we demonstrate preliminary data on toxicity profiling of a panel of common polymers used in 3D printing applications. The main motivation of our work was to evaluate toxicity profiles of most commonly used polymers using standardized biotests according to OECD guidelines for testing of chemic risk assessment. Our work for the first time provides a multispecies view of potential dangers and limitation for building biocompatible devices using FDM, SLA and MJM additive manufacturing systems. Our work shows that additive manufacturing holds significant promise for fabricating LOC and MEMS but requires caution when selecting systems and polymers due to toxicity exhibited by some 3D printing polymers.

International audience; The fish embryo toxicity (FET) biotest has gained popularity as one of the alternative approaches to acute fish toxicity tests in chemical hazard and risk assessment. Despite the importance and common acceptance of FET, it is still performed in multiwell plates and requires laborious and time-consuming manual manipulation of specimens and solutions. This work describes the design and validation of a microfluidic Lab-on-a-Chip technology for automation of the zebrafish embryo toxicity test common in aquatic ecotoxicology. The innovative device supports rapid loading and immobilization of large numbers of zebrafish embryos suspended in a continuous microfluidic perfusion as a means of toxicant delivery. Furthermore, we also present development of a customized mechatronic automation interface that includes a high-resolution USB microscope, LED cold light illumination, and miniaturized 3D printed pumping manifolds that were integrated to enable time-resolved in situ analysis of developing fish embryos. To investigate the applicability of the microfluidic FET (μFET) in toxicity testing, copper sulfate, phenol, ethanol, caffeine, nicotine, and dimethyl sulfoxide were tested as model chemical stressors. Results obtained on a chip-based system were compared with static protocols performed in microtiter plates. This work provides evidence that FET analysis performed under microperfusion opens a brand new alternative for inexpensive automation in aquatic ecotoxicology.

Implementations of Lab-on-a-Chip technologies for in-situ analysis of small model organisms and embryos (both invertebrate and vertebrate) are attracting an increasing interest. A significant hurdle to widespread applications of microfluidic and millifluidic devices for in-situ analysis of small model organisms is the access to expensive clean room facilities and complex microfabrication technologies. Furthermore, these resources require significant investments and engineering know-how. For example, poly(dimethylsiloxane) soft lithography is still largely unattainable to the gross majority of biomedical laboratories willing to pursue development of chip-based platforms. They often turn instead to readily available but inferior classical solutions. We refer to this phenomenon as workshop-to-bench gap of bioengineering science. To tackle the above issues, we examined the capabilities of commercially available Multi-Jet Modelling (MJM) and Stereolithography (SLA) systems for low volume fabrication of optical-grade millifluidic devices designed for culture and biotests performed on millimetre-sized specimens such as zebrafish embryos. The selected 3D printing technologies spanned a range from affordable personal desktop systems to high-end professional printers. The main motivation of our work was to pave the way for off-the-shelf and user-friendly 3D printing methods in order to rapidly and inexpensively build optical-grade millifluidic devices for customized studies on small model organisms. Compared with other rapid prototyping technologies such as soft lithography and infrared laser micromachining in poly(methyl methacrylate), we demonstrate that selected SLA technologies can achieve user-friendly and rapid production of prototypes, superior feature reproduction quality, and comparable levels of optical transparency. A caution need to be, however, exercised as majority of tested SLA and MJM resins were found toxic and caused significant developmental abnormalities in zebrafish embryos. Taken together, our data demonstrate that SLA technologies can be used for rapid and accurate production of devices for biomedical research. However, polymer biotoxicity needs to be carefully evaluated.

Additive manufacturing was adopted in multiple fields of life sciences. It is also becoming a popular tool for rapid prototyping of microfluidic and biomedical devices. Limited studies have been performed to investigate the biological implications of using 3D printed polymers. Here we assessed the biocompatibility of seven commercially available polymers, using a battery of standardized bioassays for chemical risk assessment. Our data show that leachates from photopolymers substrata appear to be very toxic to vertebrates and several invertebrate indicator organisms. These results demonstrate significant consequences for the use of selected photopolymers in the fabrication of bio-devices.

Background The Deepwater Horizon disaster was the largest marine oil spill in history, and total vertical exposure of oil to the water column suggests it could impact an enormous diversity of ecosystems. The most vulnerable organisms are those encountering these pollutants during their early life stages. Water-soluble components of crude oil and specific polycyclic aromatic hydrocarbons have been shown to cause defects in cardiovascular and craniofacial development in a variety of teleost species, but the developmental origins of these defects have yet to be determined. We have adopted zebrafish, Danio rerio, as a model to test whether water accumulated fractions (WAF) of the Deepwater Horizon oil could impact specific embryonic developmental processes. While not a native species to the Gulf waters, the developmental biology of zebrafish has been well characterized and makes it a powerful model system to reveal the cellular and molecular mechanisms behind Macondo crude toxicity. Results WAF of Macondo crude oil sampled during the oil spill was used to treat zebrafish throughout embryonic and larval development. Our results indicate that the Macondo crude oil causes a variety of significant defects in zebrafish embryogenesis, but these defects have specific developmental origins. WAF treatments caused defects in craniofacial development and circulatory function similar to previous reports, but we extend these results to show they are likely derived from an earlier defect in neural crest cell development. Moreover, we demonstrate that exposure to WAFs causes a variety of novel deformations in specific developmental processes, including programmed cell death, locomotor behavior, sensory and motor axon pathfinding, somitogenesis and muscle patterning. Interestingly, the severity of cell death and muscle phenotypes decreased over several months of repeated analysis, which was correlated with a rapid drop-off in the aromatic and alkane hydrocarbon components of the oil. Conclusions Whether these teratogenic effects are unique to the oil from the Deepwater Horizon oil spill or generalizable for most crude oil types remains to be determined. This work establishes a model for further investigation into the molecular mechanisms behind crude oil mediated deformations. In addition, due to the high conservation of genetic and cellular processes between zebrafish and other vertebrates, our work also provides a platform for more focused assessment of the impact that the Deepwater Horizon oil spill has had on the early life stages of native fish species in the Gulf of Mexico and the Atlantic Ocean.