Animal | EPFL Graph Search

Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. As of 2022, 2.16 million living animal species have been described—of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates—but it has been estimated there are around 7.77 million animal species in total. Animals range in length from to . They have complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes, containing animals such as nematodes, arthropods, flatworms, annelids and molluscs, and the deuterostomes, containin

Shoaling with fish: using miniature robotic agents to close the interaction loop with groups of zebrafish Danio rerio

Frank Bonnet

Robotic animals are nowadays developed for various types of research, such as bio-inspired robotics, biomimetics and animal behavior studies. The miniaturization of technologies and the increase in performance of embedded systems allowed engineers to develop more powerful, sophisticated and miniature devices. The case of robotic fish is a typical example of such challenging design: the fish locomotion and body movements are difficult to reproduce and the device has to move autonomously underwater. More specifically, in the case of collective animal behavior research, the robotic device has to interact with animals by generating and exploiting signals relevant for social behavior. Once perceived by the animal society as conspecific, these robots can become powerful tools to study the animal behaviors, as they can at the same time monitor the changes in behavior and influence the collective choices of the animal society. In this work, we present novel robotized tools that can integrate shoals of fish in order to study their collective behaviors. This robotic platform is composed of two subsystems: a miniature wheeled mobile robot that can achieve dynamic movements and multi-robot long-duration experiments, and a robotic fish lure that is able to beat its tail to generate fish-like body movements. The two subsystems are coupled with magnets which allows the wheeled mobile robot to steer the robotic fish lure so that it reaches very high speeds and accelerations while achieving shoaling. An experimental setup to conduct studies on mixed societies of artificial and living fish was designed to facilitate the experiments for biologists. A software framework was also implemented to control the robots in a closed-loop using data extracted from visual tracking that retrieved the position of the robots and the fish. We selected the zebrafish Danio rerio as a model to perform experiments to qualify our system. We used the current state of the art on the zebrafish social behavior to define the specifications of the robots, and we performed stimuli analysis to improve their developments. Bio-inspired controllers were designed based on data extracted from experiments with zebrafish for the robots to mimic the zebrafish locomotion underwater. Experiments involving a robot with a shoal of fish in a constrained environment showed that the locomotion of the robot was one of the main factor to affect the collective behavior of zebrafish. We also shown that the body movements and the biomimetic appearance of the lure could increase its acceptance by fish. Finally, an experiment involving a mixed society of fish and robots qualified the robotic system to be integrated among a zebrafish shoal and to be able to influence the collective decisions of the fish. These results are very promising for the field of fish-robot interaction studies, as we showed the effect of the robots in long-duration experiments and repetitively, with the same order of response from the animals.

EPFL2017

Gene delivery from responsive hyaluronic acid hydrogels for directed angiogenesis

Arnaud Felber

Tissue Engineering points to maintain, restore or to improve and create new tissues. This purpose typically involves the selection of a natural or synthetic biomaterial as a scaffold to create the biological substitutes. Furthermore, angiogenesis, the growth of new blood vessels from pre-existing ones, is a critical physiological process toward the success of tissue engineering. Along with this consideration, biomaterials that possess intrinsic angiogenic potential may be better candidates for tissue engineering. In the present report, we investigated the effects on the in vitro CAM assay (Folkman et al., A simple procedure for the long-term cultivation of chicken embryos, 1974; Auerbach et al., Angiogenesis assays: a critical overview, 2003) of hyaluronic acid (HA). HA derivatives were formed by reaction of the carboxylic acid groups of the soluble natural polymer with hydrazides, via carbodiimide-mediated coupling. This intermediate product was then further reacted with a cyclic thioimidate (Traut's reagent) compound for thiolation. We herein describe a physiologically compatible strategy to prepare HA hydrogels able to i) support drug delivery, and ii) support potential in situ encapsulation of cells. In this strategy, modified hyaluronic acid was cross-linked with itself and 6% (w:v) HA hydrogels were formed under physiological conditions by air oxidation of thiols to disulfides. According to a LIVE/DEAD assay, HA hydrogel showed to support cell growth and spreading. The biomaterial scaffold was loaded with plasmid and a DNA release assay was performed. However hydrogels swollen in proteases containing media indicated that only 10% of the integrated DNA remained inside after 48hours. The angiogenic properties of the hydrogel were investigated on the chicken chorioallantoic membrane assay. In addition, we also examined the involvement of plasmid Vascular Endothelial Growth Factor (VEGF) on the CAM by integrating the signal into the hydrogel. Angiogenesis was observed around the implanted biomaterial. In addition, fluorescence microscopy of perfused animal indicated the presence of blood vessels sprouting into the hydrogel matrices. We anticipate that this HA-based hydrogel is highly tunable (Shea et al., Non-viral vector delivery from PEG-hyaluronic acid hydrogels, 2007). In addition, hydrogels with this capability for localized delivery of gene therapy vectors and controllable stability have direct applications for tissue engineering and could be useful tool for several biomedical applications (Hubbell et al., Functional biomaterials design of novel biomaterials, 2001)

2008

From cineradiography to biorobots: an approach for designing robots to emulate and study animal locomotion

Tomislav Horvat, Auke Ijspeert, Konstantinos Karakasiliotis, Navid Khajeh Mahabadi, Kamilo Andres Melo Becerra, Robin Thandiackal, Stanislav Yuri Tsitkov

Robots are increasingly used as scientific tools to investigate animal locomotion. However, designing a robot that properly emulates the kinematic and dynamic properties of an animal is difficult because of the complexity of musculoskeletal systems and the limitations of current robotics technology. Here we propose a design process that combines high-speed cineradiography, optimization, dynamic scaling, 3D printing, high-end servomotors, and a tailored dry-suit to construct Pleurobot: a salamander-like robot that closely mimics its biological counterpart, Pleurodeles waltl. Our previous robots helped us test and confirm hypotheses on the interaction between the locomotor neuronal networks of the limbs and the spine to generate basic swimming and walking gaits. With Pleurobot, we demonstrate a design process that will enable studies of richer motor skills in salamanders. In particular, we are interested in how these richer motor skills can be obtained by extending our spinal cord models with the addition of more descending pathways and more detailed limb central pattern generators (CPG) networks. Pleurobot is a dynamically-scaled amphibious salamander robot with a large number of actuated degrees of freedom (27 in total). Because of our design process, the robot can capture most of the animal’s degrees of freedom and range of motion, especially at the limbs. We demonstrate the robot’s abilities by imposing raw kinematic data, extracted from X-ray videos, to the robot’s joints for basic locomotor behaviors in water and on land. The robot closely matches the behavior of the animal in terms of relative forward speeds and lateral displacements. Ground reaction forces during walking also resemble those of the animal. Based on our results we anticipate that future studies on richer motor skills in salamanders will highly benefit from Pleurobot’s design.

Royal Soc2016