Fig 4 - uploaded by Prasong Jerry Mekdara
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Robot navigating track (a), a close-up of the three-rail structure (b), and a section view along the track (c).
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Context 1
... to be simple enough for a robot to traverse robustly. A track structure was decided on with three carbon fiber rails; two of the rails are for the robot to attach to and one rail allowing vibration transmission. In order to test the robots mobility, the track was constructed in the shape of a closed loop, with the ability to add branches later (Fig. 4). The turn segments were 3D-printed from Stratsys VeroClear-RGD810 material and bonded to the straight carbon fiber segments with Loctite Super Glue. The structure is 60 x 30cm in dimension, with four constant-radius 90 degree turns. ...
Context 2
... extending vibration communication and sensing methods to a robotic platform, modeling was needed to predict how vibrations propagate through the structure, and find any limitations. To reduce the problem, a single straight segment of the structure (Fig. 4) was investigated. In the model, two piezoelectric cantilevers are included; one can- tilever provides a forcing to the structure and a second (at an- other location) senses structural vibration. These cantilevers represent the transducers on a pair of robots. A steady-state model was created from the loading configuration shown in Fig. ...
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Citations
... 31−34 Recently, this communication modality has been implemented into robotics. 35 Our study explores the ability of the fibrous ECM to effectively deliver dynamic forces between contractile cells, as a potential mechanism of vibrational communication. Indeed, ECM vibroscape (i.e., vibrational "landscape") may be crucial for such mechanocommunication efficiency. ...
... High frequency fluctuations can appear when a cell pulls on the ECM and then abruptly releases the built-up tension, for example, as a cell migrates, the exerted forces on the ECM fibers may cause vibrations to the surroundings. 40,48−50 Interestingly, myosin motor attachment and detachment rates are in the order of 35 Hz and 350 Hz, respectively; and (iv) tensegrity vibrations are high frequency natural modes arising due to cytoskeletal tension. 51−53 Apart from their ability to exert dynamic forces, cells are mechanosensitive 54 to dynamic stimuli and have shown to demonstrate (i) modified cytoskeletal structure and its fluidization at high stretch rates; 55,56 (ii) mechanoptosis; 57 (iii) mechanotropism; 58 (iv) altered ECM expression and remodeling; 59−65 (v) increase culture cell growth rate by nanokicking; 47,66,67 (vi) torsional and translational vibrations of the cell nucleus; 53 (vii) synchronization of beating cardiomyocytes, 10,15 (viii) higher cellular viability at specific frequency and amplitude ranges, 68 and (ix) altered collective cell migration. ...
The extracellular matrix (ECM) is a fibrous network supporting biological cells and provides them a medium for interaction. Cells modify the ECM by applying traction forces, and these forces can propagate to long ranges and establish a mechanism of mechanical communication between neighboring cells. Previous studies have mainly focused on analysis of static force transmission across the ECM. In this study, we explore the plausibility of dynamic mechanical interaction, expressed as vibrations or abrupt fluctuations, giving rise to elastic waves propagating along ECM fibers. We use a numerical mass-spring model to simulate the longitudinal and transversal waves propagating along a single ECM fiber and across a 2D random fiber network. The elastic waves are induced by an active contracting cell (signaler) and received by a passive neighboring cell (receiver). We show that dynamic wave propagation may amplify the signal at the receiver end and support up to an order of magnitude stronger mechanical cues and longer-ranged communication relative to static transmission. Also, we report an optimal impulse duration corresponding to the most effective transmission, as well as extreme fast impulses, in which the waves are encaged around the active cell and do not reach the neighboring cell, possibly due to the Anderson localization effect. Finally, we also demonstrate that extracellular fluid viscosity reduces, but still allows, dynamic propagation along embedded ECM fibers. Our results motivate future biological experiments in mechanobiology to investigate, on the one hand, the mechanosensitivity of cells to dynamic forces traveling and guided by the ECM and, on the other hand, the impact of ECM architecture and remodeling on dynamic force transmission and its spectral filtering, dispersion, and decay.
