Unveiling the morphology of the acetabulum in octopus suckers and its role in attachment

Tramacere, Francesca; Pugno, Nicola; Kuba, Michael J.; Mazzolai, Barbara

doi:10.1098/rsfs.2014.0050

Cited by 62 publications

(64 citation statements)

References 29 publications

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“…Figure a presents representative examples of natural adhesion with miniature architectures, such as dry/wet adhesion by the multiscale architectures of gecko lizards, beetles, endoparasites, octopi, and slugs . The feet of gecko lizards have widely been studied for their hierarchically structured hairs which enable robust, reversible and directional adhesion on dry and rough surfaces (maximum ≈10 N cm −2 ) .…”

Section: Introductionmentioning

confidence: 99%

Bioinspired Adhesive Architectures: From Skin Patch to Integrated Bioelectronics

et al. 2019

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on dry and rough surfaces (maximum ≈10 N cm −2 ). [1] Close observations have indicated nanoscale hairs of high aspect ratio (AR) with slated tips. [21][22][23][24][25][26][27][28][29][30] This geometry allows directional appliance of van der Waals forces against engaged surfaces for stable attachment. The attachment strategies and fixation systems of beetles have also been investigated. [9] Concave, mushroom-shaped architectures on the forelegs of beetles ensure stable adherences onto rough, waxy surfaces [31][32][33][34][35][36] or locomotion via capillary adhesion. [37][38][39] Studies on their attachment systems revealed that the mushroom-shaped structures with wide concave tips can generate van der Waals interactions [40] as well as a suction effect against engaged surfaces. [41,42] Moreover, needles located in the proboscis of mosquitos [43][44][45][46] or endoparasites (e.g., Pomphorhynchus laevis) [47] alike, induce mechanical interlocking on dry skin or wet organs. The needles provide strong adhesion in both normal and shear directions for the insect species to easily consume nutrients. Recently, the architectures of octopus suckers were investigated to understand their underlying attachment mechanism. Existing in clusters on octopus tentacles, suction cups are crucial for octopi's survival underwater for functions such as preying, grasping, locomotion, and even sensing. The cup-shaped protruding chamber (infundibulum) is known to adapt and seal conformably on rough surfaces. [12,13,15,48] Meanwhile, the dome-like protuberance in the lower chamber (acetabulum) forms pressure difference between the segregated lower and upper chambers within the suction cup architecture. [49] This enhances suction stress to adhere strongly onto wet or underwater surfaces. The footpads of slugs are covered with structures of microscale compression waves with viscous mucus. This can be used to both lubricate a slug's movement over surfaces and facilitate the transfer of adhesive force to the engaged surfaces. [16,19,20,[50][51][52] Specifically, the mucus with interpenetrating positively charged chemistries produce pedal waves; this in all creates an adhesive and elastic dissipative matrix, and guides the movement of slugs on attached surfaces. [53] Hence, structural features within the as-mentioned organisms have built the platform of bioinspired adhesive systems for potential use in clean transfer systems, [54][55][56][57][58][59] soft robotics, [60,61] stimuli-responsive adhesives for dry or wet surfaces, [62][63][64] and various wearable devices with diagnostic and therapeutic functionalities. [65][66][67][68][69] Among various applications of bioinspired multiscale architectures, patches attachable to skin have been of high interest (Figure 1b). Human skin, the outermost organ of the human The attachment phenomena of various hierarchical architectures found in nature have extensively drawn attention for developing highly biocompatible adhesive on skin or wet inner organs without any chemical glue. Structural adhesive sy...

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Section: Introductionmentioning

confidence: 99%

Bioinspired Adhesive Architectures: From Skin Patch to Integrated Bioelectronics

et al. 2019

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“…a rock, the infundibulum adapts its shape to that surface creating a seal and reduces its thickness by contracting the radial muscles, thereby increasing the attachment to the surface. Consequently, the contraction of the acetabular radial muscles [12] reduces the pressure inside the sucker and generates attachment [16,[21][22][23][24][25]. In fact, with water being an incompressible medium, the contraction of the acetabular muscles put the water inside the sucker in tension, resulting in a reduction of internal pressure.…”

Section: Bioinspired Stiffness-gradient Design Of the Anchoring Modulementioning

confidence: 99%

“…In [21][22][23][24][25], the structure and mechanical properties of the natural sucker were extensively investigated and a set of principles for the bioinspired design of an artificial sucker was concluded. In order to mimic the conformability of the infundibulum, this portion must be fabricated from a soft and sticky material.…”

Section: Bioinspired Stiffness-gradient Design Of the Anchoring Modulementioning

confidence: 99%

“…Biomimetic aspects of octopus suckers have been long studied; the morphology and physiology of octopus suckers and possibilities for biomimetic replication of suckers have been investigated [12,16,[21][22][23][24][25], with particular emphasis on the transition from hard to soft in the mechanical stiffness of sucker [21][22][23][24][25], also referred as stiffness gradient 2 design in some relevant literature [30][31].…”

Section: Introductionmentioning

confidence: 99%

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Anchoring like octopus: biologically inspired soft artificial sucker

Sareh

Althoefer

et al. 2017

J. R. Soc. Interface.

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This paper presents a robotic anchoring module, a sensorised mechanism for attachment to the environment that can be integrated into robots to enable or enhance various functions such as robot mobility, remaining on location or its ability to manipulate objects. The body of the anchoring module consists of two portions with a mechanical stiffness transition from hard to soft. The hard portion is capable of containing vacuum pressure used for actuation whilst the soft portion is highly conformable to create a seal to contact surfaces. The module is integrated with a single sensory unit which exploits a fibre optic sensing principle to seamlessly measure proximity and tactile information for use in robot motion planning as well as measuring the state of firmness of its anchor. In an experiment, a variable set of physical loads representing the weights of potential robot bodies were attached to the module and its ability to maintain the anchor was quantified under constant and variable vacuum pressure signals. The experiment shows the effectiveness of the module in quantifying the state of firmness of the anchor and discriminating between different amounts of physical loads attached to it. The proposed anchoring module can enable many industrial and medical applications where attachment to environment is of crucial importance for robot control.

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“…However, we were not able to reproduce that solutions based on details provided in [22]. Furthermore, the analysis in [22] is based on the prior work of Afferrante et al [23] and Tramacere et al [24], which is applicable to membrane-like structures rather than craters.…”

Section: Introductionmentioning

confidence: 95%

Suction effects in cratered surfaces

Qiao

Wang

Jeong

et al. 2017

J. R. Soc. Interface.

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It has been shown experimentally that cratered surfaces may have better adhesion properties than flat ones. However, the suction effect produced by the craters, which may be chiefly responsible for the improved adhesion, has not been properly modelled. This paper combines experimental, numerical simulation and analytical approaches towards developing a framework for quantifying the suction effect produced by isolated craters and cratered surfaces. The modelling approach emphasizes the essential role of large elastic deformation, while the airflow dynamics, microscopic mechanisms, like surface tension and air permeation, and rate-dependence are neglected. This approach is validated using experimental data for isolated hemi-spherical craters. The modelling approach is further applied to spherical cap (not necessarily hemi-spherical) craters with the objective of identifying optimal geometric and material properties, as well as the minimum preload necessary for attaining the maximum suction force. It is determined that stiff polymers with deep craters are capable of producing large suction forces. For soft materials, central to biomedical applications, large suction forces can be attained by reinforcing deep craters with thin stiff layers. Parametric optimization studies of reinforced craters reveal that some of them perform beyond common expectations. However, those high-performance reinforced craters are prone to surface instabilities, and therefore the practical use of such craters may be problematic.

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Unveiling the morphology of the acetabulum in octopus suckers and its role in attachment

Cited by 62 publications

References 29 publications

Bioinspired Adhesive Architectures: From Skin Patch to Integrated Bioelectronics

Bioinspired Adhesive Architectures: From Skin Patch to Integrated Bioelectronics

Anchoring like octopus: biologically inspired soft artificial sucker

Suction effects in cratered surfaces

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