Suction Cup Research Articles

Architected Design and Fabrication of Soft Mechanical Metamaterials

This study proposes a systematic design approach to 3D print soft mechanical metamaterials by tuning material flow behavior and using optimal toolpaths and print parameters. Planar printing tool paths, utilized in layer‐by‐layer printing such as fused deposition modeling (FDM) and prevalently used in most slicing algorithms, severely limit the realization of complex topologies required in metamaterials. Utilizing parametric design principles, the proposed approach employs discrete and continuous 3D freeform tool paths for supported and unsupported direct ink writing (DIW) of elastomeric structures. The resulting textured, soft topologies significantly enhance the performance of various mechanisms in soft robotics and impact energy‐absorbing wearable devices. Various bioinspired structures such as cilia, webs, leaf‐like structures, and lattices are explored using extrusion‐based silicone 3D printing, achieving features with high aspect ratios (L/D ≤ 12) without support. These complex structures are challenging to 3D print using conventional planar toolpaths. To demonstrate the enhanced functionalities enabled by these new topologies, cilia arrays added to suction cups increased the pull‐off forces by 18%. Additionally, 3D‐printed elastomeric lattice slabs used as energy‐absorbing structures reduced the maximum impact peak forces by 85%. Further functionalities, including magnetic, thermochromic, and signal transmission properties, are also showcased using functional soft mechanical metamaterials.

Design and Experimental Optimization of an Automated Longline-Suspended Oyster Spat Insertion Device

To address the challenges of labor-intensive and costly manual oyster spat insertion in longline-suspended farming, an automated oyster spat insertion device was designed based on negative pressure suction and bundling fixation technologies. Using this device as the experimental platform, a three-factor, three-level Box–Behnken experiment was conducted, with fixation mechanism inclination, negative pressure suction cup span, and horizontal distance between turnover and fixation mechanisms as the experimental factors. The performance of the device was evaluated using the effective fixation rate and damage rate as the experimental indicators. The quadratic polynomial regression models were established to assess the impact of these factors on operational performance, while the response surface method was employed to analyze the interaction effects between factors. Parameter optimization and experimental validation were also performed. The results indicate that the factors affecting the effective fixation rate, in order of significance, are as follows: fixation mechanism inclination, horizontal distance between turnover and fixation mechanisms, and negative pressure suction cup span. For the damage rate, the order of significance is as follows: fixation mechanism inclination > negative pressure suction cup span < horizontal distance between turnover and fixation mechanisms. The optimization results show that when the fixation mechanism inclination is set at 43°, the negative pressure suction cup span at 27 mm, and the horizontal distance between turnover and fixation mechanisms at 179 mm, the effective fixation rate reaches 92.08%, and the damage rate is 4.71%. The relative errors between the measured and model-predicted values are less than 5%, indicating that the regression models are reliable. This research provides valuable insights for advancing the mechanization of the oyster farming industry and replacing manual labor with mechanized equipment.

Towards Autonomous Retail Stocking and Picking: Methods Enabling Robust Vacuum-Based Robotic Manipulation in Densely Packed Environments.

With the advent of robotics and artificial intelligence, the potential for automating tasks within human-centric environments has increased significantly. This is particularly relevant in the retail sector where the demand for efficient operations and the shortage of labor drive the need for rapid advancements in robot-based technologies. Densely packed retail shelves pose unique challenges for robotic manipulation and detection due to limited space and diverse object shapes. Vacuum-based grasping technologies offer a promising solution but face challenges with object shape adaptability. The study proposes a framework for robotic grasping in retail environments, an adaptive vacuum-based grasping solution, and a new evaluation metric-termed grasp shear force resilience-for measuring the effectiveness and stability of the grasp during manipulation. The metric provides insights into how retail objects behave under different manipulation scenarios, allowing for better assessment and optimization of robotic grasping performance. The study's findings demonstrate the adaptive suction cups' ability to successfully handle a wide range of object shapes and sizes, which, in some cases, overcome commercially available solutions, particularly in adaptability. Additionally, the grasp shear force resilience metric highlights the effects of the manipulation process, such as in shear force and shake, on the manipulated object. This offers insights into its interaction with different vacuum cup grasping solutions in retail picking and restocking scenarios.

Dynamic control of cardboard-blank picking by using reinforcement learning

Abstract Standard packaging lines with high output rates often struggle when dealing with uncertainties in the conditions of the handled materials. This paper focuses on a piece of machinery in an automatic packaging line, namely an automated apparatus that extracts cardboard blanks from a buffer and transfers them to the next section through suction cups. In this context, the success of the operation depends on various controllable parameters, disturbances, and time-dependent variables, whose mutual relationships are not easily identifiable and whose understanding has so far been entrusted to the experiential knowledge of human operators. Currently, drops in picking success rates require the machine to be stopped and operators to intervene on-site, making use of their expertise to identify the issue and recalibrate the machine. To address the problem, this paper presents an artificial-intelligence-enabled controller, capable of continuously and autonomously recalibrating the apparatus and compensating for disturbances, in order to avoid missed or incorrectly picked cardboard blanks. In particular, this work exploits experimental data to build a model of the system, on which a reinforcement-learning algorithm is trained. The controller is tasked with regulating the controllable parameters while monitoring process variables. The developed agent is tested on the real apparatus to assess its performance.

Development of a calculation power model of a vacuum automounting device

One of the ways to improve navigation safety during water transport operation is to develop automated devices and systems that reduce the number of tasks for workers. For example, the introduction of vessels with different levels of autonomy into production activities, capable of automatically monitoring the environment or delivering cargo, helps to reduce the size of the vessel due to the absence of a residential superstructure. On inland waterways, one of the limitations of the introduction of autonomous navigation is their safe passage through shipping passages — shipping locks. Mooring a vessel in a lock chamber is very labor-intensive and is usually performed by crew members of the vessel being locked for movable (floating hoops) or fixed (berthing bollards, bollards, hoops) mooring devices, the permissible loads of which are established in regulatory documents. Over the past 10 years, the authors have not found studies describing the results of measuring the loads on mooring devices and ropes arising from the movement of the vessel in the lock chamber. Another constraint to the implementation of autonomous shipping is the lack of requirements for auto-mooring devices that ensure the retention of vessels in the lock chamber. In this regard, the purpose of this study is to compare the standard and actual values of the load on mooring eyes and ropes for the theoretical calculation of the holding forces of the vacuum automooring device model, taking into account the operating conditions in the shipping lock chamber. The measurement results presented in the article were obtained in the course of the research work “Development of scientifically based recommendations for establishing hydraulic modes for filling and emptying the chambers of locks No. 1–8 of the Federal State Budgetary Institution “Volga-Balt Administration” based on in-kind studies of the conditions of ship mooring in lock chambers” commissioned by the Federal Agency for Maritime and River Transport using a strain gauge installed in the mooring rope cut. As a result of the theoretical calculation of the holding force of the vacuum auto-mooring device, the holding forces of the vacuum gripper from the radius of one vacuum suction cup were obtained.

A novel method of cardia visualization and comfort level enhancement during magnetic capsule gastroscopy via sugar-glued tether-assisted technique: a randomized pilot study inspired by a Chinese snack-making process (with video).

Magnetic capsule gastroscopy (MCG) is a non-invasive diagnostic method for the digestive tract. However, its efficiency in visualizing the gastric cardia is often compromised due to the capsule's rapid passage. This study introduces a novel sugar-glued tether-assisted technique inspired by a traditional Chinese snack-making process to enhance cardia visualization and patient comfort during MCG. This pilot, open-label, single-center, randomized controlled, non-inferiority study was conducted at Binzhou Medical University Hospital. Seventy-eight patients were enrolled and divided into three groups: conventional MCG, suction cup tether-assisted MCG, and sugar-glued tether-assisted MCG. The primary outcomes included safety, comfort level, and gastric cardia visualization quality. Secondary outcomes assessed technique-associated performance and clinical factors. The sugar-glued tether-assisted MCG demonstrated comparable cardia visualization quality to the suction cup method, with significantly better results than conventional MCG. Comfort levels were significantly higher in the sugar-glued group compared to the suction cup group. The number of swallow attempts was significantly lower in the sugar-glued group, with no adverse events reported. Secondary outcomes showed no significant differences in MCG assembly time and ingestion-to-detachment period between the suction cup and sugar-glued groups. The sugar-glued tether-assisted MCG is a feasible and safe modification that enhances gastric cardia visualization while improving patient comfort. This technique provides a cost-effective alternative to the suction cup method, warranting further investigation in larger, multi-center studies.

Mechanochromic Suction Cups for Local Stress Detection in Soft Robotics

Advancements in smart soft materials are enhancing the capabilities of robotic manipulators in object interactions and complex tasks. Mechanochromic materials, acting as lightweight sensors, offer easily interpretable visual feedback for localized stress detection, structural health monitoring, and energy‐efficient robotic skins. Herein, an innovative mechanochromic soft end‐effector capable of discerning local contact stresses during mechanical interactions with objects is presented and their relative position is ascertained. This system utilizes a reversible force‐induced color switch in a thin layer of spiropyran‐functionalized polydimethylsiloxane, which coats a silicone‐made suction cup. The mechanochromic suction cup is integrated with a 3D‐printed compact load‐transferring system and electronic color‐changing detection elements. The assembly may serve as a synthetic receptor for robotic actuators, discerning localized interaction forces down to 3 N. The system's resilience to varying environmental factors, including illumination, tilting, and interaction with objects of various shapes is verified. The results indicate potential for exteroceptive solutions in reconfigurable manipulation tasks without compromising the overall softness of the manipulator.

Comparative research on monitoring methods for nitrate nitrogen leaching in tea plantation soils

Great concern has long been raised about nitrate leaching in cropland due to its possible environmental side effects in ground water contamination. Here we employed two common techniques to measure nitrate leaching in tea plantation soils in subtropical China. Using drainage lysimeter as a reference method, the adaptability of estimating drainage and nitrate leaching by combining the water balance equation with the suction cup technique was investigated. Results showed that the final cumulative leachate volume for the calculated and measured method was 721.43 mm and 729.92 mm respectively during the study period. However, nitrate concentration exerted great influence in the estimation of nitrate leaching from the suction cup-based method. The cumulative nitrate leaching loss from the lysimeter and suction cup-based method was 47.45 kg ha−1 and 43.58 kg ha−1 under lysimeter nitrate concentrations ranging from 7 mg L−1 to 13 mg L−1, 156.28 kg ha−1 and 79.95 kg ha−1 under lysimeter nitrate concentrations exceeding 13 mg L−1. Therefore, the suction cup-based method could be an alternative way of monitoring nitrate leaching loss within a range of 7–13 mg L−1 of nitrate concentrations in leachate. Besides, lower results occurred in suction cup samplers due to lack of representative samples which mainly leached via preferential flow when in strong leaching events. Thus, it is advisable to increase sampling frequency under such special conditions. The results of this experiment can serve as a reference and guidance for the application of ceramic cups in monitoring nitrogen and other nutrient-ion leaching in tea plantation soils.

Liquid-immersion inclined-rotated exposure system for fabricating three-dimensional microstructures with large inclination angles

Abstract This study utilized liquid-immersion inclined-rotated ultraviolet lithography to fabricate three-dimensional (3D) microstructures. The maximum achievable inclination angles obtained through conventional inclined-rotated exposure (IRE) methods were limited by the significant refractive index differences in material. We proposed an IRE with liquid-immersion and adjustable mirrors, which enabled greater inclination angles with improved adjustability. Using liquid as a medium helped minimize the refractive index disparities between materials. We fabricated polydimethylsiloxane molds for micro suction cup (MSC) array sheets to evaluate the performance of the developed liquid-immersion IRE. The resulting MSC array sheets (10 mm2) with a suction cup diameter of 500 μm, achieved inclination angles up to 51°, approximately double those obtained with the conventional IRE method. In addition, the suction force of the fabricated MSC arrays were evaluated by pulling along the vertical, horizontal, and edge directions under wet conditions. The maximum measured suction force was 0.15 N, confirming the effectiveness of the proposed liquid-immersion IRE in fabricating 3D microstructures, as demonstrated by the fabricated MSC array sheets.

An automated separator to exclude lumpfish with deformed suckers

Salmon farming is threatened by sea lice infestations, which impact fish health, compromise welfare and reduce market value. The use of lumpfish as cleaner fish offers a natural solution for sea lice control, but the delousing efficacy of lumpfish can be hindered by morphological deformities, particularly in the ventral suckers (suction cups) of the fish. Sucker deformities increase mortality rates, hamper welfare and impose a substantial financial burden. Deformed lumpfish, therefore, are typically removed before they are deployed in salmon pens, but this is done manually by visual inspection, which is laborious and time consuming, prompting the exploration of alternative exclusion solutions. We tested a novel automated separator designed to sort juvenile lumpfish based on sucker deformities, aiming at streamlining production in lumpfish hatcheries. The prototype, featuring two chambers and an air-driven rotating drum, was tested across five trials involving 293 juvenile lumpfish with varying sucker deformities. The separator was able to separate 78% of lumpfish with good functional suckers, and to exclude 79% of deformed individual. Sorting was swift and ~50% of lumpfish were sorted within 2 minutes. Binary logistic regression indicates that the probability of being sorted decreased significantly with the extent of sucker deformity and with lumpfish size. Around 22% of lumpfish with good functional suckers were not sorted by the separator likely due to behavioural avoidance, which warrants further study. Given the welfare and financial implications of having to exclude deformed lumpfish, the use of an automated separator as described here may contribute to increase the sustainability of lumpfish production for sea lice control in salmon farming.

A soft bioinspired suction cup with tunable adhesion force using shape memory alloy

Abstract Suction cups has been widely utilized to grasp objects, but they typically encounter challenges with sealing failure and non-adjustable adhesion force. In this study, a bioinspired suction cup integrated with an shape memory alloy actuated module was proposed to solve these problems. The actuating performance under different input current was firstly investigated to ensure the effectiveness of the module. Then, inspired by the surface structures of the tree frog’s toe pad, the synthetic bioinspired suction cups with hexagonal microstructures at the rims were designed. The regular cup with soft and smooth rim was also fabricated for comparison study. Furthermore, the adhesion performance and surface adaptability of different two cups were studied in both dry and water conditions on substrates with various roughness levels. The results indicated that the proposed active bioinspired suction cup exhibited higher pull-off strength and better sealing on less rough substrates. The proposed bioinspired suction cup possessed the advantages of compactness and lightweight, thus demonstrating potential for integration into arrayed suction grippers.

Plasmonic Hydrogel Actuators for Octopus-Inspired Photo/Thermoresponsive Smart Adhesive Patch.

Octopuses are notable creatures that can dynamically adhere to a variety of substrates owing to the efficient pressure control within their suction cups. An octopus' suckers are sealed at the rim and function by reducing the pressure inside the cavity, thereby creating a pressure difference between the ambient environment and the inner cavity. Inspired by this mechanism, we developed a plasmonic smart adhesive patch (Plasmonic AdPatch) with switchable adhesion in response to both temperature changes and near-infrared (NIR) light. The AdPatch incorporates an elastic, nanohole-patterned elastomer that mimics the structure of octopus suckers. Additionally, a monolayer of gold nanostars (GNSs) is coated on the patch, facilitating a NIR light-responsive photothermal effect. A musclelike, thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel functions as a volumetric actuator to regulate cavity pressure. When exposed to heat or light, the PNIPAM hydrogel shrinks, enabling the AdPatch to achieve strong suction adhesion (134 kPa at 45 °C, 71 kPa at 85 mW cm-2). Owing to its capability to achieve light-triggered remote adhesion without the need for external pressure, the Plasmonic AdPatch can be employed to transfer ultrathin films and biosensors to fragile organs without causing damage.

(Invited) 3D-Printed Bio-Inspired Electrophysiological Sensors

Miniaturized bioinspired architectures used in diagnostic and therapeutic devices have garnered considerable attention due to their ability to deliver enhanced performance coupled with excellent biocompatibility, breathability, flexibility, and minimized side effects. This is particularly significant for applications involving neonates, infants, or individuals with atopic dermatitis [1], where traditional glue-based adhesives pose risks of skin contamination, injury, and interference with biosignal monitoring near wet wound areas or wet skin.The imperative development of bioinspired, reusable, drainable, and contaminant-free transdermal patches, along with therapeutic systems or attachable devices featuring diagnostic sensing components, is crucial for patients necessitating specialized medical care. The rising demand for such adhesives is evident in their application for long-term diagnosis, therapy, or rehabilitation [2].Taking inspiration from aquatic creatures, which have evolved two primary underwater attachment strategies—pressure-driven (suction attachment) and glue-like (bioadhesive secretions)—bioinspired suction-based adhesives with diverse multiscale architectures have been reported. These designs mimic the attachment behavior of octopi, tree frogs, beetles, leeches, snails, and geckos, demonstrating impressive mechanical enhancements and accurate biosignal monitoring capabilities [3-5]. However, the microfabrication processes described in existing literature are often complex, labor-intensive, and costly.In response to this challenge, recent advancements in electrode and adhesive printing, particularly through three-dimensional (3D) printing, have gained favor among academics and researchers. 3D printing offers a viable alternative by providing high-quality signal measurements, optimal performance, cost-effectiveness, and customization. In this work, a simplified fabrication technique primarily based on Stereolithography (SLA) 3D printing is demonstrated. The technique aims to create a permeable skin patch featuring miniaturized octopus-like suckers, enhancing adhesion and facilitating precise biosignal monitoring across various skin conditions.1- S. Baik, H. J. Lee, D. W. Kim, J. W. Kim, Y. Lee, and C. Pang, “Bioinspired Adhesive Architectures: From Skin Patch to Integrated Bioelectronics,” Advanced Materials, vol. 31, no. 34, p. 1803309, Aug. 2019, doi: 10.1002/adma.201803309.2- S. Baik, J. Kim, H. J. Lee, T. H. Lee, and C. Pang, “Highly Adaptable and Biocompatible Octopus-Like Adhesive Patches with Meniscus-Controlled Unfoldable 3D Microtips for Underwater Surface and Hairy Skin,” Advanced Science, vol. 5, no. 8, Aug. 2018, doi: 10.1002/advs.201800100.3- S. Chun et al., “Conductive and Stretchable Adhesive Electronics with Miniaturized Octopus-Like Suckers against Dry/Wet Skin for Biosignal Monitoring,” Adv Funct Mater, vol. 28, no. 52, Dec. 2018, doi: 10.1002/adfm.201805224.4- D. W. Kim et al., “Highly Permeable Skin Patch with Conductive Hierarchical Architectures Inspired by Amphibians and Octopi for Omnidirectionally Enhanced Wet Adhesion,” Adv Funct Mater, vol. 29, no. 13, Mar. 2019, doi: 10.1002/adfm.201807614.5- S. Baik, D. W. Kim, Y. Park, T. J. Lee, S. Ho Bhang, and C. Pang, “A wet-tolerant adhesive patch inspired by protuberances in suction cups of octopi,” Nature, vol. 546, no. 7658, pp. 396–400, Jun. 2017, doi: 10.1038/nature22382.

Impact of split nitrogen applications on nitrate leaching and maize yield in irrigated loamy sand soils of Northeast Nebraska

AbstractLittle information is available on optimizing the number of nitrogen (N) splits based on nitrate (NO3‐N) leaching and maize yield in sandy soils. To address this gap, we evaluated the impact of multiple N splits (2‐, 3‐, 4‐, and 5‐N splits) on NO3‐N leaching and maize (Zea mays L.) grain yield in irrigated loamy sand soil at a producer site in the Bazile Groundwater Management Area of Northeast Nebraska. Porous suction cup lysimeters were installed at a depth of 120 cm to collect pore water samples from 23 leaching events in 2021, a dry year. Increasing the number of N‐splits did not affect the pore‐water NO3‐N concentration; however, it was 169%, 152%, 150%, and 129% higher in 2‐, 3‐, 4‐, and 5‐N split treatments compared to control, that is, without N application. Though the 2‐, 3‐, 4‐, and 5‐N splits had 110%, 71%, 120%, and 91% higher area‐based NO3‐N leaching than the control, less deep percolation and more evapotranspiration in control led to no significant differences in area‐based NO3‐N leaching among all treatments. All N‐splits resulted in higher maize yield, nitrogen use efficiency, plant N uptake, harvest index, and aboveground biomass than control; however, the number of N‐splits did not affect these parameters. The inclusion of environmental cost reduced the return to nitrogen by 92–143 $ ha−1 across all N‐split treatments but did not significantly affect the differences among the splits. Overall, the results indicate that increasing the number of N‐splits does not provide agronomic, economic, and environmental benefits in irrigated maize fields during a dry year.

Biomimetic Octopus Suction Cup with Attachment Force Self-Sensing Capability for Cardiac Adhesion.

This study develops a biomimetic soft octopus suction device with integrated self-sensing capabilities designed to enhance the precision and safety of cardiac surgeries. The device draws inspiration from the octopus's exceptional ability to adhere to various surfaces and its sophisticated proprioceptive system, allowing for real-time adjustment of adhesive force. The research integrates thin-film pressure sensors into the soft suction cup design, emulating the tactile capabilities of an octopus's sucker to convey information about the contact environment in real time. Signals from sensors within soft materials exhibiting complex strain characteristics are processed and interpreted using the grey wolf optimizer-back propagation (GWO-BP) algorithm. The tissue stabilizer is endowed with the self-sensing capabilities of biomimetic octopus suckers, and real-time feedback on the adhesion state is provided. The embedding location of the thin-film pressure sensors is determined through foundational experiments with flexible substrates, standard spherical tests, and biological tissue trials. The newly fabricated suction cups undergo compression pull-off tests to collect data. The GWO-BP algorithm model accurately identifies and predicts the suction cup's adhesion force in real time, with an error rate below 0.97% and a mean prediction time of 0.0027 s. Integrating this technology offers a novel approach to intelligent monitoring and attachment assurance during cardiac surgeries. Hence, the probability of potential cardiac tissue damage is reduced, with future applications for integrating intelligent biomimetic adhesive soft robotics.

Highly Adaptive Kirigami-Metastructure Adhesive with Vertically Self-Aligning Octopus-like 3D Suction Cups for Efficient Wet Adhesion to Complexly Curved Surfaces.

An essential requirement for biomedical devices is the capability of conformal adaptability on diverse irregular 3D (three-dimensional) nonflat surfaces in the human body that may be covered with liquids such as mucus or sweat. However, the development of reversible adhesive interface materials for biodevices that function on complex biological surfaces is challenging due to the wet, slippery, smooth, and curved surface properties. Herein, we present an ultra-adaptive bioadhesive for irregular 3D oral cavities covered with saliva by integrating a kirigami-metastructure and vertically self-aligning suction cups. The flared suction cup, inspired by octopus tentacles, allows adhesion to moist surfaces. Additionally, the kirigami-based auxetic metastructure with a negative Poisson's ratio relieves the stress caused by tensile strain, thereby mitigating the stress caused by curved surfaces and enabling conformal contact with the surface. As a result, the adhesive strength of the proposed auxetic adhesive is twice that of adhesives with a flat backbone on highly curved porcine palates. For potential application, the proposed auxetic adhesive is mounted on a denture and performs successfully in human subject feasibility evaluations. An integrated design of these two structures may provide functionality and potential for biomedical applications.

Octopus‐Inspired Adaptive Molecular Motion for Synergistic Photothermal and Nitric Oxide Antibacterial Therapy in Diabetic Wound Repair

AbstractBacterial infections, especially those from drug‐resistant strains, pose a significant threat to healing diabetic skin injuries, with current treatments being intricated and often unsatisfactory. Inspired by octopuses, a biomimetic material using α‐cyclodextrin (α‐CD) and polyethylene glycol (PEG) assembled with graphene oxide end‐capped polyrotaxanes (GO‐PR) is developed, where α‐CD mimics the flexible tentacles of an octopus. Further, α‐CD is cationically modified with polyethyleneimine (PEI) to resemble octopus suction cups, creating GO‐PRP, which effectively captures and adheres to bacteria. Importantly, to emulate an octopus's ink defense, GO‐PRP is used as a carrier for nitric oxide (NO), resulting in GO‐PRP/NONOate. Utilizing the photothermal conversion of GO, near‐infrared light exposure triggers rapid heating and NO release, providing efficient antibacterial activity and biofilm dispersion, significantly reducing inflammation in diabetic skin injuries in type I rats. During wound healing, sustained NO release promotes vascular endothelial growth factor production and blood vessel regeneration, enhancing collagen formation and shortening the healing time for diabetic skin infections. Thus, octopus‐inspired GO‐PRP/NONOate emerges as a novel biomaterial for treating drug‐resistant bacterial infections in diabetic wounds in the biomedical field.

A bioinspired switchable adhesive patch with adhesion and suction mechanisms for laparoscopic surgeries

Medical adhesives play an important role in clinical medicine because of their flexibility and convenient operation. However, they are still limited to laparoscopic surgeries, which have demonstrated urgent demand for liver retraction with minimal damage to the human body. Here, inspired by the suction cup structure of octopus, an adhesive patch with excellent mechanical properties, robust and switchable adhesiveness, and biocompatibility is proposed. The adhesive patch is combined by the attachment body mainly made of poly(acrylic acid) grafted with N-hydroxysuccinimide ester, crosslinked biodegradable gelatin methacrylate and biodegradable biopolymer gelatin to mimic the adhesive sucker rim, and the temperature-sensitive telescopic layer of microgel-crosslinked poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) to shrink and form internal cavity with reduced pressure. Through mechanical tests, adhesion evaluation, and biocompatibility analysis, the bioinspired adhesive patch has demonstrated its capacity not only in adhesion to tissues but also in potential treatment for medical applications, especially laparoscopic technology. The bioinspired adhesive patch can break through the limitations of traditional retraction methods, and become an ideal candidate for liver retraction in laparoscopic surgery and related clinical medicine.

Classification and Evaluation of Octopus-Inspired Suction Cups for Soft Continuum Robots.

The emergence of the field of soft robotics has led to an interest in suction cups as auxiliary structures on soft continuum arms to support the execution of manipulation tasks. This application poses demanding requirements on suction cups with respect to sensorization, adhesion under non-ideal contact conditions, and integration into fully soft systems. The octopus can serve as an important source of inspiration for addressing these challenges. This review aims to accelerate research in octopus-inspired suction cups by providing a detailed analysis of the octopus sucker, determining meaningful performance metrics for suction cups on the basis of this analysis, and evaluating the state-of-the-art in suction cups according to these performance metrics. In total, 47 records describing suction cups are found, classified according to the deployed actuation method, and evaluated on performance metrics reflecting the level of sensorization, adhesion, and integration. Despite significant advances in recent years, the octopus sucker outperforms all suction cups on all performance metrics. The realization of high resolution tactile sensing in suction cups and the integration of such sensorized suction cups in soft continuum structures are identified as two major hurdles toward the realization of octopus-inspired manipulation strategies in soft continuum robot arms.

Innovative Design of a 3D Printed Esophageal Stent Inspired by Nature: Mitigating Migration Challenges in Palliative Esophageal Cancer Therapy.

Esophageal cancer is a complex and challenging tumor to treat, with esophageal stenting being used as a palliative measure to improve the quality of life of patients. Self-expandable metal stents (SEMS), self-expandable plastic stents (SEPS), and biodegradable stents are the most commonly used types of stents. However, complications can arise, such as migration, bleeding, and perforation. To address issues of migration, this study developed a novel 3D printed bioinspired esophageal stent utilizing a highly flexible and ductile TPU material. The stent was designed to be self-expanding and tubular with flared ends to provide secure anchorage at both the proximal and distal ends of the structure. Suction cups were strategically placed around the shaft of the stent to prevent migration. The stent was evaluated through compression-recovery, self-expansion, and anti-migration tests to evaluate its recovery properties, self-expansion ability, and anchoring ability, respectively. The results indicated that the novel stent was able to recover its shape, expand, keep the esophagus open, and resist migration, demonstrating its potential for further research and clinical applications. Finite element analysis (FEA) was leveraged to analyze the stent's mechanical behavior, providing insights into its structural integrity, self-expansion capability, and resistance against migration. These results, supported by FEA, highlight the potential of this innovative stent for further research and its eventual application in preclinical settings.