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Cao Y, Xu B, Li B, Fu H. Advanced Design of Soft Robots with Artificial Intelligence. NANO-MICRO LETTERS 2024; 16:214. [PMID: 38869734 DOI: 10.1007/s40820-024-01423-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/22/2024] [Indexed: 06/14/2024]
Affiliation(s)
- Ying Cao
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hong Kong, 999077, People's Republic of China
| | - Bingang Xu
- Nanotechnology Center, School of Fashion and Textiles, The Hong Kong Polytechnic University, Hong Kong, 999077, People's Republic of China.
| | - Bin Li
- Bioinspired Engineering and Biomechanics Center, Xi'an Jiaotong University, Xi'an, 710049, People's Republic of China
| | - Hong Fu
- Department of Mathematics and Information Technology, The Education University of Hong Kong, Hong Kong, 999077, People's Republic of China.
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2
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Mete M, Jeong H, Wang WD, Paik J. SORI: A softness-rendering interface to unravel the nature of softness perception. Proc Natl Acad Sci U S A 2024; 121:e2314901121. [PMID: 38466880 PMCID: PMC10990105 DOI: 10.1073/pnas.2314901121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 02/02/2024] [Indexed: 03/13/2024] Open
Abstract
Tactile perception of softness serves a critical role in the survival, well-being, and social interaction among various species, including humans. This perception informs activities from food selection in animals to medical palpation for disease detection in humans. Despite its fundamental importance, a comprehensive understanding of how softness is neurologically and cognitively processed remains elusive. Previous research has demonstrated that the somatosensory system leverages both cutaneous and kinesthetic cues for the sensation of softness. Factors such as contact area, depth, and force play a particularly critical role in sensations experienced at the fingertips. Yet, existing haptic technologies designed to explore this phenomenon are limited, as they often couple force and contact area, failing to provide a real-world experience of softness perception. Our research introduces the softness-rendering interface (SORI), a haptic softness display designed to bridge this knowledge gap. Unlike its predecessors, SORI has the unique ability to decouple contact area and force, thereby allowing for a quantitative representation of softness sensations at the fingertips. Furthermore, SORI incorporates individual physical fingertip properties and model-based softness cue estimation and mapping to provide a highly personalized experience. Utilizing this method, SORI quantitatively replicates the sensation of softness on stationary, dynamic, homogeneous, and heterogeneous surfaces. We demonstrate that SORI accurately renders the surfaces of both virtual and daily objects, thereby presenting opportunities across a range of fields, from teleoperation to medical technology. Finally, our proposed method and SORI will expedite psychological and neuroscience research to unlock the nature of softness perception.
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Affiliation(s)
- Mustafa Mete
- Reconfigurable Robotics Laboratory, Institute of Mechanical Engineering, School of Engineering, École Polytechnique Fédérale de Lausanne, LausanneCH 1005, Switzerland
| | - Haewon Jeong
- Soft Robotics Laboratory, Department of Mechanical Engineering, College of Engineering, Hanyang University, Seoul04763, Republic of Korea
| | - Wei Dawid Wang
- Soft Robotics Laboratory, Department of Mechanical Engineering, College of Engineering, Hanyang University, Seoul04763, Republic of Korea
| | - Jamie Paik
- Reconfigurable Robotics Laboratory, Institute of Mechanical Engineering, School of Engineering, École Polytechnique Fédérale de Lausanne, LausanneCH 1005, Switzerland
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3
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Li B, Gerling GJ. An individual's skin stiffness predicts their tactile discrimination of compliance. J Physiol 2023; 601:5777-5794. [PMID: 37942821 PMCID: PMC10872733 DOI: 10.1113/jp285271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/19/2023] [Indexed: 11/10/2023] Open
Abstract
Individual differences in tactile acuity have been correlated with age, gender and finger size, whereas the role of the skin's stiffness has been underexplored. Using an approach to image the 3-D deformation of the skin surface during contact with transparent elastic objects, we evaluate a cohort of 40 young participants, who present a diverse range of finger size, skin stiffness and fingerprint ridge breadth. The results indicate that skin stiffness generally correlates with finger size, although individuals with relatively softer skin can better discriminate compliant objects. Analysis of contact at the skin surface reveals that softer skin generates more prominent patterns of deformation, in particular greater rates of change in contact area, which correlate with higher rates of perceptual discrimination of compliance, regardless of finger size. Moreover, upon applying hyaluronic acid to soften individuals' skin, we observe immediate, marked and systematic changes in skin deformation and consequent improvements in perceptual acuity in differentiating compliance. Together, the combination of 3-D imaging of the skin surface, biomechanics measurements, multivariate regression and clustering, and psychophysical experiments show that subtle distinctions in skin stiffness modulate the mechanical signalling of touch and shape individual differences in perceptual acuity. KEY POINTS: Although declines in tactile acuity with ageing are a function of multiple factors, for younger people, the current working hypothesis has been that smaller fingers are better at informing perceptual discrimination because of a higher density of neural afferents. To decouple relative impacts on tactile acuity of skin properties of finger size, skin stiffness, and fingerprint ridge breadth, we combined 3-D imaging of skin surface deformation, biomechanical measurements, multivariate regression and clustering, and psychophysics. The results indicate that skin stiffness generally correlates with finger size, although it more robustly correlates with and predicts an individual's perceptual acuity. In particular, more elastic skin generates higher rates of deformation, which correlate with perceptual discrimination, shown most dramatically by softening each participant's skin with hyaluronic acid. In refining the current working hypothesis, we show the skin's stiffness strongly shapes the signalling of touch and modulates individual differences in perceptual acuity.
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Affiliation(s)
- Bingxu Li
- Systems and Information Engineering, Mechanical Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, VA, USA
| | - Gregory J Gerling
- Systems and Information Engineering, Mechanical Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, VA, USA
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4
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Shao X, Wang Y, Frechette J. Out-of-contact peeling caused by elastohydrodynamic deformation during viscous adhesion. J Chem Phys 2023; 159:134904. [PMID: 37787141 DOI: 10.1063/5.0167300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/12/2023] [Indexed: 10/04/2023] Open
Abstract
We report on viscous adhesion measurements conducted in sphere-plane geometry between a rigid sphere and soft surfaces submerged in silicone oils. Increasing the surface compliance leads to a decrease in the adhesive strength due to elastohydrodynamic deformation of the soft surface during debonding. The force-displacement and fluid film thickness-time data are compared to an elastohydrodynamic model that incorporates the force measuring spring and finds good agreement between the model and data. We calculate the pressure distribution in the fluid and find that, in contrast to debonding from rigid surfaces, the pressure drop is non-monotonic and includes the presence of stagnation points within the fluid film when a soft surface is present. In addition, viscous adhesion in the presence of a soft surface leads to a debonding process that occurs via a peeling front (located at a stagnation point), even in the absence of solid-solid contact. As a result of mass conservation, the elastohydrodynamic deformation of the soft surface during detachment leads to surfaces that come closer as the surfaces are separated. During detachment, there is a region with fluid drainage between the centerpoint and the stagnation point, while there is fluid infusion further out. Understanding and harnessing the coupling between lubrication pressure, elasticity, and surface interactions provides material design strategies for applications such as adhesives, coatings, microsensors, and biomaterials.
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Affiliation(s)
- Xingchen Shao
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, California 94720, USA
| | - Yumo Wang
- National Engineering Laboratory for Pipeline Safety, Beijing Key Laboratory of Urban Oil and Gas Distribution Technology, China University of Petroleum, Beijing, 18# Fuxue Road, Changping District, 102249 Beijing, China
| | - Joelle Frechette
- Chemical and Biomolecular Engineering Department, University of California, Berkeley, California 94720, USA
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5
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Li B, Gerling GJ. An individual's skin stiffness predicts their tactile acuity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.17.548686. [PMID: 37502933 PMCID: PMC10370135 DOI: 10.1101/2023.07.17.548686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Individual differences in tactile acuity have been correlated with age, gender, and finger size, while the role of the skin's stiffness has been underexplored. Using an approach to image the 3-D deformation of the skin surface while in contact with transparent elastic objects, we evaluate a cohort of 40 young participants, who present a diverse range of finger size, skin stiffness, and fingerprint ridge breadth. The results indicate that skin stiffness generally correlates with finger size, although individuals with relatively softer skin can better discriminate compliant objects. Analysis of contact at the skin surface reveals that softer skin generates more prominent patterns of deformation, in particular greater rates of change in contact area, which correlate with higher rates of perceptual discrimination, regardless of finger size. Moreover, upon applying hyaluronic acid to soften individuals' skin, we observe immediate, marked and systematic changes in skin deformation and consequent improvements in perceptual acuity. Together, the combination of 3-D imaging of the skin surface, biomechanics measurements, multivariate regression and clustering, and psychophysical experiments show that subtle distinctions in skin stiffness modulate the mechanical signaling of touch and shape individual differences in perceptual acuity.
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Affiliation(s)
- Bingxu Li
- Systems and Information Engineering, Mechanical Engineering, University of Virginia
| | - Gregory J Gerling
- Systems and Information Engineering, Mechanical Engineering, University of Virginia
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6
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Nan X, Xu Z, Cao X, Hao J, Wang X, Duan Q, Wu G, Hu L, Zhao Y, Yang Z, Gao L. A Review of Epidermal Flexible Pressure Sensing Arrays. BIOSENSORS 2023; 13:656. [PMID: 37367021 DOI: 10.3390/bios13060656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/11/2023] [Accepted: 06/14/2023] [Indexed: 06/28/2023]
Abstract
In recent years, flexible pressure sensing arrays applied in medical monitoring, human-machine interaction, and the Internet of Things have received a lot of attention for their excellent performance. Epidermal sensing arrays can enable the sensing of physiological information, pressure, and other information such as haptics, providing new avenues for the development of wearable devices. This paper reviews the recent research progress on epidermal flexible pressure sensing arrays. Firstly, the fantastic performance materials currently used to prepare flexible pressure sensing arrays are outlined in terms of substrate layer, electrode layer, and sensitive layer. In addition, the general fabrication processes of the materials are summarized, including three-dimensional (3D) printing, screen printing, and laser engraving. Subsequently, the electrode layer structures and sensitive layer microstructures used to further improve the performance design of sensing arrays are discussed based on the limitations of the materials. Furthermore, we present recent advances in the application of fantastic-performance epidermal flexible pressure sensing arrays and their integration with back-end circuits. Finally, the potential challenges and development prospects of flexible pressure sensing arrays are discussed in a comprehensive manner.
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Affiliation(s)
- Xueli Nan
- School of Automation and Software Engineering, Shanxi University, Taiyuan 030006, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Zhikuan Xu
- School of Automation and Software Engineering, Shanxi University, Taiyuan 030006, China
| | - Xinxin Cao
- School of Automation and Software Engineering, Shanxi University, Taiyuan 030006, China
| | - Jinjin Hao
- School of Automation and Software Engineering, Shanxi University, Taiyuan 030006, China
| | - Xin Wang
- School of Automation and Software Engineering, Shanxi University, Taiyuan 030006, China
| | - Qikai Duan
- School of Automation and Software Engineering, Shanxi University, Taiyuan 030006, China
| | - Guirong Wu
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
| | - Liangwei Hu
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
| | - Yunlong Zhao
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
- Discipline of Intelligent Instrument and Equipment, Xiamen University, Xiamen 361102, China
| | - Zekun Yang
- Key Laboratory of Instrumentation Science and Dynamic Measurement Ministry of Education, North University of China, Taiyuan 030051, China
| | - Libo Gao
- Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361102, China
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361005, China
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7
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Li B, Hauser SC, Gerling GJ. Faster Indentation Influences Skin Deformation To Reduce Tactile Discriminability of Compliant Objects. IEEE TRANSACTIONS ON HAPTICS 2023; 16:215-227. [PMID: 37028048 PMCID: PMC10357367 DOI: 10.1109/toh.2023.3253256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
To discriminate the compliance of soft objects, we rely upon spatiotemporal cues in the mechanical deformation of the skin. However, we have few direct observations of skin deformation over time, in particular how its response differs with indentation velocities and depths, and thereby helps inform our perceptual judgments. To help fill this gap, we develop a 3D stereo imaging method to observe contact of the skin's surface with transparent, compliant stimuli. Experiments with human-subjects, in passive touch, are conducted with stimuli varying in compliance, indentation depth, velocity, and time duration. The results indicate that contact durations greater than 0.4 s are perceptually discriminable. Moreover, compliant pairs delivered at higher velocities are more difficult to discriminate because they induce smaller differences in deformation. In a detailed quantification of the skin's surface deformation, we find that several, independent cues aid perception. In particular, the rate of change of gross contact area best correlates with discriminability, across indentation velocities and compliances. However, cues associated with skin surface curvature and bulk force are also predictive, for stimuli more and less compliant than skin, respectively. These findings and detailed measurements seek to inform the design of haptic interfaces.
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8
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Cui Z, Wang W, Xia H, Wang C, Tu J, Ji S, Tan JMR, Liu Z, Zhang F, Li W, Lv Z, Li Z, Guo W, Koh NY, Ng KB, Feng X, Zheng Y, Chen X. Freestanding and Scalable Force-Softness Bimodal Sensor Arrays for Haptic Body-Feature Identification. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2207016. [PMID: 36134530 DOI: 10.1002/adma.202207016] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/13/2022] [Indexed: 06/16/2023]
Abstract
Tactile technologies that can identify human body features are valuable in clinical diagnosis and human-machine interactions. Previously, cutting-edge tactile platforms have been able to identify structured non-living objects; however, identification of human body features remains challenging mainly because of the irregular contour and heterogeneous spatial distribution of softness. Here, freestanding and scalable tactile platforms of force-softness bimodal sensor arrays are developed, enabling tactile gloves to identify body features using machine-learning methods. The bimodal sensors are engineered by adding a protrusion on a piezoresistive pressure sensor, endowing the resistance signals with combined information of pressure and the softness of samples. The simple design enables 112 bimodal sensors to be integrated into a thin, conformal, and stretchable tactile glove, allowing the tactile information to be digitalized while hand skills are performed on the human body. The tactile glove shows high accuracy (98%) in identifying four body features of a real person, and four organ models (healthy and pathological) inside an abdominal simulator, demonstrating identification of body features of the bimodal tactile platforms and showing their potential use in future healthcare and robotics.
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Affiliation(s)
- Zequn Cui
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Wensong Wang
- School of Electrical & Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Huarong Xia
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Changxian Wang
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Jiaqi Tu
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- Institute of Flexible Electronics Technology of THU, Zhejiang, Jiaxing, 314000, China
| | - Shaobo Ji
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Joel Ming Rui Tan
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zhihua Liu
- Institute of Materials Research and Engineering, the Agency for Science, Technology and Research, 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Feilong Zhang
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Wenlong Li
- Institute of Materials Research and Engineering, the Agency for Science, Technology and Research, 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Zhisheng Lv
- Institute of Materials Research and Engineering, the Agency for Science, Technology and Research, 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Zheng Li
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Wei Guo
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Nien Yue Koh
- Lee Kong Chian School of Medicine, Novena Campus, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore
| | - Kian Bee Ng
- Lee Kong Chian School of Medicine, Novena Campus, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore
| | - Xue Feng
- Laboratory of Flexible Electronics Technology, Tsinghua University, Beijing, 100190, China
| | - Yuanjin Zheng
- School of Electrical & Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Xiaodong Chen
- Innovative Center for Flexible Devices (iFLEX) & Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- Institute of Materials Research and Engineering, the Agency for Science, Technology and Research, 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
- Institute for Digital Molecular Analytics and Science (IDMxS), Nanyang Technological University, 59 Nanyang Drive, Singapore, 636921, Singapore
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9
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Nguyen DM, Wu Y, Nolin A, Lo CY, Guo T, Dhong C, Martin DC, Kayser LV. Electronically Conductive Hydrogels by in Situ Polymerization of a Water-Soluble EDOT-Derived Monomer. ADVANCED ENGINEERING MATERIALS 2022; 24:2200280. [PMID: 36275121 PMCID: PMC9586015 DOI: 10.1002/adem.202200280] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Indexed: 05/30/2023]
Abstract
Electronically conductive hydrogels have gained popularity in bioelectronic interfaces because their mechanical properties are similar to biological tissues, potentially preventing scaring in implanted electronics. Hydrogels have low elastic moduli, due to their high water content, which facilitates their integration with biological tissues. To achieve electronically conductive hydrogels, however, requires the integration of conducting polymers or nanoparticles. These “hard” components increase the elastic modulus of the hydrogel, removing their desirable compatibility with biological tissues, or lead to the heterogeneous distribution of the conductive material in the hydrogel scaffold. A general strategy to transform hydrogels into electronically conductive hydrogels without affecting the mechanical properties of the parent hydrogel is still lacking. Herein, a two‐step method is reported for imparting conductivity to a range of different hydrogels by in‐situ polymerization of a water‐soluble and neutral conducting polymer precursor: 3,4–ethylenedioxythiophene diethylene glycol (EDOT‐DEG). The resulting conductive hydrogels are homogenous, have conductivities around 0.3 S m−1, low impedance, and maintain an elastic modulus of 5–15 kPa, which is similar to the preformed hydrogel. The simple preparation and desirable properties of the conductive hydrogels are likely to lead to new materials and applications in tissue engineering, neural interfaces, biosensors, and electrostimulation.
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Affiliation(s)
- Dan My Nguyen
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716, United States
| | - Yuhang Wu
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, United States
| | - Abigail Nolin
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, United States
| | - Chun-Yuan Lo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716, United States
| | - Tianzheng Guo
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, United States
| | - Charles Dhong
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, United States
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, 19716, United States
| | - David C Martin
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, United States
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware, 19716, United States
| | - Laure V Kayser
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716, United States
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716, United States
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10
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Tan ZY, Choo CM, Lin Y, Ho HN, Kitada R. The Effect of Temperature on Tactile Softness Perception. IEEE TRANSACTIONS ON HAPTICS 2022; 15:638-645. [PMID: 35951577 DOI: 10.1109/toh.2022.3198115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We are adept at discriminating object properties such as softness and temperature using touch. Previous studies have investigated the nature of each object property, but the interactions between these properties are not fully understood. Tactile softness perception relies on multiple sensory cues such as the size of the contact area, indentation depth, and force exerted. In addition to these cues, the temperature of the stimulus may contribute to tactile softness perception by changing the sensitivity to changes in stimulus compliance. To test this hypothesis, we conducted two psychophysical experiments in which the subjects estimated the magnitude of perceived softness after touching deformable objects. We varied the compliance and temperature of the stimuli. The linear functions of compliance fit to the magnitude estimates under cold conditions (9-15°C) were steeper than the functions fit to the magnitude estimates under room temperature (21-25°C). These results indicate that temperature can sharpen our tactile softness perception of deformable surfaces by increasing the sensitivity to differences in compliance.
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11
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Cui Z, Wang W, Guo L, Liu Z, Cai P, Cui Y, Wang T, Wang C, Zhu M, Zhou Y, Liu W, Zheng Y, Deng G, Xu C, Chen X. Haptically Quantifying Young's Modulus of Soft Materials Using a Self-Locked Stretchable Strain Sensor. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2104078. [PMID: 34423476 DOI: 10.1002/adma.202104078] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Simple and rapid Young's modulus measurements of soft materials adaptable to various scenarios are of general significance, and they require miniaturized measurement platforms with easy operation. Despite the advances made in portable and wearable approaches, acquiring and analyzing multiple or complicated signals necessitate tethered bulky components and careful preparation. Here, a new methodology based on a self-locked stretchable strain sensor to haptically quantify Young's modulus of soft materials (kPa-MPa) rapidly is reported. The method demonstrates a fingertip measurement platform, which endows a prosthetic finger with human-comparable haptic behaviors and skills on elasticity sensing without activity constraints. A universal strategy is offered toward ultraconvenient and high-efficient Young's modulus measurements with wide adaptability to various fields for unprecedented applications.
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Affiliation(s)
- Zequn Cui
- Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Wensong Wang
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Lingling Guo
- International Joint Research Laboratory for Biointerface and Biodetection, State Key Lab of Food Science and Technology, and School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, P. R. China
| | - Zhihua Liu
- Institute of Materials Research and Engineering the Agency for Science, Technology and Research, 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Pingqiang Cai
- Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Yajing Cui
- Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Ting Wang
- Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Changxian Wang
- Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Ming Zhu
- Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Ying Zhou
- Nursing Department, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200080, P. R. China
| | - Wenyan Liu
- Nursing Department, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200080, P. R. China
| | - Yuanjin Zheng
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Guoying Deng
- Trauma and Emergency Center, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200080, P. R. China
| | - Chuanlai Xu
- International Joint Research Laboratory for Biointerface and Biodetection, State Key Lab of Food Science and Technology, and School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, P. R. China
| | - Xiaodong Chen
- Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
- Institute of Materials Research and Engineering the Agency for Science, Technology and Research, 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
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12
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Nolin A, Pierson K, Hlibok R, Lo CY, Kayser LV, Dhong C. Controlling fine touch sensations with polymer tacticity and crystallinity. SOFT MATTER 2022; 18:3928-3940. [PMID: 35546489 PMCID: PMC9302477 DOI: 10.1039/d2sm00264g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The friction generated between a finger and an object forms the mechanical stimuli behind fine touch perception. To control friction, and therefore tactile perception, current haptic devices typically rely on physical features like bumps or pins, but chemical and microscale morphology of surfaces could be harnessed to recreate a wider variety of tactile sensations. Here, we sought to develop a new way to create tactile sensations by relying on differences in microstructure as quantified by the degree of crystallinity in polymer films. To isolate crystallinity, we used polystyrene films with the same chemical formula and number averaged molecular weights, but which differed in tacticity and annealing conditions. These films were also sufficiently thin as to be rigid which minimized effects from bulk stiffness and had variations in roughness lower than detectable by humans. To connect crystallinity to human perception, we performed mechanical testing with a mock finger to form predictions about the degree of crystallinity necessary to result in successful discrimination by human subjects. Psychophysical testing verified that humans could discriminate surfaces which differed only in the degree of crystallinity. Although related, human performance was not strongly correlated with a straightforward difference in the degree of crystallinity. Rather, human performance was better explained by quantifying transitions in steady to unsteady sliding and the generation of slow frictional waves (r2 = 79.6%). Tuning fine touch with polymer crystallinity may lead to better engineering of existing haptic interfaces or lead to new classes of actuators based on changes in microstructure.
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Affiliation(s)
- Abigail Nolin
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
| | - Kelly Pierson
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
| | - Rainer Hlibok
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
| | - Chun-Yuan Lo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, USA
| | - Laure V Kayser
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, USA
| | - Charles Dhong
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
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Li M, Pal A, Aghakhani A, Pena-Francesch A, Sitti M. Soft actuators for real-world applications. NATURE REVIEWS. MATERIALS 2022; 7:235-249. [PMID: 35474944 PMCID: PMC7612659 DOI: 10.1038/s41578-021-00389-7] [Citation(s) in RCA: 159] [Impact Index Per Article: 79.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 05/22/2023]
Abstract
Inspired by physically adaptive, agile, reconfigurable and multifunctional soft-bodied animals and human muscles, soft actuators have been developed for a variety of applications, including soft grippers, artificial muscles, wearables, haptic devices and medical devices. However, the complex performance of biological systems cannot yet be fully replicated in synthetic designs. In this Review, we discuss new materials and structural designs for the engineering of soft actuators with physical intelligence and advanced properties, such as adaptability, multimodal locomotion, self-healing and multi-responsiveness. We examine how performance can be improved and multifunctionality implemented by using programmable soft materials, and highlight important real-world applications of soft actuators. Finally, we discuss the challenges and opportunities for next-generation soft actuators, including physical intelligence, adaptability, manufacturing scalability and reproducibility, extended lifetime and end-of-life strategies.
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Affiliation(s)
- Meng Li
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Aniket Pal
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Amirreza Aghakhani
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Abdon Pena-Francesch
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany
- Department of Materials Science and Engineering, Macromolecular Science and Engineering, Robotics Institute, University of Michigan, Ann Arbor, MI, USA
| | - Metin Sitti
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany
- Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland
- School of Medicine and College of Engineering, Koç University, Istanbul, Turkey
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14
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Inoue K, Okamoto S, Akiyama Y, Yamada Y. Surfaces With Finger-Sized Concave Feel Softer. IEEE TRANSACTIONS ON HAPTICS 2022; 15:32-38. [PMID: 34962878 DOI: 10.1109/toh.2021.3138640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The judgment of elastic softness is determined not only by mechanical parameters related to hardness, such as the elastic modulus and stiffness, but also by macroscopic surface features. This study experimentally demonstrates that objects with a finger-sized concave with a depth of 1-3 mm feel softer than flat surfaces made of the same materials when they are pushed by a finger. In Experiment 1, participants judged the surfaces of a rigid material with thumb-sized concaves to be softer than the flat and convex surfaces. Experiment 2 used rubbers of various elastic moduli, and the softness of a concave object with a Young's modulus of 0.55 MPa was subjectively equal to that of a flat object with an average Young's modulus of 0.23 MPa. Furthermore, the softness of a convex object was subjectively equal to that of a 1.68 MPa flat object. The contact phenomena between a finger pad and concave or convex objects are different from those between a finger pad and flat objects, and they influence the softness judgment. Such phenomena include the relationship between the pressing force and contact area. These results provide insights into surface design and improve comprehension of the perceptual principles of softness.
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15
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Kim AR, Mitra SK, Zhao B. Reduced Pressure Drop in Viscoelastic Polydimethylsiloxane Wall Channels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:14292-14301. [PMID: 34846896 DOI: 10.1021/acs.langmuir.1c02087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Polydimethylsiloxane (PDMS) is an important viscoelastic material that finds applications in a large number of engineering systems, particularly lab-on-chip microfluidic devices built with a flexible substrate. Channels made of PDMS, used for transporting analytes, are integral to these applications. The PDMS viscoelastic nature can induce additional hydrodynamic contributions at the soft wall/fluid interface compared to rigid walls. In this research, we investigated the pressure drop within PDMS channels bounded by rigid tubes (cellulose tubes). The bulging effect of the PDMS was limited by the rigid tubes under flowing fluids. The PDMS viscoelasticity was modulated by changing the ratio of the base to the cross-linker from 10:1 to 35:1. We observed that the pressure drop of the flowing fluids within the channel decreased with the increased loss tangent of the PDMS in the examined laminar regime [Reynolds number (Re) ∼ 23-58.6 for water and Re ∼ 0.69-8.69 for glycerol solution]. The elastic PDMS 10:1 wall channels followed the classical Hagen Poiseuille's equation, but the PDMS walls with lower cross-linker concentrations and thicker walls decreased pressure drops. The friction factor (f) for the PDMS channels with the two working fluids could be approximated as f = 47/Re. We provide a correlation between the pressure drop and PDMS viscoelasticity based on experimental findings. In the correlation, the loss tangent predominates; the larger the loss tangent, the smaller is the pressure drop. The research findings appear to be unexpected if only considering the energy dissipation of viscoelastic PDMS walls. We attributed the reduction in the pressure drop to a lubricating effect of the viscoelastic PDMS walls in the presence of the working fluids. Our results reveal the importance of the subtle diffusion of the residual oligomers and water from the bulk to the soft wall/fluid interface for the observed pressure drop in soft wall channels.
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Affiliation(s)
- A-Reum Kim
- Department of Mechanical & Mechatronics Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Ontario, N2L 3G1 Waterloo, Canada
- Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Ontario, N2L 3G1 Waterloo, Canada
| | - Sushanta K Mitra
- Department of Mechanical & Mechatronics Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Ontario, N2L 3G1 Waterloo, Canada
| | - Boxin Zhao
- Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Ontario, N2L 3G1 Waterloo, Canada
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16
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Farajian M, Leib R, Kossowsky H, Nisky I. Visual Feedback Weakens the Augmentation of Perceived Stiffness by Artificial Skin Stretch. IEEE TRANSACTIONS ON HAPTICS 2021; 14:686-691. [PMID: 33465030 DOI: 10.1109/toh.2021.3052912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tactile stimulation devices are gaining popularity in haptic science and technology-they are lightweight, low-cost, can be wearable, and do not suffer from instability during closed loop interactions with users. Applying tactile stimulation, by means of stretching the fingerpad skin concurrently with kinesthetic force feedback, has been shown to augment the perceived stiffness during interactions with elastic objects. However, to date, the perceptual augmentation due to artificial skin-stretch was studied in the absence of visual feedback. In this article, we tested whether this perceptual augmentation is robust when the stretch is applied in combination with visual displacement feedback. We used a forced-choice stiffness discrimination task with four conditions: force feedback, force feedback with skin-stretch, force and visual feedback, and force and visual feedback with skin-stretch. We found that the visual feedback weakens, but does not eliminate, the skin-stretch induced perceptual effect. Additionally, no effect of visual feedback on the discrimination precision was found.
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Nolin A, Licht A, Pierson K, Lo CY, Kayser LV, Dhong C. Predicting human touch sensitivity to single atom substitutions in surface monolayers for molecular control in tactile interfaces. SOFT MATTER 2021; 17:5050-5060. [PMID: 33929468 DOI: 10.1039/d1sm00451d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The mechanical stimuli generated as a finger interrogates the physical and chemical features of an object form the basis of fine touch. Haptic devices, which are used to control touch, primarily focus on recreating physical features, but the chemical aspects of fine touch may be harnessed to create richer tactile interfaces and reveal fundamental aspects of tactile perception. To connect tactile perception with molecular structure, we systematically varied silane-derived monolayers deposited onto surfaces smoother than the limits of human perception. Through mechanical friction testing and cross-correlation analysis, we made predictions of which pairs of silanes might be distinguishable by humans. We predicted, and demonstrated, that humans can distinguish between two isosteric silanes which differ only by a single nitrogen-for-carbon substitution. The mechanism of tactile contrast originates from a difference in monolayer ordering, as quantified by the Hurst exponent, which was replicated in two alkylsilanes with a three-carbon difference in length. This approach may be generalizable to other materials and lead to new tactile sensations derived from materials chemistry.
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Affiliation(s)
- Abigail Nolin
- Department of Materials Science & Engineering, University of Delaware, Newark, DE, USA.
| | - Amanda Licht
- Department of Materials Science & Engineering, University of Delaware, Newark, DE, USA.
| | - Kelly Pierson
- Department of Materials Science & Engineering, University of Delaware, Newark, DE, USA.
| | - Chun-Yuan Lo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, USA
| | - Laure V Kayser
- Department of Materials Science & Engineering, University of Delaware, Newark, DE, USA. and Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, USA
| | - Charles Dhong
- Department of Materials Science & Engineering, University of Delaware, Newark, DE, USA. and Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
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Hartmann F, Baumgartner M, Kaltenbrunner M. Becoming Sustainable, The New Frontier in Soft Robotics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004413. [PMID: 33336520 DOI: 10.1002/adma.202004413] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/03/2020] [Indexed: 06/12/2023]
Abstract
The advancement of technology has a profound and far-reaching impact on the society, now penetrating all areas of life. From cradle to grave, one is supported by and depends on a wide range of electronic and robotic appliances, with an ever more intimate integration of the digital and biological spheres. These advances, however, often come at the price of negatively impacting our ecosystem, with growing demands on energy, contributions to greenhouse gas emissions and environmental pollution-from production to improper disposal. Mitigating these adverse effects is among the grand challenges of the society and at the forefront of materials research. The currently emerging forms of soft, biologically inspired electronics and robotics have the unique potential of becoming not only like their natural antitypes in performance and capabilities, but also in terms of their ecological footprint. This review outlines the rise of sustainable materials in soft and bioinspired robotics, targeting all robotic components from actuators to energy storage and electronics. The state-of-the-art in biobased robotics spans flourishing fields and applications ranging from microbots operating in vivo to biohybrid machines and fully biodegradable yet resilient actuators. These first steps initiate the evolution of robotics and guide them into a sustainable future.
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Affiliation(s)
- Florian Hartmann
- Soft Matter Physics, Institute of Experimental Physics, Johannes Kepler University Linz, Altenberger Strasse 69, Linz, 4040, Austria
- Soft Materials Lab, Linz Institute of Technology LIT, Johannes Kepler University, Altenberger Strasse 69, Linz, 4040, Austria
| | - Melanie Baumgartner
- Soft Matter Physics, Institute of Experimental Physics, Johannes Kepler University Linz, Altenberger Strasse 69, Linz, 4040, Austria
- Soft Materials Lab, Linz Institute of Technology LIT, Johannes Kepler University, Altenberger Strasse 69, Linz, 4040, Austria
- Institute of Polymer Science, Johannes Kepler University, Altenberger Strasse 69, Linz, 4040, Austria
| | - Martin Kaltenbrunner
- Soft Matter Physics, Institute of Experimental Physics, Johannes Kepler University Linz, Altenberger Strasse 69, Linz, 4040, Austria
- Soft Materials Lab, Linz Institute of Technology LIT, Johannes Kepler University, Altenberger Strasse 69, Linz, 4040, Austria
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19
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Manzotti A, Chiera M, Galli M, Lombardi E, La Rocca S, Biasi P, Esteves J, Lista G, Cerritelli F. The neonatal assessment manual score (NAME) for improving the clinical management of infants: a perspective validity study. Ital J Pediatr 2021; 47:53. [PMID: 33678165 PMCID: PMC7938573 DOI: 10.1186/s13052-021-01012-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/26/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The Neonatal Assessment Manual scorE (NAME) was developed to assist in the clinical management of infants in the neonatal ward by assessing their body's compliance and homogeneity. The present study begins its validation process. METHODS An expert panel of neonatal intensive care unit (NICU) professionals investigated the NAME face and content validity. Content validity was assessed through the content validity index (CVI). Construct validity was assessed using data collected from 50 newborns hospitalized in the NICU of "Vittore Buzzi" Children Hospital of Milan, Italy. Kendall's τ and ordinal logistic regressions were used to evaluate the correlation between the NAME scores and infants' gestational age, birth weight, post-menstrual age, weight at the time of assessment, and a complexity index related to organic complications. RESULTS The CVIs for compliance, homogeneity, and the whole scale were respectively 1, 0.9, and 0.95. Construct validity analysis showed significant positive correlations between the NAME and infants' weight and age, and a negative correlation between the NAME and the complexity index (τ = - 0.31 [95% IC: - 0.47, - 0.12], p = 0.016 and OR = 0.56 [95% IC: 0.32, 0.94], p = 0.034 for categorical NAME; τ = - 0.32 [95% IC: - 0.48, - 0.14], p = 0.005 for numerical NAME). CONCLUSIONS The NAME was well accepted by NICU professionals in this study and it demonstrates good construct validity in discriminating the infant's general condition. Future studies are needed to test the NAME reliability and predictive capacity.
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Affiliation(s)
- Andrea Manzotti
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy
- Division of Neonatology, "V. Buzzi" Children's Hospital, ASST-FBF-Sacco, Milan, Italy
- Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Marco Chiera
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy
| | - Matteo Galli
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy
- Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Erica Lombardi
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy
- Division of Neonatology, "V. Buzzi" Children's Hospital, ASST-FBF-Sacco, Milan, Italy
- Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Simona La Rocca
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy
- Division of Neonatology, "V. Buzzi" Children's Hospital, ASST-FBF-Sacco, Milan, Italy
- Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Pamela Biasi
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy
- Division of Neonatology, "V. Buzzi" Children's Hospital, ASST-FBF-Sacco, Milan, Italy
- Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Jorge Esteves
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy
| | - Gianluca Lista
- Division of Neonatology, "V. Buzzi" Children's Hospital, ASST-FBF-Sacco, Milan, Italy
| | - Francesco Cerritelli
- RAISE lab, Foundation COME Collaboration, Corso Europa 29 - 66054 Vasto (Italy), Pescara, Italy.
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20
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Xu C, Wang Y, Gerling GJ. An elasticity-curvature illusion decouples cutaneous and proprioceptive cues in active exploration of soft objects. PLoS Comput Biol 2021; 17:e1008848. [PMID: 33750948 PMCID: PMC8016306 DOI: 10.1371/journal.pcbi.1008848] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 04/01/2021] [Accepted: 03/03/2021] [Indexed: 11/18/2022] Open
Abstract
Our sense of touch helps us encounter the richness of our natural world. Across a myriad of contexts and repetitions, we have learned to deploy certain exploratory movements in order to elicit perceptual cues that are salient and efficient. The task of identifying optimal exploration strategies and somatosensory cues that underlie our softness perception remains relevant and incomplete. Leveraging psychophysical evaluations combined with computational finite element modeling of skin contact mechanics, we investigate an illusion phenomenon in exploring softness; where small-compliant and large-stiff spheres are indiscriminable. By modulating contact interactions at the finger pad, we find this elasticity-curvature illusion is observable in passive touch, when the finger is constrained to be stationary and only cutaneous responses from mechanosensitive afferents are perceptible. However, these spheres become readily discriminable when explored volitionally with musculoskeletal proprioception available. We subsequently exploit this phenomenon to dissociate relative contributions from cutaneous and proprioceptive signals in encoding our percept of material softness. Our findings shed light on how we volitionally explore soft objects, i.e., by controlling surface contact force to optimally elicit and integrate proprioceptive inputs amidst indiscriminable cutaneous contact cues. Moreover, in passive touch, e.g., for touch-enabled displays grounded to the finger, we find those spheres are discriminable when rates of change in cutaneous contact are varied between the stimuli, to supplant proprioceptive feedback.
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Affiliation(s)
- Chang Xu
- School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia, United States of America
| | - Yuxiang Wang
- School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia, United States of America
| | - Gregory J. Gerling
- School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia, United States of America
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21
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Kim S, Jung Y, Oh S, Moon H, Lim H. Parasitic Capacitance-Free Flexible Tactile Sensor with a Real-Contact Trigger. Soft Robot 2021; 9:119-127. [PMID: 33428510 DOI: 10.1089/soro.2020.0051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
In this study, a parasitic capacitance-free tactile sensor with a floating electrode that is capable of identifying actual physical contact pressure by distinguishing from parasitic effects and applicable to sensor arrays is presented. Although capacitive pressure sensors are known for their excellent pressure sensing capabilities in wide range with high sensitivity, they tend to suffer from a parasitic capacitance noise and unwanted proximity effects. Electromagnetic interference shielding was conventionally used to prevent this noise; however, it was not entirely successful in multicell array sensors. Parasitic capacitance-free method involves the use of a floating electrode, which functions as a contact trigger by causing sudden changes in capacitance only when the actual physical contact pressure has been applied or removed. The proposed method is robust, consistent, and precise. Experimental results show a wide range of pressure response up to 2.4 MPa with a sensitivity of 0.179 MPa-1 (up to 0.74 MPa) and negligible hysteresis.
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Affiliation(s)
- Seonggi Kim
- Department of Nature-Inspired Nanoconvergence Systems, Korea Institute of Machinery and Materials, Daejeon, Korea
| | - Youngdo Jung
- Department of Nature-Inspired Nanoconvergence Systems, Korea Institute of Machinery and Materials, Daejeon, Korea
| | - Sunjong Oh
- Department of Nature-Inspired Nanoconvergence Systems, Korea Institute of Machinery and Materials, Daejeon, Korea
| | - Hyungpil Moon
- School of Mechanical Engineering, Sungkyunkwan University, Suwon, Korea
| | - Hyuneui Lim
- Department of Nature-Inspired Nanoconvergence Systems, Korea Institute of Machinery and Materials, Daejeon, Korea
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22
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Abstract
Multi-sensory human-machine interfaces are currently challenged by the lack of effective, comfortable and affordable actuation technologies for wearable tactile displays of softness in virtual- or augmented-reality environments. They should provide fingertips with tactile feedback mimicking the tactual feeling perceived while touching soft objects, for applications like virtual reality-based training, tele-rehabilitation, tele-manipulation, tele-presence, etc. Displaying a virtual softness on a fingertip requires the application of quasi-static (non-vibratory) forces via a deformable surface, to control both the contact area and the indentation depth of the skin. The state of the art does not offer wearable devices that can combine simple structure, low weight, low size and electrically safe operation. As a result, wearable softness displays are still missing for real-life uses. Here, we present a technology based on fingertip-mounted small deformable chambers, which weight about 3 g and are pneumatically driven by a compact and cost-effective unit. Weighting less than 400 g, the driving unit is easily portable and can be digitally controlled to stimulate up to three fingertips independently. Psychophysical tests proved ability to generate useful perceptions, with a Just Noticeable Difference characterised by a Weber constant of 0.15. The system was made of off-the-shelf materials and components, without any special manufacturing process, and is fully disclosed, providing schematics and lists of components. This was aimed at making it easily and freely usable, so as to turn tactile displays of softness on fingertips into a technology 'at fingertips'.
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Affiliation(s)
- Gabriele Frediani
- Department of Industrial Engineering, University of Florence, Via di S. Marta, 3, 50139, Florence, Italy
| | - Federico Carpi
- Department of Industrial Engineering, University of Florence, Via di S. Marta, 3, 50139, Florence, Italy.
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23
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Lipomi DJ, Dhong C, Carpenter CW, Root NB, Ramachandran VS. Organic Haptics: Intersection of Materials Chemistry and Tactile Perception. ADVANCED FUNCTIONAL MATERIALS 2020; 30:1906850. [PMID: 34276273 PMCID: PMC8281818 DOI: 10.1002/adfm.201906850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Indexed: 05/06/2023]
Abstract
The goal of the field of haptics is to create technologies that manipulate the sense of touch. In virtual and augmented reality, haptic devices are for touch what loudspeakers and RGB displays are for hearing and vision. Haptic systems that utilize micromotors or other miniaturized mechanical devices (e.g., for vibration and pneumatic actuation) produce interesting effects, but are quite far from reproducing the feeling of real materials. They are especially deficient in recapitulating surface properties: fine texture, friction, viscoelasticity, tack, and softness. The central argument of this Progress Report is that to reproduce the feel of everyday objects requires chemistry: molecular control over the properties of materials and ultimately design of materials which can change these properties in real time. Stimuli-responsive organic materials, such as polymers and composites, are a class of materials which can change their oxidation state, conductivity, shape, and rheological properties, and thus might be useful in future haptic technologies. Moreover, the use of such materials in research on tactile perception could help elucidate the limits of human tactile sensitivity. The work described represents the beginnings of this new area of inquiry, in which the defining approach is the marriage of materials science and psychology.
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Affiliation(s)
- Darren J Lipomi
- Department of NanoEngineering and Program in Chemical Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Charles Dhong
- Department of NanoEngineering and Program in Chemical Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Cody W Carpenter
- Department of NanoEngineering and Program in Chemical Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Nicholas B Root
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, Mail Code 0109, La Jolla, CA 92093-0109
| | - Vilayanur S Ramachandran
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, Mail Code 0109, La Jolla, CA 92093-0109
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24
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Carpenter CW, Malinao MG, Rafeedi TA, Rodriquez D, Melissa Tan ST, Root NB, Skelil K, Ramírez J, Polat B, Root SE, Ramachandran VS, Lipomi DJ. Electropneumotactile Stimulation: Multimodal Haptic Actuators Enabled by a Stretchable Conductive Polymer on Inflatable Pockets. ADVANCED MATERIALS TECHNOLOGIES 2020; 5:1901119. [PMID: 32905479 PMCID: PMC7469953 DOI: 10.1002/admt.201901119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/14/2020] [Indexed: 05/30/2023]
Abstract
This paper describes a type of haptic device that delivers two modes of stimulation simultaneously and at the same locations on the skin. The two modes of stimulation are mechanical (delivered pneumatically by inflatable air pockets embedded within a silicone elastomer) and electrical (delivered by a conductive polymer). The key enabling aspect of this work is the use of a highly plasticized conductive polymer based on poly(3,4-ethylenedioxythiphene) (PEDOT) blended with elastomeric polyurethane (PU). To fabricate the "electropneumotactile" device, the polymeric electrodes are overlaid directly on top of the elastomeric pneumatic actuator pockets. Co-placement of the pneumatic actuators and the electrotactile electrodes is enabled by the stretchability of the PEDOT:OTs/PU blend, allowing the electrotactiles to conform to underlying pneumatic pockets under deformation. The blend of PEDOT and PU has a Young's modulus of ~150 MPa with little degradation in conductivity following repeated inflation of the air pockets. The ability to perceive simultaneous delivery of two sensations to the same location on the skin are supported by experiments using human subjects. These results show that participants can successfully detect the location of pneumatic stimulation and whether electrotactile stimulation is delivered (yes/no) at a rate significantly above chance (mean accuracy = 94%).
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Affiliation(s)
- Cody W. Carpenter
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Marigold G. Malinao
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Tarek A. Rafeedi
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Daniel Rodriquez
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Siew Ting Melissa Tan
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Nicholas B. Root
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, Mail Code 0109, La Jolla, CA 92093-0109
| | - Kyle Skelil
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Julian Ramírez
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Beril Polat
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Samuel E. Root
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Vilayanur S. Ramachandran
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, Mail Code 0109, La Jolla, CA 92093-0109
| | - Darren J. Lipomi
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
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Xu C, He H, Hauser SC, Gerling GJ. Tactile Exploration Strategies With Natural Compliant Objects Elicit Virtual Stiffness Cues. IEEE TRANSACTIONS ON HAPTICS 2020; 13:4-10. [PMID: 31841421 PMCID: PMC7147988 DOI: 10.1109/toh.2019.2959767] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
When interacting with deformable objects, tactile cues at the finger pad help inform our perception of material compliance. Nearly all prior studies have relied on highly homogenous, engineered materials such as silicone-elastomers and foams. In contrast, we employ soft plum fruit varying in ripeness; ecological substances associated with tasks of everyday life. In this article, we investigate volitional exploratory strategies and contact interactions, for comparison to engineered materials. New measurement techniques are introduced, including an ink-based method to capture finger pad to fruit contact interactions, and instrumented force and optical sensors to capture imposed force and displacement. Human-subjects experiments are conducted for both single finger touch and two finger grasp. The results indicate that terminal contact areas between soft and hard plums are indistinguishable, but the newly defined metric of virtual stiffness can differentiate between the fruits' ripeness, amidst their local variations in geometry, stiffness, and viscoelasticity. Moreover, it affords discrimination independent of one's touch force. This metric illustrates the tie between the deployment of active, exploratory strategies and the elicitation of optimal cues for perceptual discrimination. Compared to single finger touch, perceptual discrimination improves further in pinch grasp, which is indeed a more natural gesture for judging ripeness.
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Manzotti A, Cerritelli F, Chiera M, Lombardi E, La Rocca S, Biasi P, Galli M, Esteves J, Lista G. Neonatal Assessment Manual Score: Is There a Role of a Novel, Structured Touch-Based Evaluation in Neonatal Intensive Care Unit? Front Pediatr 2020; 8:432. [PMID: 32850545 PMCID: PMC7424031 DOI: 10.3389/fped.2020.00432] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/22/2020] [Indexed: 01/08/2023] Open
Abstract
Despite the technological improvements in monitoring preterm infants in the neonatal intensive care unit, routine care in the neonatal ward is primarily based on manual procedures. Although manual clinical procedures play a critical role in neonatology, little attention has been paid to palpation as a clinical assessment tool. Palpation is a clinical evaluation tool that relies mostly on the senses of touch and proprioception. Based on recent studies investigating the role and clinical effectiveness of touch in full-term and preterm babies, this paper proposes an evaluative touch-based procedure-the Neonatal Assessment Manual Score (NAME) model-that could be useful in the neonatal ward and describes its rationale. The operator applies gentle light pressures to the infant's body. In essence, the touch stimulates low-threshold afferent fibers that could influence the interoceptive cerebral network and the autonomic nervous system, thus altering the blood flow and breathing rhythm. These events could change how bodily fluids distribute among body segments and hence the body volume. The volume modification could be felt manually through haptic perception owing to the high sensitivity of the fingers. On the basis of their clinical conditions and stage of development, infants will respond differently to the applied pressures. Evaluating the infant's response, the operator produces a score of "bad," "marginal," or "good" for communicating quickly and clearly the infant's conditions to other professionals. Because the NAME model is intended for every professional who is used to touch-based procedures, if future studies confirmed its validity and reliability in clinical practice, the NAME model could become a part of the neonatal ward routine care for better assessing and managing the infant's conditions, even during emergencies.
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Affiliation(s)
- Andrea Manzotti
- RAISE Laboratory, Foundation COME Collaboration, Pescara, Italy.,Division of Neonatology, "V. Buzzi" Children's Hospital, ASST-FBF-Sacco, Milan, Italy.,Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | | | - Marco Chiera
- RAISE Laboratory, Foundation COME Collaboration, Pescara, Italy
| | - Erica Lombardi
- RAISE Laboratory, Foundation COME Collaboration, Pescara, Italy.,Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Simona La Rocca
- RAISE Laboratory, Foundation COME Collaboration, Pescara, Italy.,Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Pamela Biasi
- RAISE Laboratory, Foundation COME Collaboration, Pescara, Italy.,Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Matteo Galli
- RAISE Laboratory, Foundation COME Collaboration, Pescara, Italy.,Research Department, SOMA, Istituto Osteopatia Milano, Milan, Italy
| | - Jorge Esteves
- Gulf National Centre, Foundation COME Collaboration, Riyadh, Saudi Arabia.,Research Department, University College of Osteopathy, London, United Kingdom
| | - Gianluca Lista
- Division of Neonatology, "V. Buzzi" Children's Hospital, ASST-FBF-Sacco, Milan, Italy
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