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Dougill G, Brassey CA, Starostin EL, Andrews H, Kitchener A, van der Heijden GHM, Goss VGA, Grant RA. Describing whisker morphology of the Carnivora. J Morphol 2023; 284:e21628. [PMID: 37585221 DOI: 10.1002/jmor.21628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/18/2023] [Accepted: 07/24/2023] [Indexed: 08/17/2023]
Abstract
One of the largest ecological transitions in carnivoran evolution was the shift from terrestrial to aquatic lifestyles, which has driven morphological diversity in skulls and other skeletal structures. In this paper, we investigate the association between those lifestyles and whisker morphology. However, comparing whisker morphology over a range of species is challenging since the number of whiskers and their positions on the mystacial pads vary between species. Also, each whisker will be at a different stage of growth and may have incurred damage due to wear and tear. Identifying a way to easily capture whisker morphology in a small number of whisker samples would be beneficial. Here, we describe individual and species variation in whisker morphology from two-dimensional scans in red fox, European otter and grey seal. A comparison of long, caudal whiskers shows inter-species differences most clearly. We go on to describe global whisker shape in 24 species of carnivorans, using linear approximations of curvature and taper, as well as traditional morphometric methods. We also qualitatively examine surface texture, or the presence of scales, using scanning electron micrographs. We show that gross whisker shape is highly conserved, with whisker curvature and taper obeying simple linear relationships with length. However, measures of whisker base radius, length, and maybe even curvature, can vary between species and substrate preferences. Specifically, the aquatic species in our sample have thicker, shorter whiskers that are smoother, with less scales present than those of terrestrial species. We suggest that these thicker whiskers may be stiffer and able to maintain their shape and position during underwater sensing, but being stiffer may also increase wear.
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Affiliation(s)
- Gary Dougill
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Charlotte A Brassey
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Eugene L Starostin
- School of Engineering, London South Bank University, London, UK
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
| | - Hayley Andrews
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Andrew Kitchener
- Department of Natural Sciences, National Museums Scotland, Edinburgh, UK
| | - Gert H M van der Heijden
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
| | - Victor G A Goss
- School of Engineering, London South Bank University, London, UK
| | - Robyn A Grant
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
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2
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Collinson DW, Emnett HM, Ning J, Hartmann MJZ, Brinson LC. Tapered Polymer Whiskers to Enable Three-Dimensional Tactile Feature Extraction. Soft Robot 2020; 8:44-58. [PMID: 32513071 DOI: 10.1089/soro.2019.0055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many mammals use their vibrissae (whiskers) to tactually explore their surrounding environment. Vibrissae are thin tapered structures that transmit mechanical signals to a wealth of mechanical receptors (sensors) located in a follicle at each vibrissal base. A recent study has shown that-provided that the whisker is tapered-three mechanical signals at the base are sufficient to determine the three-dimensional location at which a whisker made contact with an object. However, creating biomimetic tapered whiskers has proved challenging from both materials and manufacturing standpoints. This study develops and characterizes an artificial whisker for use as part of a sensory input device that is a biomimic of the biological rat whisker neurosensory system. A novel manufacturing process termed surface conforming fiber drawing (SCFD) is developed to produce artificial whiskers that meet the requirements to be a successful mechanical and geometric mimic of the biological rat vibrissae. Testing the sensory capabilities of the artificial whisker shows improved performance over previous nontapered filaments. SCFD-manufactured tapered whiskers demonstrate the ability to predict contact point locations with a median distance error of 0.47 cm.
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Affiliation(s)
- David W Collinson
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Hannah M Emnett
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Jinqiang Ning
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Mitra J Z Hartmann
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Lynda Catherine Brinson
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
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3
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Yang AET, Belli HM, Hartmann MJZ. Quantification of vibrissal mechanical properties across the rat mystacial pad. J Neurophysiol 2019; 121:1879-1895. [PMID: 30811257 PMCID: PMC6589704 DOI: 10.1152/jn.00869.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/25/2019] [Accepted: 02/25/2019] [Indexed: 11/22/2022] Open
Abstract
Recent work has quantified the geometric parameters of individual rat vibrissae (whiskers) and developed equations that describe how these parameters vary as a function of row and column position across the array. This characterization included a detailed quantification of whisker base diameter and arc length as well as the geometry of the whisker medulla. The present study now uses these equations for whisker geometry to quantify several properties of the whisker that govern its mechanical behavior. We first show that the average density of a whisker is lower in its proximal region than in its distal region. This density variation appears to be largely attributable to the presence of the whisker cuticle rather than the medulla. The density variation has very little effect on the center of mass of the whisker. We next show that the presence of the medulla decreases the deflection of the whisker under its own weight and also decreases its mass moment of inertia while sacrificing <1% stiffness at the whisker base compared with a solid whisker. Finally, we quantify two dimensionless parameters across the array. First, the deflection-to-length ratio decreases from caudal to rostral: caudal whiskers are longer but deflect more under their own weight. Second, the nondimensionalized radius of gyration is approximately constant across the array, which may simplify control of whisking by the intrinsic muscles. We anticipate that future work will exploit the mechanical properties computed in the present study to improve simulations of the mechanosensory signals associated with vibrissotactile exploratory behavior. NEW & NOTEWORTHY The mechanical signals transmitted by a whisker depend critically on its geometry. We used measurements of whisker geometry and mass to quantify the center of mass, mass moment of inertia, radius of gyration, and deflection under gravity of the whisker. We describe how variations in these quantities across the array could enhance sensing behaviors while reducing energy costs and simplifying whisking control. Most importantly, we provide derivations for these quantities for use in future simulation work.
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Affiliation(s)
- Anne En-Tzu Yang
- Department of Mechanical Engineering, Northwestern University , Evanston, Illinois
| | - Hayley M Belli
- Department of Biomedical Engineering, Northwestern University , Evanston, Illinois
| | - Mitra J Z Hartmann
- Department of Mechanical Engineering, Northwestern University , Evanston, Illinois
- Department of Biomedical Engineering, Northwestern University , Evanston, Illinois
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4
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Chang Z, Paoletti P, Hansen ML, Beck HC, Chen PY, Rasmussen LM, Akhtar R. AFM Characterization of the Internal Mammary Artery as a Novel Target for Arterial Stiffening. SCANNING 2018; 2018:6340425. [PMID: 30524642 PMCID: PMC6247466 DOI: 10.1155/2018/6340425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 09/06/2018] [Indexed: 05/05/2023]
Abstract
Using the atomic force microscopy- (AFM-) PeakForce quantitative nanomechanical mapping (QNM) technique, we have previously shown that the adventitia of the human internal mammary artery (IMA), tested under dehydrated conditions, is altered in patients with a high degree of arterial stiffening. In this study, we explored the nanoscale elastic modulus of the tunica media of the IMA in hydrated and dehydrated conditions from the patients with low and high arterial stiffening, as assessed in vivo by carotid-femoral pulse wave velocity (PWV). In both hydrated and dehydrated conditions, the medial layer was significantly stiffer in the high PWV group. The elastic modulus of the hydrated and dehydrated tunica media was significantly correlated with PWV. In the hydrated condition, the expression activity of certain small leucine-rich repeat proteoglycans (SLRPs), which are associated with arterial stiffening, were found to be negatively correlated to the medial elastic modulus. We also compared the data with our previous work on the IMA adventitia. We found that the hydrated media and dehydrated adventitia are both suitable for reflecting the development of arterial stiffening and SLRP expression. This comprehensive study of the nanomechanical properties integrated with the proteomic analysis in the IMAs demonstrates the possibility of linking structural properties and function in small biological samples with novel AFM methods. The IMA is a suitable target for predicting arterial stiffening.
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Affiliation(s)
- Zhuo Chang
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, L69 3GH, UK
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Paolo Paoletti
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, L69 3GH, UK
| | - Maria Lyck Hansen
- Department of Clinical Biochemistry and Pharmacology, Center for Individualized Medicine in Arterial Diseases, Odense University Hospital, University of Southern Denmark, Denmark
| | - Hans Christian Beck
- Department of Clinical Biochemistry and Pharmacology, Center for Individualized Medicine in Arterial Diseases, Odense University Hospital, University of Southern Denmark, Denmark
| | - Po-Yu Chen
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Lars Melholt Rasmussen
- Department of Clinical Biochemistry and Pharmacology, Center for Individualized Medicine in Arterial Diseases, Odense University Hospital, University of Southern Denmark, Denmark
| | - Riaz Akhtar
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, L69 3GH, UK
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Astreinidi Blandin A, Bernardeschi I, Beccai L. Biomechanics in Soft Mechanical Sensing: From Natural Case Studies to the Artificial World. Biomimetics (Basel) 2018; 3:E32. [PMID: 31105254 PMCID: PMC6352697 DOI: 10.3390/biomimetics3040032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/14/2018] [Accepted: 10/12/2018] [Indexed: 12/25/2022] Open
Abstract
Living beings use mechanical interaction with the environment to gather essential cues for implementing necessary movements and actions. This process is mediated by biomechanics, primarily of the sensory structures, meaning that, at first, mechanical stimuli are morphologically computed. In the present paper, we select and review cases of specialized sensory organs for mechanical sensing-from both the animal and plant kingdoms-that distribute their intelligence in both structure and materials. A focus is set on biomechanical aspects, such as morphology and material characteristics of the selected sensory organs, and on how their sensing function is affected by them in natural environments. In this route, examples of artificial sensors that implement these principles are provided, and/or ways in which they can be translated artificially are suggested. Following a biomimetic approach, our aim is to make a step towards creating a toolbox with general tailoring principles, based on mechanical aspects tuned repeatedly in nature, such as orientation, shape, distribution, materials, and micromechanics. These should be used for a future methodical design of novel soft sensing systems for soft robotics.
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Affiliation(s)
- Afroditi Astreinidi Blandin
- Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, 56025 Pisa, Italy.
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pontedera, 56025 Pisa, Italy.
| | - Irene Bernardeschi
- Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, 56025 Pisa, Italy.
| | - Lucia Beccai
- Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, 56025 Pisa, Italy.
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6
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Liu Y, He K, Chen G, Leow WR, Chen X. Nature-Inspired Structural Materials for Flexible Electronic Devices. Chem Rev 2017; 117:12893-12941. [DOI: 10.1021/acs.chemrev.7b00291] [Citation(s) in RCA: 448] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Yaqing Liu
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Ke He
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Geng Chen
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Wan Ru Leow
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Xiaodong Chen
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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7
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Lee HT, Kim HJ, Kim CS, Gomi K, Taya M, Nomura S, Ahn SH. Site-specific characterization of beetle horn shell with micromechanical bending test in focused ion beam system. Acta Biomater 2017; 57:395-403. [PMID: 28455220 DOI: 10.1016/j.actbio.2017.04.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/18/2017] [Accepted: 04/24/2017] [Indexed: 12/11/2022]
Abstract
Biological materials are the result of years of evolution and possess a number of efficient features and structures. Researchers have investigated the possibility of designing biomedical structures that take advantage of these structural features. Insect shells, such as beetle shells, are among the most promising types of biological material for biomimetic development. However, due to their intricate geometries and small sizes, it is challenging to measure the mechanical properties of these microscale structures. In this study, we developed an in-situ testing platform for site-specific experiments in a focused ion beam (FIB) system. Multi-axis nano-manipulators and a micro-force sensor were utilized in the testing platform to allow better results in the sample preparation and data acquisition. The entire test protocol, consisting of locating sample, ion beam milling and micro-mechanical bending tests, can be carried out without sample transfer or reattachment. We used our newly devised test platform to evaluate the micromechanical properties and structural features of each separated layer of the beetle horn shell. The Young's modulus of both the exocuticle and endocuticle layers was measured. We carried out a bending test to characterize the layers mechanically. The exocuticle layer bent in a brick-like manner, while the endocuticle layer exhibited a crack blunting effect. STATEMENT OF SIGNIFICANCE This paper proposed an in-situ manipulation/test method in focused ion beam for characterizing micromechanical properties of beetle horn shell. The challenge in precise and accurate fabrication for the samples with complex geometry was overcome by using nano-manipulators having multi-degree of freedom and a micro-gripper. With the aid of this specially designed test platform, bending tests were carried out on cantilever-shaped samples prepared by focused ion beam milling. Structural differences between exocuticle and endocuticle layers of beetle horn shell were explored and the results provided insight into the structural advantages of each biocomposite structure.
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8
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Huet LA, Rudnicki JW, Hartmann MJZ. Tactile Sensing with Whiskers of Various Shapes: Determining the Three-Dimensional Location of Object Contact Based on Mechanical Signals at the Whisker Base. Soft Robot 2017; 4:88-102. [PMID: 28616371 DOI: 10.1089/soro.2016.0028] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Almost all mammals use their mystacial vibrissae (whiskers) as important tactile sensors. There are no sensors along the length of a whisker: all sensing is performed by mechanoreceptors at the whisker base. To use artificial whiskers as a sensing tool in robotics, it is essential to be able to determine the three-dimensional (3D) location at which a whisker has made contact with an object. With the assumption of quasistatic, frictionless, single-point contact, previous work demonstrated that the 3D contact point can be uniquely determined if all six components of force and moment are measured at the whisker base, but these measurements require a six-axis load cell. Here, we perform simulations to investigate the extent to which each of the 20 possible "triplet" combinations of the six mechanical signals at the whisker base uniquely determine 3D contact point location. We perform this analysis for four different whisker profiles (shapes): tapered with and without intrinsic curvature, and cylindrical with and without intrinsic curvature. We show that whisker profile has a strong influence on the particular triplet(s) of signals that uniquely map to the 3D contact point. The triplet of bending moment, bending moment direction, and axial force produces unique mappings for tapered whiskers. Four different mappings are unique for a cylindrical whisker without intrinsic curvature, but only when large deflections are excluded. These results inform the neuroscience of vibrissotactile sensing and represent an important step toward the development of artificial whiskers for robotic applications.
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Affiliation(s)
- Lucie A Huet
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois
| | - John W Rudnicki
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois.,Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - Mitra J Z Hartmann
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
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9
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Belli HM, Yang AET, Bresee CS, Hartmann MJZ. Variations in vibrissal geometry across the rat mystacial pad: base diameter, medulla, and taper. J Neurophysiol 2016; 117:1807-1820. [PMID: 27881718 DOI: 10.1152/jn.00054.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 11/02/2016] [Indexed: 11/22/2022] Open
Abstract
Many rodents tactually sense the world through active motions of their vibrissae (whiskers), which are regularly arranged in rows and columns (arcs) on the face. The present study quantifies several geometric parameters of rat whiskers that determine the tactile information acquired. Findings include the following. 1) A meta-analysis of seven studies shows that whisker base diameter varies with arc length with a surprisingly strong dependence on the whisker's row position within the array. 2) The length of the whisker medulla varies linearly with whisker length, and the medulla's base diameter varies linearly with whisker base diameter. 3) Two parameters are required to characterize whisker "taper": radius ratio (base radius divided by tip radius) and radius slope (the difference between base and tip radius, divided by arc length). A meta-analysis of five studies shows that radius ratio exhibits large variability due to variations in tip radius, while radius slope varies systematically across the array. 4) Within the resolution of the present study, radius slope does not differ between the proximal and distal segments of the whisker, where "proximal" is defined by the presence of the medulla. 5) Radius slope of the medulla is offset by a constant value from radius slope of the proximal portion of the whisker. We conclude with equations for all geometric parameters as functions of row and column position.NEW & NOTEWORTHY Rats tactually explore their world by brushing and tapping their whiskers against objects. Each whisker's geometry will have a large influence on its mechanics and thus on the tactile signals the rat obtains. We performed a meta-analysis of seven studies to generate equations that describe systematic variations in whisker geometry across the rat's face. We also quantified the geometry of the whisker medulla. A database provides access to geometric parameters of over 500 rat whiskers.
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Affiliation(s)
- Hayley M Belli
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - Anne E T Yang
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois; and
| | - Chris S Bresee
- Interdepartmental Neuroscience Program, Northwestern University, Evanston, Illinois
| | - Mitra J Z Hartmann
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois; .,Department of Mechanical Engineering, Northwestern University, Evanston, Illinois; and
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10
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Adineh VR, Marceau RK, Velkov T, Li J, Fu J. Near-Atomic Three-Dimensional Mapping for Site-Specific Chemistry of 'Superbugs'. NANO LETTERS 2016; 16:7113-7120. [PMID: 27650306 PMCID: PMC5295734 DOI: 10.1021/acs.nanolett.6b03409] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Emergence of multidrug resistant Gram-negative bacteria has caused a global health crisis and last-line class of antibiotics such as polymyxins are increasingly used. The chemical composition at the cell surface plays a key role in antibiotic resistance. Unlike imaging the cellular ultrastructure with well-developed electron microscopy, the acquisition of a high-resolution chemical map of the bacterial surface still remains a technological challenge. In this study, we developed an atom probe tomography (APT) analysis approach to acquire mass spectra in the pulsed-voltage mode and reconstructed the 3D chemical distribution of atoms and molecules in the subcellular domain at the near-atomic scale. Using focused ion beam (FIB) milling together with micromanipulation, site-specific samples were retrieved from a single cell of Acinetobacter baumannii prepared as needle-shaped tips with end radii less than 60 nm, followed by a nanoscale coating of silver in the order of 10 nm. The significantly elevated conductivity provided by the metallic coating enabled successful and routine field evaporation of the biological material, with all the benefits of pulsed-voltage APT. In parallel with conventional cryo-TEM imaging, our novel approach was applied to investigate polymyxin-susceptible and -resistant strains of A. baumannii after treatment of polymyxin B. Acquired atom probe mass spectra from the cell envelope revealed characteristic fragments of phosphocholine from the polymyxin-susceptible strain, but limited signals from this molecule were detected in the polymyxin-resistant strain. This study promises unprecedented capacity for 3D nanoscale imaging and chemical mapping of bacterial cells at the ultimate 3D spatial resolution using APT.
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Affiliation(s)
- Vahid R. Adineh
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Ross K.W. Marceau
- Deakin University, Institute for Frontier Materials, Geelong, VIC 3216, Australia
| | - Tony Velkov
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
- Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3800, Australia
| | - Jing Fu
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC 3800, Australia
- ARC Centre of Excellence for Advanced Molecular Imaging, Monash University, Clayton, VIC 3800, Australia
- , Facsimile: 61-3-99051825
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11
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Sterbing-D'Angelo SJ, Liu H, Yu M, Moss CF. Morphology and deflection properties of bat wing sensory hairs: scanning electron microscopy, laser scanning vibrometry, and mechanics model. BIOINSPIRATION & BIOMIMETICS 2016; 11:056008. [PMID: 27545727 DOI: 10.1088/1748-3190/11/5/056008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Bat wings are highly adaptive airfoils that enable demanding flight maneuvers, which are performed with astonishing robustness under turbulent conditions, and stability at slow flight velocities. The bat wing is sparsely covered with microscopically small, sensory hairs that are associated with tactile receptors. In a previous study we demonstrated that bat wing hairs are involved in sensing airflow for improved flight maneuverability. Here, we report physical measurements of these hairs and their distribution on the wing surface of the big brown bat, Eptesicus fuscus, based on scanning electron microscopy analyses. The wing hairs are strongly tapered, and are found on both the dorsal and ventral wing surfaces. Laser scanning vibrometry tests of 43 hairs from twelve locations across the wing of the big brown bat revealed that their natural frequencies inversely correlate with length and range from 3.7 to 84.5 kHz. Young's modulus of the average wing hair was calculated at 4.4 GPa, which is comparable with rat whiskers or arthropod airflow-sensing hairs.
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12
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Lucianna FA, Albarracín AL, Vrech SM, Farfán FD, Felice CJ. The mathematical whisker: A review of numerical models of the rat׳s vibrissa biomechanics. J Biomech 2016; 49:2007-2014. [PMID: 27260019 DOI: 10.1016/j.jbiomech.2016.05.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/27/2016] [Accepted: 05/15/2016] [Indexed: 11/25/2022]
Abstract
The vibrissal system of the rat refers to specialized hairs the animal uses for tactile sensory perception. Rats actively move their whiskers in a characteristic way called "whisking". Interaction with the environment produces elastic deformation of the whiskers, generating mechanical signals in the whisker-follicle complex. Advances in our understanding of the vibrissal complex biomechanics is of interest not only for the biological research field, but also for biomimetic approaches. The recent development of whisker numerical models has contributed to comprehending its sophisticated movements and its interactions with the follicle. The great diversity of behavioral patterns and complexities of the whisker-follicle ensemble encouraged the creation of many different biomechanical models. This review analyzes most of the whisker biomechanical models that have been developed so far. This review was written so as to render it accessible to readers coming from different research areas.
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Affiliation(s)
- Facundo Adrián Lucianna
- Laboratorio de Medios e Interfases (LAMEIN), Instituto Superior de Investigaciones Biológicas (INSIBIO), Universidad Nacional de Tucumán (UNT), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Argentina.
| | - Ana Lía Albarracín
- Laboratorio de Medios e Interfases (LAMEIN), Instituto Superior de Investigaciones Biológicas (INSIBIO), Universidad Nacional de Tucumán (UNT), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Argentina
| | - Sonia Mariel Vrech
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Center for Numerical and Computational Methods in Engineering (CEMCI), Universidad Nacional de Tucumán (UNT), San Miguel de Tucumán, Argentina
| | - Fernando Daniel Farfán
- Laboratorio de Medios e Interfases (LAMEIN), Instituto Superior de Investigaciones Biológicas (INSIBIO), Universidad Nacional de Tucumán (UNT), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Argentina
| | - Carmelo José Felice
- Laboratorio de Medios e Interfases (LAMEIN), Instituto Superior de Investigaciones Biológicas (INSIBIO), Universidad Nacional de Tucumán (UNT), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Miguel de Tucumán, Argentina
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13
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Huet LA, Hartmann MJZ. Simulations of a Vibrissa Slipping along a Straight Edge and an Analysis of Frictional Effects during Whisking. IEEE TRANSACTIONS ON HAPTICS 2016; 9:158-169. [PMID: 26829805 PMCID: PMC5753595 DOI: 10.1109/toh.2016.2522432] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
During tactile exploration, rats sweep their whiskers against objects in a motion called whisking. Here, we investigate how a whisker slips along an object's edge and how friction affects the resulting tactile signals. First, a frictionless model is developed to simulate whisker slip along a straight edge and compared with a previous model that incorporates friction but cannot simulate slip. Results of both models are compared to behavioral data obtained as a rat whisked against a smooth, stainless steel peg. As expected, the frictionless model predicts larger magnitudes of vertical slip than observed experimentally. The frictionless model also predicts forces and moments at the whisker base that are smaller and have a different direction than those predicted by the model with friction. Estimates for the friction coefficient yielded values near 0.48 (whisker/stainless steel). The present work provides the first assessments of the effects of friction on the mechanical signals received by the follicle during active whisking. It also demonstrates a proof-of-principle approach for reducing whisker tracking requirements during experiments and demonstrates the feasibility of simulating a full array of vibrissae whisking against a peg.
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