Artificial multimodal receptors based on ion relaxation dynamics

Science ◽  
2020 ◽  
Vol 370 (6519) ◽  
pp. 961-965 ◽  
Author(s):  
Insang You ◽  
David G. Mackanic ◽  
Naoji Matsuhisa ◽  
Jiheong Kang ◽  
Jimin Kwon ◽  
...  
Keyword(s):  
Human Skin ◽  
Absolute Temperature ◽  
Signal Interference ◽  
Mechanical Stimuli ◽  
Relaxation Dynamics ◽  
Electrode Structure ◽  
Different Types ◽  
Artificial Receptor ◽  
Mechanical Information ◽  
Intrinsic Variable

Human skin has different types of tactile receptors that can distinguish various mechanical stimuli from temperature. We present a deformable artificial multimodal ionic receptor that can differentiate thermal and mechanical information without signal interference. Two variables are derived from the analysis of the ion relaxation dynamics: the charge relaxation time as a strain-insensitive intrinsic variable to measure absolute temperature and the normalized capacitance as a temperature-insensitive extrinsic variable to measure strain. The artificial receptor with a simple electrode-electrolyte-electrode structure simultaneously detects temperature and strain by measuring the variables at only two measurement frequencies. The human skin–like multimodal receptor array, called multimodal ion-electronic skin (IEM-skin), provides real-time force directions and strain profiles in various tactile motions (shear, pinch, spread, torsion, and so on).

scholarly journals Critical Factors for In Vivo Measurements of Human Skin by Terahertz Attenuated Total Reflection Spectroscopy

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4256
Author(s):  
Lixia Wang ◽  
Sayon Guilavogui ◽  
Henghui Yin ◽  
Yiping Wu ◽  
Xiaofei Zang ◽  
...  
Keyword(s):  
Human Skin ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Deep Penetration ◽  
Reference Spectrum ◽  
Critical Factors ◽  
Contact Duration ◽  
In Vivo Measurements ◽  
Different Types

Attenuated total reflection (ATR) geometry is a suitable choice for in vivo measurements of human skin due to the deep penetration of the field into the sample and since it makes it easy to measure the reference spectrum. On the other hand, there are several critical factors that may affect the terahertz (THz) response in these kinds of experiments. Here, we analyse in detail the influence of the following factors: the contact positions between the thumb and the prism, the contact pressure, the contact duration, and the materials of the prism. Furthermore, we use the THz-ATR technology to evaluate different types of handcream and also establish the theoretical model to investigate the reflectivity after interacting with the skin. The results agree well with experimental ones. Our analysis makes it clear the importance of controlling the above factors during measurements to enable reliable THz response and results which, in turn, may be used to monitor water motion in human skin and to predict possible diseases.

scholarly journals Hair cells with heterogeneous transfer characteristics encode mechanical stimuli in the lateral line of zebrafish

2018 ◽  
Author(s):  
Paul Pichler ◽  
Leon Lagnado
Keyword(s):  
Lateral Line ◽  
Hair Cells ◽  
Glutamate Release ◽  
Mechanical Stimuli ◽  
Initial Stimulus ◽  
Transfer Characteristics ◽  
Preferred Direction ◽  
Ribbon Synapses ◽  
Mechanical Information ◽  
Unique Signal

Ribbon synapses of hair cells transmit mechanical information but the transfer characteristics relating deflection of the hair bundle to glutamate release have not been assessed directly. Here we have imaged glutamate to investigate how hair cells encode information in the lateral line of zebrafish. Half the hair cells signalled cupula motion in either direction from rest, achieving maximum sensitivity for deflections of ~40 nm in the preferred direction. The remainder rectified completely and were less sensitive, extending the operating range of the neuromast beyond 1μm. Adaptation was also heterogeneous, with some hair cells generating sustained synaptic outputs and others transient. A unique signal encoded a return to rest: a transient burst from hair cells unresponsive to the initial stimulus. A mixed population of hair cells with these various transfer characteristics will allow a neuromast to encode weak stimuli as well as the amplitude and duration of stronger deflections.

scholarly journals “An intrinsically disordered intracellular domain of PIEZO2 is required for force-from-filament activation of the channel”

2021 ◽  
Author(s):  
Clement Verkest ◽  
Irina Schaefer ◽  
Juri M. Jegelka ◽  
Timo A. Nees ◽  
Wang Na ◽  
...  
Keyword(s):  
Mechanical Stimuli ◽  
Force Transmission ◽  
Transmembrane Helices ◽  
Intrinsically Disordered ◽  
Membrane Stretch ◽  
Different Types ◽  
A Cell ◽  
Filament Activation ◽  
Transmission Pathways ◽  
Biochemical Signals

AbstractA central question in mechanobiology is how mechanical forces acting in or on a cell are transmitted to mechanically-gated PIEZO channels that convert these forces into biochemical signals. Here we show that PIEZO2 is sensitive to force-transmission via the membrane (force-from-lipids) as well as force transmission via the cytoskeleton (force-from-filament) and demonstrate that the latter requires the intracellular linker between the transmembrane helices nine and ten (IDR5). Moreover, we show that rendering PIEZO2 insensitive to force-from-filament by deleting IDR5 abolishes PIEZO2-mediated inhibition of neurite outgrowth, which relies on the detection of cellgenerated traction forces, while it only partially affects its sensitivity to cell indentation and does not at all alter its sensitivity to membrane stretch. Hence, we propose that PIEZO2 is a polymodal mechanosensor that detects different types of mechanical stimuli via different force transmission pathways, which highlights the importance of utilizing multiple complementary assays when investigating PIEZO channel function.

scholarly journals A Mathematical Model to Study the Mechanical Information Induced by Lifting-Thrusting Needle

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Yi Yu ◽  
Wei Yao ◽  
Guanghong Ding
Keyword(s):  
Mathematical Model ◽  
Mechanical Response ◽  
Numerical Solutions ◽  
Stimulus Frequency ◽  
Angular Frequency ◽  
Mechanical Effect ◽  
Lower Limbs ◽  
Mechanical Stimuli ◽  
Mechanical Information ◽  
The Right

Focusing on the mechanical effect of traditional Chinese acupuncture, this study builds a mathematical model that simulates the mechanical process of lifting-thrusting needle. Analytic and numerical solutions are obtained to explore the mechanical information (displacement, strain, stress, and energy) in the skin tissue. Our results show that (1) needle manipulation leads to tissue displacement and mechanical stress field, but the needle should be inserted into the right position (about π/ω cm around the acupoint, where ω is the angular frequency) and enough depth (about 2 cm in lower limbs) to achieve effective mechanical stimuli; (2) the tissue displacement decays with an increase of distance from the stimulus position, more rapidly at higher frequencies; (3) there is an inverse relationship between the area of the ‘effective influence region’ (where shear strain > 0.2) and the stimulus frequency, which means larger needle movement is needed at higher frequencies to achieve a better curative effect; (4) more energy is required to maintain high frequency manipulation. This study proposes a preliminary comprehension of the mechanical response around the needle during the acupuncture process.

scholarly journals A potentiometric mechanotransduction mechanism for novel electronic skins

2020 ◽  
Vol 6 (30) ◽  
pp. eaba1062 ◽  
Author(s):  
Xiaodong Wu ◽  
Maruf Ahmed ◽  
Yasser Khan ◽  
Margaret E. Payne ◽  
Juan Zhu ◽  
...  
Keyword(s):  
Health Care ◽  
Membrane Potential ◽  
Power Consumption ◽  
Human Skin ◽  
Electronic Devices ◽  
Low Frequency ◽  
Sensory Cells ◽  
Mechanical Stimuli ◽  
Passive Sensing ◽  
Machine Interface

Human skin perceives external mechanical stimuli by sensing the variation in the membrane potential of skin sensory cells. Many scientists have attempted to recreate skin functions and develop electronic skins (e-skins) based on active and passive sensing mechanisms. Inspired by the skin sensory behavior, we investigated materials and electronic devices that allow us to encode mechanical stimuli into potential differences measured between two electrodes, resulting in a potentiometric mechanotransduction mechanism. We present here a potentiometric mechanotransducer that is fabricated through an all-solution processing approach. This mechanotransducer shows ultralow-power consumption, highly tunable sensing behavior, and capability to detect both static and low-frequency dynamic mechanical stimuli. Furthermore, we developed two novel classes of sensing devices, including strain-insensitive sensors and single-electrode-mode e-skins, which are challenging to achieve using the existing methods. This mechanotransduction mechanism has broad impact on robotics, prosthetics, and health care by providing a much improved human-machine interface.

The touch dome in human skin is supplied by different types of nerve fibers

2005 ◽  
Vol 58 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Christina M. Reinisch ◽  
Erwin Tschachler
Keyword(s):  
Human Skin ◽  
Nerve Fibers ◽  
Different Types ◽  
Touch Dome

Colorimetric Ionic Organohydrogels Mimicking Human Skin for Mechanical Stimuli Sensing and Injury Visualization

2021 ◽  
Author(s):  
Wenlian Qiu ◽  
Changgeng Zhang ◽  
Guoqing Chen ◽  
He Zhu ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Human Skin ◽  
Mechanical Stimuli

scholarly journals Rapid Prototyping of 3D Biochips for Cell Motility Studies Using Two-Photon Polymerization

2021 ◽  
Vol 9 ◽  
Author(s):  
Federico Sala ◽  
Carlotta Ficorella ◽  
Rebeca Martínez Vázquez ◽  
Hannah Marie Eichholz ◽  
Josef A. Käs ◽  
...  
Keyword(s):  
Cell Motility ◽  
Ad Hoc ◽  
Single Cells ◽  
Cellular Migration ◽  
Tumor Evolution ◽  
Specific Cell ◽  
Mechanical Stimuli ◽  
Two Photon ◽  
Different Types ◽  
Two Photon Polymerization

The study of cellular migration dynamics and strategies plays a relevant role in the understanding of both physiological and pathological processes. An important example could be the link between cancer cell motility and tumor evolution into metastatic stage. These strategies can be strongly influenced by the extracellular environment and the consequent mechanical constrains. In this framework, the possibility to study the behavior of single cells when subject to specific topological constraints could be an important tool in the hands of biologists. Two-photon polymerization is a sub-micrometric additive manufacturing technique that allows the fabrication of 3D structures in biocompatible resins, enabling the realization of ad hoc biochips for cell motility analyses, providing different types of mechanical stimuli. In our work, we present a new strategy for the realization of multilayer microfluidic lab-on-a-chip constructs for the study of cell motility which guarantees complete optical accessibility and the possibility to freely shape the migration area, to tailor it to the requirements of the specific cell type or experiment. The device includes a series of micro-constrictions that induce different types of mechanical stress on the cells during their migration. We show the realization of different possible geometries, in order to prove the versatility of the technique. As a proof of concept, we present the use of one of these devices for the study of the motility of murine neuronal cancer cells under high physical confinement, highlighting their peculiar migration mechanisms.

Innervation Territories of Mechanically Activated C Nociceptor Units in Human Skin

1997 ◽  
Vol 78 (5) ◽  
pp. 2641-2648 ◽  
Author(s):  
Roland Schmidt ◽  
Martin Schmelz ◽  
Matthias Ringkamp ◽  
Hermann O. Handwerker ◽  
H. Erik Torebjörk
Keyword(s):  
Human Skin ◽  
Peroneal Nerve ◽  
Human Subjects ◽  
Receptive Fields ◽  
Spatial Summation ◽  
Lower Leg ◽  
Mechanical Stimuli ◽  
Axon Reflex ◽  
C Fibers ◽  
Noxious Stimuli

Schmidt, Roland, Martin Schmelz, Matthias Ringkamp, Hermann O. Handwerker, and H. Erik Torebjörk. Innervation territories of mechanically activated C nociceptor units in human skin. J. Neurophysiol. 78: 2641–2648, 1997. Innervation territories of single mechanically activated C nociceptors in the skin of the leg and foot were explored in normal human subjects. Microneurographic recordings were obtained in the peroneal nerve from 70 mechano-heat responsive (CMH) and 7 mechano-(but not heat) responsive (CM) units. Units were identified by their constant long-latency response to intracutaneous electrical stimulation of their terminals. Responsiveness to mechanical, heat, or transcutaneous electrical stimuli was verified by transient slowing of conduction velocity after activation by such stimuli. We determined their thresholds to mechanical stimuli (mean 33.7 mN, median 30 mN, range 3–750 mN) and heat (mean 42.5°C, median 42.5°C, range 37–49°C). Most mechano-receptive fields (mRFs) were found on the foot dorsum (60 units) and some on the lower leg (14 units) and toes (3 units). Most units had one continuous mRF, but 10 units had more complex fields. Areas of mRFs mapped with a von Frey filament (750 mN) ranged from 10 to 363 mm2 (mean, 106 mm2). The mRFs were oval or irregularly shaped with greatest diameters ranging from 3 to 45 mm. Mean areas of mRFs were largest on the lower leg (198 mm2), smaller on the foot dorsum (88 mm2), and smallest on the toes (35 mm2). Forty-nine of the 77 units had identical mRFs and electro-receptive fields (eRFs). Twenty-six units had larger eRFs than mRFs, whereas the opposite was found for two units only. Areas of eRFs ranged from 16 to 511 mm2 (mean 121 mm2). An estimate of the innervation density based on the present data and the presumed number of C fibers in cutaneous fascicles of the peroneal nerve suggests a considerable overlap of nociceptive endings in the skin. Such overlapping nociceptor innervation in the skin allows for substantial spatial summation in response to punctate noxious stimuli, which may be a prerequisite for high accuracy in localizing painful events from a C-fiber input. The reduction in size of innervation territories distally allows for finer discrimination of spatial dimensions of noxious stimuli distally as compared with proximal regions of the extremities. Mean maximal diameters of the mechano-receptive fields of CMH and CM units on the lower leg (22.3 mm) and foot (15.3 mm) are of similar size as the radius of axon reflex flares evoked by noxious mechanical stimuli in these regions.

The attachment of Schistosoma mansoni cercariae to human skin cells

Parasitology ◽  
2002 ◽  
Vol 124 (1) ◽  
pp. 25-30 ◽  
Author(s):  
N. KHAMMO ◽  
A. BARTLETT ◽  
R. H. CLOTHIER ◽  
P. J. WHITFIELD
Keyword(s):  
Schistosoma Mansoni ◽  
Human Skin ◽  
Cell Types ◽  
Laboratory Animals ◽  
Normal Human Skin ◽  
Skin Cells ◽  
Skin Cell ◽  
Different Types ◽  
Human Skin Cells

Most of our knowledge about the process of penetration of skin, by cercariae of Schistosoma mansoni, has been gained from studies carried out in vivo with laboratory animals. Human skin is significantly different from that of other animals but there are obvious practical difficulties in directly studying attachment and penetration with human skin. Techniques have been developed which enable a 3-dimensional ‘skin equivalent’ to be grown in tissue culture, made from different types of human skin cells. The aim of the present study was to investigate cercarial interactions with confluent cultures of the individual skin cell types that make up normal human skin and which will be used to construct a multi-component model. Cercariae behaved differently towards the various cell types tested. They responded least to monolayers of endothelial cells and most to primary keratinocytes, derived from human foreskin and differentiated at an air/liquid interface. This study demonstrates, therefore, that cercariae are capable of distinguishing between different types of skin cells and they preferentially attach to differentiated cells which form the epidermis.

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