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 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.

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.

scholarly journals An ultrafast system for signaling mechanical pain in human skin

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw1297 ◽  
Author(s):  
Saad S. Nagi ◽  
Andrew G. Marshall ◽  
Adarsh Makdani ◽  
Ewa Jarocka ◽  
Jaquette Liljencrantz ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Human Skin ◽  
Single Unit ◽  
High Threshold ◽  
Mechanical Stimuli ◽  
Loss Of Function ◽  
Conduction Velocities ◽  
Low Threshold ◽  
Healthy Participants ◽  
Stimulation Of

The canonical view is that touch is signaled by fast-conducting, thickly myelinated afferents, whereas pain is signaled by slow-conducting, thinly myelinated (“fast” pain) or unmyelinated (“slow” pain) afferents. While other mammals have thickly myelinated afferents signaling pain (ultrafast nociceptors), these have not been demonstrated in humans. Here, we performed single-unit axonal recordings (microneurography) from cutaneous mechanoreceptive afferents in healthy participants. We identified A-fiber high-threshold mechanoreceptors (A-HTMRs) that were insensitive to gentle touch, encoded noxious skin indentations, and displayed conduction velocities similar to A-fiber low-threshold mechanoreceptors. Intraneural electrical stimulation of single ultrafast A-HTMRs evoked painful percepts. Testing in patients with selective deafferentation revealed impaired pain judgments to graded mechanical stimuli only when thickly myelinated fibers were absent. This function was preserved in patients with a loss-of-function mutation in mechanotransduction channel PIEZO2. These findings demonstrate that human mechanical pain does not require PIEZO2 and can be signaled by fast-conducting, thickly myelinated afferents.

Hyperalgesia in human skin and deep-tissues inside and outside of a UVB irradiated area

2012 ◽  
Vol 3 (3) ◽  
pp. 190-190 ◽  
Author(s):  
Silvia Lo Vecchio ◽  
Lars J. Petersen ◽  
Thomas Graven-Nielsen ◽  
Sara Finocchietti ◽  
Parisa Gazerani ◽  
...  
Keyword(s):  
Blood Flow ◽  
Human Skin ◽  
Mechanical Stimuli ◽  
Deep Tissue ◽  
Tissue Pressure ◽  
Pain Thresholds ◽  
Pressure Pain ◽  
Uvb Irradiation ◽  
Pressure Pain Thresholds ◽  
Mechanical Pain Thresholds

Abstract Background/aims The ultraviolet B (UVB) inflammatory pain model is often used to induce a steady hyperalgesic area in human skin. UVB causes a well-described erythema, developing maximal response within about 24 h. The aim of the present study was to investigate if cutaneous UVB irradiation can influence both superficial and deep-tissue mechanical pain thresholds in the site of irradiation and in the surrounding area. Methods An area of 3 cm × 4 cm, located on the low back of 16 healthy volunteers, was irradiated by UVB (Medlight, Germany; 3xMED: Minimal Erythema Dose). The degree of inflammation was detected by measuring superficial blood flow before and after irradiation, inside and outside the stimulated area. Applying quantitative sensory assessments, mechanical pain threshold changes were detected one day after irradiation, within and outside of the irradiated area. Sensitivity to cutaneous mechanical stimuli was assessed using pin prick and deep-tissue pressure pain thresholds were evaluated on 12 spots (4 within and 8 outside, 1.5 cm distant from the irradiated area) by a computer-controlled pressure algometer (Aalborg University, Denmark; 1.0 cm2 flat probe, 0.5 cm2 flat probe and a V-shaped probe with a contact surface of 0.03 cm2). Results 24 h after exposure, the irradiated skin showed clear erythema with a boundary matching the irradiated area and a statistically significant increase in cutaneous blood flow (P < 0.001) compared with baseline assessment. Cutaneous pin prick pain thresholds and deep-tissue pressure pain thresholds (all probes) were significantly decreased inside and outside the irradiated area (P < 0.05). Conclusions Cutaneous UVB irradiation reduces mechanical pain thresholds to pin-prick and pressure stimulation which may indicate allodynic responses in both the skin and in deep-tissues. Expansion of the responses to areas outside the irradiated zone confirmed the presence of secondary hyperalgesia to mechanical stimuli.

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).

A web-like network of type vi collagen in human skin is revealed by immuno-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 382-383
Author(s):  
Douglas R. Keene ◽  
Robert W. Glanville ◽  
Eva Engvall
Keyword(s):  
Electron Microscopy ◽  
Monoclonal Antibody ◽  
Human Skin ◽  
Basement Membranes ◽  
Primary Antibody ◽  
Fat Cells ◽  
Secondary Antibody ◽  
Type Vi Collagen ◽  
Dermal Matrix ◽  
Immuno Electron Microscopy

A mouse monoclonal antibody (5C6) prepared against human type VI collagen (1) has been used in this study to immunolocalize type VI collagen in human skin. The enbloc method used involves exposing whole tissue pieces to primary antibody and 5 nm gold conjugated secondary antibody before fixation, and has been described in detail elsewhere (2).Biopsies were taken from individuals ranging in age from neonate to 65 years old. By immuno-electron microscopy, type VI collagen is found to be distributed as a fine branching network closely associated with (but not attached to) banded collagen fibrils containing types I and III collagen (Fig. 1). It appears to enwrap fibers, to weave between individual fibrils within a fiber, and to span the distance separating fibers, creating a “web-like network” which entraps fibers within deep papillary and reticular dermal layers (Fig. 2). Relative to that in the dermal matrix, the concentration of type VI collagen is higher around endothelial basement membranes limiting the outer boundaries of nerves, capillaries, and fat cells (Fig. 3).

Effect of Acetone and Kerosene on Skin Ultrastructure

1972 ◽  
Vol 30 ◽  
pp. 92-93
Author(s):  
A. P. Lupulescu ◽  
H. Pinkus ◽  
D. J. Birmingham
Keyword(s):  
Electron Microscopy ◽  
Human Skin ◽  
Osmium Tetroxide ◽  
Human Epidermis ◽  
Ultrastructural Changes ◽  
Chemical Agents ◽  
Skin Ultrastructure ◽  
Volar Surface

Our laboratory is engaged in the study of the effect of different chemical agents on human skin, using electron microscopy. Previous investigations revealed that topical use of a strong alkali (NaOH 1N) or acid (HCl 1N), induces ultrastructural changes in the upper layers of human epidermis. In the current experiments, acetone and kerosene, which are primarily lipid solvents, were topically used on the volar surface of the forearm of Caucasian and Negro volunteers. Skin specimens were bioptically removed after 90 min. exposure and 72. hours later, fixed in 3% buffered glutaraldehyde, postfixed in 1% phosphate osmium tetroxide, then flat embedded in Epon.

Changes in corneocyte element concentrations occur in skin inner stratum corneum

1990 ◽  
Vol 48 (2) ◽  
pp. 146-147
Author(s):  
R. R. Warner
Keyword(s):  
Stratum Corneum ◽  
Human Skin ◽  
Element Concentration ◽  
Skin Barrier ◽  
Barrier Properties ◽  
Brick Wall ◽  
Inorganic Elements ◽  
Dry Skin ◽  
Skin Biopsies ◽  
Intercellular Lipid

Keratinocytes undergo maturation during their transit through the viable layers of skin, and then abruptly transform into flattened, anuclear corneocytes that constitute the cellular component of the skin barrier, the stratum corneum (SC). The SC is generally considered to be homogeneous in its structure and barrier properties, and is often shown schematically as a featureless brick wall, the “bricks” being the corneocytes, the “mortar” being intercellular lipid. Previously we showed the outer SC was not homogeneous in its composition, but contained steep gradients of the physiological inorganic elements Na, K and Cl, likely originating from sweat salts. Here we show the innermost corneocytes in human skin are also heterogeneous in composition, undergoing systematic changes in intracellular element concentration during transit into the interior of the SC.Human skin biopsies were taken from the lower leg of individuals with both “good” and “dry” skin and plunge-frozen in a stirred, cooled isopentane/propane mixture.

Desmosomal distribution in the epidermis of a non-contracting human skin equivalent

1992 ◽  
Vol 50 (1) ◽  
pp. 896-897
Author(s):  
L.X. Oakford ◽  
S.D. Dimitrijevich ◽  
R. Gracy
Keyword(s):  
Human Skin ◽  
Basal Layer ◽  
Skin Equivalent ◽  
Tissue Component ◽  
Intact Skin ◽  
Similar Sequence ◽  
Sequence Of Events ◽  
Suprabasal Keratinocytes ◽  
Human Skin Equivalent

In intact skin the epidermal layer is a dynamic tissue component which is maintained by a basal layer of mitotically active cells. The protective upper epidermis, the stratum corneum, is generated by differentiation of the suprabasal keratinocytes which eventually desquamate as anuclear comeocytes. A similar sequence of events is observed in vitro in the non-contracting human skin equivalent (HSE) which was developed in this lab (1). As a part of the definition process for this model of living skin we are examining its ultrastructural features. Since desmosomes are important in maintaining cell-cell interactions in stratified epithelia their distribution in HSE was examined.

The distribution and density of ciliary tufts on the siphons of Anodonta cygnea (Mollusca: Bivalvia)

1990 ◽  
Vol 48 (3) ◽  
pp. 518-519
Author(s):  
Wen-lung Wu
Keyword(s):  
Osmium Tetroxide ◽  
Internal Surface ◽  
Mechanical Stimuli ◽  
Type Ii ◽  
Sensory Receptors ◽  
Anodonta Cygnea ◽  
Type Iv ◽  
Sem Study ◽  
Inhalant Siphon ◽  
Type V

The mantle of bivalves has come entirely to enclose the laterally compressed body and the mantle margin has assumed a variety of functions, one of the pricipal ones being sensory. Ciliary tufts, which are probably sensory, have been reported from the mantle and siphons of several bivalves1∽4. Certain regions of the mantle margin are likely to be more or less, sensitive to certain stimuli than others. The inhalant siphon is likely to be particularly sensitive to both chemical and mechanical stimuli, whereas the exhalant siphon will be less sensitive to both. The distribution and density of putative sensory receptors on the in-and ex-halant siphon is compared in this paper.The excised siphons were fixed in glutaraldehyde and osmium tetroxide, the whole procedure of SEM study is recorded in Wu's thesis.Type II cilia cover the tips of tentacles, 6.13um. Type IV and type V cilia are found on the surface of tentacles. Type IV cilia are occasionally present at the tips of tentacles, 8 um long. They are the commonest type on the surface of tentacles. Type VI cilia occor in the internal surface of the inhalant siphon, but are not found on the surface of tentacles, 6.7-10um long.

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