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Study of human skin mechanical properties by mean of Cutometer
Abstract
Cutometer is a commercially available non-invasive suction skin elasticity meter. The present study discusses some aspects of the biological informativeness and interpretation of the results obtained in studying skin mechanical properties with cutometer. We analyze the results of previously published studies on the mechanical properties of healthy and diseased skins and their changes after external influences. Studying human skin using cutometer gives objective and biologically meaningful information about the mechanical properties of healthy and diseased human skin.
... In case of B-NLC-E these values were insignificant with a matter of time. The slight change by B-NLC-E in TEWL index is associated with an insulation effect that increased skin hydration level [68] and this occlusive effect depends significantly on the particle size, small size makes a dense film on skin surface [63]. Mango extract contain high amount of vitamin A, which increases the hyaluronic acid level as reported by Toshida et al., 2012 [69] and it may be the possible reason of increased in volunteers skin hydration by M-NLC-E. ...
... This increase in skin elasticity is due to the M-Ext as it has a reversible inhibitory effect on elastase and collagenase [13]. The decrease in TEWL index and increase in skin hydration level ( Figure 10) also enhanced the skin elasticity as described by Dobrev (2000) [68]. Sebum is formed in the sebaceous glands and its overproduction leads to oily skin, larger pore sizes, acne, and pimples [70,71]. ...
... This increase in skin elasticity is due to the M-Ext as it has a reversible inhibitory effect on elastase and collagenase [13]. The decrease in TEWL index and increase in skin hydration level ( Figure 10) also enhanced the skin elasticity as described by Dobrev (2000) [68]. Wrinkle formation is a prominent effect of skin aging, secondary to actinic elastosis and prominent in sun-exposed areas [74,75]. ...
Although Mangifera indica L. extract (M-Ext) of the peel and kernel possesses potent antioxidant and excellent antiaging qualities, the effects are only partially seen because of the skin’s limited ability to absorb it. M-Ext was loaded into nanolipid carriers (M-NLCs) in this work to create a green topical formulation that would boost antiaging efficacy and address penetration deficit. Compound identification was done using GCMS and atomic absorption spectroscopy for heavy metals in M-Ext. M-Ext was also evaluated against oxidative stress antioxidant enzymes. The M-NLCs were fabricated and evaluated for their physicochemical characterizations. Cytotoxicity and cell permeation analysis of M-Ext and M-NLCs were carried out in fibroblasts and HaCaT cell lines. An ex vivo permeation study of M-Ext and M-NLC-loaded emulsion was performed through rat skin and the kinetic parameters were determined. Kinetic data showed that the ex vivo permeation of M-NLC-loaded emulsion through rat skin followed the Higuchi model. The safety profile was evaluated in human volunteers after written consent. Three months’ in vivo investigations were conducted using the optimized M-NLC-loaded emulsion and vehicle (B-NLC-loaded emulsion) on human cheeks for comparison. The volunteers’ skin erythema level, melanin contents, TEWL index, moisture contents, sebum level, elasticity, pH, and pore size were examined after the first, second, and third month via noninvasive techniques. There were significant findings for physicochemical characterizations and in vitro and ex vivo studies. The findings demonstrate that the green nanolipid carriers amplified the overall antioxidant effectiveness and may represent an emerging treatment strategy for oxidative stresses and aging.
... The anatomy of the venepuncture site varies from patient to patient due to age, sex and pre-existing diseases [3], which impedes the performance of a correct venepuncture without complications. Possible complications can occur, e.g. if the needle is inserted only partially into the vessel, causing leakage of blood and the formation of hematomas in the surrounding tissue [2]. ...
Venepuncture is one of the most common invasive procedures performed worldwide, however, complications still occur. Currently, commercial single layer silicone phantoms used for venepuncture training do not accurately imitate the geometry and mechanical properties seen in the various patient groups. This paper presents the development of a realistic artificial venepuncture phantom. Three multilayered tissue phantoms are developed simulating venepuncture sites of paediatric, adult and geriatric patients. Silicone materials of different stiffnesses were selected to imitate the epidermis, dermis, subcutaneous fat, muscle and superficial veins. Singleaxis indentation tests were carried out on silicone samples and the multi-layered phantom inserts to characterize the material properties. The measured Young's moduli for the artificial dermis, fat and muscle show sufficient agreement with corresponding literature values. However, characterization of the complete phantom inserts showed stiffnesses four times larger than prior in-vivo studies. Future studies will work on developing a more comparable in-vivo study.
... The Ur/Uf parameter was used to characterize the elastic property of the skin. The curves from the skin viscoelasticity measurement were analyzed using the Software Cutometer ® MPA 580 to obtain the final distension of the first curve (U f ) and the ratio of elastic recovery to the total deformation (U r /U f ) parameters [14]. All measurements were performed in triplicate. ...
Moringa oleifera seed oil has been recognized for its benefits in relation to the skin. The objective of this study was to evaluate the chemical composition and antioxidant activity of moringa seed oil, to formulate a moringa seed oil cream, and to determine the efficacy of moringa seed oil cream in vivo. The chemical components of moringa seed oil were analyzed by high-performance liquid chromatography and gas chromatography. The antioxidant activity of the oil was determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging assay. An oil-in-water cream containing moringa seed oil was developed and characterized for antioxidant activity. The moringa seed oil cream was further subjected to the accelerated stability test of heating–cooling cycles for six cycles and stored isothermally at 4, 30, and 45 °C for 28 days. The efficacy of moringa seed oil cream was investigated in 32 participants by measuring their skin hydration, erythema, melanin values, and visco-elasticity. The results showed that moringa seed oil contained α-tocopherol, plant sterols, and fatty acids. The oil had antioxidant activity with a 50% of initial concentration (IC50) value of 121.9 mg/mL. The stability study indicated that the pH, viscosity, and rheological behavior of the cream containing moringa seed oil were not significantly changed after storage at 4, 30, and 45 °C for 28 days and six heating–cooling cycles. The moringa seed oil cream exhibited in vitro antioxidant activity and increased the in vivo skin hydration level compared with the cream base. There was no report of skin irritation from moringa seed oil cream application, suggesting that the moringa seed oil cream developed in this study was appropriate for pharmaceutical and cosmetic uses. A M. oleifera seed oil cream was successfully developed. The moringa seed oil cream possessed antioxidant activity, enhanced the skin hydration level, and reduced skin erythema, but did not affect the melanin content and skin visco-elasticity. The moringa seed oil cream did not induce skin irritation and, thus, was safe to use.
... Measuring suction time or suction force serves to calculate various parameters of skin mechanical properties (Table II) Skin elasticity is reflected by the U and R parameters, defined as: Ur (immediate retraction), Ue (immediate deformation), Uf (final deformation), Ur/Uf (biological elasticity), Ur/Ue (net elasticity without viscous deformation) and Ua/Uf (gross elasticity including viscous deformation). These parameters are related to the function of elastic fibers and reflect their changes in physiological or pathological skin conditions, while the viscoelasticity of the skin is related to the displacement of interstitial fluid through the fiber network in the dermis and is reflected by the parameters Uv (delayed deformation), Uv/Ue (viscoelastic ratio, i.e., the ratio of viscoelastic to elastic distension) and Ua (called also R8, meaning the final retraction after removal of the vacuum) (11). ...
Non-invasive bioengineering technologies are constantly being developed, as they can provide useful insights and contribute to the improvement of medical care and scientific education. The purpose of this study was to assess skin viscoelasticity using the suction chamber method in patients with allergic contact dermatitis vs. healthy subjects, before and after applying a moisturizer safety testing cream. This was a prospective controlled study over a 3-year period (March 2016-March 2019), with 81 subjects being divided in two balanced groups: Patients with allergic contact dermatitis and healthy subjects, respectively. The skin viscoelasticity was determined for all subjects with Cutometer®, using the suction method, by performing a dynamic assessment of parameters before and after applying a moisturizing cream. The results indicate a decrease in the elasticity parameters in both groups, indicating an improvement of the elastic properties under the treatment. Skin capacity to return to its previous form after the deformation, i.e., pure elasticity and biological elasticity, showed overall elevated values in the group with contact dermatitis, demonstrating the efficacy of the emollient cream after applying it for 28 days (increase by 11.7 and 4.9% respectively, compared with baseline, when patients had dry, untreated skin). However, in healthy subjects, these parameters do not achieve important values, but they remain rather stable over time with a very slight improvement (6.6% after 28 days). The Cutometer is an easy to use, efficient and widely used instrument for measurements in studies that perform a quantitative assessment of the effectiveness of different formulations intended for application on the skin.
... Suction cups with hypobaric pressure are widely adopted in various devices to interact with skin for various medical /therapeutic/cosmetic purposes, such as Cutometer® for skin elasticity analysis, drug delivery devices, and suction cups in acupuncture treatment or spa treatment (Dobrev, 2017;Xiaoxuan Zhang et al., 2020). Suction domes with various extent of skin deformation are formed upon application of hypobaric pressure. ...
Suction cups are widely used in applications such as in measurement of mechanical properties of skin in vivo, in drug delivery devices or in acupuncture treatment. Understanding the mechanical response of skin under hypobaric pressure are of great importance for users of suction cups. The aims of this work are to assess the capability of linear elasticity (Young's modulus) or hyperelasticity in predicting hypobaric pressure induced 3D stretching of the skin. Using experiments and computational Finite Element Method modelling, this work demonstrated that although it was possible to predict the suction dome apex height using both linear elasticity and hyperelasticity for the typical range of hypobaric pressure in medical applications (up to -10 psi), linear elasticity theory showed limitations when predicting the strain distribution across the suction dome. The reason is that the stretch ratio reaches values exceeding the initial linear elastic stage of the stress-strain characteristic curve for skin. As a result, the linear elasticity theory overpredicts the stretch along the rim of domes where there is stress concentration. In addition, the modelling showed that the skin was compressed consistently along the thickness direction, leading to reduced thickness. Using hyperelasticity modelling to predict the 3D strain distribution paves the way to accurately design safe commercial products that interface with skin.
DESCRIPTION
Imaging probes for optical coherence elastography (OCE) are undergoing development to enable its practical implementation in a number of applications. The specific challenges posed by each application defines the technical requirements for each probe, leading to the development of a range of benchtop, handheld and endoscopic probes. In addition, a number of more compact OCE imaging probes have been proposed, including finger-mounted and needle-based probes. In this chapter, we describe each of these probes in detail within the context of the relevant applications they are proposed for. An analysis of each probe is provided, with particular focus on optical design, mechanical loading, and image acquisition protocol.
Background
Suction cups are widely used in applications such as in measurement of mechanical properties of skin in vivo, in drug delivery devices or in acupuncture treatment. Understanding mechanical response of skin under hypobaric pressure is of great importance for users of suction cups. The aim of this work is to predict the hypobaric pressure induced 3D stretching of the skin.
Methods
Experimental skin tensile tests were carried out for mechanical property characterization. Both linear elasticity and hyperelasticity parameters were determined and implemented in Finite Element modelling. Skin suction tests were performed in both experiments and FEM simulations for model validation. 3D skin stretching is then visualized in detail in FEM simulations.
Results
The simulations showed that the skin was compressed consistently along the thickness direction, leading to reduced thickness. At the center of the dome, the radial and angular strain decreases from the top surface to the bottom surface, although always in tension. Hyperelasticity modelling showed superiority over linear elasticity modelling while predicting the strain distribution because the stretch ratio reaches values exceeding the initial linear elastic stage of the stress‐strain curve for skin.
Conclusion
Hyperelasticity modelling is an effective approach to predict the 3D strain distribution, which paves a way to accurately design safe commercial products that interface with the skin.
Systematically mapping the mechanical properties of skin and tissue is useful for biomechanics research and disease diagnostics. For example, breast cancer and lymphoma manifest themselves as hard nodes under the skin. Currently, mechanical measurements are done manually, with a sense of touch or a hand-held tool. Manual measurements do not provide quantitative information and vary depending on the skill of the practitioner. Research shows that tactile sensors could be more sensitive than a hand. We propose a method that uses our previously developed skin-crawling robots to systematically and noninvasively test the mechanical properties of soft tissue. The robots are more systematic and repeatable than humans. Using the data collected with a cutomoter or indenter integrated into the miniature robot, we trained a convolutional neural network to classify the size and presence of the lumps. The classification works with 98.9% accuracy for lump size with a diameter of 0 to 10 mm embedded in depth of 1 to 5 mm in a simulated tissue. We conducted a limited evaluation on a forearm, where the robot imaged dry skin with a cutometer. We hope to improve the ability to test tissues noninvasively, and ultimately provide better sensitivity and systematic data collection.
Dermal fillers have become popular due to the increased demand for skin rejuvenation products. Polycaprolactone (PCL), a newly developed bioresorbable medical polymer, has emerged as a durable and safe dermal filler. However, available PCL fillers cause irritation; carrier gels can coagulate PCL particles, block the injection needle, and cause nonhomogeneity of particle suspensions that could be responsible for the observed side effects. To relieve pain, pre‐mixing PCL filler with lidocaine. However, this formulation changes the property of the CMC portion of the PCL filler, and possibly results in an uneven suspension of the PCL particles. Hence, a particle‐free PCL homogeneously solubilized in water was developed to overcome these limitations. This study aimed to assess the in vivo safety, biodegradability, and neocollagenesis ability of a novel PCL filler, DLMR01 using a rat model. Fillers were characterized after injecting a vehicle control or DLMR01 using a digital camera, folliscope, and a three‐dimensional profiling system. Biopsy was performed to evaluate biocompatibility and neocollagenesis. Skin elasticity was measured using a Cutometer. DLMR01 caused no needle occlusion by particle aggregation or laborious injectability. Filler nodules dispersed to surrounding tissues within 6 h without further granuloma formation. Histological inspection revealed no tissue residual material or foreign body reaction during the 12‐week test period. DLMR01 increased dermal thickness, collagen regeneration, and skin elasticity. In conclusion, this study demonstrates the potential of DLMR01 for dermal rejuvenation in a rat model.
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Background
The possible contribution of head flexion posture while using a smartphone to the formation of “smartphone face,” is an increasing concern. Smartphone face describes the facial changes in a stooped posture receiving more gravitational pull on the jowl area.
Aims
In this study, we quantified facial sagging in different postural changes using a three‐dimensional imaging technique.
Methods
Faces of 21 young (30.45 ± 2.81 yo, n = 11) and old (59.50 ± 3.37 yo, n = 10) Korean female subjects were scanned in different body postures including standing, supine, and head flexion (30°, 45°). The landmark displacements and volumetric changes in facial areas were assessed and correlated with skin elasticity. In addition, 22 Korean female subjects (45.45 ± 3.81 yo) were recruited to test the anti‐gravity effect of facial cream A, which was formulated with Stem III complex™, for 8 weeks.
Results
The landmarks shifted inferior‐laterally with the supine posture, while the upper face shifted more laterally and the lower face shifted more inferiorly. With a head flexion posture, facial sagging occurred mainly toward the anterior direction with more prominent changes in the lower face. The changes were greater in the older group, and skin elasticity exhibited negative correlation with the shifting distances. A significant decrease in facial sagging was noted after an 8‐week treatment of facial cream A.
Conclusion
The use of a three‐dimensional imaging technique could accurately assess the gravity‐induced facial changes in different postures. The head flexion posture particularly gives more gravitational pull to the lower face, which could contribute to the drooping jawline.
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