Biological Skin Research Articles

Trace element zinc and skin disorders.

Zinc is a necessary trace element and an important constituent of proteins and other biological molecules. It has many biological functions, including antioxidant, skin and mucous membrane integrity maintenance, and the promotion of various enzymatic and transcriptional responses. The skin contains the third most zinc in the organism. Zinc deficiency can lead to a range of skin diseases. Except for acrodermatitis enteropathic, a rare genetic zinc deficiency, it has also been reported in other diseases. In recent years, zinc supplementation has been widely used for various skin conditions, including infectious diseases (viral warts, genital herpes, cutaneous leishmaniasis, leprosy), inflammatory diseases (hidradenitis suppurativa, acne vulgaris, rosacea, eczematous dermatitis, seborrheic dermatitis, psoriasis, Behcet's disease, oral lichen planus), pigmentary diseases (vitiligo, melasma), tumor-associated diseases (basal cell carcinoma), endocrine and metabolic diseases (necrolytic migratory erythema, necrolytic acral erythema), hair diseases (alopecia), and so on. We reviewed the literature on zinc application in dermatology to provide references for better use.

Successful treatment of critical burns on the example of firefighters: case study presentation

Relevance. The profession of a firefighter involves performing tasks in extreme conditions and is associated with an increased risk of occupational injuries. Despite organizational and technological measures aimed to prevent occupational injuries or death, there are frequent cases of traumatic events in the line of duty, including extensive burns. Such cases are often of a group nature and attract significant public attention.Intention. To present a clinical case of successful treatment of two firefighters who got severe burn injuries in the line of duty.Methodology. The surgical tactics and features of the intensive care of two severely burned firefighters with an unfavorable prognosis, according to the common prognostic scales, are described. The first national experience of large-scale (more than 15 % TBSA) application of novel skin equivalents – dermal regeneration templates is discussed.Results and Discussion. Outcomes of injuries in both cases were favorable. It was possible to avoid severe disability of the patients. This result was achieved through the implementation of modern treatment strategy of critical burns, namely multidisciplinary approach from the moment of admission; early aggressive removal of non-viable tissues, which allows interrupting the pathogenetic mechanism of burn disease; active use of temporary substitutes for the skin, including those of biological origin – the so-called skin equivalents; early restoration of the skin with the priority of functionally active areas (hands, neck, large joints); primary reconstructive surgeries, involving the use of complex plastic methods in the acute period иof injury. Being more resource-demanding, early surgical treatment of burns provides not only reduction of hospital stay, but also a decrease in mortality and improvement in the functional outcomes.Conclusion. The experience of treating these patients demonstrates on the high role of the organization of burn care and the use of new technologies. Novel biological skin substitutes help overcome the lack of donor resources, associated with extensive deep burns. Despite the unfavorable prognosis, the complex application of innovative medical technologies not only provided a favorable outcome for injured firefighters with severe burns, but also allowed them to return to service.

Digital Image Correlation by Natural Textures on Biological Skin

Digital Image Correlation by Natural Textures on Biological Skin

Advances in Skin Tissue Engineering and Regenerative Medicine.

There are an estimated 500,000 patients treated with full-thickness wounds in the United States every year. Fire-related burn injuries are among the most common and devastating types of wounds that require advanced clinical treatment. Autologous split-thickness skin grafting is the clinical gold standard for the treatment of large burn wounds. However, skin grafting has several limitations, particularly in large burn wounds, where there may be a limited area of non-wounded skin to use for grafting. Non-cellular dermal substitutes have been developed but have their own challenges; they are expensive to produce, may require immunosuppression depending on design and allogenic cell inclusion. There is a need for more advanced treatments for devastating burns and wounds. This manuscript provides a brief overview of some recent advances in wound care, including the use of advanced biomaterials, cell-based therapies for wound healing, biological skin substitutes, biological scaffolds, spray on skin and skin bioprinting. Finally, we provide insight into the future of wound care and technological areas that need to be addressed to support the development and incorporation of these technologies.

Recent advances in electronic skins: material progress and applications.

Electronic skins are currently in huge demand for health monitoring platforms and personalized medicine applications. To ensure safe monitoring for long-term periods, high-performance electronic skins that are softly interfaced with biological tissues are required. Stretchability, self-healing behavior, and biocompatibility of the materials will ensure the future application of electronic skins in biomedical engineering. This mini-review highlights recent advances in mechanically active materials and structural designs for electronic skins, which have been used successfully in these contexts. Firstly, the structural and biomechanical characteristics of biological skins are described and compared with those of artificial electronic skins. Thereafter, a wide variety of processing techniques for stretchable materials are reviewed, including geometric engineering and acquiring intrinsic stretchability. Then, different types of self-healing materials and their applications in electronic skins are critically assessed and compared. Finally, the mini-review is concluded with a discussion on remaining challenges and future opportunities for materials and biomedical research.

Advances in Biodegradable Electronic Skin: Material Progress and Recent Applications in Sensing, Robotics, and Human-Machine Interfaces.

The rapid growth of the electronics industry and proliferation of electronic materials and telecommunications technologies has led to the release of a massive amount of untreated electronic waste (e-waste) into the environment. Consequently, catastrophic environmental damage at the microbiome level and serious human health diseases threaten the natural fate of the planet. Currently, the demand for wearable electronics for applications in personalized medicine, electronic skins (e-skins), and health monitoring is substantial and growing. Therefore, "green" characteristics such as biodegradability, self-healing, and biocompatibility ensure the future application of wearable electronics and e-skins in biomedical engineering and bioanalytical sciences. Leveraging the biodegradability, sustainability, and biocompatibility of natural materials will dramatically influence the fabrication of environmentally friendly e-skins and wearable electronics. Here, the molecular and structural characteristics of biological skins and artificial e-skins are discussed. The focus then turns to the biodegradable materials, including natural and synthetic-polymer-based materials, and their recent applications in the development of biodegradable e-skin in wearable sensors, robotics, and human-machine interfaces (HMIs). Finally, the main challenges and outlook regarding the preparation and application of biodegradable e-skins are critically discussed in a near-future scenario, which is expected to lead to the next generation of biodegradable e-skins.

Ultrahigh sensitive, sensing-actuating integrated, and multi-functional intelligent skin based on electromechanical-hydraulic coupling

Electronic skin (e-skin) has great application prospects in the field of robots, smart medical care, and wearable electronics. However, the existing e-skin is far inferior to biological skin in intelligent response, which limits the miniaturization, intelligence, and versatility of e-skin. Herein, inspired by biological skin, an intelligent skin with a skin-like microchannel (SMC) structure, which can realize the sensing function of pressure and the actuating function of fluid simultaneously, is realized by using 3D printing. Due to the SMC structure, the intelligent skin has an ultrahigh sensitivity of 1363.9 kPa−1 in the pressure range of 0–5 kPa, which is superior to the existing E-skin. Uniquely, based on the mechanical-hydraulic coupling between fluid in SMC structure and external pressure, the intelligent skin has a real-time in-situ fluid-actuating intelligent response to external pressure, which enables the skin to realize a sensing-actuating integration without adding components. Moreover, with the sensing-actuating coupling characteristic, the skin can achieve diversified intelligent functions by introducing a variety of functional fluids into SMC structure, such as drug delivery, self-backup of sensing signal, and visual overload alarm. Besides, the realization of sensing-actuating integration in the intelligent skin provides a new strategy for the miniaturization and multi-functionalization of wearable devices.

Design and Evaluation of Complex Polypeptide-Loaded Dissolving Microneedles for Improving Facial Wrinkles in Different Areas.

Wrinkles are one of the most intuitive manifestations of skin aging. Complex polypeptide-loaded dissolving microneedles (CP-DMNs) for facial wrinkles in different areas have been developed and evaluated for the first time. In optimizing formulations, we compared the differences in CP-DMNs heights on skin insertion depth and skin repair and healing. Furthermore, systemic safety experiments were carried out to provide a reference for clinical application. On this basis, an 84-day efficacy assessment based on the improvement of facial wrinkles in different areas and a comparison between CP-DMNs vs. placebo was performed on 30 healthy subjects. As a result, DMNs with a height of 300 μm presented sufficient strength to pierce the stratum corneum with minimized skin damage. In addition, CP-DMNs possessed excellent biological safety and skin compatibility for clinical application. Compared with placebo, CP-DMNs exhibited obvious improvements in wrinkles distributed in the corners of eyes, under-eyes, and nasolabial folds. Furthermore, after using CP-DMNs for 84 days, facial wrinkles in five different areas were smoothed. In short, the complex polypeptides showed apparent anti-wrinkle efficacy with the aid of DMNs technology, and CP-DMNs seemed to work better on deeper wrinkles, such as frown lines and nasolabial folds.

Chiral smart bionic skin film with changeable structural colors and tunable luminescence by polymer-assisted supramolecular assembly of the photonic crystals

The biological skin system of advanced organisms can obtain various environmental stimuli to change skin colors by adjusting the micro-nano structure of the skin surface or by electroluminescence and photoluminescence. The assembly of biominetic skin materials with both changeable structural colors and tunable luminescence is a significant challenge in the fields of advanced materials and light science. This work describes a novel chiral smart bionic skin film with changeable structural colors, tunable luminescence by the polymer-assisted supramolecular assembly of the photonic crystals. A smart nanodot based on the molecule with four-armed mimosa-like structure was assembled on the cellulose nanocrystals (CNC) photonic crystal. The chiral bionic skin film obtained had multi-channel fluorescence-emission, sensitive structural color stimulus responses to the light and humidity and the tunable chiral helical nematic domains. It demonstrates a series of the supramolecular interactions that trigger multiple intelligent signals, including the adjustable chiral pitch, photo-induced electron transfer (PET), intramolecular fluorescence resonance energy transfer (FRET), π-π stacking and the changes of the hydrogen bonds. The photonic crystal skin materials with sensitive multi-signals intelligent responses as smart bionic skin have potential applications for the tissue engineering, 3D printing materials, bionic artificial skin materials, and optical devices.

Cellular technologies in the treatment of scalded patients

Over the past decades, new methods of treating burn wounds based on biotechnology have appeared. The review presents the main materials for the treatment of burns, which were created using tissue engineering - biological wound dressings and skin substitutes.

Miniaturized Skin-Integrated Electronics in Real Time for Virtual Assistance - A Review

The skin acts as a conduit between the brain and the outside environment. The information it receives, such as a touch on the shoulder or the heat from a fire, is processed and used to choose an appropriate response by the brain. A skin functionality may be achieved by incorporating sensors onto bionic skins that are on par with the sensitivity of biological skins. However, doing so is not simple. Recent developments in physiological sensing, sensory perception, and virtual and augmented reality are discussed, as are other intelligent uses of skin-integrated electronics. These skin-integrated systems are advancing the materials and structural designs necessary for the next generation of electronic eyes, ears, and skin. Future progress in this area of study will be aided by interdisciplinary exploration into fields such as materials science, electrical engineering, mechanics, and biomedical engineering.

Transdermal Delivery and Biological Activity of Arginine Oligomer Conjugation of Palmitoyl Tripeptide-1

GHK is a promising cosmeceutical peptide that stimulates the synthesis of ECM and modulates the activity of Matrix Metallo Proteinases (MMPs). However, due to the hydrophilic properties of GHK, skin permeability is a challenge. To overcome this limitation, we considered two peptide modifications, namely palmitoyl attachment and arginine oligomer conjugation. First, we evaluated the optimal modification of GHK for skin penetration using the Franz diffusion cell assay with 3D human reconstructed skin. We found that skin permeability was slightly increased by attaching palmitoyl at the N-terminus of GHK, while it was significantly increased by conjugating arginine oligomers at the C-terminus of GHK. In the comparison between R4, R6, and R8, R4 showed the highest penetrating potential, and the permeability of Pal-GHK-R4 was about 7-fold higher than that of GHK. Based on the skin permeability results, the optimal peptide, Pal-GHK-R4, was synthesized using SPPS, after which its biological activities were verified. Evaluating MMP-2 activity by gelatin zymography and collagen production by Sircol collagen assay showed that Pal-GHK-R4 had approximately100-fold lower active concentrations than GHK. In other words, we established the novel peptide Pal-GHK-R4 as a modification that significantly increases both the biological activities and skin permeability of GHK.

Role of Indigenous Cost Effective Two Layer Regenerative Scaffold in Wound Bed Preparation

The quality of skin wound healing can be improved by the application of collagen scaffolds as biological dermal substitutes. Dermal extract helps to improves wound healing and quality of the scars. They serve as a scaffold into which cells can migrate and repair the injury. In the current scenario where in many biological and cellular engineering skin substitutes are available, wound management is a multimodality treatment with use of multiple available methods to augment wound healing at various levels. An excellent dermal substitute should be affordable, long-lasting, ready-to-use, analgesic, durable, flexible, non-antigenic, stops water loss, conforms to uneven wounds, anti-microbial, and may be applied in one sitting. In this study, we attempted to mimic the same technique in our two-layered regenerative scaffold, which is created locally and is cost-effective.

Biomimetic color‐changing skin based on temperature‐responsive hydrogel microspheres with the photonic crystal structure

AbstractThe responsive color‐changing bionic skin imitation of certain organisms such as chameleons has potential applications in the fields of chemical sensing and information transfer. Inspired by the cellular structure of the chameleon iridophores, a flexible and scalable fabrication strategy was proposed in the present study, which centers on the modular assembly of miniature color‐changing pixel dots. The color‐changing pixel dots were formed by self‐assembling charged silica particles inside hydrogels and fabricated in bulk using microfluidic methods. The pixel dots were immobilized in hydrogels to encapsulate in a membrane structure similar to biological skin. With thermal stimulation, the bionic color‐changing skin can change color from green to red and has an angle‐independent color display with good environmental adaptability.

Biological Graft as an Innovative Biomaterial for Complex Skin Wound Treatment in Dogs: A Preliminary Report.

Complex wounds in dogs are a recurrent problem in veterinary clinical application and can compromise skin healing; in this sense, tissue bioengineering focused on regenerative medicine can be a great ally. Decellularized and recellularized skin scaffolds are produced to be applied in different and complex canine dermal wounds in the present investigation. Dog skin fragments are immersed in a 0.5% sodium dodecyl sulfate (SDS) solution at room temperature and overnight at 4 °C for 12 days. Decellularized samples are evaluated by histological analysis, scanning electron microscopy (SEM) and gDNA quantification. Some fragments are also recellularized using mesenchymal stem cells (MSCs). Eight adult dogs are divided into three groups for the application of the decellularized (Group I, n = 3) and recellularized scaffolds (Group II, n = 3) on injured areas, and a control group (Group III, n = 2). Wounds are evaluated and measured during healing, and comparisons among the three groups are described. In 30- and 60-day post-grafting, the histopathological analysis of patients from Groups I and II shows similar patterns, tissue architecture preservation, epithelial hyperplasia, hyperkeratosis, edema, and mononuclear inflammatory infiltrate. Perfect integration between scaffolds and wounds, without rejection or contamination, are observed in both treated groups. According to these results, decellularized skin grafts may constitute a potential innovative and functional tool to be adopted as a promising dog cutaneous wound treatment. This is the first study that applies decellularized and recellularized biological skin grafts to improve the healing process in several complex wounds in dogs, demonstrating great potential for regenerative veterinary medicine progress.

Ridges and riblets: Shark skin surfaces versus biomimetic models

Shark skin has been an inspiration for biomimetic materials and structures due to its role in reducing drag and enhancing thrust, properties believed to be due to the textured surface composed of ridges on the surface of individual tooth-like scales (denticles). Attempts to replicate the hydrodynamic performance of shark skin have involved manufacturing both engineered riblets and fabrics with textured surfaces. However, there are no studies that compare the surface ornamentation of shark denticles to bioinspired materials. Using three-dimensional surface profilometry we analyzed the cross-sectional profile of the surface of shark denticles at two locations on 17 species and compared these data to values obtained from engineered structures (e.g., riblets) and competition swimsuits that are often proposed as having a comparable surface texture to shark skin. Of the variables measured, crown aspect ratio (p = 0.007), ridge height, ridge spacing, ridge aspect ratio, and ridge bumpiness (all p < 0.001) differed among the three materials. Overall, engineered riblet surfaces were very different than biological shark skin. Some of the competition swimsuit materials were more shark-like, with the fabric texture having similar height variation, but with irregular ridge spacing. Cross-sectional profile, which includes pathlength and aspect ratio in addition to ridge spacing and height, is an important feature of the skin’s surface, affecting water flow over the individual denticles, and future research will address these parameters. Quantitative 3D analysis of the surface of real shark denticle ridges enables the design of more biomimetic engineered shark skin surfaces.

Development and characterisation of hybrid composite skin simulants based on short polyethylene fibre and bioactive glass particle-reinforced silicone

Silicone elastomers are widely recognised as artificial skins for medical prosthesis and cranial injury assessment. Since silicone is not an ideal skin simulant due to the lack of mechanical stiffness and a fibrous structure, the present study aimed to tailor the mechanical and structural characteristics of silicone by integrating biocompatible reinforcements (namely, short polyethylene fibres and bioglass particles) to develop suitable bio-integrative skin simulant candidates. The influences of short polyethylene fibres and bioglass particles in the selected platinum silicone on the mechanical properties of silicone-based composite skin simulants were investigated with various factors, including filler concentration, KMnO4 surface treatment of the polyethylene fibre, and particle size. A comprehensive assessment of the tensile, compressive, and hardness properties of the examined composites was conducted, and they were compared with the properties of human biological skin. The results exhibited that the elastic moduli and the hardness of all composites increased with the concentration of both reinforcements. While integrating only the bioglass particles had the advantage of an insignificant effect on the hardness change of the silicone matrix, the composite with polyethylene fibres possessed superior tensile elastic modulus and tensile strength compared to those of the bioglass reinforced composite. The composites with 5% untreated polyethylene fibres, KMnO4 surface-treated fibres, and bioglass reinforcements enhanced the tensile elastic moduli from the pure silicone up to 32%, 44%, and 22%, respectively. It reflected that the surface treatment of the fibres promotes better interfacial adhesion between the silicone matrix and the fibres. Moreover, the smaller bioglass particle had a greater mechanical contribution than the larger glass particle. Systematically characterised for the first time, the developed composite skin simulants demonstrated essential mechanical properties within the range of the human skin and constituted better skin alternatives than pure silicone for various biomedical applications.

Robots with a human touch

Robotics offers an unprecedented means to support people's daily lives. However, human-robot interactions remain challenging because of the appearance of robots. Kawai et al. propose to overcome this by growing biological skin equivalents on robots. Their study opens new possibilities to further humanize perception of robots and improve human-robot interactions.

Modeling an Optimal 3D Skin-on-Chip within Microfluidic Devices for Pharmacological Studies.

Preclinical research remains hampered by an inadequate representation of human tissue environments which results in inaccurate predictions of a drug candidate’s effects and target’s suitability. While human 2D and 3D cell cultures and organoids have been extensively improved to mimic the precise structure and function of human tissues, major challenges persist since only few of these models adequately represent the complexity of human tissues. The development of skin-on-chip technology has allowed the transition from static 3D cultures to dynamic 3D cultures resembling human physiology. The integration of vasculature, immune system, or the resident microbiome in the next generation of SoC, with continuous detection of changes in metabolism, would potentially overcome the current limitations, providing reliable and robust results and mimicking the complex human skin. This review aims to provide an overview of the biological skin constituents and mechanical requirements that should be incorporated in a human skin-on-chip, permitting pharmacological, toxicological, and cosmetic tests closer to reality.

Biomimetic Chromotropic Photonic‐Ionic Skin with Robust Resilience, Adhesion, and Stability

AbstractThe growing interest in mimicry of biological skins greatly promotes the birth of high‐performance artificial skins. Chameleon skins can actively transform environmental information into bioelectrical and color‐change signals simultaneously through manipulating ion transduction and photonic nanostructures. Here, inspired by chameleon skins, a novel biomimetic chromotropic photonic‐ionic skin (PI‐skin) capable of outputting synergistic electrical and optical signals under strain with robust adhesion, stability, and resilience is ingeniously constructed. The PI‐skin exhibits sensitive structural color change synchronized with electrical response via adjusting the lattice spacing of the photonic crystal (mechanochromic sensitivity: 1.89 nm per %, Δλ > 150 nm). Notably, the polyzwitterionic network provides abundant electrostatic interactions, endowing the PI‐skin with excellent adhesion, environmental tolerance, and outstanding mechanical stability (>10 000 continuous cycles). Meanwhile, the high loading of ionic liquid (IL) weakens the electrostatic interaction between the polyzwitterionic molecular chains, leading to high resilience. The PI‐skin is finally applied to construct a visually interactive wearable device, realizing precise human motion monitoring, remote communication, and visual localization of pressure distribution. This work not only expands design ideas for the construction of advanced biomimetic I‐skins but also provides a general optical platform for high‐level visual interactive devices and smart wearable electronics.