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st Century
Published in Tatiana G. Volova, Yuri S. Vinnik, Ekaterina I. Shishatskaya, Nadejda M. Markelova, Gennady E. Zaikov, Natural-Based Polymers for Biomedical Applications, 2017
Tatiana G. Volova, Yuri S. Vinnik, Ekaterina I. Shishatskaya, Nadejda M. Markelova, Gennady E. Zaikov
Depending on the degree of injury and the stage of skin regeneration (inflammation, regeneration, and formation of new epithelial skin), the artificial skin must meet different requirements. In the first stage, artificial skin must ensure wound cleansing; in the second, it must create conditions favoring the growth of new connective tissue; and in the third stage, it must ensure proliferation and migration of epithelial cells and formation of new epidermis. Artificial skin is made from various natural and synthetic materials in the form of gels, fabrics, nonwovens, films, powders, fibers, porous covering, etc. Traditional textile bandages, which are generally used in first aid procedures, are currently being replaced by materials and systems with enhanced cleansing, sorbing, and hemostatic properties. Polymer-based sorption materials are produced as fibers, sponges, and powders. When wetted, powders form a film on the wound surface. Natural polymers used to prepare sorption skin covering include collagen compositions in the form of sponges. For example, Digispon is a system based on collagen and crosslinked polyvinyl alcohol, containing an antiseptic. Agarose-based gel systems are also used. Materials designed in Russia (Algipor and Algimaf) are porous sponges loaded with furacilin. Sorption skin materials have been prepared from synthetic polymers, including materials based on polyvinyl alcohol, polyvinylpyrrolidone, cross-linked polyethylene glycol, and block-copolymers of ethylene oxide and propylene (Pluronik F-127).
Soft Tissue Replacements
Published in Joyce Y. Wong, Joseph D. Bronzino, Biomaterials, 2007
K.B. Chandran, K.J.L. Burg, S.W. Shalaby
The need for percutaneous (trans or through the skin) implants has been accelerated by the advent of artificial kidneys and hearts and the need for prolonged injection of drugs and nutrients. Artificial skin is urgently needed to maintain the body temperature and prevent infection in severely burned patients. Actual permanent replacement of skin by biomaterials is still a great clinical challenge.
Artificial Skin
Published in Muhammad Mustafa Hussain, Nazek El-Atab, Handbook of Flexible and Stretchable Electronics, 2019
Skin is our body’s largest organ; it is elastic, helps preserve fluid balance, controls body temperature, helps prevent and fight diseases, but it’s also self-healing. Skin is constantly subjected to damages from the environment; when the safety of our body is compromised from a wound, it is an essential attribute of skin to act as a barrier against infectants (e.g., germs) and self-heal to close the cut and protect us from external surroundings. The incorporation of a repetitive self-healing capability becomes critical to extend the E-skin’s lifetime while maintaining robust functionality, especially in the areas of soft robotics and biomimetic prostheses. It is common to witness insulating self-healing polymers, but the challenging task is the advancement of self-healing materials that incorporate conductive electrical properties, vital for the integration of connectors and sensors in self-healing electronic skins [65]. Self-healing can be either realized through external stimulation (viz. heat, light, or solvents) to activate the process or it can be an intrinsic property of the material. Leibler et al. showed the first demonstration of an insulating elastomer that can self-heal at room temperature [81]. The intrinsic self-healing process was accomplished by incorporating hydrogen bonds into the polymer matrix. After which Bao et al. developed the first conductive polymer that can intrinsically self-heal at room temperature, both electrically and mechanically [49]. The self-healing conductor is achieved by embedding nickel nanostructured microparticles in a supramolecular organic polymer (Figure 10.5a). Within few seconds, the skin regains 75% of its mechanical strength and electrical conductivity, and within 30 minutes, the artificial skin is fully restored [49]. A highly stretchable and self-healing actuating elastomer is further demonstrated by incorporating a network of complex crosslinks into the PDMS polymer chains, achieving high dielectric strength and mechanical actuation [82]. Hydrogel material has been recently engineered to incorporate self-healing properties due to its desirable soft and elastic yet tough bonding properties with the human skin [83]. Martin Kaltenbrunner and colleagues demonstrated a self-healing transparent E-skin incorporating ionic hydrogel conductors that can restore function instantly, while the multi-layered structure of the elastomer hybrids and ionic hydrogels can endure biaxial strain beyond 2000% [84] (Figure 10.5b).
Preoperative design of flap based on computer-aided design technology: morphological flattening and analysis of three-dimensional wound
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Xiaogang Ji, Yuhao Luan, Hao Gong, Yushun Duan, Jianan Zhang, Lin Deng
At present, flap transplantation is the most common and effective method to repair soft tissue defects and to cover the wound. The process involves cutting the flap from the leg and back of the patient or from artificial skin through the design of the preoperative scheme, followed by suturing. Fiakos et al. (2020) introduced the use of decellularized fish skin as an inexpensive and effective alternative for wound repair, which has been widely used in clinical practice. Sasaki et al. (2021) found that the use of gradation skin grafts, including the gradational boundary belt of the plantar instep area, is more effective than traditional flap grafting, but it still needs to be compared with local flaps. Without fascial and skin graft transplantation, Wang et al. (2020) obtained satisfactory results with a natural outline using tissue expansion for total auricular reconstruction.
Development of chitosan/gelatin hydrogels incorporation of biphasic calcium phosphate nanoparticles for bone tissue engineering
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Lei Nie, Qiaoyun Wu, Haiyue Long, Kehui Hu, Pei Li, Can Wang, Meng Sun, Jing Dong, Xiaoyan Wei, Jinping Suo, Dangling Hua, Shiliang Liu, Hongyu Yuan, Shoufeng Yang
Gelatin was a partial derivative of collagen, also as a denatured biopolymer, which was selected as a scaffolding material could circumvent the concerns of immunogenicity and pathogen transmission associated with chitosan, collagen, etc [37–39]. Furthermore, some retained information signals in gelatin, such as the Arg–Gly–Asp (RGD) sequence, might promote cell adhesion, differentiation, and proliferation [40]. Due to the higher solubility and lower cost when compared with collagen, gelatin has been applied for artificial skin, bone-related scaffolds construction [3]. The three-dimensional porous chitosan-gelatin scaffold could be fabricated by polyelectrolyte complex formation, freeze-drying and post-glutaraldehyde cross-linking, and so on, at the same time, the growth factors and localized controlled release carrier could be entrapped [41–43]. It was confirmed that the chitosan-gelatin composited with nanosized bioactive particles, the mechanical performances of composite scaffold could be regulated by controlled size and colloidal stability [44]. Some results showed CaPs nanoparticles, such as β-TCP, incorporated into chitosan-gelatin, the obtained scaffolds were bioactive and biocompatible, which allowed cell internalization [45].
The role of quantitative information about slip and grip force in prosthetic grasp stability
Published in Advanced Robotics, 2018
Dana D. Damian, Marco Fischer, Alexandro Hernandez Arieta, Rolf Pfeifer
The schematics of the experimental setup are depicted in Figure 1. An object’s slip speed and a user’s grip force information related to the grasp of a slipping object on an artificial skin mounted on a robot hand are displayed virtually to a user that controls the grasp through a joystick. The main components of the experimental setup are shown in Figure 4. A robot hand (specifications in [43,44]) was fixed on a wooden frame such that its palm was at an angle of with respect to the floor of the frame (Figure 4(A)). The robot hand was used as a ramp surface for the slipping object and was not actuated during experiments in order to avoid factors that do not contribute to testing our hypothesis. The robot hand was equipped with an artificial ridged skin (Figure 4(B)) whose design and functionality are a simplified version of the skins described in [15,40]. The artificial skin was built using a two-compound silicone, Neukasil RTV 28 and Neukasil binder A140 (Swiss-Composite). The resulting silicone paste was solidified into a 3D mask built by rapid prototyping. The artificial skin featured uniformly distributed ridges that are 10 mm apart. The transversal shape of the ridge is an equilateral triangle with a side of 6 mm (Figure 4(C)). The artificial ridged skin had a length of 90 mm and width of 40 mm, suitable for the robot hand’s palm. Underneath the silicone patch, one single force sensor, FSR (Interlink Electronics), acquired the contact force values as the object slid over the ridges. The signals from the FSR sensor were collected by a DAQ system (National Instruments) at 400 Hz and input to a PC running Ubuntu OS for real-time processing.