Engineered artificial skins:Current construction strategies and applications

Skin damage resulting from burns,injuries,or diseases can lead to significant functional and esthetic deficits.However,traditional treatments,such as skin grafting,have limitations including limited donor skin availability,poor aesthetics,and functional impairment.Skin tissue engineering provides a promising alternative,with engineered artificial skins offering a highly viable avenue.Engineered artificial skin is designed to mimic or replace the functions of natural human skin and find applications in various medical treatments,particularly for severe burns,chronic wounds,and other skin injuries or defects.These artificial skins aim to promote wound healing,provide temporary coverage,permanent skin replacement,and restore the skin’s barrier function.Artificial skins have diverse applications in medicine and wound care,addressing burns,chronic wounds,and traumatic injuries.They also serve as valuable tools for research in tissue engineering,offering experimental models for studying wound healing mechanisms,testing new biomaterials,and exploring innovative approaches to skin regeneration.This review provides an overview of current construction strategies for engineered artificial skin,including cell sources,biomaterials,and construction techniques.It further explores the primary application areas and future prospects of artificial skin,highlighting their potential to revolutionize skin reconstruction and advance the field of regenerative medicine.

An anti-freezing biomineral hydrogel of high strain sensitivity for artificial skin applications

Mineral hydrogels have caught a lot of attention for their strong competency as artificial skin-like materials.Nonetheless,it remains a great difficulty in fulfilling in one hydrogel system a range of key functionalities that are needed for practical artificial skin applications,i.e.,to be biocompatible,strain-sensitive,ion-conductive,elastic and robust,anti-swelling,and anti-freezing.Here we present a such type of versatile hydrogel that is not only capable to deliver all the above-mentioned key functionalities but also highly stable.This novel hydrogel is constructed by introducing a gelatinous and amorphous multi-ionic biomineral(denoted as Mg-ACCP,containing Mg^(2+),Ca^(2+),CO_(3)^(2−),and PO_(4)^(3−))into the network of biocompatible polyvinyl alcohol(PVA)and sodium alginate(SA).The presence of Mg^(2+)and PO_(4)^(3−)in this hydrogel helps prohibit the crystallization of the biominerals,leading to significantly improved stability.The hydrogel thus obtained delivers excellent mechanical performance due to the chelation between the mineral ions and the organic matrix,and high sensitivity even to subtle pressure and strain applied,such as slight finger bending and gentle tapping.Furthermore,the novel hydrogel features high ionic conductivity,high resistance to swelling,and extraordinary anti-freezing property,holding great promise for applications in different practical scenarios,particularly in aqueous or cold environments.

Development of Novel Magnetic Responsive Intelligent Fluid, Hybrid Fluid (HF), for Production of Soft and Tactile Rubber

For the purpose of the replacement of Magnetic Fluid (MF) which is effective in the production of an artificial soft and tactile skin for the robot, etc. by utilizing a rubber solidification method with electrolytic polymerization, we proposed a novel magnetic responsive intelligent fluid, Hybrid Fluid (HF). HF is structured with water, kerosene, silicon oil having Polydimethylsiloxane (PDMS) and Polyvinyl Alcohol (PVA) as well as magnetic particles and surfactant. The state of HF changes as jelly or fluid by their rates of the constituents and motion style. In the present paper, we presented the characteristics of HF: the viscosity and the magnetization are respectively equivalent to those of other magnetic responsive fluids, MF and their solvents. For the structure, HF is soluble simultaneously with both diene and non-diene rubbers. The diene rubber such as Natural Rubber (NR) or Chloroprene (CR) has a role in the feasibility of electrolytic polymerization and the non-diene rubber such as silicon oil rubber (Q) has a role in defense against deterioration. Therefore, the electrolytically polymerized HF rubber by mixing NR, CR as well as Q is effective for the artificial soft and tactile skin. It is responsive to pressure and has optimal property on piezoelectricity in the case of the mixture of Ni particles as filler. HF is effective in the production of the artificial soft and tactile skin made of rubber.

Conservative Surgery for Subungual Melanoma In Situ Using Matriderm^(■)

Background: Standard treatment for subungual melanoma is wide local excision including digit amputation in order to obtain safety margins. Level of amputation has been discussed in order to achieve appropriate oncological results along with preservation of limb function wherein local excision of subungual melanoma in situ without amputation is an option. Methods: We report two cases of subungual melanoma in situ treated by using a conservative approach. Both cases were treated with local excision with the resected tumor defect covered with an artificial dermis, Matriderm?. One case was of a 65-year-old male with a left thumb subungual melanoma in situ and another of a 41-year-old female with the same type of melanoma in the left hallux. Full-thickness skin graft was used for reconstruction after 7 weeks from the first surgery in the latter, and in the former case re-epithelization occurred within 90 days after surgery. To date, no clinical signs of recurrence have been found, and finger/toe functions were completely preserved with a minimized scar and little graft bed sensitivity. Follow-up time is two years and ten months for the left thumb case, and one year and six months for the left hallux subungual melanoma in situ. Conclusion: We present two cases of subungual melanoma in situ treated with digit sparing surgery including excision of the periosteum followed by the use of an artificial dermal template to guarantee coverage of the tumor bed defect, providing good functional and cosmetic outcome.

Intrinsically stretchable polymer semiconductor based electronic skin for multiple perceptions of force,temperature,and visible light

As a stretchable seamless device,electronic skin(E-skin)has drawn enormous interest due to its skin-like sensing capability.Besides the basic perception of force and temperature,multiple perception that is beyond existing functions of human skin is becoming an important direction for E-skin developments.However,the present E-skins for multiple perceptions mainly rely on different sensing materials and heterogeneous integration,resulting in a complex device structure.Additionally,their stretchability is usually achieved by the complicated microstructure design of rigid materials.Here,we report an intrinsically stretchable polymer semiconductor based E-skin with a simple structure for multiple perceptions of force,temperature,and visible light.The E-skin is on the basis of poly(3-hexylthiophene)(P3HT)nanofibers percolated polydimethylsiloxane(PDMS)composite polymer semiconductor,which is fabricated by a facile solution method.The E-skin shows reliable sensing capabilities when it is used to perceive strain,pressure,temperature,and visible light.Based on the E-skin,an intelligent robotic hand sensing and controlling system is further demonstrated.Compared with conventional E-skins for multiple perceptions,this E-skin only has a simple monolayer sensing membrane without the need of combining different sensing materials,heterogeneous integration,and complicated microstructure design.Such a strategy of utilizing intrinsically stretchable polymer semiconductor to create simple structured E-skin for multiple perceptions will promote the development of E-skins in a broad application scenario,such as artificial robotic skins,virtual reality,intelligent gloves,and biointegrated electronics.

Post-burn breast reconstruction using an artificial dermis—a long-term follow-up

Background:Full thickness burns of the chest in childhood are a devastating problem that requires challenging reconstructive options.Integra is a bilaminate artificial dermis composed of shark chondroitin 6-sulfate and bovine collagen.The dermal matrix serves as a scaffold for fibroblasts and endothelial cells.Vascularization of the matrix begins after 2-3 weeks,and eventually,the matrix incorporates with the tissue to create a new dermis.The main advantage of the Integra is that the neodermis is of the same quality as a native dermis.Case presentation:In this case report,we present post-burn breast reconstruction of a 12-year-old girl using Integra,with a long follow-up of 7 years.To the best of our knowledge,there is no published follow-up of breast development after reconstruction with Integra from its beginning point at the age of puberty until after the growing process has terminated.Conclusions:Integra is a reliable reconstructive tool for burned breast.If done before puberty,it can help in getting normal developing tissue with satisfying esthetic results of size,shape and symmetry.

Biomechanical properties of four dermal substitutes

Many kinds of cell-free dermal substitutes have been developed during the past several years, however,their biomechanical properties, including hysteresis, stress relaxation, creep, and non-linear stress-strain, are still unknown. In this study, we tested these biomechanical characteristics of four dermal substitutes, and compared them with those of fresh human skin （FHS）.