Self-healable ionic sensing materials with fatigue resistance are imperative in robotics and soft electronics for extended service life. The existing artificial ionic skins with self-healing capacity were prepared by network reconfiguration, constituting low-energy amorphous polymer chains. Consequently, these materials suffer from a low fatigue threshold and are susceptible to crack propagation.
In an article published in the journal Nature Communications, a self-healable, fatigue-free hybrid ionic skin was engineered. Ruggedness was imparted by incorporating an elastic nanomesh that was a complex network of nanofibers. Thus, the engineered ionic skin mimicked the human skin with a repairable interwoven structure based on nanofibers.
The designed hybrid ionic skin exhibited a fatigue threshold of 2950 joules per square meter while conserving stretchability, skin-like compliance, and strain adaptive stiffening behavior. The nanofibers in the material endowed the ionic matrix with moisture breathing capacity due to the induced tension, leading to a gauge factor of 66.8, which was higher than the existing artificial ionic skins. The present concept created a new path toward durable ion-conducting materials that mimicked the incomparable combinatory properties of human skin.
Integrating Nanofibers into Artificial Skin
Human skin is a multifunctional organ that is self-healing and protective with good sensing capacity. Various artificial skins were developed based on the properties and functionalities approximating those of natural skin. To this end, stretchability, conductivity, toughness, softness, healing ability, and durability are desirable in designing materials for soft robotics and human-machine interface applications.
Although self-healing capacity in these materials permits a long service life, their resistance against crack propagation during high fatigue loads further begets robustness in them. Incorporating physical crosslinks into the ion-conducting network causes chain rearrangement leading to network reconfiguration.
The ion-rich nanofibrous yet repairable structure of human skin reconciles the interchange between fatigue resistance and healing capacity, defined by a soft interwoven elastic matrix enveloping the stiff collagen fibril scaffold. The healing of human skin is based on dermal fibroblasts and repairing the crack tip at the collagen nanofibrils imparting high fracture toughness. Thus, the human skin can withstand tear fractures and deformations like muscles.
Nanofibers have diameters between 1 nanometer and 1 micrometer and are made from synthetic or natural materials. Nanofibers are commonly obtained via the electrospinning technique and resemble the natural extracellular matrix (ECM). The polymer-based nanofibers have a large surface area-to-volume ratio, high porosity, appreciable mechanical strength, and flexibility.
These properties of nanofibers have a significant effect on cell adhesion, proliferation, and differentiation, as reported in previous studies. Hence matrices based on nanofibers are explored as scaffolds in tissue engineering.
Nanofiber Reinforced Artificial Ionic Skin
In the present work, a high-energy, elastic, and self-healable nanomesh scaffold was embedded into another self-healable soft ionic matrix to design an artificial sensing ionic skin. This hybrid structure showed high fracture energy of 16.3 kilojoules per square meter, fatigue threshold of 2950 joules per square meter, 680% stretchability, and 67.5 megapascals of strain-stiffening response.
The tension-induced rearrangement of nanofibers caused reversible moisture breathing of the hygroscopic ionic matrix and led to a gauge factor of 66.8 (higher than the existing artificial skin materials) for the ionic conductors that are intrinsically stretchable.
Moreover, such hybrid ionic skin based on nanofibers had a few intriguing properties that mimicked the natural human skin, including self-healing efficiency of up to 85%, modulus of approximately 1.8 megapascals, 37 times enhanced strain-adaptive stiffness, 0.11 siemens per centimeter of ionic conductivity, and superior strain sensation. The prepared hybrid ionic skin was adhesive, transparent, and ambiently stable.
Thus, the reported artificial ionic skin resembled the human skin in terms of sensing and mechanical properties and had potential applications in durable sensors for utilization in human-machine interfaces and wearable electronics.
Conclusion
To conclude, transparent hybrid ionic skin based on nanofibers was designed using elastic polyurethane (PU) nanomesh, composed of a network of nanofibers with self-healing capacity and a supramolecular ionic matrix with a high modulus ratio.
The hybrid ionic skin was endowed with desirable properties, including softness (modulus approximately 1.8 megapascals), self-healing capacity (up to 85%), stretchability (680%), fatigue resistance (approximately 2950 joules per square meters), and strain-adaptive stiffening (37 times enhanced stiffness).
The high gauge factor of 66.8, which is the strain-sensing parameter, was due to the induced tension that led to a rearrangement of nanofiber’s alignment resulting in a reversible moisture breathing effect in a hygroscopic ionic matrix driven by water-sensitive ionic complexations.
In concurrence with its adhesiveness, transparency, and stability at room temperature, the designed ionic skin demonstrated its potential as a durable sensor with high sensitivity and applicability in wearable electronics.
![](https://www.nanoappsmedical.com/wp-content/uploads/2017/05/spacer.jpg)
News
Ethics in Nanomedicine: Key Issues and Principles
Nanomedicine, a branch of nanotechnology, is revolutionizing healthcare by enabling the manipulation of materials at the nanoscale to diagnose, treat, and prevent diseases. Unlike traditional treatments, nanoparticles (NPs) are highly precise in targeting diseased [...]
A call for robust H5N1 influenza preparedness and response
As the global threat of H5N1 influenza looms with outbreaks across species and continents including the U.S., three international vaccine and public health experts say it is time to fully resource and support a [...]
Mucosal COVID-19 boosters outperform mRNA shots in preventing upper airway infections
In a recent study published in Nature Immunology, a team of researchers from the United States used non-human primate models to compare the protection conferred by an intramuscular booster dose of the bivalent messenger ribonucleic acid [...]
How Space Travel Really Changes Astronauts – From the Inside Out
International team reveals previously unknown effects on physiology that could shape the future of long-duration space missions. Researchers have discovered significant changes in the gut microbiome due to spaceflight, which affects host physiology and [...]
Breakthrough in blood stem cell development offers hope for leukemia and bone marrow failure
Melbourne researchers have made a world first breakthrough into creating blood stem cells that closely resemble those in the human body. And the discovery could soon lead to personalized treatments for children with leukemia [...]
Scientists Develop Game-Changing Needle-Free COVID-19 Intranasal Vaccine
A new mucosal COVID-19 vaccine poised to revolutionize the delivery process is especially beneficial for those with a fear of needles. A next-generation COVID-19 mucosal vaccine is set to be a game-changer not only when delivering [...]
Scientists Develop All-in-One Solution To Catch and Destroy “Forever Chemicals”
A new water treatment system developed by UBC researchers efficiently removes and destroys PFAS pollutants using a dual-action catalyst, offering a sustainable and cost-effective solution for water purification challenges. Chemical engineers at the University of [...]
New method accelerates drug discovery from years to months
Researchers from the University of Cincinnati College of Medicine and Cincinnati Children's Hospital have found a new method to increase both speed and success rates in drug discovery. The study, published Aug. 30 in [...]
A new smart mask analyzes your breath to monitor your health
Your breath can give away a lot about you. Each exhalation contains all sorts of compounds, including possible biomarkers for disease or lung conditions, that could give doctors a valuable insight into your health. [...]
Study reveals the role of blood clotting in COVID-19
In a study that reshapes what we know about COVID-19 and its most perplexing symptoms, scientists have discovered that the blood coagulation protein fibrin causes the unusual clotting and inflammation that have become hallmarks [...]
A Novel Cancer Vaccine Combining Nano-11 and ADU-S100
In a recent article published in npj Vaccines, researchers detailed the development of a novel cancer vaccine that combines a plant-derived nanoparticle adjuvant, Nano-11, with a clinically tested STING agonist, ADU-S100. The primary objective was [...]
AI spots cancer and viral infections with nanoscale precision
Researchers have developed an artificial intelligence which can differentiate cancer cells from normal cells, as well as detect the very early stages of viral infection inside cells. The findings, published today in a study [...]
Tiny shards of plastic are increasingly infiltrating our brains, study says
Human brain samples collected at autopsy in early 2024 contained more tiny shards of plastic than samples collected eight years prior, according to a preprint posted online in May. A preprint is a study which has not yet [...]
Scientists Have Discovered Strange DNA in Our Brains – and It Could Be Shortening Our Lives
According to the research, these mitochondrial DNA insertions could be linked to early death. Mitochondria in brain cells frequently insert their DNA into the nucleus, potentially impacting lifespan, as those with more insertions were found to [...]
Watch Out After a Hospital Stay: You Could Be Exposing Your Family to Superbugs
Research indicates hospitals contribute to the local spread of antibiotic-resistant infections. A recent study published in the journal Infection Control & Hospital Epidemiology by the Society for Healthcare Epidemiology of America suggests that family members of [...]
Molecular Trickery: How COVID-19 Silently Sabotages the Human Immune System
Researchers have discovered that SARS-CoV-2 manipulates the human immune system by forcing cells to produce non-functional proteins, hindering the body’s antiviral defenses. This groundbreaking study by teams from prestigious Brazilian universities highlights potential targets for new COVID-19 treatments, [...]