"The ability to replicate the sense of touch and integrate it into a variety of technologies opens up new possibilities for human-computer interaction and advanced sensory experiences that have the potential to revolutionize the industry and improve the quality of life for people with disabilities," said Dr. Akhilesh Gaharwar, professor and director of research at the Department of Biomedical Engineering.
The lead authors of the paper are Kaivalya Deo, a former student of Dr. Gaharwar and now a scientist at Axent Biosciences, and Shounak Roy, a former Fulbright Nehru researcher in Gaharwar's lab.
The challenge in the manufacture of electronic skin is to develop materials that are both durable and mimic the flexibility of human skin, incorporate bioelectric sensing capabilities, and are suitable for wearable or implantable devices. "In the past, the stiffness of these systems was too high for our body tissues, hindering signal transduction and creating mechanical mismatches at the bio-abiotic interface," Deo said. Researchers have successfully addressed one of the key limitations in the field of flexible bioelectronics by introducing a "triple crosslinking" strategy in a hydrogel-based system.
The use of nanoengineered hydrogels solves some of the challenges in the process of 3D printing electronic skin. The hydrogel is able to reduce viscosity under shear stress during the e-skin creation process, making it easier to handle and manipulate. The team says this feature helps build complex 2D and 3D electronic structures, an important aspect of replicating the multifaceted nature of human skin.
The researchers also used "atomic defects" in molybdenum disulfide nanocomponents (a material with defects in its atomic structure that allow for high electrical conductivity) and polydopamine nanoparticles to help the electronic skin adhere to wet tissue.
Roy explains: "These specially designed molybdenum disulfide nanoparticles act as a crosslinking agent, form a hydrogel, and give the electronic skin electrical and thermal conductivity. We are the first to report using it as a key ingredient, and the material's ability to adhere to wet tissue is particularly important for potential healthcare applications, as electronic skin needs to conform to and adhere to dynamic, wet biological surfaces."
Other collaborators include researchers from Dr. Limei Tian's group in the Department of Biomedical Engineering at Texas A&M University and Dr. Amit Jaiswal of the Mandi Institute of Technology in India.
Future applications for e-skin are broad, including wearable health devices that can continuously monitor vital signs such as movement, body temperature, heart rate and blood pressure. These devices will provide feedback to users and assist them in improving motor skills and coordination