Researchers have developed lifelike, skin-like models using Ecoflex, a type of silicone rubber, which could be utilized to assess the risks of bacterial infections associated with intravenous catheters and evaluate wearable sensors, among other medical functions.
In the festive film “The Grinch,” it’s said that makeup artists dedicated hours each day to covering Jim Carrey’s face with prosthetics to transform him into the beloved, grouchy green character. The intricate use of prosthetics, often achieved with materials such as silicone rubbers, may have unexpectedly led to a significant advancement in biomedical engineering, as reported by a new study from Texas A&M University.
A research article published in the journal Scientific Reports reveals that the team has crafted realistic, skin-like replicas using Ecoflex, a silicone rubber that provides a promising platform to examine the risk of bacterial infections from intravenous catheters as well as to test wearable sensors and other biomedical uses. The findings indicate that EcoFlex-based skin models can be designed to imitate the textures, moisture levels, and elasticity of actual skin, effectively simulating the environments where bacteria thrive and attach.
“We believe that this material has great potential for exploring infections at catheter insertion sites due to naturally occurring skin bacteria,” stated Majed Othman Althumayri, a graduate student in the Texas A&M Biomedical Engineering Department and the lead author of the study. “Our aim was to develop a skin-like substance using easily accessible ingredients. Ecoflex is not only user-friendly but also cures quickly with minimal additional procedures, making it quite convenient.”
Human skin is home to approximately one million bacteria per square centimeter, with Staphylococcus being the most prevalent, particularly Staphylococcus epidermidis, a common inhabitant of the skin microbiome. Infections are likely to occur when there is a cut or wound on the skin, allowing bacteria to infiltrate the bloodstream. A notable source of infection in hospitals stems from the surgical placement of tubes or catheters into veins. Annually, around 80,000 catheter-related bloodstream infections occur in intensive care units alone, highlighting its critical public health impact in the U.S.
“We have made slow progress in finding solutions to prevent infections from intravenous catheters,” Althumayri explained. “One reason might be our lack of suitable platforms for testing new catheter designs, wearable biosensor technologies, and staff training, which could help reduce infection rates.”
To fill this gap, the researchers utilized Ecoflex 00-35, a quick-curing, biocompatible rubber commonly used in various applications, including special effects prosthetics. They first created molds of typical intravenous insertion sites, such as the elbow, hand, and forearm. By pouring Ecoflex into these molds, along with artificial bones and tubing to represent veins, they successfully produced skin-like models.
The next phase involved verifying whether the Ecoflex skin replicas had characteristics similar to actual human skin. The team assessed properties like wettability, bacterial adhesion, and mechanical features such as elasticity and resilience. They discovered that the Ecoflex models could accurately replicate human skin roughness with just a 7.5% margin of error, and high-resolution imaging confirmed that bacteria could adhere to and proliferate on the skin replica.
In a pivotal experiment, the researchers simulated inserting an intravenous catheter into their Ecoflex hand model. This artificial hand effectively represented stages of bacterial growth, suggesting that these replicas could be useful for implementing infection control strategies and refining the design of medical devices like catheters.
However, the researchers acknowledged that their current experiments do not fully replicate real-world conditions.
“Creating realistic skin models that resemble human skin is a crucial first step,” said Dr. Hatice Ceylan Koydemir, the study’s corresponding author and an assistant professor in the Department of Biomedical Engineering at Texas A&M University. “We believe that integrating additional components, such as bodily fluids and other clinically relevant factors, in future experiments will enhance our findings and further validate Ecoflex’s medical potential.”
Other research contributors included Azra Yaprak Tarman, a graduate student in the Biomedical Engineering Department.
This study was supported in part by the National Institute of General Medical Sciences (a component of the National Institutes of Health), the Department of Defense Office of Naval Research, and the Engineering Research Center PATHS-UP funded by the National Science Foundation. Additional support came from the Department of Biomedical Engineering, the Center for Remote Health Technologies and Systems, the Texas A&M Engineering Experiment Station, the AggieFab Nanofabrication Facility, and the Soft Matter Facility.
