Reviewed by Lexie CornerMay 8 2025
Imagine concrete that heals itself like human skin. That’s the vision behind Dr. Congrui Grace Jin’s latest research, which was recently published in Materials Today Communications.
Jin, an assistant professor in the Department of Engineering Technology and Industrial Distribution, has taken inspiration from nature to develop a synthetic lichen system that enables concrete to self-repair, potentially solving one of construction’s most costly and persistent challenges.
Concrete is the most widely used building material in the world, yet it cracks easily—a flaw that can lead to serious structural issues. Even small, seemingly harmless fissures can eventually cause catastrophic failures, as seen in the collapse of buildings, bridges, and highways.
The key to addressing this vulnerability is understanding how concrete forms and using that knowledge to intervene. Concrete is made by combining powdered clay, limestone, crushed stone, and sand. When water is added, a chemical reaction called hydration causes the mixture to harden.
Once cured, it becomes strong enough to support everything from multi-story buildings to heavy freight traffic. But over time, factors like drying shrinkage, freeze-thaw cycles, and heavy loads cause it to crack. Even hairline fractures allow moisture and air to reach the steel reinforcements inside, leading to corrosion and structural degradation.
Detecting and repairing these cracks before they become dangerous is a major logistical and financial challenge. The U.S. alone spends tens of billions of dollars annually to maintain concrete infrastructure. Monitoring active roads and bridges is especially complex, adding urgency to the need for a better solution.
Microbe-mediated self-healing concrete has been extensively investigated for more than three decades, but it still suffers from one important limitation—none of the current self-healing approaches are fully autonomous since they require an external supply of nutrients for the healing agents to continuously produce repair materials.
Dr. Congrui Grace Jin, Assistant Professor, Department of Engineering Technology and Industrial Distribution, Texas A&M University
For example, even after the time-consuming process of detecting a crack, inspectors may still need to inject or spray nutrients into it—an impractical and labor-intensive task.
Jin’s solution? Use the power of lichen systems to allow concrete to heal itself without external intervention.
Lichen, often seen clinging to trees and rocks, is a quiet presence in everyday life. Its true resilience comes from its unique symbiotic relationship between fungi and algae—specifically cyanobacteria—which form a self-sustaining alliance that enables survival in extreme environments.
With support from DARPA’s Young Faculty Award program, Jin and her collaborators (Dr. Richard Wilson, Nisha Rokaya, and Erin Carr from the University of Nebraska–Lincoln) set out to create a synthetic lichen system that mimics this natural partnership.
Their system uses cyanobacteria, which produce food from air and sunlight, and filamentous fungi, which generate minerals to fill cracks. Together, these microbes survive on nothing more than air, light, and water. This autonomous approach sets the system apart from previous self-healing concrete technologies.
In lab tests, the microbial pairs successfully grew and produced crack-filling minerals, even under the harsh conditions of a concrete environment.
Jin is also expanding her research to explore broader implications. She is collaborating with faculty from Texas A&M University’s social sciences departments to better understand public perceptions of using living organisms in construction, along with the ethical, social, environmental, and legal questions such approaches raise.
This innovative research holds significant potential. Self-healing concrete could dramatically reduce maintenance costs, extend infrastructure lifespan, and even save lives by improving structural safety. It could also play a key role in sustainable construction efforts, including applications in space infrastructure.
Journal Reference:
Rokaya, N., et al. (2025). Design of Co-culturing system of diazotrophic cyanobacteria and filamentous fungi for potential application in self-healing concrete. Materials Today Communications. doi.org/10.1016/j.mtcomm.2025.112093