The University of California San Diego, in collaboration with researchers from the Scripps Institution of Oceanography and the University of Amsterdam, has made a significant breakthrough in the field of materials science. Led by Professor Shengqiang Cai, the team has successfully developed soft yet durable materials that illuminate when subjected to mechanical stress. This advancement has the potential to revolutionize various fields, including soft robotics and biomedical devices. Inspired by the bioluminescent waves observed during red tide events in San Diego, California, the researchers have harnessed the power of nature to create self-sustaining materials.
The primary components of these luminescent materials are single-celled algae called dinoflagellates and a seaweed-based polymer called alginate. By combining these elements in a solution and processing them with a 3D printer, the researchers were able to create a diverse array of shapes. The resulting 3D-printed structures were then cured, resulting in materials that glow in response to mechanical stress. Similar to the natural behavior of dinoflagellates in the ocean, which produce flashes of light as a defense mechanism against predators, these materials emit light when compressed, stretched, or twisted.
The researchers conducted extensive tests to evaluate the materials’ mechanical stress sensing capabilities. When subjected to compression or traced patterns on their surface, the materials exhibited a vibrant glow. Impressively, even the weight of a foam ball rolling on their surface was sufficient to activate their luminescence. The intensity of the glow was found to be directly proportional to the applied stress, enabling the researchers to develop a mathematical model for predicting the glow’s brightness.
To ensure the materials’ longevity and stability under various conditions, the researchers implemented several strategies. They reinforced the materials by adding a second polymer called poly(ethylene glycol) diacrylate to bear substantial mechanical loads. Additionally, coating the materials with a stretchy rubber-like polymer called Ecoflex provided protection against acidic and basic solutions. As a result, the materials retained their form and bioluminescent properties even after being stored in seawater for up to five months. These enhancements make the materials suitable for long-term use in practical applications.
Another remarkable characteristic of these materials is their minimal maintenance requirements. The dinoflagellates within the materials rely on periodic cycles of light and darkness to sustain their functionality. During the light phase, the dinoflagellates photosynthesize, producing food and energy. In turn, these resources are utilized during the dark phase to emit light when subjected to mechanical stress. This self-sustaining behavior mirrors the natural processes that occur during red tide events in the ocean.
The potential applications for these luminescent materials are vast. One significant possibility is their use as mechanical sensors for measuring pressure, strain, or stress. The materials’ ability to emit light in response to mechanical stimuli makes them ideal for such applications. Additionally, these materials can be utilized in soft robotics, where light signals are utilized for controlled movement and interaction. In the field of biomedical devices, the materials could play a pivotal role in treatment or controlled drug release, employing light signals to activate specific actions.
The research team acknowledges that there is still much work to be done before the full potential of these materials can be harnessed. Ongoing efforts are focused on further improving and optimizing the materials to enhance their sensing capabilities and durability. With continued research and development, these soft yet durable materials have the potential to revolutionize several industries and pave the way for new scientific advancements.
The University of California San Diego’s groundbreaking research in developing luminescent materials that respond to mechanical stress represents a significant stride in materials science. Inspired by the natural bioluminescent waves observed during red tide events, the researchers have successfully harnessed the power of nature to create self-sustaining materials. Combining dinoflagellates and alginate in a solution and processing them with a 3D printer has led to the creation of soft yet durable materials that glow in response to compression, stretching, or twisting. These materials hold immense potential for various applications, including mechanical sensors, soft robotics, and biomedical devices. With further advancements and optimization, these luminescent materials may soon become an integral part of technological innovation.