From Shiitake to Honey: The Rise of Organic Memristors
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A new wave of research is exploring unconventional materials – from fungi and honey to even human blood – to create the next generation of electronic components, offering potential benefits in sustainability, flexibility, and specialized applications.
The world of electronics is built on materials meticulously engineered for their conductive and insulative properties. But what if the key to the future of computing lay not in synthetic compounds, but in the natural world around us? Researchers are increasingly discovering that everyday substances possess a hidden talent: the ability to function as memristors, electrical components that “remember” past states and are crucial for both data storage and computation.
Traditional memristors are constructed from materials like titanium dioxide, but a growing body of work suggests organic alternatives could offer unique advantages. These include increased flexibility, biodegradability, and, surprisingly, resilience in harsh environments.
The Mushroom Revolution: Shiitake as a Radiation-Resistant Component
Last month, a team at The Ohio State University made headlines by demonstrating that shiitake mushrooms can, in fact, act as memristors. The project, which one researcher playfully described as having “really mushroomed into something cool,” began as an attempt to find a biological proxy for brain circuitry in electrical stimulation research.
The team cultivated shiitake mushrooms, carefully controlling their growing conditions with a diet of farro, wheat, and hay. Once matured, the mushrooms were dried and rehydrated to achieve a conductive state. Tests revealed that the fungi’s internal structure mimics the oxygen vacancies found in conventional memristors, allowing them to effectively “remember” electrical signals up to 5.85 kilohertz – a notable performance for a biological material.
While not yet competitive with the speeds of traditional materials, shiitake mushrooms offer a compelling benefit: exceptional radiation resistance. “They’re growing in logs in Fukushima and a lot of very rough parts of the world, so that’s one of the appeals,” explained a lead researcher. This characteristic positions mushroom-based memristors as potential candidates for applications in aerospace and medical technology, where exposure to radiation is a significant concern. Furthermore, the existing commercial infrastructure for mushroom cultivation could streamline potential manufacturing. “One could simply leverage existing logistics chains,” the researcher noted, suggesting a relatively straightforward path to commercialization, albeit for niche applications.
A Sweet Solution: Honey’s Biodegradable Potential
Beyond fungi, researchers are exploring the potential of honey as a sustainable alternative in electronics. In 2022, engineers at Washington State University investigated honey’s viability as a biodegradable memristor, motivated by the staggering amount of e-waste generated annually – 50 million tons, with only 20% recycled.
Their process involved blending honey with water, removing air bubbles under vacuum, and spreading the mixture onto copper. After baking the stack at 90°C for nine hours and capping it with copper electrodes, they created a functional honey-based memristor. The honey layer acted as a dielectric, allowing for the formation and dissolution of conductive pathways with applied voltage.
The resulting device demonstrated switching speeds comparable to some existing non-food-based memristive materials, achieving transitions between low and high resistance in 500 nanoseconds and 100 nanoseconds, respectively. “Honey offers a biodegradable alternative,” stated Feng Zhao, who led the work. “It’s also cheap and widely available, making it an attractive candidate for scalable fabrication.” However, the researchers acknowledged that achieving full biodegradability requires replacing the copper electrodes with dissolvable metals like magnesium or tungsten, an area still under investigation.
The Cutting Edge: Exploring the Potential of Human Blood
The exploration of organic memristors extends to even more surprising territory: human blood. As early as 2011, a research group in India investigated whether blood could function as a memristor, driven by the potential for innovative healthcare applications.
Their experiments, while preliminary, involved applying voltages to blood samples and observing changes in resistance. They found that resistance could be set by applying voltage and remained relatively stable for at least 30 minutes after application, leading the scientists to conclude that their setup “looks like a human blood memristor.”
The researchers theorized that this technology could offer a novel approach to treating illnesses by addressing ion imbalances within the body using a circuit component made of the patient’s own tissue. Subsequent research has explored blood-based memristors for conditions ranging from high blood sugar to nearsightedness.
The development of organic memristors represents a paradigm shift in electronics, moving beyond traditional materials and embracing the potential of the natural world. While challenges remain in optimizing performance and scalability, the promise of sustainable, flexible, and specialized electronic components is driving continued innovation in this exciting field.
