Harnessing Nature: Growing Batteries and Solar Cells with Viruses

Imagine a world where batteries and solar cells grow in a lab, self-assembling with the precision of a seashell. This isn't science fiction; it's the groundbreaking work of researchers who are learning to harness the power of nature at the nanoscale.

Nature's Blueprint: The Abalone Shell

The abalone shell, a marvel of natural engineering, is composed of 98% calcium carbonate and 2% protein. Yet, it's 3,000 times tougher than its geological counterpart, chalk. The secret lies in its nanoscale structure, meticulously built by proteins encoded in its DNA. This inspires the question: Could we imbue non-living structures, like batteries and solar cells, with similar capabilities?

The vision is to create materials at room temperature and pressure, using non-toxic chemicals, without harming the environment. What if a battery could evolve and improve over time, guided by its own genetic information?

Genetic Instructions: Diatoms and Beyond

Consider diatoms, glass-like structures that replicate and pass on the genetic information to build perfectly nanostructured glass in the ocean. This raises an exciting possibility: could we program solar cells or batteries with similar genetic instructions?

Instead of complex organisms, scientists are turning to simpler life forms like bacteria and viruses. The goal is to equip them with a new toolbox, enabling them to construct structures with practical applications.

The Cambrian Explosion: A Lesson in Material Science

Life on Earth took a billion years to emerge, rapidly evolving into multicellular organisms capable of replication and photosynthesis. However, it wasn't until the Cambrian period, about 500 million years ago, that organisms began creating hard materials. This era saw an increase in calcium, iron, and silicon in the environment, prompting organisms to develop the ability to build hard structures. The challenge now is to convince biology to work with the entire periodic table.

Nature's Nanostructures: A Ready-Made Toolkit

Nature already provides exquisite nanostructures like DNA, antibodies, proteins, and ribosomes. The challenge is to harness these structures and redirect their function. Instead of fighting diseases, could they be engineered to build solar cells?

Directed Evolution: Guiding Viruses to Build

The abalone shell's strength comes from negatively charged proteins that extract calcium from the environment, laying down layers of calcium and carbonate. These proteins have specific amino acid sequences dictated by DNA. The idea is to find the DNA sequence that codes for a protein sequence capable of building any structure from any element on the periodic table.

Accelerating Evolution: From Millions of Years to the Lab

Nature took 50 million years to perfect the abalone shell. To accelerate this process, scientists use a non-toxic virus called M13 bacteriophage. This virus infects bacteria and has a simple DNA structure that can be modified. By inserting additional DNA sequences, the virus expresses random protein sequences. This process can be repeated billions of times, creating a vast library of viruses, each with a slightly different protein sequence.

By exposing these viruses to different materials, researchers can select for those that interact in desired ways, such as growing a battery or a solar cell. Once a promising virus is identified, it's infected into bacteria to create millions of copies.

Building Batteries and Splitting Water with Viruses

Viruses can be engineered to grow semiconductors or battery materials. One example is a high-powered battery where viruses pick up carbon nanotubes and grow an electrode material, wiring themselves to the current collector. Through directed evolution, researchers have created record-breaking high-powered batteries at room temperature.

Harnessing Sunlight: Virus-Based Photocatalysis

Viruses can also be used for photocatalysis, splitting water into hydrogen and oxygen for clean fuel. By engineering viruses to absorb light and grow inorganic materials, researchers can create nanowires that generate oxygen bubbles when exposed to light.

Enhancing Solar Cells: Virus-Carbon Nanotube Complexes

In solar cells, viruses can pick up carbon nanotubes and grow titanium dioxide around them, improving electron transport. Genetic engineering has led to record efficiencies in these types of solar cells.

The Future of Materials Science

By understanding how nature makes materials and harnessing biological systems, we can create new materials with unprecedented properties. This approach opens up exciting possibilities for clean energy, sustainable manufacturing, and a future where technology works in harmony with the environment.

Key Takeaways:

• Nature provides inspiration and tools for advanced materials science.
• Viruses can be programmed to build batteries, solar cells, and catalysts.
• Directed evolution accelerates the development of new materials.
• Biomimicry offers a sustainable and environmentally friendly approach to technology.