The Transformative Power of Nanomaterials

Nanomaterials (the prefix “nano” derives from the Greek ν?νος (Latin nanus), meaning "dwarf") are referred to materials with a size between 1 and 100 nanometer (nm). To help envision 1 nm (10-9 m or one billionth of a meter), think of a human hair (80,000–100,000 nm wide) or a sheet of paper (about 100,000 nm thick).  The power of nanomaterials is derived from this nanoscopic scale, where they can have different chemical and physical properties depending on their size. 

To harness this superpower, scientists have had to learn how to make, characterize, and apply nanomaterials with control and precision at the atomic level. 

A brief history of nanomaterials

Nanomaterials have been abundant on Earth since its formation. They are all around us and part of us: from the subcellular machinery of every cell (e.g., the ribosome) to the dirt-repelling surfaces of lotus flowers and the inorganic nanomaterials spewed by volcanoes, nanomaterials are continuously forming through physical, chemical, and biological processes. Early examples of people synthesizing and applying nanomaterials have been recorded since the fourth century. Fast forward to 1959, the American physicist and Nobel Prize laureate Richard Feynman, PhD, laid the foundation for the field of nanomaterials application (called nanotechnology) in his famous lecture “There's Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics,” where he challenged the scientific community to think about this tiny world and suggested that we would soon able to store the entire 24 volumes of the Encyclopedia Britannica on the head of a pin. In 1974, Japanese scientist Norio Taniguchi first defined the term nanotechnology as "the processing of separation, consolidation, and deformation of materials by one atom or one molecule." After four Nobel Prices revolving around nanomaterials (1996, 2016, and 2019 in chemistry and 2010 in physics), , precisely constructing materials at the nanoscale is ubiquitous—nanomaterials continue to revolutionize our lives by enabling the next generation of energy and health systems.

Nanomaterials in energy

“When we talk about the application of nanomaterials in the energy sector, two areas are energy capture from renewable sources and storage of that energy until needed. Good examples include the generation of what is called ‘green hydrogen’, and of course batteries,” says Jillian Buriak, PhD, emeritus professor of chemistry at the University of Alberta, and executive editor at ACS Nano. “I’ll use the analogy of herding cats: it takes exquisite control of a material at the nanoscale to, for instance, capture light from the sun within a solar panel and then efficiently move and store those electrons to where you would like to use them.” 

Nanomaterials continue to revolutionize our lives by enabling the next generation of energy and health systems.

Green hydrogen is an approach to storing energy derived from renewable sources as a fuel. Hydrogen is clean burning fuel as it generates only water upon combustion and is one of the projected paths to the net-zero emission future. The “green” means that this fuel is created by electrolysis—using electricity derived from clean energy sources to split water into its atomic constituents, hydrogen and oxygen gas. This reaction takes place in an electrolyzer, where platinum is commonly used as a catalyst to increase reaction efficiency by minimizing the kinetic energy barrier to the reaction, called the overpotential. However, platinum is expensive, and when these catalysts are prepared in traditional ways, they are not sufficiently efficient to be commercially viable. To overcome this barrier, researchers have been using nanomaterials in a number of creative ways—for example, by creating catalysts with more highly engineered platinum nanomaterials at a lower cost or by eliminating the costly electrolyzer setup altogether. 

In February 2023, SunHydrogen, Inc., an Iowa-based company, unveiled the world’s largest first-ever nanomaterial-based green hydrogen generator—a solar hydrogen panel that directly uses electrical charges created by sunlight to generate hydrogen. How? Inspired by the process of photosynthesis, the SunHydrogen team created nanoparticles called photoelectrosynthetically active heterostructures, where each nanoparticle is comprised of multiple layers enabling the solar electrolysis reaction, and then bundled them into panels. Think solar panels, but instead of electricity, they produce hydrogen fuel. Like solar panels, they are integrated with renewable grid electricity enabling their operation 24/7 when the sun is not shining locally. This breakthrough brings us a step closer to economical mass-produced green hydrogen—think solar hydrogen farms where the next question would be safe hydrogen storage and transportation. And nanomaterials are on it too.

When it comes to the world of electronics, rechargeable batteries are critical components for small portable devices as well as grid-scale buffering and storage. Nanomaterials are the focus of enormous attention globally and are the key to improving the performance, stability, and safety of conventional lithium-based batteries. Next-generation batteries promise to go “beyond lithium-ion” with higher levels of safety, longer lifespans, and lower costs, which may enable large-scale decarbonization of our energy grid and heavy-duty transportation—elements crucial for meeting the United Nations's net-zero emissions goal by 2050.

Nanomaterials for human health

The biochemistry of life is built upon self-assembled structures at the nanoscale, from viruses and DNA to the complex architecture in chloroplasts that enable photosynthesis in plants, to name a few. Breakthroughs in the areas of human, animal, and plant health are now benefitting from integrating established clinical tools with nanomaterials and devices that operate at the same scale. Together, they can not only diagnose but also treat disease. For example, promising theranostic tools, which combine diagnosis and treatment,  can identify cancer and a host of other diseases and then be harnessed to eliminate/treat them in a noninvasive manner. 

Compared to conventional treatments of chemotherapy, invasive surgery, and radiation therapy, nanomaterials can specifically target the delivery of drugs to the desired tissue, thus improving efficacy and reducing side effects while providing unintrusive real-time monitoring as a part of the standard repertoire of medical imaging technologies (e.g., MRI and PET). A great example of the success of nanomaterials in the field of theranostics has been demonstrated by Naomi Halas, PhD, Stanley C. Moore professor in electrical and computer engineering at Rice University, who has invented nanomaterials that can absorb red light that passes harmlessly through the body and convert this light into a localized heat that can destroy tumors with minimal damage to surrounding healthy tissue. These nanomaterials have been commercialized by Nanospectra Biosciences, Inc., a Houston-based company that has demonstrated the safety and efficacy of these nanomaterials in a four-year clinical trial for prostate cancer—the most common cancer in men in the US.

Although nanomaterials have already experienced great success in disease prevention and treatment, their therapeutic potential is yet to be vastly explored...

Over the past few years, nanomaterials have also been used to develop vaccines for SARS-CoV-2, the virus that causes COVID-19. Nanomaterials lowered the probability of severe outcomes (~95 percent efficacy in Phase 3 clinical trials) of the Pfizer-BioNTech and Moderna vaccines. A key piece of these mRNA-based vaccines is based upon lipid-based nanoparticles that stabilize and carry mRNA into intramuscular sites where it would slowly be released to interact with the immune system. These tiny fat-based nanocapsules needed to be precisely tailored to bind the mRNA biomolecule and then deliver as needed.

Although nanomaterials have already helped improve disease prevention and treatment, their vast therapeutic potential is yet to be explored. 

As Steve Edwards, a biologist and the author of The Nanotech Pioneers, writes: “There is something god-like about manipulating matter at its most basic level.” Indeed, the journey of developing and applying nanomaterials has been wondrous, transforming our lives with next-generation energy storage devices and precision therapeutics. And they promise to continue pushing the boundaries of science, technology, and human life.