New Study Reveals Detrimental Effects of Nanoparticles on Plant Photosynthesis

A recent study led by researchers at the University of California, Riverside (UCR) has unveiled significant findings regarding the interaction between nanoparticles and plant cells, highlighting how these tiny particles, which can originate from both natural and anthropogenic sources, adversely affect plants' ability to perform photosynthesis. The study, published in *Nature Nanotechnology* on June 18, 2025, indicates that these nanoparticles can undergo transformations upon entering plant cells, which ultimately weakens the plants' capability to convert sunlight into food.

Nanoparticles are minuscule particles that can be produced through various processes, including engine combustion, industrial activities, and natural events such as forest fires and volcanic eruptions. These particles, often thousands of times smaller than the width of a human hair, are increasingly being explored for their potential applications in agriculture and biofuels. Juan Pablo Giraldo, an associate professor of plant biology at UCR and the study's lead author, emphasized the necessity for improvements in agricultural practices, stating, "Half of all fertilizer applied on farms is lost in the environment and pollutes groundwater. With the most commonly used pesticides, it's even worse—only 5% may reach their intended targets. There's a lot of room for improvement."

The findings from the study reveal that when nanoparticles enter plant cells, they undergo changes in pH and acquire lipid coatings from the plant membranes. This process enhances their ability to bind to RuBisCO, a protein essential for photosynthesis. However, this binding interferes with RuBisCO's function, consequently diminishing its activity by threefold, as highlighted by Giraldo. RuBisCO plays a crucial role in enabling plants and algae to absorb carbon dioxide and convert it into sugars, which are vital for growth, making it the most abundant protein on Earth.

According to Lin He, deputy division director at the U.S. National Science Foundation's Division of Chemistry, the prevalence of nanoparticles in Earth's ecosystems has prompted a growing interest in understanding their interactions with the environment. He stated, "Nanoparticles, both natural and anthropogenic, are prevalent in many of Earth's ecosystems, but scientists are only recently starting to understand how they interact with different parts of the environment."

The research team, which included collaborators from Santa Clara University, the University of Illinois, Johns Hopkins University, and the Connecticut Agricultural Experiment Station, conducted multi-year investigations to quantify the impact of these nanoparticles on RuBisCO function. They measured the carbon dioxide uptake in Arabidopsis leaves, an indicator of RuBisCO activity. While laboratory tests indicated minimal impact from nanoparticles on RuBisCO, the results changed dramatically in living plant cells, underscoring the complexity of these interactions.

"This is the first time we've been able to compare the effect of a nanoparticle on a protein both outside and inside a living plant cell," Giraldo noted. Previous inquiries had suggested that the positive charge of nanoparticles might impair protein function, but the study's findings clarified that it is the transformation upon entry into plant cells that poses the significant risk.

The multidisciplinary nature of the research team enhanced their ability to gain insights into these complex interactions. Rigoberto Hernandez, a chemistry professor at Johns Hopkins University and a co-author of the study, remarked that advanced computer simulations allowed them to observe the structural and motion dynamics at microscopic scales, facilitating a better understanding of how lipids are acquired by nanoparticles in the presence of RuBisCO.

The researchers advocate for further exploration into the chemical transformations induced by nanoparticles within organisms, as this understanding could lead to the development of safer and more effective applications in agriculture and biotechnology. "Through the NSF Center for Sustainable Nanotechnology, researchers from different branches of chemistry and environmental science have collaborated to produce a new understanding of how nanoparticles transform and interact with a protein involved in plant photosynthesis," He emphasized.

Catherine Murphy, a chemistry professor at the University of Illinois Urbana-Champaign and a study co-author, concluded, "This landmark study tells us that we have a long way to go to make nanoparticles that are truly beneficial in the environment. But now that we know the mechanism of action, we can re-tune our methods to solve these problems."

These findings not only advance the scientific community's understanding of nanoparticle-plant interactions but also raise important questions about the future use of nanoparticles in agricultural practices. As the global demand for food continues to rise, the need for innovative and sustainable agricultural solutions that do not compromise plant health becomes increasingly critical.