New Copper Oxides Found with Potent Antiviral Power

Composite copper-lanthanum and copper-yttrium oxides developed by researchers from Japan demonstrate exceptionally high antiviral activity against non-enveloped virus. These oxides are highly stable and achieve over 99.999% viral inactivation in laboratory tests. Using first-principles calculations and experimental analysis, researchers identified how surface charge, protein inactivation, and copper valence states drive the antiviral performance-setting the stage for advanced antiviral material design.

Novel Copper-Based Composite Oxides with Improved Antiviral Activity

Viruses have been a threat to human health since ages, from seasonal outbreaks to global crises such as COVID-19. While most familiar viruses are enveloped, meaning they are surrounded by a lipid membrane that can be disrupted using common disinfectants. Non-enveloped viruses pose a greater threat as they are more resistant to inactivation. One promising strategy is to use metal oxides as antiviral materials, especially copper and copper oxides which are known for their broad-spectrum antiviral activity against both enveloped and non-enveloped viruses.

While copper and copper oxides show promising results, their effectiveness decreases over time as highly active cuprous oxide (Cu₂O) gradually oxidizes into less active cupric oxide (CuO). This limitation has been a long-standing challenge in the route for the development of durable antiviral materials. To overcome this challenge, a research team from Institute of Science Tokyo (Science Tokyo), in collaboration with Kanagawa Institute of Industrial Science and Technology (KISTEC), Japan, developed a new class of composite copper oxides that exhibit strong antiviral activity with improved stability.

Led by JSPS Research Fellow Ryuju Kiribayashi, Assistant Professor Yasuhide Mochizuki, and Professor Akira Nakajima from Science Tokyo, the study explores antiviral activity of two novel compounds, La₂CuO₄and Y₂Cu₂O₅, synthesized by combining CuO with lanthanum or yttrium oxides. The findings of the research were made available online on October 21, 2025 and were published in Volume 17, Issue 45 of the journal ACS Applied Materials & Interfaces on November 12, 2025.

"We aimed to overcome the degradation of copper and Cu₂O by forming composites of the low-activity CuO with lanthanum oxide or yttrium oxide," notes Nakajima. "To our surprise, the outcomes exceeded our expectations."

When evaluated using International Organization for Standardization-based antiviral tests, both the composite oxides La₂CuO₄ and Y₂Cu₂O₅ showed striking performance. In just four hours, the oxides achieved over 99.999% inactivation against the non-enveloped bacteriophage Qβ, outperforming their individual constituent oxides. Moreover, they also exhibited a certain antiviral activity against enveloped virus Φ6. These effects were further validated by enzyme-based protein inactivation assays, which showed significantly higher reactivity, compared to the individual binary oxides.

To understand the underlying mechanism behind this behavior, the team developed a new software tool that constructs atomic-scale surface models for computational analysis. Using first-principles calculations, the researchers found that the composite oxides exhibited cation-rich surfaces and monovalent (Cu^＋)-like valence states, similar to those found in highly active Cu₂O. These positively charged surfaces enhanced electrostatic adsorption of viruses. Since viruses carry negative surface charges, they were readily attracted to the positively charged surfaces of La₂CuO₄ and Y₂Cu₂O₅.

Once adsorbed, the viral proteins were destabilized and inactivated. Calculations showed that destabilization resulted from cleavage of their disulfide bonds at the surface of the oxides. With this elucidation, the study marked an important milestone in understanding how antiviral activity arises at oxide surfaces. The researchers also conducted stability testing to analyze the durability of the oxides.

"We demonstrated the world's first density-functional-theory calculations to understand the disulfide bond cleavage on oxide surfaces. The results we obtained were striking. La₂CuO₄ retained more than 70% of its antiviral activity even after 1.5 years, outperforming all previously reported cuprous-oxide-based materials," highlights Kiribayashi.

With the demonstrated durability, the oxides hold great potential for applications in public facilities, transportation, healthcare environments, and consumer products where long-lasting antiviral performance is essential. Overall, by integrating materials synthesis, surface chemistry, and computational science, the study offers a novel framework for designing next-generation antiviral materials-with stronger, more durable protection against viruses in real-world environments.

Authors:

Authors: Ryuju Kiribayashi^１, Kayano Sunada², Toshihiro Isobe¹, Keiichi Kobayashi², Takeshi Nagai², Hitoshi Ishiguro², Yasuhide Mochizuki¹*, and Akira Nakajima¹*

*Corresponding authors

Title:

Preparation and antiviral activity of La₂CuO₄ and Y₂Cu₂O₅ with mechanistic insights from first-principles

Journal:

ACS Applied Materials & Interfaces

DOI:

10.1021/acsami.5c17978

Affiliations:

¹Department of Materials Science and Engineering, School of Materials and Chemical Technology, Institute of Science Tokyo, Japan

²Life Science Technology Project, Kanagawa Institute of Industrial Science and Technology, Japan