WASHINGTON, Oct. 28, 2025 – Copper intrauterine devices are a common contraceptive due to their long-acting effects and affordability. However, the first few months of use are associated with several side effects.
When a copper IUD is first implanted in the uterus, it undergoes a chemical reaction with uterine fluid. This reaction corrodes its surface, causing a burst of copper ions, which can lead to symptoms such as menstrual irregularity, increased menstrual cramps, and pelvic inflammatory disease.
In Biointerphases, an AVS journal published by AIP Publishing, researchers from Changchun University and Northeast Normal University took inspiration from a common houseplant to develop a better, safer copper IUD.
The researchers noticed that pothos leaves are hydrophobic — a distinctive microstructure on the leaf's surface causes water droplets to ball up and slide off.
The team realized that mimicking this pattern on the surface of a copper IUD might repel uterine fluid. Less contact between the surface and fluid would decrease corrosion, releasing fewer copper ions and mitigating side effects.
Under a scanning electron microscope, the researchers observed that the dried pothos leaf was covered with a system of ridges and hexagonal valleys. Researchers quantified this pattern by calculating the average diameter of the ridges, the depths of the valleys, and the angle between each ridge and valley. Then, the simplified, bioinspired pattern was engraved onto the surface of the IUD using lasers.
"The pothos structure offered a balance of simplicity, stability, and effectiveness, making it well suited for our goal of improving copper IUDs," said author Junbo Liu.
The researchers saw the engraved surface repelled water significantly better than the traditional IUD. After testing the corrosion of the IUD, researchers found that it released fewer copper ions into simulated uterine fluid. Cell viability and cytotoxicity tests determined potential tissue responses to cells in contact with the IUD.
Compared to a traditional copper IUD, the plant-inspired device is more hydrophobic and more corrosion-resistant, releases fewer copper ions, causes less cell death, and increases cell viability. The laser texturing technique is scalable and avoids supply-chain risks associated with the creation of mixed-metal IUDs and the degradation of polymer IUD coatings.
The team plans to optimize their prototype for larger-scale laser patterning and efficient production and to conduct in vivo studies to measure the long-term behavior of their IUD.
"On a broader level, this study demonstrates how surface engineering inspired by natural structures can provide innovative solutions to biomedical challenges, bridging materials science with women's health care," said Liu.
