Houseplant-Inspired Copper IUD Design May Reduce Side Effects
The laser-engraved microstructure helps mitigate the burst release of copper ions, improving IUD safety.
A copper intrauterine device (IUD), also known as “the coil”, is a popular form of non-hormonal birth control, thanks to its long-lasting effects and reversability. However, many women who choose to get an IUD often report troublesome side effects during the first few months of use, including period-like pain in the initial days, and heavier or longer-lasting periods for several months.
A new approach to designing copper IUDs could help to mitigate some of these effects. As reported in the journal Biointerphases, researchers from Changchun University and Northeast Normal University, China, have taken inspiration from the leaves of a common houseplant to develop an IUD that avoids the cause of these complications.
Copper corrosion causes discomfort for IUD users
Copper IUDs work by slowly releasing copper ions into the uterus, making it a toxic environment for sperm, preventing the fertilization of a woman’s eggs. In the event that a fertilized egg does make it into the uterus, an IUD can also prevent it from implanting into the uterine lining, avoiding pregnancy.
When a copper IUD is first inserted into the uterus, it begins to react with the uterine fluid. This reaction corrodes the copper surface, resulting in a sudden, large release of copper ions during the first week of implantation. The corrosion and initial ion burst is thought to be responsible for several side effects of IUD implantation, such as menstrual irregularity, increased menstrual cramps and pelvic inflammatory disease. Solving this initial ion burst issue could represent a significant quality of life increase for the women who this method of contraception.
A golden pothos plant (Epipremnum aureum) and a scanning electron microscope image of its surface microstructures. Researchers are taking inspiration from its surface patterns to make a safer copper IUD. Credit: Liu et al.
The leaves of the pothos plant feature a distinctive microstructure that repels water, causing rain droplets to ball up and slide right off a leaf’s surface.
By mimicking this hydrophobic microstructure on the surface of a copper IUD, the researchers theorized that they could repel uterine fluid in a similar fashion. By reducing the contact between the copper surface and the fluid, this could decrease the extent of the corrosion, thus releasing fewer copper ions and avoiding side effects.
Laser-patterned IUDs release fewer copper ions
To test their theory, the researchers first studied the leaves of a golden pothos plant (Epipremnum aureum) using a scanning electron microscope. From this, they were able to calculate the average dimensions of the leaves’ hexagonal-shaped ridges and valleys, including their diameter, depth and the angle between each ridge and valley.
“The pothos structure offered a balance of simplicity, stability and effectiveness, making it well suited for our goal of improving copper IUDs,” said study author Junbo Liu, a researcher at the Affiliated Hospital of Changchun University of Traditional Chinese Medicine.
From their measurements, the research team created a simplified version of the pattern that could be engraved onto the copper surfaces of an IUD using a laser-patterning technique.
When this patterned IUD was exposed to simulated uterine fluid for a period of five days, the researchers found that it released fewer copper ions into the fluid, due to its increased hydrophobicity and lessened corrosion. Cell viability and cytotoxicity tests also determined that, compared to a traditional copper IUD, the plant-inspired device caused less cell death and increased cell viability in tissues that would potentially be in contact with the device.
According to the research team, their laser-patterning technique is scalable, making it a realistic alternative to other proposed solutions, such as mixed-metal IUDs and polymer IUD coatings.
“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.
Looking ahead, the team plans to optimize their laser-patterning technique for efficient, larger-scale use. They also intend to conduct in vivo studies to measure the long-term effectiveness of patterned copper IUDs.
Reference: Liu J, Zhou L, Liu L, Li Y. A femtosecond laser-textured copper surface for reducing initial copper ion burst release in intrauterine devices. Biointerphases. 2025. doi: 10.1116/6.0004923
This article is a rework of a press release issued by the American Institute of Physics. Material has been edited for length and content.
