Researchers have developed a new generation of menstrual cup technology designed to eliminate the most common barriers to using the sustainable products. By creating a self-cleaning surface and a biodegradable insert that prevents spills, the innovations directly address user concerns about hygiene, convenience, and mess, potentially accelerating the shift away from disposable tampons and pads.
The two-part solution, developed by a team at McMaster University, consists of a silicone oil-infused coating that prevents blood and bacteria from sticking to the cup, and a small, plant-based tablet that absorbs menstrual fluid and solidifies it for spill-proof removal. This approach aims to make reusable cups more practical for a wider audience, reducing the environmental footprint of menstrual care while improving user experience and safety. The work combines advanced materials science with women’s health to create a product that is not only easier to use but also opens avenues for future health monitoring.
Overcoming Adoption Hurdles for Reusable Cups
While menstrual cups offer a cost-effective and environmentally friendly alternative to single-use products, their adoption has been limited by several persistent challenges. Many potential users are deterred by the cleaning regimen and hygiene concerns. Standard medical-grade silicone, while safe, is not inherently resistant to bacterial adhesion, which can lead to biofilm formation—a thin, slimy layer of bacteria. To ensure safety, manufacturers typically recommend users sterilize their cups by boiling them in water between cycles, a time-consuming and often inconvenient process.
Another significant barrier is the process of emptying the cup. Spills during removal are a common complaint, making the process messy and difficult, especially in public restrooms or situations with limited access to private sinks. These practical drawbacks have hindered the widespread acceptance of cups, despite their benefits of reducing waste and offering longer wear times than traditional tampons. The research team targeted these specific issues to engineer a more user-friendly product that aligns with the needs of the nearly 2 billion people who menstruate worldwide and are increasingly seeking sustainable options.
A Slippery Solution for a Cleaner Surface
To address the challenge of keeping the cup clean, the researchers developed a novel surface treatment using a biocompatible silicone oil. The team infused and coated a commercially available medical-grade silicone cup with the oil, creating what is known as a lubricant-infused surface. This technology transforms the cup’s texture, making it extremely slippery and nonstick. This property is highly effective at repelling liquids like blood and, more importantly, preventing bacteria from gaining a foothold.
Testing Against Bacteria
In laboratory tests, the team evaluated the modified surface’s ability to resist contamination. They tested three types of commercially available cups and found that the one infused with silicone oil demonstrated a significant reduction in bacterial adhesion compared to its untreated counterparts. Specifically, the treated cup showed a threefold reduction in the adhesion of E. coli, a common bacterium used to assess the anti-fouling properties of medical surfaces. By inhibiting this initial attachment, the technology effectively prevents the formation of biofilms, which are much harder to remove.
Eliminating the Need for Boiling
The practical benefit of this self-cleaning property is a dramatically simplified maintenance routine. The nonstick surface ensures that menstrual fluid rinses off cleanly with just soap and water. According to the researchers, this could eliminate the need for monthly boiling or other complex sterilization methods. This convenience not only saves time but also makes the cups more accessible to individuals in regions where consistent access to boiling water may be limited, thereby lowering the barrier to entry for a safer and more sustainable menstrual health product.
Spill-Proofing with Plant-Based Technology
To solve the problem of messy removal, the team engineered a separate but complementary innovation: a superabsorbent tablet designed to fit inside the cup. This small, teardrop-shaped insert is made from alginate, a natural polymer sourced from brown algae. The alginate is spun into fibers that are then linked together with calcium chloride to form a highly absorbent, biodegradable material.
The tablet is capable of soaking up a substantial amount of fluid, with tests showing it can absorb up to 15 milliliters of whole human blood over an eight-hour period. This capacity is equivalent to the full volume of many menstrual cups. By absorbing the collected fluid and retaining it within its fibrous structure, the tablet effectively solidifies the cup’s contents. This prevents any liquid from spilling during the removal process, making emptying the cup a cleaner and more manageable experience. After use, the tablet is designed to decompose into biocompatible compounds when placed in a salt solution, a process that takes about four days. The team is now working to confirm its flushability for easier disposal.
Implications for Global Health and Sustainability
The dual innovations represent a significant step forward in menstrual product design. By focusing on user-centric problems, the researchers have created a system that enhances both hygiene and convenience, thereby tipping the scales in favor of reusable products. Making cups easier and safer to use could encourage millions of people to switch from disposable products, which generate a tremendous amount of plastic and fiber waste annually. The project underscores a commitment to advancing global environmental stewardship through thoughtful engineering.
Senior researcher Tohid Didar stated that the research bridges advanced engineering with women’s health. He also noted that beyond its immediate benefits, the technology “opens doors for future health monitoring.” A stable, clean surface within a collection device could potentially be integrated with biosensors to analyze menstrual fluid for various health markers, offering a new, non-invasive diagnostic tool. The team’s work provides a platform for further advancements in feminine hygiene, with the potential to improve the health, comfort, and environmental impact of menstrual care for people around the world.