A fold inside an artery

The waterbomb base — the fold that turns a flat square into a hollow chamber — has a second life in medicine.

At the University of Oxford, a group including Zhong You built a stent from nickel-titanium foil creased in the waterbomb pattern. Folded, it was narrow enough to pass through a catheter; released, it expanded into an open scaffold, the kind used to hold a blocked vessel open. The expansion was fast enough to require a high-speed camera to capture. The work was published in 2006.

The careful part

It is easy, and tempting, to say that origami stents are saving lives. They are not — not yet. A 2018 review of biomedical origami states plainly that none of the origami devices described had, at that time, entered clinical use. The Oxford stent is a research prototype. Twenty years on, it has not been placed in a human artery.

This matters to us. There is a real and beautiful principle here — a fold that opens inside the body — and it does not need to be exaggerated to be worth telling. We will tell you when something is a prototype, and when it is a product, and we will not blur the two.

The wider field

The waterbomb stent is not alone. A team at UC Irvine has designed an origami-based heart valve intended to grow with a child; as of 2025 it had passed animal testing and was some years from human trials. At Brigham Young University, origami-inspired surgical forceps — small enough to pass through a three-millimetre incision — have been licensed by the maker of the da Vinci surgical robot.

The fold is entering medicine slowly, and honestly, one prototype at a time.