A temporary fix to a complex issue.

Sterinova develops high-quality pharmaceutical products and approached us to address an important issue in hospitals. Pain relief medication is often injected into saline bags through a silicone seal, but some individuals misuse this access to steal the medication using syringes, often without medical staff noticing. Sterinova tasked us with designing a theft-proof clip to secure the bag after injection, preventing tampering and ensuring patient safety.

During the design process, we created three concepts, but one stood out early on. Given the small details and features involved, we adopted a "fail fast" approach. This meant designing multiple variations of the clip, testing and validating each iteration to identify what worked, what didn’t, and what needed improvement before immediately printing a new version. Instead of focusing all our efforts on what we assumed would work, we relied on rapid prototyping and validation. Fun fact: we broke every single prototype during testing, so none remain intactt.

At first, making the clip easy to snap on with one hand, without holding the bag, seemed straightforward. However, as we progressed, challenges emerged: how to position the clip correctly, ensure it fits securely on the bag's exit, and design it so that every part stays on your fingers during snapping—all while keeping it as compact as possible. We couldn’t rely on large features, so we added grips in some areas and small ledges in others. Thanks to our rapid prototyping approach, we were able to test many designs and refine the features until achieving a smooth, one-motion snap.

The part is designed with two shells of but made as a single polypropylene part, utilizing a living hinge similar to those found on plastic lunch boxes. When folded, the hinge securely closes around the tube, forming a snap fit. Attempting to insert a syringe through any cracks would result in leaks, making tampering immediately visible—just as if the syringe had been inserted directly into the bag. Even trying to pierce the clip from underneath or along the axis is impossible due to the design, and the sloped bottom adds to the frustration of any attempt to breach it.

Designing something "tamper-proof" is never about making it completely impenetrable—it’s about creating a design that’s as much of a hassle as possible for someone determined to break it. With the right tools, time, and privacy, anything can be compromised. To test every design, we used cutters and screwdrivers, often risking our fingers as we tried to open each prototype as quickly as possible. We even held an internal contest, where the winner set a 28-second record—and walked away with a bleeding thumb as their prize.