 A new type of catheter has been developed that combines the advantages of superwetting and structural color to provide both visual and quantitative feedback on drug release. This bio-inspired catheter is made from an inverse opal photonic crystal hydrogel and features a slippery liquid-infused porous surface, slips. The slips property allows the catheter to change its appearance depending on the amount of drug released, while the structural color provides a visual indication of the drug's progress. Additionally, the catheter's ability to monitor drug release makes it ideal for use in biomedical applications such as drug delivery. This article was authored by Jijin Jiang, Yufei Chen, Ming Tian Su, and others.