Microfluidic devices sense and sort through molecules by channeling them down nanoscale pipes etched from polymer substrates. Unfortunately, the tiny channels often clog when biological materials stick to them, degrading performance. Researchers at the Rensselaer Polytechnic Institute (RPI, Troy, N.Y.) think they have found a remedy: a material that optically switches from slippery to sticky. When exposed to UV light, the polymer dislodges molecules stuck to its surfaces by becoming more slippery. The property enables even the most clogged microfluidic channels to be flushed clean. The researchers predicted that the polymer will be useful for filtering specific proteins from biological fluids, which often clog the pores of conventional filters.