A robust, portable chip containing a single protein nanopore would be a significant development in the practical application of stochastic sensing technology. Here, we describe a chip in which a single alpha-hemolysin (alpha HL) pore in a planar phospholipid bilayer is sandwiched between two layers of agarose gel. These encapsulated nanopore chips remain functional after storage for weeks. The detection of the second messenger inositol 1,4,5-trisphosphate (IP3) was demonstrated with a chip containing a genetically engineered alpha HL pore as the sensor element.