The present invention provides a sensor for detecting the binding of molecules to membrane surfaces. The sensor comprises a nanoparticle coated with a continuous layer of silica, and having a ligand attached thereto, for detection of an analyte in a solution. The nanoparticle can be further coated with a continuous membrane, such as a lipid bilayer.
STATEMENT OF GOVERNMENTAL SUPPORT
 The invention was made with government support under Contract Nos. DE-AC02-05CH11231 awarded by the U.S. Department of Energy. The government has certain rights in the invention.