The ion channel biosensor is a fully operational nanomachine that can detect minute concentrations of analytes. This talk describes mathematical models for the dynamics of the ion channel biosensor from atomic resolution (using molecular dynamics for gramicidin channels), mesoscopic time scales (using fluid flow partial differential equations for how the analyte in a flow chamber interacts with the sensing device), and finally macroscopic ordinary differential equation models (how the current voltage response of the sensor varies with concentration). Examples of how sensor arrays can further enhance the estimation accuracy will be described. Futuristic extensions to noninvasive sensing of cells and molecular drug delivery by exploiting the dynamics of electroporation (how pores form spontaneously in the cell membrane) will be discussed briefly.