string. An aerosol of the sample is produced by an electrospray. This aerosol is pumped through the orifice in the sensor chip. While passing the nanomechanical string with high velocities, the micelles are collected on the string by inertial impaction with an estimated total sampling efficiency on the order of 10% (number of micelles collected on string vs. number of micelles electrosprayed). (b) SEM image of a silicon nitride resonator coated with micelles.