Measuring the impedance of a tethered bilayer membrane biosensor

In this paper we present a method for measuring the complex impedance of a tethered bilayer membrane (tBLM). Measuring the impedance of a tBLM can involve large, nonportable, expensive instrumentation. Here we present a method of complex impedance measurement that is portable and inexpensive; requiring only a laptop or palm-pocket computer with a USB interface. The complex impedance measurement is improved by using a type of pseudorandom binary sequence (PRBS) called a maximum length sequence (MLS). This method of impedance measurement improves the resolution over conventional sinusoidal frequency sweeping methods.