Development and characterization of a low noise current amplifier for biological signals
DEI PhD Student
DEI - Alpha Room
November 8th, 2011
Multiple electrochemical measurements can be obtained from cellular and sub-cellular entities using microelectrodes. In this way real-time, continuous and parallel electrochemical monitoring allow the extraction of important information from biological systems investigated in a liquid environment. In order to obtain good results, the design of circuits capable to correctly amplify and read out currents of about ten femtoampere plays a crucial role.
In this work a current amplifier with high performance and small dimensions, created using commercial products, is designed and tested. Without neither introducing a relevant noise nor limiting the frequency band, it reads the current obtained from a previously existent integrated chip (IC), designed to amplify a current signal from a metal electrode.
The circuit has been divided in two boxes: a first one, containing the probe, the IC and a transimpedance amplifier, and a second one, where the power sources are stabilized and filtered, the offset is eliminated and two different outputs (current and voltage) are provided.
Sensors and Instrumentation