Low voltage electrophoresis on a CMOS chip

Electrophoresis is a valuable technique for the separation and analysis of chemical and biological specimens. Typically, an electric field is established between two electrodes that induces charged particles to move and separate. Instead of using only one electrode at each end of the separation area, this paper presents a very small, low voltage system that utilizes electrodes beneath the entire separation area, enabling better control of high electric fields using very small voltages over small areas. By employing multiple electrodes, strong electric fields can be established using very low voltages (less than 5 V) over small distances. The electrodes are also used to sense sample locations and concentrations using amperometric detection, and integrated electronics allow precise control over the fields. The system presented here includes 100 individually addressable electrodes and their corresponding circuitry on a 2 mm by 2 mm chip and is designed using the AMI 1.5 mum CMOS process available through MOSIS.