Gold microelectrodes array embedded in PDMS for electrical stimulation and signal detection

Abstract In this paper, an innovative low cost fabrication process of a biocompatible MEA, composed of a group of gold microelectrodes embedded in a cavity filled with PDMS is presented. This MEA is part of a more complex system, which has been designed to stimulate, detect and amplify electrical signals. It is possible to control the temperature and heat the MEA, with the purpose of making this system suitable for biomedical application, such as cell or tissues culture, or monitoring neuronal activity. A deeply characterization of the MEA has been performed. The main experiment carried out consists in the introduction of an electrical signal through a gold microelectrode. This electrical signal is transmitted between microelectrodes through a water-based salt solution, in particular with Phosphate Buffered Saline (PBS). In order to have the possibility of amplifying a wide range of signals, different INA 333 amplifiers with different gains, between 3.13 and 213, have been included. Nevertheless, the gain could be easily modified. The behavior of the system is controlled via Labview software, provided by National Instruments. This program allows for detecting the stimulus, the stimulation and an accurate measurement of the temperature's system. An electronic circuit, which includes the conditioning circuits needed to run the whole system, is used as an interface between the MEA and the Labview software. The proper functioning of the system introduced, and the stimulation and detection of electrical signals, as well as its amplification through a water-based salt solution, using gold microelectrodes embedded in PDMS, have been demonstrated. A survival test with mice retinas has been performed to demonstrate the biocompatibility of the MEA.