Research Article A Low-Noise, Modular, and Versatile Analog Front-End Intended for Processing In Vitro Neuronal Signals Detected by Microelectrode Arrays Giulia Regalia, 1 Emilia Biffi, 1,2 Giancarlo Ferrigno, 1 and Alessandra Pedrocchi 1 1 Neuroengineering and Medical Robotics Laboratory, Electronics, Information and Bioengineering Department, Politecnico di Milano, 20133 Milan, Italy 2 Bioengineering Laboratory, Scientiic Institute IRCCS Eugenio Medea, 23842 Bosisio Parini, Italy Correspondence should be addressed to Giulia Regalia; giulia.regalia@polimi.it Received 21 December 2014; Accepted 2 April 2015 Academic Editor: J. Alfredo Hernandez Copyright © 2015 Giulia Regalia et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. he collection of good quality extracellular neuronal spikes from neuronal cultures coupled to Microelectrode Arrays (MEAs) is a binding requirement to gather reliable data. Due to physical constraints, low power requirement, or the need of customizability, commercial recording platforms are not fully adequate for the development of experimental setups integrating MEA technology with other equipment needed to perform experiments under climate controlled conditions, like environmental chambers or cell culture incubators. To address this issue, we developed a custom MEA interfacing system featuring low noise, low power, and the capability to be readily integrated inside an incubator-like environment. Two stages, a preampliier and a ilter ampliier, were designed, implemented on printed circuit boards, and tested. he system is characterized by a low input-referred noise (<1 V RMS), a high channel separation (>70dB), and signal-to-noise ratio values of neuronal recordings comparable to those obtained with the benchmark commercial MEA system. In addition, the system was successfully integrated with an environmental MEA chamber, without harming cell cultures during experiments and without being damaged by the high humidity level. he devised system is of practical value in the development of in vitro platforms to study temporally extended neuronal network dynamics by means of MEAs. 1. Introduction At the present time, the in vitro study of neuronal net- work electrical activity under physiological or pathological conditions largely relies on Microelectrode Arrays (MEA), which are substrate-integrated extracellular electrode matri- ces kept permanently in contact with neurons in culture [1–5]. hanks to the distributed (i.e., ∼60–250 electrodes in standard MEAs) and noninvasive character, this well- established technology provides the possibility to perform network-level long-term studies, overcoming conventional in vitro electrophysiology techniques (i.e., patch clamp). MEA- based neuronal-electronics interfaces have been shown to facilitate the study of a bulk of neuronal network processes, including network dynamics, network development, learning and memory, short-term and long-term neuronal plasticity, excitotoxicity, efects of pharmacological treatments, and mechanisms underlying pathological conditions [2, 3, 5, 6]. Nowadays, complete systems for the interfacing elec- tronic circuitry (i.e., ampliication and iltering) and the acquisition of MEA signals are commercially available to researchers by few principle players on the market (e.g., Multi Channel Systems GmbH, Plexon Inc., Axion Biosystems Ltd., and Alpha MED Scientiic Inc.). Nonetheless, commercial solutions do not always meet some demanding needs, such as low power, compactness, compatibility with experimental setup constraints (e.g., size, environmental conditions), lex- ibility (e.g., easiness to change component values if needed), or cost-efectiveness. For this reason, some researchers have resorted to the utilization of in-house designed MEA inter- facing electronics [7–14]. Hindawi Publishing Corporation Computational Intelligence and Neuroscience Volume 2015, Article ID 172396, 15 pages http://dx.doi.org/10.1155/2015/172396