A 64-channel, 1.1-pA-accurate on-chip potentiostat for parallel electrochemical monitoring

Electrochemical monitoring is crucial for both industrial applications, such as microbial electrolysis and corrosion monitoring as well as consumer applications such as personal health monitoring. Yet, state-of-the-art integrated potentiostat monitoring devices have few parallel channels with limited flexibility due to their channel architecture. This work presents a novel, widely scalable channel architecture using a switch capacitor based Howland current pump and a digital potential controller. An integrated, 64-channel CMOS potentiostat array has been fabricated. Each individual channel has a dynamic current range of 120dB with 1.1pA precision with up to 100kHz bandwidth. The on-chip working electrodes are post-processed with gold to ensure (bio)electrochemical compatibility

An affordable multichannel potentiostat with 128 individual stimulation and sensing channels

(Bio)electrochemical reactions are a promising, environmentally friendly alternative for many chemical processes. These processes, however, are known to be slow in time, to be strongly dependent on the environment and to vary between different samples. This necessitates research on studying optimal operating conditions of the (bio)electrochemical cells. Yet, current experiments have to rely on slow, sequential tests. To overcome these, this work proposes a potentiostat with 128 parallel channels to speed up research experiments. The 128-channel potentiostat makes extensive use of time-sharing and is implemented with PCB technology resulting in a cost-per-channel of only 5$, 4x lower than the state-of-the-art (SotA) and an area-per-channel of ≈ 93 mm 2 , 5x lower than the SotA. Realtime digital compensation of each individual channel is used to obtain a channel-to-channel mismatch below 1%. A cyclic voltametry experiment on all channels simultaneously illustrates the low channel-to-channel mismatch. A chronoamperometry experiment with 128 different potential steps in parallel illustrates the 128x experiment speedup

Electrochemical noise limits of femtoampere-sensing, CMOS-integrated transimpedance amplifiers

Low-noise operational amplifiers are an important tool in the life sciences. Biosensor measurements typically rely on low-noise transimpedance amplifiers to record biological signals. Two different techniques were used to leverage the advantages of low-noise circuitry for bioelectronics. A CMOS-integrated system for measuring redox-active substrates using electrochemical read-out at very low noise levels is presented. The system incorporates 112 amplifier channels capable of current sensing with noise levels below 1 fArms in a 3.5-Hz bandwidth. The amplifier is externally connected to a gold microelectrode with a radius of 15 µm. The amplifier enables measurement of redox-couples such as potassium ferrocyanide/ferricyanide with concentrations down to 10 nM at current levels of only 300 fA. The electrochemical noise that sets the limits of detection is also measured and analyzed based on redox mass transfer equation and electrochemical impedance spectroscopy. Secondly, CMOS-integrated low noise junction field-effect transistors (JFETs) were developed in a standard 0.18-µm CMOS process. These JFETs reduce input referred flicker noise power by more than a factor of 10 when compared with equally sized n-channel MOS devices by eliminating oxide interfaces in contact with the channel. We show that this improvement in device performance translates into a factor-of-10 reduction in the input-referred noise of integrated CMOS operational amplifiers when JFET devices are used at the input