Detecting Particles Flowing through Interdigitated 3D Microelectrodes

Counting cells in a large microchannel remains challenging and is particularly critical for in vitro assays, such as cell adhesion assays. This paper addresses this issue, by presenting the development of interdigitated three-dimensional electrodes, which are fabricated around passivated pillar-shaped silicon microstructures, to detect particles in a flow. The arrays of micropillars occupy the entire channel height and detect the passage of the particle through their gaps by monitoring changes in the electrical resistance. Impedance measurements were employed in order to characterize the electrical equivalent model of the system and to detect the passage of particles in real-time. Three different geometrical micropillar configurations were evaluated and numerical simulations that supported the experimental activity were used to characterize the sensitive volume in the channel. Moreover, the signal-to-noise-ratio related to the passage of a single particle through an array was plotted as a function of the dimension and number of micropillars

Detecting particles flowing through interdigitated 3D microelectrodes

Counting cells in a large microchannel remains challenging and is particularly critical for in vitro assays, such as cell adhesion assays. This paper addresses this issue, by presenting the development of interdigitated three-dimensional electrodes, which are fabricated around passivated pillar-shaped silicon microstructures, to detect particles in a flow. The arrays of micropillars occupy the entire channel height and detect the passage of the particle through their gaps by monitoring changes in the electrical resistance. Impedance measurements were employed in order to characterize the electrical equivalent model of the system and to detect the passage of particles in real-time. Three different geometrical micropillar configurations were evaluated and numerical simulations that supported the experimental activity were used to characterize the sensitive volume in the channel. Moreover, the signal-to-noise-ratio related to the passage of a single particle through an array was plotted as a function of the dimension and number of micropillars

Interference at INRIM in L2 and related analysis

INRIM TN 0

Interference at INRIM in L2 and related analysis

INRIM TN 0

Integrating Bio-sensing Functions on CMOS Chips

The paper discusses the recent achievements in the development of chips with integrated sensing of biomolecules. In particular, it focuses on integrated sensing electrodes on silicon and presents innovative solutions for the enhanced robustness of the electrodes towards cleaning processes and electrolytes. In this study, a microfabrication technology for 3D-integrated disposable chip layers that enables the reusability of the overall system for many times is presented

Characterization and modelling of differential sensitivity of nanoribbon-based pH-sensors

We report accurate characterization, modelling and simulation of SOI nanoribbon-based pH sensors and we compare operation in air (dry) and electrolyte (wet) environments. We find remarkably different current density distributions and geometry scaling rules, but similar series resistances and active trap state densities in the two configurations. Calibrated TCAD based simulations implementing an original approach to model the site-binding harge, and in good agreement with experiments, provide the necessary insights to interpret the non trivial dependence of the threshold voltage and current sensitivity on pH

A Portable Setup for Molecular Detection by Transmission LSPR

In the framework of bioanalytics and multiple array detection, we developed a fully portable and low-cost detection system based on Localized Surface Plasmon Resonance (LSPR) in a transmission configuration (T-LSPR). The transmission approach is suitable to be scaled to small dimension systems and to enable high-density array measurements on the same platform. Our setup is made out of off-the-shelf components and consists of a set of discrete light sources and a couple of light-detectors which enable a differential measurement setup. An algorithm fits the measured data and extracts the information of the plasmon peak position in the spectrum. The performance of our T-LSPR measurement system has been characterized on a set of Fluorinated Tin Oxide-coated glass slides covered with gold Nanoislands (NIs). The samples have been modified with a single-stranded DNA layer and a real-time DNA hybridization experiment has been performed. Here we demonstrate that the proposed T-LSPR device, based on the characterization of the plasmon peak with a differential approach, is able to monitor real-time DNA hybridization on surface, and to precisely measure the position of the peak with a standard deviation in wavelength of 0.2 nm