Computing centroids in current-mode technique

A novel current-mode circuit for calculating the centre of mass of a discrete distribution of currents is described. It is simple and compact, an ideal building block for VLSI analogue IC design. The design principles are presented as well as the simulated behaviour of a one-dimensional implementation

An Automatic Offset Correction Platform for High-Throughput Ion-Channel Electrophysiology

High-throughput ion channel screening for drug discovery is at the base of the recent shift of resources in the pharmaceutical industry towards addressing drug safety issues earlier in the discovery process. Very few examples of parallel ion-channel recording platforms are currently present in literature, due to the complexity of the setup. However, single-junction Ag/AgCl electrodes suffer of intrinsic voltage offsets, due to the electrode-buffer interface variability. This is very critical, since ion- channel recording requires high accuracy (pA resolution) within the full-scale (nA range), limiting the operability of the measurement, especially on a multi-channel approach. This paper presents an automatic offset correction system fully implemented on a lipid bilayer membrane platform. The platform allows offset-free recording of ion-channel signals acquired and displayed by means of a graphical user interface

Development of an electrical impedance tomography set-up for the quantification of mineralization in biopolymer scaffolds

Objective. 3D cell cultures are becoming a fundamental resource for in-vitro studies, as they mimic more closely in-vivo behavior. The analysis of these constructs, however, generally rely on destructive techniques, that prevent the monitoring over time of the same construct, thus increasing the results variability and the resources needed for each experiment. Approach. In this work, we focus on mineralization, a crucial process during maturation of artificial bone models, and propose electrical impedance tomography (EIT) as an alternative non-destructive approach. In particular, we discuss the development of an integrated hardware/software system capable of acquiring experimental data from 3D scaffolds and reconstructing the corresponding conductivity maps. We also show how the same software can test how the measurement is affected by biological features such as scaffold shrinking during the culture. Main results. An initial validation, comprising the acquisition of both a non-conductive phantom and alginate/gelatin scaffolds with known calcium content will be presented, together with the in-silico study of a cell-induced mineralization process. This analysis will allow for an initial verification of the systems functionality while limiting the effects of biological variability due to cell number and activity. Significance. Our results show the potential of EIT for the non-destructive quantification of matrix mineralization in 3D scaffolds, and open to the possible long term monitoring of this fundamental hallmark of osteogenic differentiation in hybrid tissue engineered constructs

A broadband current sensor based on the X-Hall architecture

A broadband current sensor, which is fully integrated and galvanically-isolated, is presented in this paper. The current sensor relies only on a Hall-effect probe to realize the magnetic sensing core so as to minimize the cost and the occupied space. Bandwidth limitations of state-of-the-art Hall-effect probes are overcame by combining the novel X-Hall architecture with a wide bandwidth differential-difference current-feedback amplifier. A prototype implemented in 0.16 \u3bcm BCD technology demonstrates a bandwidth wider than 20 MHz. Offset, sensitivity and power consumption are comparable to the state of the art. This is the first Hall-only current sensor achieving a bandwidth higher than 3 MHz

Microstructured soft devices for the growth and analysis of populations of homogenous multicellular tumor spheroids

: Multicellular tumor spheroids are rapidly emerging as an improved in vitro model with respect to more traditional 2D culturing. Microwell culturing is a simple and accessible method for generating a large number of uniformly sized spheroids, but commercially available systems often do not enable researchers to perform complete culturing and analysis pipelines and the mechanical properties of their culture environment are not commonly matching those of the target tissue. We herein report a simple method to obtain custom-designed self-built microwell arrays made of polydimethylsiloxane or agarose for uniform 3D cell structure generation. Such materials can provide an environment of tunable mechanical flexibility. We developed protocols to culture a variety of cancer and non-cancer cell lines in such devices and to perform molecular and imaging characterizations of the spheroid growth, viability, and response to pharmacological treatments. Hundreds of tumor spheroids grow (in scaffolded or scaffold-free conditions) at homogeneous rates and can be harvested at will. Microscopy imaging can be performed in situ during or at the end of the culture. Fluorescence (confocal) microscopy can be performed after in situ staining while retaining the geographic arrangement of spheroids in the plate wells. This platform can enable statistically robust investigations on cancer biology and screening of drug treatments

Energy autonomous systems : future trends in devices, technology, and systems

The rapid evolution of electronic devices since the beginning of the nanoelectronics era has brought about exceptional computational power in an ever shrinking system footprint. This has enabled among others the wealth of nomadic battery powered wireless systems (smart phones, mp3 players, GPS, …) that society currently enjoys. Emerging integration technologies enabling even smaller volumes and the associated increased functional density may bring about a new revolution in systems targeting wearable healthcare, wellness, lifestyle and industrial monitoring applications

Towards Stochastic Molecular Sensing: the Receptronics Project

Molecular sensing is a technique where Technology cannot compete with Nature. As an example, the accuracy of chemical senses in insects is 100 billions greater than state-of-the-art electronic noses. The incredible sensitivity of living beings is based on the molecular recognition paradigm associated with the the ligand-receptor interaction. This technique is the primordial process of biological communication required by any regulatory process: cells send data by means of a complex network of molecular messengers. There are perhaps millions of regulatory substances in the human body and any imbalance between them may have dramatic consequences for well-being and health. Thus, molecular recognition is one of the first steps for a deep understanding of biological mechanisms and being able to detect specific molecules at very low concentrations might be a new promising area for diagnostics. However, it raises several challenges that require new design approaches with strong synergy between different disciplines: from microfluidics to ionics and from nanoelectronics to stochastic data processing. The presentation, will focus on objectives, challenges and results of the RECEPTRONICS project funded by the European Commission, aimed at developing a biomimetic approach for molecular recognition