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A microelectronic chip for the ultra-rapid detection of cells in few micro-liters drop samples is presented. The architecture is based on a two-dimentional 640times480 array of microsites. Dielectrophoresis (DEP) is the physical phenomenon used to manipulate the cells. A corresponding array of photodiodes is used for integrated optical detection. The chip implements a column-parallel, reconfigurable read-out and A/D conversion. The single readout channel is composed by a pre-amplifier with programmable gain and an algorithmic analog-to-digital converter with a 1.5-bit/stage architecture. The chip is implemented in 0.35 mum CMOS technology with a 3.3 V supply.

Fully-electronic detection of cells and microbeads is achieved on a 320x320 array of capacitive sensors in 0.35/spl mu/m 2P3M CMOS technology that also integrates particle actuation by dielectrophoresis. Particle-associated equivalent input capacitance variations larger than 0.42fF are measured with 39dB SNR. Output noise is /spl les/1.6mV, the resolution of the 12b ADC.

A novel approach to the size characterization and separation of bio-particles is presented. Fluid-flow is not required to activate the separation since moving dielectrophoretic cages (MDC) (G. Medoro et al., IEDM, pp. 415-418, 2000) are used. By sequencing a set of cage patterns in a micro-fabricated chip, a movement can be induced or not on bio-particles depending on the ratio between the dielectrophoretic (DEP) mobility (H. Morgan and N.G. Green, Research Studies Press, 2003) and the cage-speed, causing selective particle transport. The effectiveness of the approach has been proven by experimental results with different sized beads. This approach can be easily combined with optical or impedance measurement for on-chip quantification of the mixture constituents for a miniaturized, automatic detection system.

Manipulation of populations of living cells on an individual basis is essential for the investigation of complex interactions among cells. We present a new approach to the integration on silicon of dielectrophoretic actuators and optical sensors that allow us to carry out this task. The device presented in this paper is an 8/spl times/8 mm/sup 2/ chip implemented in a two-poly three-metal 0.35-/spl mu/m CMOS technology, featuring 102,400 actuation electrodes, arranged in an array of 320/spl times/320, 20 /spl mu/m/spl times/20/spl mu/m microsites each comprising addressing logic, an embedded memory for electrode programming, and an optical sensor. The chip enables software-controlled displacement of more than 10,000 individual living cells, allowing biologists to devise complex interaction protocols that are impossible to manage otherwise. The manipulation does not damage the viability of the cells, so that this approach could be a unique extension to the techniques already available to biologists.

This paper introduces an approach for decoding the pressure information exerted over a broad piece of fabric by means of capacitive sensing. The proposed sensor includes a distributed passive array of capacitors (i.e. an array where no active elements are involved), whose capacitance depends on the pressure exerted on the textile surface, and an electronic system that acquire and process the subsequent capacitance variations. Capacitors can be made in different ways, though, in our demonstrator they have been implemented between rows and columns of conductive fibers patterned on the two opposite sides of an elastic synthetic foam. Measures performed over a prototype has been demonstrated the reliability of the approach by detecting pressure images at 3 F/s and by measuring capacitances as low as hundreds of fF spaced apart at meters of distance.

Presents a lab-on-a-chip for electronic manipulation and detection of microorganisms based on the use of closed dielectrophoretic (DEP) cages combined with impedance sensing. A printed circuit board (PCB) prototype has been used to trap, concentrate, and quantify polystyrene micro-beads in agreement with CAD simulations. The experiment was successfully repeated with S. cerevisiae. The results prove the effectiveness of the approach for particle manipulation and detection without the need for external optical components nor chemical labeling. With the proposed approach, particle concentration may be increased on-chip of more than three orders of magnitude, correspondingly boosting the detection sensitivity.

A current-mode weak-inversion circuit for analog function approximation is proposed. It is based on the fuzzy logic paradigm and exploits a modular architecture with respect to the number of inputs and the number of rules. Simulation results show that a 2-input, 1 output transcendental function can be approximated with a 50% RMS error at the expense of 5 /spl mu/W of power consumption with a 3.3 V supply.

A standard-CMOS pointing device for portable applications, such as palmtop and credit-card size computers, is based on fingerprint-motion detection. The device behaves much the same as a track-ball, but it does not require mechanical moving parts and can be fabricated in a smaller package. Pointing devices based on image motion estimation were previously reported. In contrast to these devices, this implementation produces the moving image by direct chip-finger contact.

The implementation of the defuzzification interface by means of operational transconductance amplifiers (OTA) and the use of their model by the algorithms which are in charge of translating user specifications into circuit parameters are discussed. Proper hardware and software design criteria are discussed to ensure the accuracy of the usual functional model, to clarify its use for automatic parameter adaptation and to achieve a better reproduction of the ideal center of gravity defuzzification.

In this paper an analog synthesizer of nonlinear functions is applied to integrated color processing in CMOS cameras. For reproducing images on a display with desired contrast and color correction, a nonlinear distortion of the signal associated with pixels of different colors is needed. The adoption of a design flow for the implementation of nonlinear analog functions allows the integration of this processing on the same chip containing the sensor before the final A/D conversion.

This work describes an analog circuit for function approximation working in current-mode. It implements a piecewise-linear fuzzy system: the membership functions are generated by the daisy-chain connection of identical blocks, resulting in a grid placement of the rules, and programming is achieved by binary encoded digital words representing the consequence of the rules. An approximated analytical model is derived, relating the I/O spread with the bias current variation. The current level allows speed and precision to be traded off for power consumption, while maintaining the same normalized I/O characteristic. The circuit is shown to operate correctly both in strong and weak inversion, with a bias current varying by two orders of magnitude.

A design-flow for the development of applications based on the use of an analog fuzzy processor is presented. A top-down methodology for the specification of the desired behavior is adopted. Verification is supported at each abstraction level by means of simulations and bread-board prototyping facilities are also supported. This allows a step by step development, and eventually leads to the layout of an analog fuzzy processor implementing the desired function. As an example, the design flow is successfully applied to the control of a DC/DC power regulator.

This paper presents a mixed-signal system-on-chip (SOC) for decoding the pressure exerted over a large piece of smart fabric. The image map of the pressure applied over the fabric surface is achieved by detecting the capacitance variation between rows and columns of conductive fibers patterned on the two opposite sides of an elastic layer, like synthetic foam. The SOC approach allows one to reduce design time maintaining the flexibility to accommodate for different sensor sizes and to perform some image enhancement such as fixed pattern noise compensation and gamma correction. The chip has been designed in a 0.35 /spl mu/m 5 ML CMOS process to work at 40 MHz, 3.3 V power supply, in a fully reconfigurable arrangement of 128 rows and columns. The core area is 32 mm/sup 2/.

Microelectronics holds the promise to bring to biology the advantages of miniaturization for carrying out highly automated experiments, under software control, with increased speed and low cost. This paper describes an essential building block for this scenario: a method for the stable levitation and independent motion of microorganisms in a liquid and their precise displacement by means of an electronic programmable device.