Microinductive Signal Conditioning With Resonant Differential Filters: High-Sensitivity Biodetection Applications

Abstract

Abstract-Inductive-based devices integrated with Si technology for biodetection applications are characterized, using simple resonant differential filter configurations. This has allowed the corroboration of the viability of the proposed circuits, which are characterized by their very high simplicity, for microinductive signal conditioning in high-sensitivity sensor devices. The simulation of these simple circuits predicts sensitivities of the differential output voltage which can achieve values in the range of 0.1-1 V/nH, depending on the coil parameters. These very high-sensitivity values open the possibility for the experimental detection of extremely small inductance changes in the devices. For real microinductive devices, both series resistance and parasitic capacitive components contribute to the decrease of the differential circuit sensitivity. Nevertheless, measurements performed using microcoils fabricated with relatively high series resistance and coupling parasitic effects have allowed detection of changes in the range of 2 nH, which are compatible with biodetection applications with estimated detection limits below the picomolarity range.

Review of methods used for identification of biothreat agents in environmental protection and human health aspects

“…Among other up-to-date diagnostic technologies one should also mention Interferometric Reflectance Imaging Sensor (IRIS) used for the detection of the H1N1 virus [125]; immunomagnetic biosensors [126]; microphysiometric devices based on electrokinetics, which are used for detection of cells and bacteria [127]; MBA (BioThreat Multiplex Assay) microfluidic system for the detection of Bacillus anthracis, Yersinia pestis, Francisella tularensis, Burkholderia pseudomallei, Burkholderia mallei and Variola major [128]; as well as Si technology based on microinductive devices [129]. A combination of protein screen and pH screen technology has been used in a BioCheck Powder Screening Test Kit based on identification of all protein containing powders.…”

Development Integrated Inductive Sensors for Magnetic Immunoassay in "Lab on Chip" Devices

“…In Fig.1 the detection principle is shown. several different works have been presented in the scientific literature which deal with the problem of detect-ing the presence of magnetic markers into a selected area, [Baglio et al 2005], [Serre et al 2006], [Baglio et al 2007], [Azimi et al 2007], [Vilà et al 2005]: in these sensors the inductance value changes as function of a certain density of magnetic particles in the active region of the sensor device. First the active region must be functionalized, very often silanizated, to allow the binding of the antibody over the sensor surface; then both the active region and the magnetic particles must be functionalized with a antibody specific to the analyte to be detected.…”

Optimisation of copper electrodeposition processes for Si technology based inductive microsystems

“…In the last years, Si technology based inductive microsystems are receiving an increasing interest for different kinds of applications, including microactuators, power microgenerators and biosensors [1][2][3][4]. These systems are based on the electromagnetic interaction between a planar coil and a magnetic material.…”

“…In the case of the microactuators and inertial microgenerators, the design of the device includes a fixed coil and a permanent magnet that is usually mounted onto a mobile microstructure [1][2][3]. On the other hand, the use of inductive devices for high sensitivity biodetection applications based on the use of magnetic particles as biological labels has also been reported [4]. In all these cases, it clearly appears that the high value of series resistance, inherent to the planar technology of the microsystems, severely hinders the performance of these devices.…”