P3.9 - Measuring System and Method Eliminating Drifts and Parasitic Influences for Cantilever Based Bio-Sensors

Event
SENSOR+TEST Conferences 2009
2009-05-26 - 2009-05-28
Congress Center Nürnberg
Band
Proceedings SENSOR 2009, Volume II
Chapter
P3 - Chemo-/Bio-Sensors
Author(s)
G. Minchev, T. Mincheva - Bulgarian Academy of Sciences, Sofia, Bulgaria, V. Stavrov - AMG Technology Ltd., Botevgrad, Bulgaria
Pages
359 - 362
DOI
10.5162/sensor09/v2/p3.9
ISBN
978-3-9810993-5-5
Price
free

Abstract

The most natural and universal approach for identification of nano-sized biological objects (macromolecules, molecular complexes, viruses, bacterial spores, etc.) is to immobilize them with respective antibodies on cantilever surface and then to measure the sensor mass change. Difficulties arise due to the ultra small magnitude of these changes. An added to the cantilever mass could be registered as a change in deflection or a shift in resonance frequency. Using only one cantilever as an ultrasensitive balance faces serious obstacles. The frequency change (used as measure for mass change) forms as a sum of many influences (from mass change, but also from temperature, pressure, illumination, etc.) and accumulates several types of drifts (ageing/wearing, degradation of functionalization, irreversible chemical transformations, etc.). Moreover, for the mass-change range of interest those parasitic influences dominate by magnitude.
To overcome the problems we composed a self-consistent solution covering several levels: MEMS construction level, measuring procedures (method) level, data processing level and system level. MEMS structures with four specifically diverged cantilevers for one sensing task, a set of simultaneously taken differential measurements, computing several aggregate quantities from huge amount of precise measurement data and inner for the system continuous calibrations are the key advances.

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