Measuring system and method eliminating drifts and parasitic influences for cantilever based bio-sensors

摘要

The most natural and universal approach for identification of nano-sized biological objects (macrornolecules, 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.