RESUMO
A compact biosensor platform with giant magneto-resistive (GMR) sensors suited for the detection of superparamagnetic nanoparticle labels is presented. The platform consist of disposable biosensor cartridges and an electronic reader, which enables quantitative detection with high analytical performance, combined with robustness, ease of use and at low cost. In order to optimise the signal-to-noise ratio (SNR), magnetic labels are excited at high frequency. Wires, integrated in the silicon of the sensor chip are used to generate a well-defined magnetic field on the sensor surface, thus removing the need for mechanical alignment with external apparatus. A signal modulation scheme is applied to obtain optimal detection accuracy. The platform is scalable and can be adapted according to application-specific requirements. Experimental results indicate that three beads of 300 nm diameter can be detected on a sensor surface of 1500 microm2 for a measurement time of 1s.