Aptamer-based surface plasmon resonance probe

Specific and cost-effective biosensors have been developed based on small surface plasmon resonance (SPR) fiber-sensors functionalized with DNA-aptamers. The lab-made sensors have a 1 cm long gold covered sensor zone and a mirror layer at the end tip. Aptamers against immunoglobulin E were immobilized onto the gold layer at the fiber tip. The sensitivity of the sensors proved to be sufficient to monitor accurately the different immobilization steps of the biorecognition layer and the interaction of the specific proteins with the DNA-aptamers. Experiments with other proteins did not show any non-specific binding. Different possibilities to regenerate the SPR-probe were tested. Earlier papers discussed the limited resolution of this type of multimode SPR-probes compared to prism-based sensors. By analyzing the data with the ‘Savitsky-Golay filter’ and the ‘Minimum Hunt Method’, we could however minimize the impact of the mixing of modes and the loss of polarization on the sensor quality.