Enhanced antibody recognition with a magneto-optic surface plasmon resonance (MO-SPR) sensor

A comparison between sensing performance of traditional SPR (Surface Plasmon Resonance) and magneto-optic SPR (MOSPR) transducing techniques is presented in this work. MOSPR comes from an evolution of traditional SPR platform aiming at modulating Surface Plasmon wave by the application of an external magnetic field in transverse configuration. Previous work demonstrated that, when the Plasmon resonance is excited in these structures, the external magnetic field induces a modification of the coupling of the incident light with the Surface Plasmon Polaritons (SPP). Besides, these structures can lead to an enhancement in the magneto-optical (MO) activity when the SPP is excited. This phenomenon is exploited in this work to demonstrate the possibility to use the enhanced MO signal as proper transducer signal for investigating biomolecular interactions in liquid phase. To this purpose, the transducer surface was functionalized by thiol chemistry and used for recording the binding between Bovine Serum Albumin molecules immobilized onto the surface and its complementary target. Higher sensing performance in terms of sensitivity and lower limit of detection of the MOSPR biosensor with respect to traditional SPR sensors is demonstrated. •Surface Plasmon Resonance transducer platform is compared with Magneto-Optic Surface Plasmon Resonance (MO-SPR) transducing technique.•MO-SPR transducer is composed of a metal trilayer Au/Co/Au of proper thickness.•MO-SPR signal is obtained by the modulation of the Surface Plasmon Polaritons by the application of an external magnetic field in transverse configuration.•The obtained sensor signal is used to monitor BSA immobilization onto the transducer surface and its binding with the complementary antibody at increasing concentration. Regeneration step is also tested.•The obtained sensor signal is demonstrated to have enhanced functionalities with respect to traditional SPR sensor in terms of better signal-to-noise ratio better sensitivities and lower limit of detection.