Dual-channel differential surface plasmon ellipsometry for bio-chemical sensing

This work demonstrates a dual-channel surface plasmon sensing device based upon the differential surface plasmon ellipsometry method. Experiments showing the removal of common-mode noise, the linearity of response to changes in refractive index and the use of a reference sensing channel in a comparative protein – antibody study are presented. The ease of multiplexing inherent within the differential surface plasmon ellipsometry method allows for the potential development of sensing systems with many parallel channels. Coupled with the use of reference channels for common-mode noise subtraction, multi-analyte sensing at detection limits comparable to those of the best single channel surface plasmon sensors currently available becomes a realistic goal. In this paper we present the first multi-channel sensing results obtained using the differential surface plasmon ellipsometry method and provide a comparison between the linearity of response to changes in refractive index and a protein–antibody binding study with a commercially available SPR instrument (Nomadics SensiQ Discovery).