Photosystem I Bio-Photosensor Integrated with Complementary Metal–Oxide–Semiconductor Source–Drain Follower on a Chip

概要

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A new bio-photosensor where photons are converted to electrons by photosystem I (PSI) of Thermosynechococcus elongatus is described; in this bio-photosensor, the converted electronic charge is sensed by a complementary metal–oxide–semiconductor (CMOS) source–drain follower circuit fabricated by the 1.2 μm standard CMOS process. Thin Au/Ti films are deposited and patterned with a $4.255\times 4.255$ μm2 extended-gate electrode, and an SU-8 layer is formed, with the exception of the electrode, to reduce the light-induced drift of silicon nitride. As a result, only the Au electrode and the SU-8 layer come into contact with the electrolyte. The PSI is immobilized on the electrode, and the photoresponse due to the photovoltaic effect of PSI is measured as the output voltage of the CMOS source–drain follower. The action spectrum from the light source is consistent with the PSI absorption spectrum. In addition, the selectivity of the photoresponse between two adjacent sensor cells is confirmed, which is promising for ultrasensitive bioimage sensing.
2010-01-25