Ultrahigh-Sensitivity Biomarker Sensing System Based on the Combination of Optical Disc Technologies and Nanobead Technologies

The detection of biomarkers in body fluids is useful for the early detection of diseases or preventive medical care. Various types of equipment that detect biomarkers have been developed and used for various occasions. It is expected that further improvement of the detection sensitivity of biomarkers will enable the extension for their applications to various diseases. In this paper, we propose a new biomarker sensing system with higher sensitivity. In the system, by combining optical disc technologies and nanobead technologies, we developed a new sensing method. Target biomarkers are specifically immobilized onto the optical disc surface through an antigen-antibody reaction, then the nanobeads are immobilized on top of the biomarkers. Since the biomarkers and beads bind to each other one-on-one, the number of target biomarkers can be measured by counting the number of nanobeads using an optical pickup. The most significant advantage of this method is that measurement can be carried out in a fully digital scheme, in contrast to current sensing systems which measure light intensity in an analog scheme.