We designed a SERS based on immunoassay sensor using the three-dimensional network of carbon nanotubes (3DN-CNTs) having a large contact area for cancer detection and diagnosis. The platform has many advantages such as high sensitivity, and small sample volume requirement for analysis. Three-dimensional network of carbon nanotubes has a net like structure which enhances the surface area. In this study, the detection of oral cancer biomarker CA125 is analyzed by SERS mapping method. Antigen biomarkers can be quantitatively assayed by the changing intensity of specific SERS peak.⁽¹⁾ SERS mapping images were used for the peak area at 1615 cm^-1 for 5 different CA125 biomarker concentration in the 10^-12 ~ 10^-6 g/ml range and represented by 20 x 20 pixels. As the result, limit of detection of 3DN-CNTs was below 100 ng/ml and this value was 3 times higher than that of 2D planar substrate. The platform will be an attractive tool as a sensor for cancer biomarker detection. References 1. Lee, M., Lee, K., Kim, K. H., Oh, K. W. and Choo, J. Lab on a Chip, 2012, 12, 3720-3727