Plasmonic nanograting enhanced fluorescence for protein microarray analysis of carcinoembryonic antigen (CEA)

The low sensitivity of protein microarrays has limited the wide application in diagnostics and high-throughput proteomic analysis. We present, for the first time, the exploration of protein microarray analysis on nanostructured plasmonic gold nanograting that showed a 10-fold fluorescence enhancement. The as-fabricated plasmonic protein microarray showed a limit of detection (LOD) of 0.36 ng mL(-1) with the dynamic detection range of 1 ng mL(-1) to 100 mg mL(-1) for detecting the cancer biomarker of carcinoembryonic antigen (CEA). The LOD determined in this study is one order lower than that of the commercial planar glass substrates, which is attributed to the surface plasmon field enhanced fluorescence (SPFS) from the plasmonic coupling. The highly sensitive and wide dynamic detection range of plasmonic microarrays presents new opportunities in proteomic applications and diagnostics research.