Multiplexed cytokine detection on plasmonic gold substrates with enhanced near-infrared fluorescence

Protein microarrays based on fluorescence detection have been widely utilized for high-throughput functional proteomic analysis. However, a drawback of such assays has been low sensitivity and narrow dynamic range, limiting their capabilities especially for detecting low abundance biological molecules such as cytokines in human samples. Here, we present fluorescence-enhanced microarrays by plasmonic gold films for multiplexed cytokine detection with up to three orders of magnitude higher sensitivity than on conventional nitrocellulose and glass substrates. Cytokine detection on the gold plasmonic substrate is about 1 to 2 orders of magnitude more sensitive than enzyme-linked immunosorbent assay (ELISA) and can be multiplexed. A panel of 6 cytokines (VEGF, IL-1β, IL-4, IL-6, IFN-γ, and TNF) are detected in the culture media of cancer cells. This work establishes a new method of high throughput multiplexed cytokine detection with higher sensitivity and dynamic range than ELISA.