Colorimetric plasmon resonance microfluidics on nanohole array sensors

We present the label-free colorimetric visualization in microfluidics using plasmon resonance on a large-area and over a wide field-of-view (>100 mm2) nanohole array device called nanoLycurgus Cup Array (nanoLCA). We demonstrate the spectral detection and colorimetric sensing of static solutions of different concentrations of glycerol–water confined in parallel microfluidic channels integrated with nanoLCA. Taking advantage of the large sensor area and the colorimetric sensing capability of nanoLCA, we visualize in real-time the modulation of two immiscible solutions (water and oil), generated with integrated flow-focus microfluidics, in a label-free manner. Finite Element Method (FEM) based simulation tool (COMSOL) was used to verify the droplet formation in the microfluidics. Finite Difference Time Domain (FDTD) electromagnetic simulation was used to identify the resonance modes of the plasmonic sensor. Finally, we demonstrate the real-time monitoring of streptavidin–biotin biomolecular interaction with the plasmonic biosensor.