Surface-Enhanced Raman Scattering Based Microfluidics for Single-Cell Analysis

The integration of surface-enhanced Raman scattering (SERS) with droplet microfluidics has the potential to improve our understanding of cellular systems. Herein, we present the first application of SERS droplet microfluidics for single-cell analysis. A microfluidic device was used to encapsulate single prostate cancer cells and wheat germ agglutin (WGA)-functionalized SERS nanoprobes in water-in-oil droplets that were subsequently locked into a storage droplet array for spectroscopic investigation. The stationary droplets enabled the rapid identification of SERS regions of interest in live cancer cells by allowing collection of "fast" coarse maps over an area of several square millimeters followed by "slower" detailed interrogation of the identified hotspots. We demonstrate SERS at cellular resolution via a proof-of-concept assay that detects glycan expression on the surface of prostate cancer cells using WGA-modified metallic nanoparticles. The data illustrates the potential of SERS optofluidic systems for high-throughput cell screening and illustrates a previously unobserved high degree of cell-to-cell variability in the size and number of glycan islands.