2D profiling of tumor chemotactic and molecular phenotype at single cell resolution using a SERS-microfluidic chip

Emerging single-cell technologies create new opportunities for unraveling tumor heterogeneity. However, the development of high-content phenotyping platform is still at its infancy. Here, we develop a microfluidic chip for two-dimensional (2D) profiling of tumor chemotactic and molecular features at single cell resolution. Individual cells were captured by the triangular micropillar arrays in the cell-loading channel, facilitating downstream single-cell analysis. For 2D phenotyping, the chemotactic properties of tumor cells were visualized through cellular migratory behavior in microchannels, while their protein expression was profiled with multiplex surface enhanced Raman scattering (SERS) nanovectors, in which Raman reporter-embedded gold@silver core–shell nanoparticles (Au@Ag REPs) were modified with DNA aptamers targeting cellular surface proteins. As a proof of concept, breast cancer cells with diverse phenotypes were tested on the chip, demonstrating the capability of this platform for simultaneous chemotactic and molecular analysis. The chip is expected to provide a powerful tool for investigating tumor heterogeneity and promoting clinical precision medicine.