Single-cell digital microfluidic mass spectrometry platform for efficient and multiplex genotyping of circulating tumor cells

Gene mutation profiling of heterogeneous circulating tumor cells (CTCs) offers comprehensive and real-time molecular information of tumors for targeted therapy guidance, but the lack of efficient and multiplex genotyping techniques for single-CTC analysis greatly hinders its development and clinical application. Researchers at Xiamen University have developed a single-CTC mass spectrometry analysis method for efficient and multiplex mutation profiling based on digital microfluidics. Digital microfluidics affords integrated single-CTC manipulation, from single-CTC isolation to high-performance whole genome amplification, via nanoliter droplet-based wettability trapping and hydrodynamic adjustment of cell distribution. Coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, multiplex mutation information of individual CTCs can be efficiently and accurately identified by the inherent mass differences of different DNA sequences. This platform achieves Kirsten rat sarcoma viral oncogene mutation profiling of heterogeneous CTCs at the single-cell level from cancer patient samples, offering new avenues for genotype profiling of single CTCs and cancer therapy guidance.

Design of DMF chip for DMF-scMS

(A) Computer-aided design of DMF chip. (B) Photograph of the chip made by lithography and wetting. Scale bar, 500 μm. (C) The enlarged view of the hydrophilic spot on the electrode. Scale bar, 100 μm. (D) Schematic diagram of DMF chip with 6 reservoirs for reagent loading, storage and waste as well as an array of hydrophilic spots.