In-situ SERS monitoring of membrane receptor PTK7 for assessing cancer cell migration at single-cell level on a microfluidic chip

Protein tyrosine kinase-7 (PTK7), an important membrane receptor, is crucial in cell migration. Accumulated evidence suggests that aberrant PTK7 expression is associated with the occurrence of cancer. Lots of research has focused on revealing the role of PTK7 in the development of cancers, the conventional methods need transwell and western blot, masking intrinsic differences among cells, and the integrity of the cells cannot be preserved, which is important for revealing the role of PTK7 on cancer development. Herein, we present a method to monitor the expression of PTK7 receptor at single-cell level using a surface-enhanced Raman scattering (SERS) microfluidic chip. Cell migration channel arrays were designed, and controllable chemical stimulation was generated on the microfluidic chip, enabling the cell migration at single-cell level. Raman reporter-embedded gold@silver core–shell nanoparticles (Au@4-Mercaptobenzonitrile@AgNPs) modified with DNA aptamers (Sgc8) exhibit promising binding ability to cell membrane receptor PTK7. The different migration abilities of cancer cells were accurately distinguished in the microfluidic chip. We explored the reduced expression of PTK7 on high migration ability cells at single-cell level. And the discrimination of different colorectal cancer cells was successfully realized using the SERS probes. The developed platform is expected to provide a powerful tool for investigating tumor heterogeneity and promoting clinical precision medicine.