Bi-Module Sensing Device to In Situ Quantitatively Detect Hydrogen Peroxide Released from Migrating Tumor Cells

Cell migration is one of the key cell functions in physiological and pathological processes, especially in tumor metastasis. However, it is not feasible to monitor the important biochemical molecules produced during cell migrations in situ by conventional cell migration assays. Herein, for the first time a device containing both electrochemical sensing and trans-well cell migration modules was fabricated to sensitively quantify biochemical molecules released from the cell migration process in situ. The fully assembled device with a multi-wall carbon nanotube/graphene/MnO₂ nanocomposite functionalized electrode was able to successfully characterize hydrogen peroxide (H₂O₂) production from melanoma A375 cells, larynx carcinoma HEp-2 cells and liver cancer Hep G2 under serum established chemotaxis. The maximum concentration of H₂O₂ produced from A375, HEp-2 and Hep G2 in chemotaxis was 130±1.3 nM, 70±0.7 nM and 63±0.7 nM, respectively. While the time required reaching the summit of H₂O₂ production was 3.0, 4.0 and 1.5 h for A375, HEp-2 and Hep G2, respectively. By staining the polycarbonate micropore membrane disassembled from the device, we found that the average migration rate of the A375, HEp-2 and Hep G2 cells were 98±6%, 38±4% and 32 ±3%, respectively. The novel bi-module cell migration platform enables in situ investigation of cell secretion and cell function simultaneously, highlighting its potential for characterizing cell motility through monitoring H₂O₂ production on rare samples and for identifying underlying mechanisms of cell migration.