Fig. 1. Diagrams of preparation processes of PDMS microchannel. (a) Preparation of PDMS glue; (b) preparation of microchannel

Fig. 2. Characterization results of CNTs/AgNPs substrate. (a) SEM image of CNTs/AgNPs substrate; (b) size distribution of Ag nanoparticles

Fig. 3. Microfluidic SERS device. (a) Real product; (b) microchannel diagram under Raman confocal microscope

Fig. 4. Raman spectra of R6G molecules of PDMS, CNTs/AgNPs substrate, and microfluidic SERS device

Fig. 5. Raman experimental results at different points. (a) Raman spectra of the randomly selected 6 points in the microchannel; (b) intensity curves corresponding to the 6 points at 1510 cm-1 and 1649 cm-1

Fig. 6. Raman experimental results at different time. (a) Raman spectra of R6G vary with time at the same position in the microchannel; (b) intensity curves corresponding to different time at 1510 cm-1and 1649 cm-1

Fig. 7. Simulation result of CNTs/AgNPs composite structure