In a study published in Analyst, a research group led by Prof. LI Bei from the Changchun Institute of Optics, Fin Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences(CAS) proposed a more convenient and accuracy way to detect carcinoembryonic antigen (CEA).

Cancer markers have played an important role in early diagnosis, intervention and curative effect monitoring of cancer. Cancer marker detection has important meaning in the field of clinical treatment of cancer.

Therefore, CEA was choice as the detection target. CEA is a broad-spectrum cancer marker, which has significant clinical value in the differential diagnosis, disease monitoring and efficacy evaluation of gastric cancer, lung cancer, colorectal cancer and other cancer.

Through image analysis method and the control of a high-precision motorized stage, CEA detection can be performed automatically. And the final image data can be analyzed to create a standard curve for CEA in the sample for quantitative analysis of CEA. This makes CEA detection much easier, and the introduction of microfluidics technology greatly reduces detection costs.

In this study,a droplet array microfluidics chip based on polydimethylsiloxane (PDMS) and glass was designed to detect the concentration of CEA combined with a working platform to realize the automatic detection process. The detection method was based on colorimetric signal generating by 3,3',5,5'-tetramethylbenzidine(TMB) color development.

The best condition was also explored for the structure of the microfluidics chip and the working platform. The width of link channel between reagents chambers was optimized to 700 μm and the moving speed of the magnet was optimized to 500 μm/s which ensure that the immunomagnetic beads capturing CEA are transferred as much as possible.

The results showed the standard curve of the CEA detection following the linear equation: y = -4.773ln(x) + 156.26 with a correlation of R² = 0.9924. The detection of the CEA with LOD of 14.347 pg/mL in the droplet-array microfluidic chip was achieved within 80 min.