Rapid isolation and detection of cancer cells by utilizing integrated microfluidic systems

The present study reports a new three-dimensional (3D) microfluidic platform capable of rapid isolation and detection of cancer cells from a large sample volume (e.g. ∼1 mL) by utilizing magnetic microbead-based technologies. Several modules, including a 3D microfluidic incubator for the magnetic beads to capture cancer cells, a microfluidic control module for sample transportation and a nucleic acid amplification module for genetic identification, are integrated into this microsystem. With the incorporation of surface-modified magnetic beads, target cancer cells can be specifically recognized and conjugated onto the surface of the antibody-coated magnetic microbeads by utilizing a swirling effect generated by the new 3D microfluidic incubator, followed by isolating and purifying the magnetic complexes via the incorporation of an external magnet and a microfluidic control module, which washes away any unbound waste solution. Experimental results show that over 90% of the target cancer cells can be isolated from a large volume of bio-samples within 10 min in the 3D microfluidic incubator. In addition, the expressed genes associated with ovarian and lung cancer cells can also be successfully amplified by using the on-chip nucleic acid amplification module. More importantly, the detection limit of the developed system is found to be 5 × 10¹ cells mL^-1 for the target cancer cells, indicating that this proposed microfluidic system may be adapted for clinical use for the early detection of cancer cells. Consequently, the proposed 3D microfluidic system incorporated with immunomagnetic beads may provide a promising automated platform for the rapid isolation and detection of cancer cells with a high sensitivity.