Rapid and precise tumor cell separation using the combination of size-dependent inertial and size-independent magnetic methods

Circulating tumor cells (CTCs) play a significant role in cancer diagnosis and treatment monitoring. One of the major challenges in isolating and detecting rare CTCs from blood is that white blood cells (WBCs) have a size overlap with the target CTCs. To address this issue, we constructed a three-stage i-Mag device integrated with passive inertial microfluidics and active magnetophoresis, enabling rapid and precise separation of tumor cells from blood. The first-stage spiral inertial sorter was applied to rapidly remove small-sized red blood cells (RBCs), and then the second-stage serpentine inertial focuser and the third-stage magnetic sorter were used for removing the magnetically labeled WBCs size-independently, to significantly purify the captured tumor cells. Then, the separation performance of our i-Mag device was explored. The results indicated rapid and precise separation of breast cancer cells from diluted whole blood at a high separation efficiency of 93.84% and at a high purity of 51.47%. The purity of the collected tumor cells could be further improved to 93.60% when the blood dilution ratio was increased. We also successfully applied our i-Mag device for the isolation and detection of trace tumor cells. Our i-Mag device has numerous advantages, such as enabling high-throughput processing and high-precision separation, requiring easy manufacturing at a low cost, and providing tumor antigen-independent operation. We believe that the i-Mag device has great potential to act as a precise tool for separating various bioparticles.

Automated summary

The i-Mag device constructed in the study enables rapid and precise separation of cancer cells from blood, achieving high separation efficiency and purity. It has numerous advantages and great potential to act as a precise tool for separating various bioparticles.