In general, the number of circulating tumor cells (CTCs) in a cancer patient’s blood stream is a strong indicator for the progress of the disease. Moreover, CTC presence in the blood stream is linked to the spread of cancer throughout the body. However, due to the high volume of normal cells and the rarity of CTCs in any given blood sample, biochemical and immunofluorescent techniques typically result in a slow, inefficient process. Hence, the fact that a group of researchers out of Peking University in China have developed a microfluidic CTC isolation system with a >90% efficiency is a significant achievement in the world of cancer research.
The use of spatial gradation makes this microfluidic chip immensely more effective than previous technologies, while maintaining simplicity in principle: a blood sample is passed through the system where tumor cell “filters” allow passage of smaller red blood cells as well as similarly sized white blood cells, due to their greater malleability. As the blood sample filters through the chip, over 90% of present CTCs are captured, unharmed, while other blood constituents pass through. In order to further improve the effectiveness of this technique, the blood sample is exposed to a red blood cell lysis buffer, which effectively removes RBCs from the blood, reducing the chances of a clot forming during screening.
“Experimental results show that our microﬂuidic system is a fast, accurate, and efﬁcient system for the detection, capture, and recovery of CTCs. By lysing the RBCs, we not only achieved a signiﬁcant reduction in the overall processing time but also mitigated the blood clogging problem encountered in most microﬂuidic-based CTC ﬁltering systems. We were also able to successfully capture CTCs in the peripheral blood of ten liver cancer patients with our chip. Our rapid CTC detection, segregation, and recovery system appears promising for use in cancer screening using blood samples (or liquid biopsy), for monitoring cancer development and assessing chemotherapeutic response, and for evaluating pharmacological and genetic analysis of single CTCs.”
Article in Biomicrofluidics: Spatially gradated segregation and recovery of circulating tumor cells from peripheral blood of cancer patients
American Institute of Physics: Microfluidic chip captures live tumor cells in the blood…