Chinese scientists have developed a first-of-its-kind purifier designed to remove breakaway tumour cells from the bloodstream, a move that could potentially prevent the recurrence and spread of various cancers. The Shanghai Jiao Tong University-led team announced the proof-of-concept platform in a peer-reviewed research paper published on November 2.
The researchers stated the system could lower the risk of metastasis, which they identified as the leading cause of cancer-related deaths worldwide. In a study published in the journal Microsystems & Nanoengineering, part of the Nature portfolio, the team tested the device on mouse models of breast cancer. The results showed the device effectively removed breakaway cells, delaying tumour relapse and extending survival.
According to the paper, half of the mice that received the purification treatment alongside chemotherapy after surgery survived the study period. In comparison, only a fifth of those given just one of the therapies survived, while none of the mice that received no additional therapy survived.
The researchers described the "black-hole system" as a potential safe and effective additional therapy for post-operative cancer management. They noted that metastasis accounts for more than 90 per cent of cancer-related deaths. The process relies on the spread of circulating tumour cells that break away from a primary site or a secondary lesion. While these cells are currently used in liquid biopsies to track cancer progress, the team noted that existing strategies to eliminate them—such as photodynamic therapy or 3D scaffolds—face hurdles like low capture efficiency and biosafety concerns.
The new system uses a pump to draw blood from the left carotid artery into an external microfluidic reservoir, which the team calls the "black hole." This reservoir is engineered to selectively trap circulating tumour cells using antibodies that target EpCAM, a surface protein found on cancer cells but absent in normal blood components. The blood then returns to the body through the right jugular vein.
The team stated, "This system enables real-time in vivo detection and removal of circulating tumour cells from peripheral circulation and holds significant promise as an adjuvant therapy to enhance the efficacy of post-surgical chemotherapy."
During testing, the reservoir achieved a capture efficiency above 99 per cent for human breast cancer cells at a low flow rate. This remained at around 95 per cent when the speed was increased to 1.2ml per hour, a speed the team chose to balance efficiency with the need to reduce stress on the animals. The researchers also confirmed the system worked on multiple cancer cell lines expressing the same surface protein, including human lung and prostate cancer.
In the live mouse models, the team surgically removed tumours once circulating cells were detected. Over a four-week monitoring window, the combined treatment of the black-hole system and chemotherapy achieved a 50 per cent survival rate and a 16.7 per cent reduction in overall tumour recurrence. Analysis later found no overt toxicity in the mice's organs, suggesting the system is biocompatible.
The researchers noted that the study "should be viewed primarily as a proof-of-concept investigation." They identified several hurdles before clinical application, including scaling the system to process larger volumes of blood for humans and enabling multiple elimination sessions.
The team is currently working to extend experiments into larger rat models. They stated, "Future studies will focus on the optimisation of the black-hole system for repeated use, assessment of long-term safety and performance in larger animal models, and evaluation of its applicability across a broader spectrum of cancer types." They added that "Further engineering optimisation and larger-scale validation will be required before the clinical feasibility and cost-effectiveness of this strategy can be fully determined."
