Antibody-Functional Microsphere-Integrated Filter Chip with Inertial Microflow for Size–Immune-Capturing and Digital Detection of Circulating Tumor Cells

Abstract

Circulating tumor cells (CTCs) in blood is the direct cause of tumor metastasis. The isolation and detection of CTCs in the whole blood is very important and of clinical value in early diagnosis, postoperative review, and personalized treatment. It is difficult to separate all types of CTCs that efficiently rely on a single path due to cancer cell heterogenicity. Here, we designed a new kind of "filter chip" for the retention of CTCs with very high efficiency by integrating the effects of cell size and specific antigens on the surface of tumor cells. The filter chip consists of a semicircle arc and arrays and can separate large-scale CTC microspheres, which combined with CTCs automatically. We synthesized interfacial zinc oxide coating with nanostructure on the surface of the microsphere to increase the specific surface area to enhance the capturing efficiency of CTCs. Microspheres, trapped in the arrays, would entrap CTCs, too. The combination of the three kinds of strategies resulted in more than 90% capture efficiency of different tumor cell lines. Furthermore, it is easy to find and isolate the circulating tumor cells from the chip as tumor cells would be fixed inside the structure of a filter chip. To avoid the high background contamination when a few CTCs are surrounded by millions of nontarget cells, a digital detection method was applied to improve the detection sensitivity. The CTCs in the whole blood were specifically labeled by the antibody−DNA conjugates and detected via the DNA of the conjugates with a signal amplification. The strategy of the antibody−functional microsphere-integrated microchip for cell sorting and detection of CTCs may find broad implications that favor the fundamental cancer biology research, the precise diagnosis, and monitoring of cancer in the clinics.

Bioinspired Tumor Calcification Enables Early Detection and Elimination of Lung Cancer

“…The dissected lung exhibited significantly reduced numbers of metastatic nodules upon CiP treatment (Figure S10E, Supporting Information). Consistently, the numbers of circulating tumor cells (CTCs) in mouse blood captured by human epithelial cell adhesion molecule (EpCAM) antibody [ 21 ] were also reduced 2 weeks after the initiation of CiP and Dox treatment (Figure S10F, Supporting Information), and tumor‐bearing lungs in the CiP exposure group also showed clear calcification by micro‐CT (Figure S10G, Supporting Information).…”

Application of Microfluidics in Detection of Circulating Tumor Cells

“… Chen K. et al (2019) used the chip with lateral microcolumn array structure, modified EpCAM antibody on the microcolumn ( Figure 5B ), combined size based separation with immunoaffinity based separation to improve the capture efficiency of CTCs and reduce the nonspecific geometric capture of normal cells. Using the same principle, Su et al (2019) developed a functional antibody microsphere integrated microchip ( Figure 5C ) by integrating cell size and tumor cell surface-specific antigen and introducing surface-functionalized modified zinc oxide microsphere, which greatly improved the effective capture area.…”

“… CTCs Enrichment by combining biological affinity with physical screening (A) The Octopus chip for cell capture ( Song et al, 2019 ); (B) The LFAM device consisting of four serpentine main channels (Chen et al, 2019); (C) The antibody functional microsphere integrated filter chip ( Su et al, 2019 ). …”

Automatic medium exchange for micro‐volume cell samples based on dielectrophoresis

“…Centrifugation [34–38] and filtration [39–43] are two conventional cell medium exchange methods commonly used in biological experiments. The principle of centrifugal cell medium exchange is based on the fact that the cell density is higher than the medium, hence the cell will sink to the bottom under high‐speed rotation.…”