Captor™ - Label-Free, Microfiltration System for Isolation, Enumeration, and Retrieval of CTCs
Abnova’s Captor™ is a label-free, microfiltration system for isolation, enumeration, and retrieval of circulating tumor cells (CTCs). Circulating tumor cells are cancer cells that have detached from the main tumor before entering the bloodstream. They represent an important transition in cancer transformation and metastasis, and portend significant clinical impact in diagnosis, prognosis, treatment, and monitoring. Current isolation methods of circulating tumor cells rely on more complicated and harsher techniques and use of general surface biomarkers to capture the CTCs. This results in biochemical alterations and damages to the CTCs rendering them unsuitable for downstream protein and gene analysis and cell culture.
Captor™ system utilizes a proprietary Clear Cell™ CTChip® technology based on sophisticated fluid dynamics and myriads of crescent-shaped microwells to ensure capturing of CTCs while leaving other whole blood constituents to flow through. Although CTCs and larger white blood cells are of comparable sizes, CTCs are stiffer, less deformable, and effectively trapped within the microwells. This elegant and simplistic design maximizes CTCs isolation efficiency, purity, and function by preserving CTCs surface integrity, allowing retrieval of the viable cells in their native state.
Captor™ has a built-in real time imaging system for viewing and digitizing the images during the isolation process. CTChip® allows for cell enumeration by counting the numbers of CTCs which have been isolated in the chip. The entire CTChip® can also be transferred to a fluorescent microscope for immunofluorescence and FISH probe staining for examination and characterization of tumor cells. Cells retrieved using the CTChip® have been shown to be similar to their normal cultures in terms of proliferation rate and morphology, supporting that CTCs are not altered and remain viable.
CTC isolation from clinical blood samples of metastatic lung cancer patients. (A) Phase contrast images of isolated CTC after blood processing. Scale bar represents 10μm. (B) Immunofluorescence staining of isolated cells being Pan-CK positive (green), CD45 negative (red) and DAPI positive (blue) to identify cancer and hematopoietic cells. Scale bar represents 20 μm.
Retrieval of Wholly Intact, Viable CTCs
Cell proliferation comparison between normal cultures (control) and retrieved cells over a period of 5 days. No observable differences in cell proliferation rate for MCF-7 cancer cells. Scale bar represents 100μm.
Label-Free, Not Rely on Capture Antibody
Crescent-shaped isolation wells gently separate CTCs from other blood components based on the difference in sizes and cell deformability while protecting the cells from damage.
High Cell Purity
CTC isolation from clinical blood samples of metastatic lung cancer patients. Immunofluorescence staining of isolated cells to identify cancer cells (A) DAPI with blue fluorescence and (B) Pan-CK with green fluorescence, and hematopoietic cells (C) CD45 negative. (D) Merged picture of (A), (B), and (C). Only CTCs are trapped in our device, while the rest of blood constituents continue to flow through smoothly, thereby achieving higher specificity and purity of the sample. Scale bar represents 20 μm.
High Isolation Sensitivity & Retrieval Efficiency
Whole blood processing in the CTChip® from actual cancer patient blood. Bottom Left: CTC isolated during blood processing; Right: CTC isolated after completed blood processing. Under optimum conditions, CTChip® is able to successfully trap cancer cells with at least 80% isolation efficiency. Retrieval is done by simply altering the flow direction such that the CTCs stream towards the cell collection point. The rounded crescent base of the wells minimizes obstruction and protects the CTCs against trauma, thereby ensuring a high percentile of retrieval.