Biotin-Triggered Decomposable Immunomagnetic Beads for Capture and Release of Circulating Tumor Cells

Abstract

Isolation of rare, pure, and viable circulating tumor cells (CTCs) provides a significant insight in early cancer diagnosis, and release of captured CTCs without damage for ex vivo culture may offer an opportunity for personalized cancer therapy. In this work, we described a biotin-triggered decomposable immunomagnetic system, in which peptide-tagged antibody designed by chemical conjugation was specifically immobilized on engineered protein-coated magnetic beads. The interaction between peptide and engineered protein can be reversibly destroyed by biotin treatment, making capture and release of CTCs possible. Furthermore, the peptide could mediate multiple antibodies' coimmobilization on engineered protein-coated magnetic beads, by which capture efficiency for CTCs was obviously improved. Quantitative results showed that 70% of captured cells could be released by biotin addition, and 85% of released cells remained viable. In addition, 79% of cancer cells spiked in human whole blood were captured and could also be successfully released for culture. Finally, immunomagnetic beads simultaneously loaded with anti-EpCAM, anti-HER2, and anti-EGFR were successfully applied to isolate and detect CTCs in 17 cancer patients' peripheral blood samples, and 2-215 CTCs were identified with high purity. These results suggest that our method is reliable and has great potential in CTC detection for CTC-based molecular profiling, diagnosis, and therapy.

Current detection technologies for circulating tumor cells

“…Lu et al developed a biotin-triggered decomposable immunomagnetic system, in which peptide-tagged antibody designed by chemical conjugation was specifically immobilized on engineered protein coated magnetic beads. 19 The interaction between peptide and engineered protein can be reversibly destroyed by biotin treatment, making capture and release of CTCs possible. Quantitative results showed that 70% of captured cells could be released by biotin addition, and 85% of released cells remained viable.…”

“…In addition, the purity of separated SK-BR-3 cells was calculated to be 84 ± 3%. 19 Wen et al fabricated magnetic nanospheres (MNs) by a convenient and highly controllable layer-by-layer assembly method, and successfully captured rare tumor cells in whole blood with an efficiency of more than 94% via only a 5 min incubation (Figure S5). …”

“…After enrichment, the CTCs could be detected by fluorescence ( e.g. fluorescent microscope, fluorescent spectrophotometer and flow cytometry), 18,19 surface-enhanced Raman scattering (SERS), 20 or electrical impedance. 21 The enriched CTCs can also be released for further phenotype identification and molecular analysis ( e.g.…”

Beyond Capture: Circulating Tumor Cell Release and Single‐Cell Analysis

“…Such approaches share the drawbacks of discounted cell viability and unsatisfied release efficiency. Xie and co‐workers further designed biotin‐triggered decomposable immunomagnetic beads for reversibly capture and release of CTCs . Strep‐Tactin, an engineered streptavidin with biotin‐binding site, could be bound by Strep‐tag II with intrinsic affinity.…”

“…a) Biotin‐triggered decomposable immunomagnetic beads for reversibly capture and release of CTCs. Reproduced with permission . Copyright 2015, American Chemical Society.…”