Early detection and isolation of circulating tumor cells (CTCs) can provide helpful information for diagnosis, and functional readouts of CTCs can give deep insight into tumor biology. In this work, we presented a new strategy for simple isolation and release of CTCs using engineered nanobioprobes. The nanobioprobes were constructed by Ca(2+)-assisted layer-by-layer assembly of alginate onto the surface of fluorescent-magnetic nanospheres, followed by immobilization of biotin-labeled anti-EpCAM. As-prepared anti-EpCAM-functionalized nanobioprobes were characterized with integrated features of anti-EpCAM-directed specific recognition, fluorescent magnetic-driven cell capture, and EDTA-assisted cell release, which can specifically recognize 10(2) SK-BR-3 cells spiked in 1 mL of lysed blood or human whole blood samples with 89% and 86% capture efficiency, respectively. Our proof-of-concept experiments demonstrated that 65% of captured SK-BR-3 cells were released after EDTA treatment, and nearly 70% of released SK-BR-3 cells kept their viability, which may facilitate molecular profiling and functional readouts of CTCs.

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.

7-Aminocoumarin compound was synthesized and used as phototrigger to cage EpCAM-antibody to construct a photocontrolled CTCs capture and release system.

Multifunctional nanomaterials simultaneously possessing attractive properties, such as strong fluorescent intensity, excellent superparamagnetic behavior, easy modification and good biocompatibility, are always desired in a wide range of applications. In this work, we present a facile ultrasonication-assisted one-step self-assembly strategy for the fabrication of smart fluorescent-magnetic nanobeads (FMNBs) without using a matrix. Via one-step ultrasonication, organic-soluble superparamagnetic nanoparticles (MNPs) and quantum dots (QDs) were automatically encapsulated by amphiphilic (2-hydroxyl-3-dodecanoxyl) propylcarboxymethylchitosans (HDP-CMCHSs) through hydrophobic interaction to form hydrophilic FMNBs, presenting a good QD fluorescent property and a strong MNP magnetic response. The outer surface of the FMNBs was derived from natural biopolymer chitosans, enabling FMNBs with good biocompatibility and convenience for biological modification. As-prepared FMNBs can be easily modified with streptavidin, facilitating bioconjugation with biotin-labeled human epidermal growth factor (hEGF). hEGF-functionalized FMNBs are able to specifically recognize and capture rare target cells spiked in white blood cells, and the recovered cells can be further cultured for a long time. All of these excellent properties make nanobeads promising for circulating tumor cell (CTC) detection.