Efficient Release of Affinity-Captured Cells Using a Coiled-Coil-Based Molecular Trigger.

Affinity-based cell separation is label-free and highly specific, but it is difficult to efficiently and gently release affinity-captured cells due to the multivalent nature of cell-material interactions. To address this challenge, we have developed a platform composed of a capture substrate and a cell-releasing molecular trigger. The capture substrate is functionalized with a cell-capture antibody and a coiled-coil A. The cell-releasing molecular trigger B-PEG (polyethylene glycol), a conjugate of a coiled-coil B and polyethylene glycol, can drive efficient and gentle release of the captured cells, because A/B heterodimerization brings B-PEG to the substrate and PEG chains adopt extended conformations and break nearby multivalent antibody-biomarker interactions. No enzymes or excessive shear stress are involved, and the released cells have neither external molecules attached nor endogenous cell-surface molecules cleaved, which is critical for the viability, phenotype, and function of sensitive cells.