Engineered surface design of recognition site-ordered biomimetic sensor for efficient detection of circulating tumor cells.

The oriented assembly of cell membrane coating plays an important role in advancing the application of this strategy in biomedical fields, particularly in detecting circulating tumor cells (CTCs). Unfortunately, there is a formidable challenge in achieving effective membrane orientation during the coating process owing to the asymmetric properties of cell membranes. Herein, magnetic vesicles released by tumor cells were designed to break down these barriers in the same way that microvesicles are actively secreted from cells, which completely inherited the orientation and characteristics of the parent cell membranes, exhibiting a satisfactory self-targeting ability for homologous cells. To cope with the complex application environment, spatially ordered aptamers were integrated into magnetic vesicles and combined with catalytic hairpin assembly (CHA) technology to construct a recognition site-ordered biomimetic sensor for high-performance detection of CTCs. In this strategy, the ordered arrangement of membrane proteins and aptamers markedly improved capture efficiency of traditional biomimetic strategy for CTCs. Additionally, CHA-induced fluorescence and colorimetric analysis ensured the detection accuracy and sensitivity, with a linear range of 0 to 10 cells mL and a low detection limit of 3 cells mL for fluorometry and 6 cells mL for colorimetry. Overall, the biomimetic sensor offered broader possibilities for detecting rare CTCs and provided new insight to expand the application of cell membrane biomimetic strategies in biomedicine.