Bamboo Leaf‐Like Micro‐Nano Sheets Self‐Assembled by Block Copolymers as Wafers for Cells

Bamboo leaf shaped poly(ethylene oxide)‐ b ‐poly(ϵ‐caprolactone) (PEO‐ b ‐PCL) sheets were prepared via crystallization‐driven self‐assembly. By selecting an appropriate mixed solvent, the polymer sheets, with a PCL single‐crystal layer sandwiched by two PEO layers, were obtained efficiently. The morphology and structure of the sheets were characterized by microscopes and diffraction techniques. As a non‐spherical model particle, endocytosis of the sheets was investigated on RAW 264.7, U937, HUVECs, HeLa, and 293T cells. The polymer sheets, just like wafers for cells, displayed a selective internalization to different cells, which showed a potential application in accurate cell targeting drug delivery and imaging.