TEM ultrathin sections of HeLa cells after 12 h incubation with fluorescent magnetopolymersomes (PBD(1200)- b -PEO(600), 10% SPION, 5% DEAC). ( A ) Overview of a typical preparation showing few polymersomes as dark spherical objects and ( B ) peripheral cell region with a rare observation of an internalized magnetopolymersome. The inset depicts a close-up of a multilamellar magnetopolymersome judged from contrast and membrane thickness.
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