Engineered nanogels shape templated by closo-dodecaborate nano-ion and dictated by chemical crosslinking for efficient boron delivery

Abstract The shape of nanoparticles is a key factor for efficient delivery of a cargo to cells. We prepared nanogels of controllable shape suitable for boron delivery from cationic triblock terpolymers poly(ethylene oxide)-b-poly(2-(N, N, N’, N’-tetramethyl guanidium) ethyl acrylate)-b-poly(2-(dimethylamino)ethyl acrylate), PEO-b-PGEA-b-PDMAEA, and closo-dodecaborate nano-ions. The physical crosslinking based on ion pairing of closo-dodecaborate with PGEA blocks led to preassembled nanogels of spherical and wormlike shape. PDMAEA blocks were later chemically crosslinked with 1,2-bis(2-iodoethoxy)ethane, BIEE, to maximize the boron loadings and the nanogels stability. Depending on the blocks lengths, a shape transition was observed after the chemical crosslinking. As confirmed by flow cytometry and confocal microscopy in cervical carcinoma cell lines in vitro, the wormlike chemically crosslinked nanogels were internalized the most efficiently.