Abstract
Although cationic porous polymers have been widely used for gene and drug delivery, the delivering function of anionic porous polymers has rarely been explored. Herein, we prepare a polyanionic flexible organic framework (pa-FOF) through the quantitative formation of the acylhydrazone bond from a tetraanionic tetraaldehyde and a tetraanionic diacylhydrazine. Pa-FOF is highly water-soluble and has a size of 26 to 51 nm, which depends on the concentration of the monomers, and an aperture of approximately 3.8 nm. Fluorescence, zeta potential, confocal laser scanning microscopic and flow cytometric experiments reveal that pa-FOF can adsorb basic proteins, including lysozyme, trypsin and cytochrome c, which is driven by intermolecular ion-pairing electrostatic attraction and hydrophobicity, and realizes efficient intracellular delivery of the adsorbed proteins. Confocal laser scanning microscopic imaging experiments further illustrate that the delivery of cytochrome c can significantly increase its ability of causing cell apoptosis.