Disclosed are compositions for delivering gene editing molecules to a cell. Exemplary compositions comprise a micelle assembled from a plurality of triblock copolymers, wherein each triblock copolymer having at least one hydrophobic block, at least one hydrophilic block, and at least one poly(L-histidine) block, wherein: the at least one poly(L-histidine) block complexes with the at least one gene editing molecule; and the at least one poly(L-histidine) block is capable of a pH dependent release of the at least one gene editing molecule.