a) Cytotoxicity of the SE8Y (S1), S2E8Y (S2) and S4E8Y (S4) protein polymers against Hela cells. b) In vitro cytotoxicity of SE8Y/Dox (S1/Dox), S2E8Y/Dox (S2/Dox), S4E8Y/Dox (S4/Dox) complexes and free doxorubicin against HeLa cells. c) IC50 values of S1/Dox, S2/Dox, S4/Dox complexes and free doxorubicin against HeLa cells.