Fig. 7. Probability density of PARP1 or HSP90 corona residues adsorbed onto neutral and cationic NPs under physiological ionic strength (KCl at 0.15 M) and their protein secondary structures over the last 50 ns of MD production phase. For the sake of clarity, DA ligands around the TiO₂ NP core are not shown but only protonation or charge state is indicated by + or 0. (a) PARP1 and cationic NP complex at pH 7.4, (b) PARP1 and neutral NP complex at pH 11.5, (c) HSP90 and cationic NP complex at pH 7.4, (d) HSP90 and neutral NP complex at pH 11.5. (e, left-hand side) Color code for the protein secondary structures, (e, right-hand side) color code for the electrostatic potential.