Siani and Di Valentin simulated the binding between dopamine-functionalized TiO2 nanoparticles and proteins overexpressed in cancer cells such as poly (ADP-ribose) polymerase 1 (PARP1) and heat shock protein (HSP90), showing that a less acidic intracellular pH under cytosolic ionic conditions strengthened the interactions between PARP1 and nanoparticles but weakened those between HSP90 and nanoparticles, which was interpreted by electrostatic and vdW contributions (Figure 7) [63]. This evidence concerns the gene PARP1 and cancer.