Biotransformation of rare earth oxide (REO) nanoparticles on biological membranes may trigger a series of adverse health effects in biosystems. However, the physicochemical mechanism of the complicated biotransformation behavior remains elusive. By investigating the distinctly different biotransformation behavior of two typical REOs (Gd2O3 and CeO2) on erythrocyte membranes, we demonstrate that dephosphorylation by stripping phosphate from phospholipids correlates highly with the membrane destructive effects of REOs. Density functional theory calculations decode the decisive role of the d-band center in dephosphorylation. Furthermore, using the d-band center as an electronic descriptor, we unravel a universal structure-activity relationship of the membrane-damaging capability of 13 REOs (R2 = 0.82). The effect of ion release on dephosphorylation and physical damage to cell membranes by Gd2O3 are largely excluded. Our findings depict a clear physicochemical microscopic picture of the biotransformation of REOs on the nano-bio interface, providing a theoretical basis for safe application of REOs.
Keywords: biotransformation; d-band center; density functional theory; nano-bio interface; rare earth oxides.