The impact of Zn doping on CdTe quantum dots-protein corona formation and the subsequent toxicity at the molecular and cellular level

Understanding the formation of protein corona (PC) is of vital importance for exploring the toxicity of nanoparticles and promoting their safe applications. In this study, CdTe QDs doping with 0, 1%, 5% and 10% Zn were synthesized using one-pot hydrothermal methods. Afterwards, this study explored and compared the formation of pure and Zn doped-QDs PC as well as the subsequent molecular and cellular toxicity. Result found that Zn doping regulated the toxicity of Cd-QDs by controlling their ability to adsorb serum proteins. The adsorption to Cd-QDs induced the dispersion, unfolding, secondary structural changes and the activity loss of bovine serum albumin (BSA). Among the synthesized Cd-QDs, 10%Zn-QDs exhibited the highest fluorescence quantum yield and lowest molecular toxicity. The formations of pure QDs and 10%Zn-QDs with BSA corona are majorly driven by different forces with different patterns. The regulation of BSA on the cytotoxicity differences of pure QDs and 10%Zn-QDs was similar with fetal bovine serum, proving the significant contribution of BSA to the cytotoxicity of Cd-QDs PC. Compared with pure QDs PC, the higher cytotoxicity and oxidative stress level of 10%Zn-QDs PC were correlated with higher intracellular [Cd²⁺]. Both larger amount of BSA adsorption and higher level of intracellular reactive oxygen species could accelerate the dissolution rates of 10%Zn-QDs and thus result in higher intracellular [Cd²⁺].