Enantioselective cellular uptake of chiral semiconductor nanocrystals

Abstract

The influence of the chirality of semiconductor nanocrystals, CdSe/ZnS quantum dots (QDs) capped with L- and D-cysteine, on the efficiency of their uptake by living Ehrlich Ascite carcinoma cells is studied by spectral- and time-resolved fluorescence microspectroscopy. We report an evident enantioselective process where cellular uptake of the L-Cys QDs is almost twice as effective as that of the D-Cys QDs. This finding paves the way for the creation of novel approaches to control the biological properties and behavior of nanomaterials in living cells.

Enantioselective cytotoxicity of ZnS:Mn quantum dots in A549 cells

“…After the synthesis of the QDs, optical activity was induced by exchange of the original oleylamine ligands with D‐ and L‐Cys ligands . It has been demonstrated before that the ligand exchange method used in this work does not influence either the size or morphology of QDs .…”

“…This difference in cytotoxicity can be explained by the following effects. First, L‐Cys and D‐Cys‐QDs can exhibit enantioselective cellular uptake . This means that the concentration of QDs inside the cells and the corresponding cytotoxicity will be different.…”

“…First, L-Cys and D-Cys-QDs can exhibit enantioselective cellular uptake. 26 This means that the concentration of QDs inside the cells and the corresponding cytotoxicity will be different. Second, L-Cys and D-Cys-QDs can induce different mechanisms of cytotoxicity, such as level of ROS generation, apoptosis, or autophagy.…”

“…8,14,24,25 It has been recently shown that NPs capped with opposite enantiomers of chiral ligands demonstrate different biological activity, including cytotoxicity within living cells. [26][27][28] There is a wide variety of NPs that are very promising for a range of biomedical applications. 29 In particular, quantum dots (QDs) are of great interest.…”

Completely Chiral Optical Force for Enantioseparation

“…Much like enantiomeric molecules, chiral nanocrystals feature significantly different interactions with biomolecules and biological tissues14. For example, it has been experimentally demonstrated that certain cancer cells (e.g., HT1080 fibrosarcoma) exhibit a highly selective uptake of chiral CdS quantum dots (QDs), with an almost 100% uptake of the D-type QDs and a negligible uptake of the L-type QDs15. The need of individually testing each enantiomer of a chiral nanoparticle for its bioactivity and safety naturally extends the problem of enantioseparation from the pharmaceutical field to the entire field of chiral nanotechnology.…”