Tri-mode Responses to Reactive Oxygen Species In Vivo by Chiral Vanadium-Based Nanoparticles

Reactive oxygen species (ROS) are closely associated with the redox balance of the physiological environment, and monitoring ROS can aid in the early diagnosis of many diseases, including cancer. In this study, chiral vanadium trioxide/vanadium nitride (V2O3/VN) nanoparticles (NPs) modified with an organic dye (cyanine 3 [Cy3]) were prepared for ROS sensing. Chiral V2O3/VN NPs were prepared with the "ligand-induced chirality" strategy and showed a g-factor of up to 0.12 at a wavelength of 512 nm. To the best of our knowledge, this g-factor is the highest value of all chiral ceramic nanomaterials. The very high g-factor of the nanoprobe confers very high sensitivity, because the higher g-factor, the higher sensitivity. In the presence of ROS, V3+ in the chiral V2O3/VN nanoprobe undergoes a redox reaction to form V2O5, reducing the circular dichroism and absorbance signals, whereas the fluorescence signal of Cy3 is restored. With this nanoprobe, the limits of detection for the circular dichroic and fluorescence signals in living cells are 0.0045 nmol/106 and 0.018 nmol/106 cells, respectively. This chiral nanoprobe can also monitor ROS levels in vivo by fluorescence. This strategy provides an innovative approach to the detection of ROS and is expected to promote the wider application of chiral nanomaterials for biosensing.