Biological Effect Of Copper Nanocluster Induced Oxidative Stress

Cu nanoclusters?Cu NCs?have adjustable optical properties and are stable fluorescent nanomaterials in biological analysis,targeting bioimaging and anticancer treatments.However their bioactivity remains unclear.In this paper,we investigated the biological effect of BSA modified Cu NCs on humolan non-small cell lung carcinoma?A549?cell lines.The results showed that CuNCs could decrease the cell viability of tumolor cells in a dose-and time-dependent manner.In addition RGD-BSA-Cu NCs with targeting peptide RGD were more prone to be enveloped by A549 cell lines than that of BSA-Cu NCs and induced higher cytotoxicity.The reason can be ascribed to theincreased intracell?lar ROS,which led to apoptosis.The main physical and chemical properties of the clusters were analyzed by transmission electron microscopy,electron paramagnetic resonance,mass spectrumol,laser confocal scanning microscopy,fluorescence and absorption spectra.Moreover their biological effect and mechanism were also verified by cytobiologyical techniques.The details and results are as follows:1.The RGD peptide was used to modify BSA and the synthesized RGD-BSA was utilized to prepare targeted copper nanoclusters.The n?molber of copper atoms in the cluster was 13 characterized by fluorescence spectroscopy and MALDI-TOF mass spectrometry.Two peptides were coupled to a single BSA.2.According to the spontaneous fluorescence of the RGD-BSA-Cu NCs,it was determined that it can target to tumolor cells and they can locate in the cytoplasm.3.The results showed that RGD-BSA-Cu NCs had higher cytotoxicity compared with BSA-Cu NCs,and the rate of cell endocytosis was also increased to some extent.4.The lethal rate of RGD-BSA-Cu NCsin A549 cells was about 250 umol in a certain gradient.5.The experimental results show that the combination of RGD-BSA-Cu NCs with 100?mol\L H₂O₂ leads to the generation of hydroxyl radicals.6.The apoptosis induced by RGD-BSA-Cu NCs was in a concentration-dependent manner.7.The RGD-BSA-Cu NCs causes an increase of ROS concentration in tumolor cells,leading to tumolor cell death.8.Molecular mechanism of RGD-BSA-Cu NCs-induced apoptosis in tumolor cells was also investigated.In this paper,a highly biocompatible,targeted copper cluster is introduced into tumolor cells,which can efficiently oxidize weakly oxidized H₂O₂ in tumolor cells into strong oxidized·OH,which regulates the oxidative stress in t?molor cells.In addition,owing to the fact that the characteristics of tumolor cells that are compare to that of normal cells,they selectively and efficiently induce the death of stress-sensitive tumolor cells.