Dual-purpose nanoparticle assembly for identifying preferential intracellular targets of oxindolimine copper(II) complexes through SERS imaging

Abstract

In this study, the main goal was to identify the intracellular targets of oxindolimine copper(II) complexes by SERS and Raman imaging of living HeLa cells, whose action as a cancer inhibitor has been previously determined. The used SERS probe was constituted of spherical gold nanoparticles together with the Raman reporter 5,5′-dithiobis-2-nitrobenzoic acid (DTNB) and oxindolimine copper(II) complexes, [Cu(isatp)Cl] and [Cu(nisatp)H2O]. Two excitation radiations were used to acquire living single HeLa cells images: 532 nm to acquire the conventional Raman information of the cells and 785 nm to acquire the localization of the modified SERS probe inside the cells. The Raman images of the main intracellular components were obtained by multivariate analysis, and the SERS images were obtained by univariate analysis using a Raman reporter. The SERS and Raman images showed that the complexes could enter the cells together with the gold nanoparticles, causing main damage to the nuclei and lipids-rich region. In addition, there was no evidence of water entry into the cell.