In Situ Cellular Localization of Nonfluorescent [60]Fullerene Nanomaterial in MCF-7 Breast Cancer Cells

Abstract

Cellular localization of carbon nanomaterials in cancer cells is essential information for better understanding their interaction with biological targets and a crucial factor for further evaluating their biological properties as nanovehicles or nanotherapeutics. Recently, increasing efforts to develop promising fullerene nanotherapeutics for cancer nanotechnology have been made. However, the main challenge regarding studying their cellular effects is the lack of effective methods for their visualization and determining their cellular fate due to the limited fluorescence of buckyball scaffolds. Herein, we developed a method for cellular localization of nonfluorescent and water-soluble fullerene nanomaterials using the in vitro dick chemistry approach. First, we synthesized a triple-bonded fullerene probe (TBC(60)ser), which was further used as a starting material for 1,3-dipolar cydoaddition using 3-azido-7-hydroxycoumarin and sulfo-cyanineS azide fluorophores to create fluorescent fullerene triazoles. In this work, we characterized the structurally triple-bonded [60]fiillerene derivative and confirmed its high symmetry (T-h) and the successful formation of fullerene triazoles by spectroscopic techniques (ie., ultraviolet-visible, fluorescence, and Fourier transform infrared spectroscopies) and mass spectrometry. The created fluorescent fullerene triazoles were successfully localized in the MCF-7 breast cancer cell line using fluorescent microscopy. Overall, our findings demonstrate that TB(60)ser localizes in the lysosomes of MCF-7 cells, with only a small affinity to mitochondria.