Synthesis of Exosome-Based Fluorescent Gold Nanoclusters for Cellular Imaging Applications.
Eun Sung LeeByung Seok ChaSeokjoon KimKyungmoon ParkPublished in: International journal of molecular sciences (2021)
In recent years, fluorescent metal nanoclusters have been used to develop bioimaging and sensing technology. Notably, protein-templated fluorescent gold nanoclusters (AuNCs) are attracting interest due to their excellent fluorescence properties and biocompatibility. Herein, we used an exosome template to synthesize AuNCs in an eco-friendly manner that required neither harsh conditions nor toxic chemicals. Specifically, we used a neutral (pH 7) and alkaline (pH 11.5) pH to synthesize two different exosome-based AuNCs (exo-AuNCs) with independent blue and red emission. Using field-emission scanning electron microscopy, energy dispersive X-ray microanalysis, nanoparticle tracking analysis, and X-ray photoelectron spectroscopy, we demonstrated that AuNCs were successfully formed in the exosomes. Red-emitting exo-AuNCs were found to have a larger Stokes shift and a stronger fluorescence intensity than the blue-emitting exo-AuNCs. Both exo-AuNCs were compatible with MCF-7 (human breast cancer), HeLa (human cervical cancer), and HT29 (human colon cancer) cells, although blue-emitting exo-AuNCs were cytotoxic at high concentrations (≥5 mg/mL). Red-emitting exo-AuNCs successfully stained the nucleus and were compatible with membrane-staining dyes. This is the first study to use exosomes to synthesize fluorescent nanomaterials for cellular imaging applications. As exosomes are naturally produced via secretion from almost all types of cell, the proposed method could serve as a strategy for low-cost production of versatile nanomaterials.
Keyphrases
- fluorescent probe
- living cells
- quantum dots
- energy transfer
- high resolution
- electron microscopy
- sensitive detection
- endothelial cells
- low cost
- label free
- mesenchymal stem cells
- stem cells
- light emitting
- induced pluripotent stem cells
- single molecule
- magnetic resonance
- gas chromatography mass spectrometry
- solid state
- bone marrow
- cell proliferation
- fluorescence imaging
- high intensity
- dual energy
- anaerobic digestion