Human Nontumorigenic Microglia Synthesize Strongly Fluorescent Au/Fe Nanoclusters, Retaining Bioavailability

Area of Science:

• Biomedical Engineering
• Cell Biology
• Nanotechnology

Background:

• Cellular synthesis of metal-core nanoclusters (mcNCs) is established in tumorigenic cell lines.
• Nontumorigenic cell line synthesis of mcNCs remains largely unexplored.
• Microglial cells are key immune cells in the central nervous system.

Purpose of the Study:

• To investigate the capacity of human nontumorigenic microglial cells to self-synthesize gold (Au) and iron (Fe) mcNCs.
• To assess cellular uptake of pre-synthesized Au and Fe mcNCs.
• To evaluate the toxicity of metallic salts and synthesized mcNCs.

Main Methods:

• Exposure of microglial cells to gold and iron metallic salts.
• Cellular fluorescence microscopy for imaging and quantification.
• Scanning transmission electron microscopy (STEM) for elemental presence.
• Transmission electron microscopy (TEM) for nanocluster structure confirmation.

Main Results:

• Human microglial cells demonstrated self-synthesis of Au and Fe mcNCs.
• Increased cellular fluorescence observed, dose-dependently with Au salt.
• STEM and TEM confirmed intracellular metal presence and nanocluster formation.
• Self-synthesized mcNCs exhibited similar size and structure to pre-synthesized ones.
• Au salt and pre-synthesized Au/Fe mcNCs showed no significant toxicity.
• Fe salt exhibited higher toxicity and cellular stress.

Conclusions:

• Nontumorigenic microglial cells can self-synthesize Au and Fe mcNCs, expanding their application in cellular imaging.
• Cellular uptake of mcNCs is feasible, with gold-based materials showing a favorable toxicity profile.
• Further research into Fe mcNCs is warranted due to observed toxicity concerns.