Surface-engineered graphene navigate divergent biological outcomes toward macrophages

Area of Science:

• Biomaterials Science
• Nanotechnology
• Cell Biology

Background:

• The nano-bio interface is critical for cell-nanomaterial interactions and cell fate.
• Graphene, a 2D material, shows promise for biomedical applications.
• Understanding graphene's interaction with macrophages is crucial for its safe use.

Purpose of the Study:

• To investigate how surface modifications on nanographene oxide (nGO) affect macrophage behavior and viability.
• To elucidate the mechanisms behind nGO-PEI-induced macrophage apoptosis.

Main Methods:

• Synthesis of nanographene oxide (nGO) and surface engineering with polyethylene glycol (PEG), bovine serum albumin (BSA), and poly(ether imide) (PEI).
• Assessment of cellular uptake (endocytosis) and macrophage viability.
• Stepwise analysis of intracellular mechanisms, including mitochondrial interactions, reactive oxygen species, cytochrome c release, and caspase activation.

Main Results:

• PEG and BSA coatings on nGO hindered endocytosis and improved biocompatibility with macrophages.
• nGO-PEI exhibited initial endocytosis but led to macrophage stagnation and compromised viability.
• nGO-PEI interacted electrostatically with mitochondria, disrupting their potential and integrity.
• Mitochondrial disruption triggered reactive oxygen species and cytochrome c release, activating caspases and inducing apoptosis.

Conclusions:

• Surface functionalization of nGO significantly influences macrophage responses.
• PEG and BSA coatings enhance the safety of nGO for biomedical applications.
• nGO-PEI induces macrophage apoptosis via mitochondrial-mediated pathways, highlighting potential toxicity concerns.
• These findings provide insights into graphene-biomaterial interactions and guide future biotechnological applications.