Janus nanoparticles designed for extended cell surface attachment.

Area of Science:

• Biotechnology
• Nanomedicine
• Cell Biology

Background:

• Isotropic nanoparticles are rapidly internalized by cells via endocytosis.
• Controlling nanoparticle-cell interactions is crucial for biomedical applications.
• Developing methods for stable nanoparticle attachment to cell surfaces is needed.

Purpose of the Study:

• To design and synthesize Janus nanoparticles for firm eukaryotic cell surface attachment with minimal uptake.
• To investigate the interaction of these Janus nanoparticles with NIH 3T3 fibroblasts in vitro.
• To elucidate the endocytosis pathways involved in any observed nanoparticle uptake.

Main Methods:

• Synthesis of rhodamine-doped silica Janus nanoparticles using the wax-Pickering emulsion technique.
• Functionalization with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) and poly(ethylene glycol) (PEG).
• In vitro studies with NIH 3T3 fibroblasts, including incubation with endocytosis inhibitors.

Main Results:

• Janus nanoparticles adhered strongly to the fibroblast cell surface.
• Negligible nanoparticle uptake was observed, contrasting with isotropic control particles.
• Endocytosis inhibitors confirmed Janus particles are unaffected by caveolae- and receptor-mediated endocytosis.
• Prolonged attachment is attributed to an incomplete macropinocytosis process.

Conclusions:

• Janus nanoparticles provide a strategy for stable, non-invasive cell surface attachment.
• These nanoparticles exhibit minimal cellular uptake, enabling prolonged surface interaction.
• Potential applications include cell surface tagging, magnetic manipulation, and non-invasive drug/gene delivery.