Size and Surface Properties of Functionalized Organosilica Particles Impact Cell-Particle Interactions Including...

Area of Science:

• Biomaterials Science
• Immunology
• Cell Biology

Background:

• Macrophage-nanoparticle interactions are key for developing macrophage-based immunotherapies.
• Understanding how particle size and surface properties affect these interactions is crucial.

Purpose of the Study:

• To investigate the impact of fluorescent thiol-organosilica particle size and surface properties on macrophage interactions.
• To analyze particle uptake, mitochondrial activity, and cell membrane morphology in J774A.1 macrophages.

Main Methods:

• Preparation of thiol-organosilica particles of varying sizes (150, 400, 680 nm) with and without PEI functionalization.
• Utilized flow cytometry, time-lapse imaging, 3D fluorescence imaging, and scanning electron microscopy.
• Performed correlative light and electron microscopy for integrated analysis.

Main Results:

• Particle uptake and mitochondrial activity varied based on particle size, surface properties, and individual cell characteristics.
• Smaller particles (OS/F150, OS/F150PEI) exhibited higher uptake and mitochondrial activity.
• Observed endosome-mitochondria interaction involving iron transport and alterations in cell membrane morphology.

Conclusions:

• Macrophage-nanoparticle interactions are highly dependent on particle characteristics and individual cell responses.
• These findings are vital for understanding macrophage immunological functions and designing effective immunotherapies.
• Integrated imaging techniques provide a comprehensive approach to analyzing these complex interactions.