Three-dimensional localization of polymer nanoparticles in cells using ToF-SIMS

Area of Science:

• Biomedical Engineering
• Cell Biology
• Analytical Chemistry

Background:

• Cellular uptake and localization of nanoparticles are crucial for drug delivery and nanomedicine.
• Accurate imaging techniques are needed to visualize nanoparticle distribution within cells.

Purpose of the Study:

• To evaluate the capability of Time-of-flight secondary ion mass spectrometry (ToF-SIMS) 3D depth profiling for localizing polymeric nanoparticles within cells.
• To compare ToF-SIMS results with traditional optical imaging methods.

Main Methods:

• Utilized Time-of-flight secondary ion mass spectrometry (ToF-SIMS) with 3D depth profiling.
• Developed and applied a novel background subtraction method for enhanced signal detection.
• Incubated HeLa cells with fluorescently labeled polymer nanoparticles for comparative optical imaging.

Main Results:

• ToF-SIMS 3D depth profiling successfully localized polymer nanoparticles within HeLa cells.
• Results from ToF-SIMS showed good agreement with optical images of fluorescently labeled nanoparticles.
• Both imaging techniques revealed nanoparticle clustering in punctate regions, suggesting endosomal localization.

Conclusions:

• ToF-SIMS 3D depth profiling is a viable technique for intracellular nanoparticle localization.
• The developed background subtraction method improves the analysis of ToF-SIMS data for biological samples.
• Findings support the endosomal uptake mechanism for the designed polymer nanoparticles.