Cryo-soft X-ray tomography as a quantitative three-dimensional tool to model nanoparticle:cell interaction.

Area of Science:

• Nanobiotechnology
• Nanomedicine
• Cell Biology

Background:

• Recent advances in nanoparticle design offer new possibilities in nanobiotechnology and nanomedicine.
• Superparamagnetic iron oxide nanoparticles (SPION) are being investigated for various biomedical applications.

Purpose of the Study:

• To characterize the interaction of SPION with a breast cancer cell line using cryo-soft X-ray tomography (cryo-SXT).
• To validate and contextualize new 3D data using a previously studied SPION-MCF-7 cell system.

Main Methods:

• Incubation of MCF-7 cells with SPION (15 nm diameter, DMSA coated) for 0-24 hours.
• Vitrification of cells followed by correlative cryo-epifluorescent microscopy to identify SPION accumulation.
• Analysis of vitrified cells using cryo-SXT to generate whole cell volume 3D maps at nanometric resolution.

Main Results:

• SPION were observed to accumulate in acidic vesicles within the endocytic pathway.
• Cryo-SXT enabled quantitative statistical analysis of SPION-containing vesicle (SCV) accumulation, including vesicle number, size, and proximity to the nucleus.
• Internalized SPION showed continuous transfer towards an accumulation area near the cell nucleus.

Conclusions:

• The 3D cryo-SXT approach allows comprehensive quantitative description of SPION:cell interactions.
• Increased incubation time led to a significant increase in SCV number, size, and accumulated volume.
• This quantitative data is crucial for designing nanoparticles for hyperthermia treatment, drug delivery, and imaging in nanomedicine.