Dynamics of nanoparticle diffusion and uptake in three-dimensional cell cultures

Area of Science:

• Biomaterials Science
• Cell Biology
• Nanotechnology

Background:

• Cellular uptake of nanoparticles (NPs) is crucial for drug delivery.
• Standard 2D cell cultures may not accurately reflect in vivo nanoparticle behavior.
• The extracellular matrix (ECM) significantly influences cellular processes and NP interactions.

Purpose of the Study:

• To investigate the impact of 3D extracellular matrix on cell behavior and NP diffusion.
• To elucidate the mechanisms of NP cellular uptake in a 3D environment.
• To compare NP uptake in 3D versus 2D cell culture models.

Main Methods:

• Culturing human dermal fibroblasts (HDF) and HT1080 cells in 3D collagen gels.
• Exposing cells to polystyrene nanoparticles (PS NPs) of 44nm and 100nm sizes.
• Analyzing cell morphology, NP diffusion, and cellular uptake using mathematical modeling and microscopy.

Main Results:

• Cell morphology significantly differs in 3D cultures compared to 2D.
• NP diffusion is hindered in 3D collagen gels due to interactions with collagen fibers.
• NP cellular uptake is slower in 3D, particularly for 100nm NPs, due to restricted diffusion.

Conclusions:

• The 3D microenvironment profoundly affects NP-cell interactions and uptake pathways.
• Cytoskeleton, especially actin, plays a vital role in 3D NP uptake.
• Macropinocytosis is a primary uptake mechanism in 3D, but other pathways are also involved, depending on cell type and NP size.