There are several pathways through which nanoparticles can enter cells:
1. Endocytosis: This is a common mechanism where cells engulf nanoparticles in vesicles. Endocytosis can be further classified into: - Phagocytosis: Typically used by immune cells to engulf large particles. - Pinocytosis: Involves the uptake of fluids and small particles. - Receptor-Mediated Endocytosis: This is a highly selective process where nanoparticles bind to specific cell surface receptors.
2. Passive Diffusion: Smaller nanoparticles may diffuse directly through the cell membrane, driven by concentration gradients.
3. Membrane Fusion: Some nanoparticles are designed to fuse with the cell membrane, releasing their contents directly into the cytoplasm.
