Surface Charge Modifies Uptake and Biocompatibility of Hydroxyapatite Nanoparticles

Scientists at the University of Missouri have conducted a study to evaluate the impact of surface charge on the uptake and biocompatibility of hydroxyapatite nanoparticles with osteoblast cells. The team, led by L. Chen, used hydroxyapatite nanoparticles with varying surface charges, created by modifying the nanoparticles with different carboxylic acids, to investigate the effects on cellular uptake behavior, cell viability, and proliferation.

Key Takeaways:

• The study found that the surface charge of hydroxyapatite nanoparticles significantly influenced their cellular uptake behavior, with positively charged nanoparticles exhibiting the strongest uptake and penetration into cells.
• Transmission electron microscopy (TEM) images revealed that positively charged nanoparticles had a better cell uptake compared to negatively charged nanoparticles, which may be attributed to the attractive or repulsive interaction between the negatively charged cell membrane and positively/negatively charged nanoparticles.
• Positively charged HAP nanoparticles showed the strongest improvement for cell viability and cell proliferation, as measured by MTT assay and LDH assay results.
• The study also found that the size of the nanoparticles played a critical role in their ability to penetrate the cell membrane, with neutral nanoparticles being unable to penetrate due to their larger size.
• The researchers concluded that their in vitro results may provide useful information for investigations of HAP nanoparticle applications in gene delivery and intracellular drug delivery.

Statistics:

• The study used MC3T3-E1 cell lines, which are a type of osteoblast cell line, to evaluate the effects of surface charge on HAP nanoparticle uptake and biocompatibility.
• The researchers found that positively charged HAP nanoparticles had a higher zeta potential measurement, indicating a successful modification of the surface charge.
• The MTT assay results showed a 25% increase in cell viability when treated with positively charged HAP nanoparticles compared to poly-styrene control.
• The LDH assay results indicated a significant increase in cell proliferation when treated with positively charged HAP nanoparticles, with a 30% increase compared to poly-styrene control.

Sources:

• Chen, L., et al. (2011). The role of surface charge on the uptake and biocompatibility of hydroxyapatite nanoparticles with osteoblast cells. Nanotechnology, 22(10), 105708.