Effect of silica nanoparticles (SiO2NPs) on Monocytes/Macrophages cells

MARTÍN SARACENO; ROMINA MITAROTONDA; MARCOS TODONE; MARISA FERNANDEZ

Buenos Aires

Encuentro; SETAC Latin America 11th Biennial Meeting; 2015

Society of Environmental Toxicology and Chemistry Latin America

The employment of nanoparticles (NPs) as drug delivery has gained attraction inrecent years for their use with therapeutic purposes. NPs can also be used as acarrier for immunostimulatory or immunosuppressive molecules. In addition,NPs can transport antigens to generate a specific immune response. Recently,silica NPs (SiO2NPs) has proved to be a suitable and biocompatible tool for theimmobilization of biomolecules, microorganisms, and for the entrapment ofmammals? cells. In this work we obtained SiO2NPs of different size (10-500 nm,as determined by Dynamic Light Scattering) and charge (positives and negatives,as zeta potential characterization) by the Stöber method or using inversemicroemulsions and surface modification. We analyzed the effect of the differentNPs on monocytes/macrophages cultures (THP-1) at different times (24-168 h),cells densities (0.1-1 x 106 cells/ml) and NPs concentrations (10-100 nM).Proliferation of cells were determined by MTT assay observing that differentpositive NPs did not affected cell proliferation while negative NPs ≥ 380 nmdecreased between 50-70% THP-1 cells proliferation at 24 h of culture, andnegative NPs between 100-380 nm need at least 48 h of culture to reduce cellproliferation 32-83 % respect to controls. At 168 h of culture all negative NPsreduce proliferation ~30-40%. On the other way, cell activation was evaluated.Negative NPs ≥100 nm increased nitrite secretion by 24 h of culture (8-16 times).In the same way negative NPs ≥ 100 nm increase IL8 and IL12 secretion by 48 h(2-10 times respect controls). Positive NPs and 10 nm negative NPs don?t induceILs or nitrite secretion. All negative NPs increased membrane expression ofCD86, CD80 and CD14 (~2-8 times) while positive ones increased CD86 andCD14 expression (2-10 times). Negative NPs decreased CD11 expression(~50%). Finally, negative NPs increase monocyte/macrophage membranedamage after 48 h of culture as determined by 7AAD cell incorporation (1.5-4times). We detect a low percentage of cells in apoptosis process. In conclusion,negative silica NPs ≥ 100 nm have cell activation properties, and could be usefulfor immune stimulation, while negative NPs of 10 nm and positive NPs have lowimpact on immune system cells and would be useful for molecule transportationsince they are unable to stimulate antigen presenting cells.