In vitro biocompatibility of calcined mesoporous silica particles and fetal blood cells

Background: The biocompatibility of two forms of calcined mesoporous silica particles, labeled as MCM41-cal and SBA15-cal, with fetal blood mononuclear cells was assessed in vitro. Methods and results: Fetal mononuclear cells were isolated from umbilical cord blood and exposed to 0.5 mg/mL of MCM41-cal or SBA15-cal for several hours. Transmission electron micrographs confirmed the presence of particles in the cytosol of macrophages, neutrophils, and lymphocytes without noticeable damage to the cellular organelles. The particles (especially MCM41-cal) were in close proximity to plasma, and nuclear and mitochondrial membranes. Biocompatibility was assessed by a functional assay that measured cellular respiration, ie, mitochondrial O₂ consumption. The rate of respiration (k_c, in μM O₂ per minute per 10⁷ cells) for untreated cells was 0.42 ± 0.16 (n= 10), for cells treated with MCM41-cal was 0.39 ± 0.22 (n= 5, P> 0.966) and for cells treated with SBA15-cal was 0.44 ± 0.13 (n= 5, P> 0.981). Conclusion: The results show reasonable biocompatibility of MCM41-cal and SBA15-cal in fetal blood mononuclear cells. Future studies are needed to determine the potential of collecting fetal cells from a fetus or neonate, loading the cells in vitro with therapeutic MCM41-cal or SBA15-cal, and reinfusing them into the fetus or neonate.