Skip to main content

Table 1 Particle characterization

From: MyD88-dependent pro-interleukin-1β induction in dendritic cells exposed to food-grade synthetic amorphous silica

Particle descriptiona

Specific surface areab [m2 g−1]

Hydrodynamic diameter [nm] in H2Oc in CMd

Shapee

Endotoxin contaminationf [EU per 250 μg particles]

7-nm SAS

326

147 (105–193)g

147 ± 5

Irregular

< LODh

13-nm SAS

175

182 (130–241)

127 ± 1

Irregular

< LOD

11-nm FePO4

188

183 (124–267)

255 ± 35

Irregular

< LOD

21-nm FePO4

98

178 (110–258)

230 ± 40

Irregular

0.006

33-nm TiO2

47

205 (91–335)

67 ± 18

Almost spherical

< LOD

140-nm TiO2

11

Not measured

352 ± 6

Almost spherical

< LOD

50-nm PS-NH2 i

Not measured

Not measured

Not measured

Spherical

0.043

100-nm PSk

Not measured

104(91–114)

Not measured

Spherical

Not measured

  1. aThe primary particle diameter was calculated from specific surface area and weight (2.6 kg m−3 for SAS, 2.9 kg m−3 for FePO4 and 3.9 kg m−3 for TiO2)
  2. bCalculated from nitrogen adsorption (Micromeritics Tristar 3000) at 77 K and relative pressure range p/p0 = 0.05–0.25 using the Brunauer-Emmett-Teller (BET) theory
  3. cDetermined using Nanoparticle Tracking Analysis 2.3 on a NanoSight instrument (Malvern)
  4. dDetermined by dynamic light scattering using a Zetasizer Nano ZS (Malvern). CM, complete cell culture medium; values are reported as mean ± standard deviation (n = 3) and remained stable during 24 h
  5. eDetermined by transmission electron microscopy (TEM)
  6. fDetermined in the Endosafe PTS endotoxin test (Charles River). A control with Escherichia coli LPS at the concentration of 10 pg ml−1 yielded 0.037 EU ml−1; EU, endotoxin units
  7. gNumbers in parenthesis show the 10% and 90% probability range
  8. hLOD, limit of detection (0.005 EU ml−1)
  9. iThis endotoxin finding obtained with a purchased batch of polystyrene (PS) particles is included to show an example of contaminated commercial material
  10. kThese 100-nm traceable standard particles from Thermo Scientific served as a size standard for hydrodynamic diameter measurements by Nanoparticle Tracking Analysis