Skip to main content

Table 3 Grouping hypothesis and read-across of comet assay results. TiO2 R and TiO2 A are the two target NMs. According to the grouping hypothesis based on the presence or absence of the coating, the two target NMs are assigned to the negative and positive group, respectively. Missing values are indicated with a dash (−)

From: Grouping of nanomaterials to read-across hazard endpoints: from data collection to assessment of the grouping hypothesis by application of chemoinformatic techniques

Name

NM-100

NM-101

NM-102

NM-103

NM-104

NM-105

TiO2 R

TiO2 A

In vitro comet assayb

1

0

1

0

0

1

0

1

What they are

Total non-TiO2 content including coating and impurities (% w/w)

1.5

9

5

11

11

0.11

13

0.5

Surface coating (%)

0

0

0

8

8

0

11

0

Organic matter (% w/w)

0

8

0

2

2

0

9

0

Crystal type (Anatase)

1

1

1

0

0

0.84

0

1

Crystal type (Rutile)

0

0

0

1

1

0.16

1

0

Crystal type (Cubic)

0

0

0

0

0

0

0

0

Crystallite size (mean) (nm)

117.81

7.69

23.93

24.32

24.71

22.44

Shape (elongated = 1, spherical = 0)

0

0

0

1

0

1

1

0

Aspect ratio

1.53

1.53

1.53

1.7

1.53

1.36

6.2

1

Primary particle diameter (mean) (nm)

93.45

5.25

22.00

24.00

24.50

20.13

62 × 10

14

Specific surface area (m2/g)

9.23

316.07

77.87

53.98

54.33

47

177

149

Where they go

Isoelectric Point (Mean) (pH)

5.5

6

8.3

8.5

6.8

Density (g/ml)

3.84

3.99

3.84

4.02

4.09

4.05

Mean of total pore volume (ml/g)

0.032

0.319

0.300

0.262

0.194

0.194

Micro surface area (m2/g)

0

13.625

1.108

0

0

0

Micropore volume (ml/g)

0

0.00179

0.00034

0

0

0

Dustiness-Respirable(mg/kg)

1500

5600

9200

19,000

6400

11,000

Biodurability 24 h 0.05% BSA (Ti content) (μg/l)

5.2

0

0

0

0

0

Biodurability 24 h Gambles solution (Ti content) (μg/l)

0

0

3388

0

0

0

Biodurability 24 h Caco2 (Ti content) (μg/l)

796

3414

1741

222

3386

2724

What they do

Redox Caco2 mediuma

1

-1

-1

1

-1

-1

Redox Gamble’s solutiona

1

0

-1

1

-1

-1

Redox BSAa

0

0

0

0

0

0

  1. avalues obtained from deliverable 4.7 of Nanogenotox [33] determined by measuring the content of O2. Oxidising properties (1), neutral (0), reducing (−1)
  2. b1: NM is considered genotoxic in the in vitro comet assay; 0: NM is considered not genotoxic in the in vitro comet assay. In vitro comet results are predicted for TiO2 R and TiO2 A (characters in italics in the last two columns)