Durability and inflammogenic impact of carbon nanotubes compared with asbestos fibres

Table 3 Average widths and lengths, and length distributions, of samples incubated in Gambles solution for 0 weeks or 10 weeks, as determined by TEM measurements

Sample	Incubation Period (week)	Width (nm) ± SE	Length μ(m) ± SE	% ≥ 100 μm	100 μm > % ≥ 20 μm	20 μm > % ≥ 15 μm	15 μm > % ≥ 10 μm	10 μm > % ≥ 5 μm	% < 5 μm
X607	0	3500 ± 190	123 ± 7	58	36	4	1	1	0
	10	2100 ± 169*	76 ± 5*	33	55	6	3	2	0
LFA	0	550 ± 39	34 ± 3	5	50	8	16	13	8
	10	820 ± 52*	56 ± 4*	18	56	6	6	7	6
LFC	0	42 ± 1	10.8 ± 1	0	20	6	9	17	49
	10	43 ± 2	1.9 ± 0.3*	0	0	0	0	0	100
CNT _SW	0	5 ± 0.3	3.6 ± 0.2	0	0	0	0	19	81
	10	5 ± 0.3	3.2 ± 0.4	0	0	0	0	18	82
CNT _SPIN	0	9 ± 0.3	NAs	NAs	NAs	NAs	NAs	NAs	NAs
	10	14 ± 0.3*	NAs	NAs	NAs	NAs	NAs	NAs	NAs
CNT _LONG1	0	60 ± 2	12.4 ± 0.5	0	10	20	29	37	4
	3	65 ± 2	10.9 ± 0.5*	0	8	10	27	45	10
	10	63 ± 2	11.1 ± 0.4*	0	4	9	42	38	7
CNT _TANG2	0	10 ± 0.4	NAs	NAs	NAs	NAs	NAs	NAs	NAs
	10	10 ± 0.4	NAs	NAs	NAs	NAs	NAs	NAs	NAs

The dimensions of fibres, for which a start and end point could be identified in representative TEM images, were measured using Image J (NIH) calibrated software. The mean widths and lengths of samples incubated for 10 weeks were compared to their equivalent 0 weeks samples by an unpaired t-test, where statistical significance was set at p < 0.05 (denoted by an asterisk). Fibre dimensions were additionally determined for CNT_LONG1 at 3 weeks incubation to assess whether the shortening seen at 10 weeks was part of a consistent trend.
NAs: not assessable
Note: Due to the difficulty in identifying and measuring individual CNTs within bundles in TEM images, these numbers should not be taken as absolute but indicative of trends only.

ISSN: 1743-8977