Table 1. Average irritant ranking score, comparison with negative control and degree of irritant for six samples.

Sample (four-week implantation)	Average irritant ranking score	Δ Between test sample and control	Non-irritant (0.0–2.9)Slight irritant (3.0–8.9)Moderate irritant (9.0–15.0)Severe irritant (>15)
Negative control	4.0	—	—
Gel	18.0	14.0	Moderate irritant
Gel+IL	15.5	11.5	Moderate irritant
Gel+CNT	18.3	14.3	Moderate irritant
Gel+IL+CNT	15.3	11.3	Moderate irritant
Au	22.0	18.0	Severe irritant

CNT, carbon nanotube; gel, polyrotaxane-based gel with movable cross-linker (cyclodextrin/polyethylene); IL, ionic liquid; Negative control, high-density polyethylene sheet.

The assays were quantified based on ISO 10993-6:2007, Biological Evaluation of Medical Devices—Part 6: Tests for Local Effects After Implantation.