Table 3 Summary of the charge characteristics and in vitro and in vivo toxicity of the NPs investigated herein

Charge characteristics

ζ-potential (mV)

− 38.5 ± 1.9

+ 26.9 ± 1.6

+ 21.0 ± 1.5

+ 20.6 ± 1.2

+ 23.9 ± 2.0

+ 22.7 ± 0.1

Q_ek (µmol/mg)

nd

0.23

0.78

1.35

4.39

2.95

In vitro toxicity in THP-1 cells

Viability loss

–

–

**

**

***

***

Oxidative stress

–

–

–

–

*

*

IL-8

–

–

–

–

***

***

Mitochondrial perturbation

–

–

–

–

**

**

Lysosome integrity

–

–

*

–

***

***

In vivo toxicity in healthy mice

Total cells

–

–

–

–

***

***

Neutrophils

–

–

–

–

***

***

IL-6

–

–

–

***

***

***

KC

–

–

–

–

***

**

MCP-1

–

–

–

–

***

***

In vivo toxicity in allergic mice

Total IgG1

–

–

–

nd

***

nd

HMD-specific IgG1

–

–

–

nd

***

nd

Total cells

–

–

–

nd

***

nd

Eosinophils

–

–

–

nd

***

nd

Eotaxin

–

–

–

nd

***

nd