Table 1.
Summary of PEI modifications carried out in recent years.
| Modification Types | Aims | Ref. |
|---|---|---|
| Carboxylation modification | Gene delivery, absorption of heavy metals in sewage. | [60,61,62,63] |
| Acetylation modification | Gene delivery efficiency improvement, cytotoxicity reduction. | [63,64,65] |
| Hydroxylation modification | Biocompatibility enhancement, gene delivery, transformation improvement of NPs. | [66,67,68] |
| PEG modification | Stability and transfection efficiency improvement. | [69,70,71] |
| FA modification | Tumor-targeted delivery. | [72,73] |
| HA modification | Tumor-targeted gene delivery, stability improvement. | [74,75] |
| Protein modification | Gene delivery, protein transduction. | [76,77,78] |
| FI modification | Fluorescence imaging. | [57] |