Table 1 Classification of nano-delivery systems for aptamer targeting tumors

Passive targeting

The aptamer is modified onto the surface of the drug-carrying nanocarrier to form the aptamer targeting nanocarrier

Targeting tumor markers by aptamers to target tumor tissue sites can be used to diagnose or treat tumors

[2, 214,215,216]

[9, 16, 17, 22, 37, 62, 92, 95, 98, 107,108,109, 111, 124, 125, 168,169,170, 209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225]]

Active targeting

The aptamer is directly linked to the drug/fluorescent substance to form an aptamer-drug/fluorescent substance conjugate

[2, 16, 38, 118, 173, 217, 219]

Nucleic acid aptamer

The aptamer itself acts as a drug carrier to form an aptamer-drug assembly

[6, 72, 202,203,204,205,206,207, 207,208,209, 221,222,223]