Table 2 Application of CNT-based DDS in targeting various intracellular therapeutic spots and TME components

Nucleus

PEG-SWNTs-DOX

Photothermal therapy + Chemotherapy

Breast cancer

Increase delivery efficiency, promote the accumulation and localization of DOX inside the nucleus, cause effective cancer cell death

N/A

[63]

Nucleus

SWNTs-carrier

Chemotherapy

Colorectal cancer

Achieve targeted therapy and controlled drug release

Show good biocompatibility

[64]

Nucleus

f-SWNTs-p53 plasmid complexes

Gene therapy

Breast cancer

Transport the target gene into the nucleus effectively, induce apoptosis strongly

N/A

[65]

Cytoplasm

Chim/PEI/5-FU/CNT nanoparticles

Gene therapy + Chemotherapy

Gastric cancer

Achieve targeted delivery and silence the drug-resistant gene, promote the apoptosis of drug-resistant cancer cells

Show negligible in vivo toxicity, and none of the mice dead after treatment with no statistically significant difference in body weight between the groups

[66]

Cytoplasm

MWNTs/Sor/siRNA

Gene therapy + Chemotherapy

Liver cancer

Enhance the release of sorafenib and improve siRNA stability, display significant antitumor effect

N/A

[67]

Cytoplasm

SWNT-HIF-1α siRNA complexes

Gene therapy

Pancreas cancer

Transfect and induce the RNAi response, effectively suppress tumor growth

Negligible toxic effect in vitro and in vivo

[68]

Cytoplasm

oxDWNT-siRNA

Gene therapy

Prostate cancer

Release siRNA into the cytoplasm to suppress survivin protein synthesis, directly cause cancer cell apoptosis

Show good biocompatibility

[69]

Mitochondria

MWNT-Rho (PtBzt + BP)

Chemotherapy

Ovarian cancer

Increase the selectivity of platinum-based chemotherapy, minimize the side effects

N/A

[70]

Mitochondria

PEG-CNTs-ABT737

Chemotherapy

Lung cancer

Improve the mitochondrial targeting of lung cancer cells, cause cancer cell apoptosis

Show lower cytotoxicity in NHFB normal cells than A549 lung cancer cells

[71]

Mitochondria

P-D-CS-CNTs

Photothermal therapy

Bladder cancer

Enhance mitochondrial targeting, induce the ROS burst, result in mitochondrial damage and cell death

N/A

[72]

Mitochondria

PL-PEG-SWNT

Photoacoustic therapy

Breast cancer

Transform pulse laser energy into sound energy, bomb the mitochondria into dysfunction and trigger mitochondrial outer membrane permeabilization

Show low toxicity without epidermis injury

[73]

Extracellular matrix

MWNTs

Photothermal therapy

Epidermoid carcinoma

Significant soften tumors together with volume reduction, induce the destruction of collagen and cell damage

N/A

[74]

Cancer stem cells

SWNT-Raw and SWNT-COOH

Chemotherapy

Osteosarcoma

Specifically bind to TGFβ1-induced activation of TGFβR1 and suppress its downstream signaling, decrease the OSCs population

Exhibit no obvious toxicity to normal cells

[75]

Tumor vasculature

DOX/CD-CNT and CUR/CD-CNT

Photothermal therapy + Chemotherapy

Hepatocellular carcinoma

Enhance drug entrapment efficiency and achieve sustained release of both drugs

Cause minimal damage to normal cells

[76]

Tumor vasculature

iRGD-PEI-MWNT-SS-CD/pAT2

Chemotherapy

Lung cancer

Promote the cellular uptake and transfection efficiency, inhibit angiogenesis, suppress tumor growth significantly

Not induce obvious tissue damage or inflammatory cell infiltration, not affect blood, hepatic or kidney function in mice

[77]

PD-1/PD-L1

Rg3-CNT

Immunotherapy

Triple-negative breast cancer treatment

Inhibit PD-1/PD-L1 axis and the TNBC cell growth

N/A

[78]

Immune cells

MWNTs-DOX and MWNTs-CpG

Immunotherapy + Chemotherapy + Phototherapy

Melanoma

Inhibit tumor growth, enhance the number of CD4⁺ and CD8⁺ T cells, promote TAM shifting, reduce the number of Tregs in TME

Show non-toxicity to the organs (liver, spleen, kidneys, heart and lungs) in mice

[79]