Sonodynamically-induced Anticancer Effects of Polyethylene Glycol-Modified Carbon Nano Tubes

Abstract

Background/Aim: Sonodynamic cancer therapy is based on the preferential uptake and/or retention of a sonosensitizing drug (sonosensitizer) in tumor tissues and the subsequent activation of the drug by ultrasound irradiation. In the present study, we investigated the sonodynamically-induced antitumoral effect with functionalized carbon nanotubes, such as poly-ethylene glycol-modified carbon nanotubes (PEGmodified CNTs). Materials and Methods: Antitumor effects were evaluated using histological observation and assessing tumor growth following sonodynamic exposure to PEGmodified CNTs. Results: The combined treatment of 100 μM PEG-modified CNT and ultrasound induced a 2-fold cytotoxicity. Sodium azide, which quenches singlet oxygen, significantly inhibited ultrasonication induced cell damage in the presence of PEG-modified CNTs. This suggests that singlet oxygen produced by the combined use of PEG-modified CNTs and ultrasound is involved in the induction of antitumoral effects. The destruction of tumor tissue was observed with the ultrasonic treatment in combination with PEG-modified CNTs, while neither the treatment with PEG-modified CNTs alone nor ultrasound alone caused any necrosis. Conclusion: These results indicate that PEG-modified CNT functions as a sonosensitizer and is effective for sonochemical treatment of solid tumors.There is a new promising strategy for cancer treatment using the synergistic effect of ultrasound and chemicals, which can efficiently cause crushing (cavitation), as a result of repeated expansion and contraction of microbubbles by ultrasound irradiation. In this way the biological effects of some chemicals can be enhanced. Substances activated via this non-thermal action are called ultrasound sensitizers (1-5). However, compared to the thermal effects of an ultrasoundabsorbing tumor treatment, there are only few research reports on non-thermal effects, such as sonochemical effects based on cavitation (2, 6-7).We have previously reported that photochemically active compounds, such as hematoporpyrin, ATX-70, pheophorbide A, rose bengal, adriamycin FAD104, THP-adriamycin, ATX-S10, and porfimer sodium, may be sonosensitizers that can be activated by ultrasound irradiation (2-4, 6, 8-16). Porphyrins have been observed to accumulate in tumor tissues following intravenous administration (5,7,(17)(18). The administration of such compounds followed by ultrasound to treat implanted murine tumors has been shown to significantly suppress tumor growth, whereas the application of ultrasound alone only slightly inhibits growth (5,7,(19)(20)(21)(22)(23)(24)(25)(26). This suggests that combinational use of sonodynamically active porphyrins and ultrasound may have antitumoral effects. We have proposed that this potential modality be called sonodynamic therapy (2,26).Nanomedicine is a medical application of nanotechnology for the diagnosis and treatment of human illnesses, using precisely designed materials (nanoparticles) with a diameter of typically 1-100 nm (27). Nanomaterials, such as functionalized car...

SWCNT–porphyrin nano-hybrids selectively activated by ultrasound: an interesting model for sonodynamic applications

“…36,37 However, CNT-based nanocarriers shows unique properties, such as the photoinduced electron transfer, making them an intriguing multifunctional hybrid nanoplatform suitable for the development of the next generation of US responsive nanosystems. Moreover, the results reported herein are supported by the work of Yumita et al 38,39 highlighting the great potential of CNT-based nanosystems in exploiting the US-mediated ROS generation, representing the pivotal step of sonodynamic applications.…”

A Bio‐Conjugated Fullerene as a Subcellular‐Targeted and Multifaceted Phototheranostic Agent

“…[ 34 ] Beyond their PS properties, fullerenes also produce ROS upon ultrasound wave irradiation. [ 35,36 ]…”

Surface Wettability of Nanoparticle Modulated Sonothrombolysis

“…[ 1 ] Owing to the unique advantages, SDT was applied against cancer, bacterial infection, and atherosclerosis. Up to now, several theories have been proposed to explain the mechanism of SDT, such as sonoluminescence, [ 2 ] cavitation effect, [ 3 ] etc.…”