Preparation and Sonodynamic Antitumor Effect of Protohemin-Conjugated Multiwalled Carbon Nanotubes Functionalized with Carboxylic Group

Sonodynamic therapy (SDT) is a cutting edge approach to treating cancer that involves necrosis and/or apoptosis. Multiwalled carbon nanotubes functionalized with carboxylic groups (MWCNTs-COOH) due their physicochemical structure represent a novel drug delivery system in the field of nanomedicine. The purpose of the research reported in this paper was to increase the antitumor potency and reduce the potential side effects of protohemin (Ph), a sonosensitizer for SDT, which was noncovalently encapsulated into MWCNTs-COOH (MWCNTs-Ph). The Ph loading efficiency in MWCNTs-COOH carrier was determined as approximately 68.8% (w/w). The growth inhibition rate of MWCNTs-Ph (Ph: 180 mu g/mL) was approximately 95 +/- 8.5%, whereas Ph-F (Ph: 180 mu g/mL) inhibited 58 +/- 4.5% of tumor cell. Ph (Ph: 180 mu g/mL) alone had no antitumor effect in HepG-2 cells using ultrasound treatment at 1.0 MHz and 0.5 W/cm(2) for 100 s. Assessment of the antitumor effects of MWCNTs-Ph and Ph-F at day 11 after SDT showed that he tumor inhibition ratio for MWCNTs-Ph (6.18 x 10(-2) g.kg(-1) . d(-1)) was 82.8%, twice that of Ph-F (6.18 x 10(-2) g.kg(-1) . d(-1)) ay 41.8%. In conclusion, MWCNTs-Ph had increased antitumor efficiency and also decreased potential side effects. (C) 2016 Wiley Periodicals, Inc.