Covalent functionalization of SWCNT with combretastatin A4 for cancer therapy

Abstract

Single walled carbon nanotubes (SWCNT) are currently under intensive investigation by many labs all over the world for being promising candidates for cancer chemotherapy delivery. On the other hand, combretastatin A4 (CA4) is an anticancer drug that induces cell apoptosis by inhibiting tubulin polymerization. However, it has the disadvantage of low water solubility and the non-selective targeting. Therefore, we aim to create nano-drug from the functionalization of SWCNT covalently with CA4 through click reaction in the presence of tetraethylene glycol linker in order to improve its dispersibility. Scanning electron microscopy and transmission electron microscopy showed good dispersibility of the functionalized SWCNT with diameters of 5-15 nm. Moreover, thermogravometric analysis showed that the efficiency of SWCNT functionalization was around 45%. The in vitro release profile of CA4 at physiological conditions showed that approximately 90% of the loaded drug was released over 50 h. After that MTS test was used to determine the suitable concentration range for the in vitro investigation of the SWCNT-CA4. After that the cytotoxic activity of the SWCNT-CA4 was evaluated by flow cytometry using annexin V/propidium iodide (PI) test. In comparison with free CA4, SWCNT-CA4 treatment demonstrated a significant increase in necrotic cells (around 50%) at the expense of the proportion of the apoptotic cells. Moreover, cell cycle PI test demonstrated that free CA4 and SWCNT-CA4 caused G2/M arrest. However with CA4 treatment higher proportion of cells were in the S-phase while with SWCNT-CA4 treatment greater proportion of cells appeared to be in the G1-phase. Taken together, the provided data suggest that the novel SWCNT-CA4 has a significant anticancer activity that might be superior to that of free CA4.

RP-HPLC Method Development and Validation of Synthesized Codrug in Combination with Indomethacin, Paracetamol, and Famotidine

“…The synthesized codrug was incubated with an esterase enzyme to study its hydrolysis to its parent drugs (IND & PAR). This was achieved by incubating 1 mg of codrug into 10 mL phosphate buffer saline solution (pH 7.4) containing 1 mg of esterase enzyme (10 U) at 37°C for 1 h [ 31 – 33 ]. At different time intervals, aliquots of 1 mL were obtained, and then the concentrations were analyzed by the developed HPLC method.…”

Enhancement of wound healing by single-wall/multi-wall carbon nanotubes complexed with chitosan

“…[18][19][20] CNTs are currently being functionalized by different kinds of pharmacologically active molecules with the aim of enhancing drug delivery, controlling drug release and improving drug activity, which has been successful to a certain extent. 21,22 In this project, SWCNTs and MWCNTs were complexed with chitosan, which is a hydrophilic polymer, via van der Waals' interactions, so that the chitosan polymer would wrap on to the CNT with the hydrophilic regions of chitosan exposed to the aqueous environment. This resulted in a hydrogel incorporating a scaffold of CNTs (chitosan-single-wall carbon nanotubes [C-SWCNTs] and chitosan-multi-wall carbon nanotubes [C-MWCNTs]).…”

Effect of Functionalized Carbon Nanotubes and their Citric Acid Polymerization on Mesenchymal Stem Cells In Vitro

“…Another way to generate functional groups on CNTs is by modification with dendritic and hyperbranched biocompatible polymers [16][17][18] by attaching chains, like molecules of the extracellular matrix, to the CNTs walls [18], allowing biocompatibility and an easier interaction between the polymerized CNTs and the cells. In addition, some polymers also improve the solubility in water and the dispersion in biological fluids [15,19].…”

“…For example, polyethylene terephthalate (PET) and polyurethane (PU) have shown a favorable cellular response in MSCs [19,20]. Synthetic polyethylene glycol (PEG) together with chondroitin sulfate (CS) has been used as scaffolding on chondrogenesis induced by MCSs [21][22][23].…”

“…Thus, the production of adequate scaffolds for proliferation and anchorage of MSCs is a fundamental aspect for future investigation [37] Despite that polymerized CNTs with other materials have effects on the MSC behavior, promoting adhesion [18,[38][39][40], changing stem cell's shape [7,8,41,42], and providing signals that may promote proliferation or differentiation [18], it is unknown if polymerized CNTs with PCA could help as intermediaries or structurally could act as a kind of staple between the extracellular matrix of a damaged tissue with the extracellular matrix of MSCs previously treated in vitro with PMWNT before injected. However, based on the reports of cytotoxic effects of fCNTs [11,14,15,19,25] and polymerized CNTs (PCNT), with PEG, PU, and PET [19,25], prior to considering PMWCNT as biological scaffolding for MSCs, it is mandatory and fundamental to start by performing cytotoxic assays of cells in contact with fCNTs and fPCA-CNTs. Thus, the aim of this work is to generate and characterize a set of functionalized and PCA-polymerized CNTs to evaluate their behavior on a cellular in vitro model of MSCs derived from primary cultures (bone marrow).…”