Polyethylene glycol and octa-arginine dual-functionalized nanographene oxide: an optimization for efficient nucleic acid delivery

Abstract

The successful application of nucleic acid-based therapy for the treatment of various cancers is largely dependent on a safe and efficient delivery system. A dual-functionalized graphene oxide (GO)-based nanocarrier with the conjugation of aminated-polyethylene glycol (PEG-diamine) and octa-arginine (R8) for the intracellular delivery of nucleic acids is proposed. The functionalized sites are covalently co-conjugated and the PEG : R8 molar ratio is optimized at 10 : 1 to achieve a hydrocolloidally stable size of 252 ± 2.0 nm with an effective charge of +40.97 ± 1.05 and an amine-rich content of 10.87 ± 0.4 μmol g-1. The uptake of the nanocarrier in breast cancer cell lines, MCF-7 and MDA-MB 231, is investigated. The siRNA and pDNA condensation ability in the presence and absence of enzymes and the endosomal buffering capacity, as well as the intracellular localization of the gene/nanocarrier complex are also evaluated. Furthermore, the delivery of functional genes associated with the nanocarrier is assessed using c-Myc protein knockdown and EGFP gene expression. The effective uptake of the nanocarrier by the cells shows superior cytocompatibility, and protects the siRNA and pDNA against enzyme degradation while inhibiting their migration with N : P ratios of 10 and 5, respectively. The co-conjugation of PEG-diamine and the cationic cell-penetrating peptide (CPP) into the GO nanocarrier also provides a superior internalization efficacy of 85% in comparison with a commercially available transfection reagent. The c-Myc protein knockdown and EGFP expression, which are induced by the nanocarrier, confirm that the optimized PEG-diamine/R8-functionalized GO could effectively deliver pDNA and siRNA into the cells and interfere with gene expression.

Intracellular Fate and Impact on Gene Expression of Doxorubicin/Cyclodextrin-Graphene Nanomaterials at Sub-Toxic Concentration

“…Moreover, the interactions of GO with integrins activated the integrin-FAK-Rho-ROCK pathway, leading to suppression of integrin expression as well as perturbation of cell membrane and cytoskeleton, and a subsequent cellular priming state [28]. The polyethylene glycol-diamine/R8-functionalized GO has been shown to effectively down-regulate c-Myc protein and EGFP expression [29]. The treatment with GO-poly-l-lysine hydrobromide/folic acid (GPF)/DOX/siRNA was able to silence gene expression and inhibit tumors by about 70% without exhibiting testable cytotoxicity; moreover, there was a decrease of 50% in vascular endothelial growth factor (VEGF), mRNA, and protein levels [30].…”

Strategies for the Controlled Covalent Double Functionalization of Graphene Oxide

“…Even if GO is composed of different functional groups, mainly epoxides, hydroxyls, and a little amount of carboxylic acids, most approaches mainly exploited the same functional groups on the surface of GO or different functional groups without any selectivity. Few research groups developed a double functionalization process targeting selectively two functional groups already present on the surface of GO, such as the epoxides or hydroxyls, and the carboxylic acids . For instance, Imani et al.…”

“…For instance, Imani et al. prepared multifunctionalized GO by derivatization of the hydroxyls using chloroacetic acid and sodium hydroxide, followed by amidation of the carboxylated GO with a mixture of polyethylene glycol diamine and octa‐arginine . Rezaei et al.…”

Nanocomposites as biomolecules delivery agents in nanomedicine

“…The complexes (cationic polymers/nucleic acid) are based on electrostatic interactions, which are formed between the positively charged cationic polymers and negatively charged nucleic acid. PEI has been used as a gold standard in both in vitro and in vivo gene delivery agent, given its high buffering capacity for the endosomal escape of the delivered genes [246, 247]. For a summary of all polymer-based nucleic acid nonviral vectors characterized to date, the reader is referred to the following excellent reviews [81, 83, 248].…”