Gene therapy nanovehicle prospect based on graphene oxide (GO), citric acid (CA) and polyethylene glycol diamine (PEGDA)

Abstract

Event Abstract Back to Event Gene therapy nanovehicle prospect based on graphene oxide (GO), citric acid (CA) and polyethylene glycol diamine (PEGDA) Bexi Bustillo1, Leticia Arregui1 and Ferdinando Tristán1 1 UAM Cuajimalpa, Natural sciences and engineering, Mexico Introduction: Gene therapy is defined by the intentional modulation of gene expression in cells to treat specific diseases and it has had problems during application in patients, particularly in gene delivery[1]. Due to its physicochemical, and mechanical properties, graphene oxide (GO) has been extensively explored in many fields and it has emerged as a prospect in biomedicine for drug and gene delivery[2],[3]. In this work, we obtained a conjugate based on GO, citric acid and polyethyleneglycol diamine (PEGDA) as a prospect for biocompatible gene delivery vector. Materials and Methods: GO was obtained from expanded graphite by using a modified version of Hummer's method. CA was covalently attached to carboxilated GO; next, PEGDA was added in order to obtain free amine groups. Every step of the synthesis was characterized using several techniques (FTIR, AFM, Zeta potential). The cytotoxicity of synthesized materials was evaluated by Alamar blue assay. Agarose gel electrophoresis analysis at different (w/w) ratios was used to explore the plasmid-nanovehicle complex formation. Results: GO showed typical IR bands at 3320 cm-1 for O-H bond; 1720-1740 cm-1 for C=O; 1250 cm-1 for C-O corresponding to O-H and -COOH functional groups. After PEGD functionalization, 1630-1695 cm-1 bands for the amide bond in the GO-CA-PEGDA conjugate was identified. GO thickness by AFM micrographs was ~ 1.1 nm. No significant difference in viability was found amongst control, GO and GO derivatives treated cultures by Alamar blue assay. Zeta potential measurements showed that all the modifications decreased negative charge of GO, which is helpful for the interactions with DNA. Discussion: CA covalent attachment to GO as well as attachment of PEGDA amine groups was confirmed by FTIR where typical adsorption bands were observed. The ratio C/O and C/N was evaluated by elemental analysis indicating the positive functionalization with PEGDA. AFM results indicated that synthesized GO can be found as monolayers and functionalization with PEGDA modifies the texture of the surface of GO derivatives. The surface charge of GO and GO derivatives was modified due to the functionalization. GO, GO-CA and GO-CA-PEGDA conjugates do not induce cytotoxicity. Conclusion: Amine terminated nanovehicles are very useful to design gene and drug delivery systems[4]. Regardless of the extensive interest in biomedical applications of nanovehicles there is concern regarding toxicity. That is why the main purpose was to prepare a novel prospect of biocompatible gene delivery system based on GO, CA and PEGDA. CA was expected to generate branches onto GO surface and enhance amide bonding with PEGDA. All these materials were chosen due to their good water solubility, low toxicity and biocompatibility, making this system a good candidate for gene delivery.