A photodispositive based on reduced graphene oxide modified with polyethylenimine to deliver amphotericin B

Amphotericin B (AmB) is an antifungal used to treat leishmaniasis symptoms but presents low water solubility and severe side effects, such as nephrotoxicity.1 Aiming to enhance drug solubility and reduce drug´s toxicity, new drug delivery systems (DDSs) based on functionalized reduced graphene oxide (rGO) have been developed. These DDSs have good biocompatibility, high drug loading efficiency and excellent near-infrared (NIR) light absorbance, which can be used to stimulate drug release.2 Thus, herein, we report the synthesis, characterization and drug loading of a new photodispositive based on rGO modified with polyethylenimine (PEI). To prepare rGO-PEI, graphene oxide was obtained by a modified Hummers method3 followed by exfoliation, coated with PEI and reduced with hydrazine hydrate. The device was evaluated by ATR-IR, which showed the absence of C-O-C and C=O bands indicating the reduction step was successful carried out. The bands of C-H and C-N indicated the presence of PEI. TEM analysis (Fig. 1a) showed a two dimensional structure formed by thin and wrinkled sheets. Zeta potential measurements revealed a positive charge surface up to pH = 9 due to the protonated amino groups of PEI. The device was loaded with AmB to yield rGO-PEI-AmB with loading efficiency of 96%. AmB release from rGO-PEI-AmB in a dispersion of 2.36 mg/mL was investigated at pH = 4.5, under NIR irradiation (=800 nm) and monitored by UV-Vis spectroscopy. AmB was released under NIR irradiation. This material will be further tested for cutaneous leishmaniasis.