Chitosan-coated iron oxide/graphene quantum dots as a potential multifunctional nanohybrid for bimodal magnetic resonance/fluorescence imaging and 5-fluorouracil delivery

Abstract

Incorporating nanostructures with magnetic and fluorescent features in one nanosystem leads to designing effective multifunctional nanosystems for bimodal imaging-based diagnosis and cancer treatment procedures such as anticancer drug delivery. In this study, the chitosan-coated magnetic iron oxide/graphene quantum dots (MGC) nanohybrid was synthesized and loaded with 5-fluorouracil (MGC-FU) to consider its potential for bimodal magnetic resonance/fluorescence imaging (MRI/FI) and 5-fluorouracil delivery. The nanohybrid was investigated using FT-IR, TEM, and VSM to evaluate physicochemical characteristics, MTT assay to determine A549 cancer cells toxicity, MRI to assess relaxivity, and fluorescence spectrometry to analyze fluorescence properties. In addition, the in vitro loading/release studies of 5-fluorouracil were performed. MGC-FU nanohybrid showed less than 20 nm in size, uniform dispersion, and superparamagnetic behavior. MGC nanohybrid possesses low cytotoxicity, while MGC-FU had the significant cancer cell killing effect even higher than pure 5-fluorouracil. MRI and fluorescence spectroscopy results revealed a high value of transverse relaxivity (r2 = 690 mM−1s−1) and strong fluorescence emission at 493 nm, dependent on the excitation wavelength of 400 nm. The findings of in vitro loading/release studies suggested that the MGC nanohybrid could be employed as a nanocarrier for 5-fluorouracil due to the significant drug loading capacity of 90% and pH-dependent sustained release (84% after 48 h, at pH = 5). This study promises to use MGC-FU as a potential multifunctional nanohybrid for bimodal MRI/FI and cancer therapy.