The Preparation Of Functional Graphene Oxide And Applications As Carriers For Drug Delivery

In this paper, graphene oxide （GO） was prepared by ultrasonic dissection ofgraphite oxide firstly, and then it was modified by magnetic nanoparticles and folicacid, respectively to prepare the functional GO. The applications of GO and functionalgraphene oxide as carriers for drug delivery were researched and their in-vitocytotoxicity to Hela cell were also evaluated to investigate their biological safety.Graphite oxide was prepared via a modified Hummers method, after sonication inultra pure water, graphene oxide with nano lamellar structure was obtained. Themicrostructure and chemical structure of graphene oxide were characterized byScanning electron microscopy （SEM）, Transmission electron microscopy （TEM）,Atomic force microscopy （AFM）, Raman spectroscopy （Raman）, Fourier IR spectra（FTIR）, X-ray diffraction （XRD）. The results showed that the single layer of grapheneoxide has been successfully prepared, and its thickness is about0.752nm. But not allthe graphene oxide is single layer structure, some of them superimposed together in alarge size. After ultrasonic dissection, the dispersion of graphene oxide in water isgreatly improved. Compared with graphite, the structure regularity of graphene oxideis decreased. The loading and release behavior of graphene oxide to doxorubicinhydrochloride （DOX） were also studied. It was found that the loading rate of grapheneoxide to DOX reaches87.13%. After95h, the cumulative release rate is96.91%,70.62%at the pH of5.8and7.4, respectively. The graphene oxide has a goodsustained-release performance and a strong pH dependence. In-Vitro cytotoxicityconfirmed that at the concentration of5μg/mL the relative cell viability of grapheneoxide is97.76%. When treated with graphene oxide at the concentration of50μg/mL for68hours, most of Hela cell grow well, indicating graphene oxide is a safety drugcarrier.The magnetic graphene oxide （Fe₃O₄@GO） has been successfully prepared byin-situ reduction of Iron （III） acetylacetonate in the mixture solution of triethyleneglycol and GO. Furthermore, DOX was loaded onto it, and the release behavious ofDOX from Fe₃O₄@GO were investigated at different pH in phosphate buffer solution.The in-vito cytotoxicity to Hela cell were also evaluated. The experiment shows thatthe optimal reaction condition is285℃for30min with the material ratio1:1. Theprepared Fe₃O₄@GO can be considered as superparamagnetism, and magnetizationsaturation reaches16.4emu/g. The loading rate of Fe₃O₄@GO to DOX is58.52%,lower than GO’s. After96h, the cumulative release rate is42.11%and48.73%at thepH of5.8and7.4, respectively. The Fe₃O₄@GO has a good sustained-releaseperformance. In-vito cytotoxicity confirmed that at the concentration of5μg/mL therelative cell viability of Fe₃O₄@GO is85.11%. After treated with Fe₃O₄@GO at theconcentration of50μg/mL for68hours, Hela cell grow well, which meansFe₃O₄@GO as drug carrier is safe.The folic acid modified graphene oxide materials （FA@GO） was successfullyprepared with N-hydroxy succinimide （NHS） and1-ethyl-3-（3-dimethylaminopropyl）carbondiimide （EDC） as modifier. The loading and release behavior of DOX, andin-vito cytotoxicity to Hela cell were also evaluated. The results showed that theloading rate of FA@GO to DOX reaches52.40%. After156h, the cumulative releaserate is40.52%,38.54%at the pH of5.8and7.4, respectively. The FA@GO has a goodsustained-release performance and a strong pH dependence. In-vito cytotoxicityconfirmed that at the concentration of5μg/mL the relative cell viability of FA@GO is84.38%. When treated with FA@GO at the concentration of50μg/mL for68hours,Hela cell grow well. With time increasing, more and more particles agglomerated atthe surrounding of Hela cell, showing a high affinity to Hela cell. This means FA@GOas drug carrier is safe and has a certain biological targeting effect.