ИСТИНА

Nowadays graphene oxide (GO) attracts researcher’s attention as a promising drug delivery carrier. GO is a layered material comprising graphene-like unoxidized domains and regions of oxygen-functionalized graphene. GO-based drug delivery systems are commonly used as water dispersions. Since many drug molecules are pH-labile, one of the most important char-acteristics of such system is pH value of water inside the inter-plane space of GO. In this work acidity of water intercalated into GO was measured for the first time. Two pH-sensitive nitroxides (MTI, DPI) were used for this purpose (see Fig. 1). EPR spectrum of MTI in GO containing intercalated water is shown in Figure 2. The distance 2aN reflects pH value of water confined between the oxidized graphene layers. pH value of water intercalated into GO synthesized according to Brodie method was found to be 2.25±0.05.