Surface interaction at the biomaterial–cell interface is essential for a variety of cellular functions, such as adhesion, proliferation, and differentiation. Nevertheless, changes in the biointerface enable to trigger specific cell signaling and result in different cellular responses. In order to manufacture biomaterials with higher functionality, biomaterials containing immobilized bioactive ligands have been widely introduced and employed for tissue engineering and regenerative medicine applications. Moreover, a number of physical and chemical strategies have been used to improve the functionality of biomaterials and specifically at the material interface. Here, the interactions between materials and cells at the interface levels are described. Then, the importance of surface properties in cell function is discussed and recent methods for surface modifications are systematically highlighted. Additionally, the impact of bulk material properties on the cellular responses is briefly reviewed.

In this work, we have developed a novel nanocomposite material of ceria (CeO 2 )-reduced graphene oxide (RGO) by sonochemical route for the application as symmetric supercapacitors. CeO 2 nanoparticles have been anchored on RGO sheets in order to maximize the specific capacitances of these materials. Nanostructure studies and electrochemical performances of the CeO 2 nanoparticles on the RGO sheets were systematically investigated. The morphology and crystalline structure of nanocomposites were examined by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR), and X-ray diffraction (XRD). Electrochemical properties of the nanocomposite electrodes were examined by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurements. CeO 2 -RGO nanocomposite electrodes exhibited excellent supercapacitive behavior with high specific capacitance of (211 F g -1 at 2 mV s -1 and 185 F g -1 at 2.0 A g -1 ), high rate capability and well reversibility. Cycling stability of electrode was measured by continues cyclic voltammetry (CCV) technique. Upon 4000 cycles, the specific capacitance of the electrode increases and reaches a maximum value of 105.6 % of the initial value. ARTICLE Journal NameWhere SC is the specific capacitance (F g -1 ), ν is the potential scan rate (mV s -1 ), V c -V a is the potential range and I denotes the response current (mA g -1 ) based on the mass of electroactive material. Fig. 6b and 6c show the CV curves of