Abstract

Graphene is a substance made of pure carbon, with atoms arranged in a regular hexagonal pattern similar to graphite, but in a one-atom thick sheet. It is an allotrope of carbon whose structure is a single planar sheet of sp ² -bonded carbon atoms that are densely packed in a honeycomb crystal lattice. Hence, graphene may be considered as the mother of graphite, fullerene and carbon nanotubes. Graphene can also be considered as the final member of the series of fused polycyclic aromatic hydrocarbons, such as naphthalene, anthracene and coronene It has many exceptional features which make it a superstar in the world of nanotechnology as thinnest material, practically transparent (3,000,000 sheets equal to 1mm), stiffest, strongest (Youngs modulus >0.51 TPa, tensile strength ~130 Gpa) largest surface-to-weight ratio (~2,700 m2/gram) very stretchable (stretch up to 20%), conducts heat and electricity better than any metal, impermeable to gases, large specific surface area, non-toxic, low cost and drug can attach on both sides of its sheet. Graphene can be successfully used as a non-toxic nano carrier for efficient gene transfection, a novel gene delivery, nano- vector with low cytotoxicity and high transfection efficiency, which is promising for future applications in non-viral-based gene therapy. Experimental studies have demonstrated that the shape of carbonaceous nanomaterials plays an extremely important role in how they interact with cells and potentially other biological systems, such as tissues and organisms. The cytotoxicity of graphene depends on the exposure environment and mode of interaction with cells as bacteria came directly contact with graphene, intensive physical interactions between graphene and bacterial cells may cause physical damages on cell membranes, and result in the release of intracellular contents and cytotoxicity and genotoxicity occur.