Graphene based materials with outstanding optical and electrical characteristics attract substantial interest of the researchers to improve sensitivity and performance of sensing element of SURFACE PLASMON RESONANCE (SPR) based biosensors. In this research carrier density variation because of functionalized element on graphene based SPR biosensor modeling is employed. The molecular specifications such as electro-negativity, molecular mass and periodic table group effect are engaged. The refractive index shift equation is defined and related coefficients are proposed. Finally a semi-empirical model for interpretation of changes in SPR curve is suggested.

Background & Objectives: The use of gold nanoparticles due to the medical field is expanding for special physical and chemical properties. So in this review we attempted to collect and review previous research into the diagnosis area.Material & Methods: This review is based on studies about gold nanoparticles in more than 100 papers in journals and written books on cancer until now. Accordingly 37 relevant cases were selected and studied. Resource selections were based on relevance to the topic, the research year, not duplicate, comprehensive resource and its contents. Keywords for this search were gold Nanoparticles, AU Nanoparticles, Cancer, Diagnosis, Drug delivery, Imaging, Protein respectively.Results: The conducted studies indicate the current tendency toward use of gold nanoparticles is owing to the selective delivery capability, ease of access and low toxicity, allowing scientists to detect cancer at early stage within fewer time frames.Conclusion: Biofunctionalized gold particles are detectable in target organs and in vivo with microscopes. These improvements have made the nanoparticles detectable and increased their contrast , providing the ability to measure them easily. Because of the high density of electrons in the gold nanoparticles, images are of greater clarity.