Electrochemically Addressed Molecules and Nanoparticles for a Novel Nanoarchitecture for Biosensing Applications

Biosensors are analytical devices that consists of biological sensing elements either integrated within or in close vicinity of a transducer element which transforms the selective information of the presence of an analyte of interest into a quantifiable signal. A typical biosensor architecture consists of three important features: a biological recognition element which is usually immobilized on the surface of a suitable transducer for converting the primary signal into a proportional change of a physical or chemical property and an amplification or processing element. The design of appropriate sensor architectures for a given analyte depends on the specific demands arising from the analytical problem which has to be either minimized or solved such as selectivity, sensitivity, dynamic range, detection limit, response time, precision, reproducibility, stability and cost of the measurement.In this work, we employ a novel carbon based material called graphene as a platform for designing the biosensor. Since its discovery, graphene has been widely investigated with respect to all possible applications. The wide spread application of graphene is attributed to its unique properties such as high surface area, excellent electronic properties, thermal conductivity and strong mechanical strength. Though graphene has been explored for several applications, there are only a very few reports available about graphene based biosensors. For instance, large-sized graphene film field effect transistors (FETs) were fabricated for the electrical detection of DNA hybridization, graphene oxide (GO) was used in single-bacterium and label-free DNA sensors. In addition, electrolyte-gated graphene FETs for electrical detection of pH and protein adsorption were reported. Despite these biosensing applications, to the best of our knowledge, there are no graphene based biosensing devices available till date for other biosensing applications such as detection of tumor biomarkers or HIV. Herein, we propose a graphene-gold nanoparticle platform that will be employed for the detection of cancer biomarkers. In this work, we will intentionally perform the electrochemical deposition of gold nanoparticles (AuNPs) onto graphene nanosheets (GN) in order to demonstrate a reliable and a stable approach to immobilize various biomolecules through a noble metal on any graphene based bio-device.