This Small Business Innovation Research (SBIR) Phase I project aims to develop specialized materials formulations based on functionalized graphene sheets (FGS) for electrochemical biosensor platforms. While carbon-based electrodes have been applied in a wide range of electrochemical sensor applications, electron transfer rates are small, leading to rather poor electrochemical activity, and existing commercially available electrochemical sensing platforms vary greatly in reactivity and general performance. Graphene has emerged in recent years as a promising alternative material for the development of electrochemical biosensors with high sensitivity and specificity. In the proposed program FGS materials formulations will be developed for detecting specific biologically relevant analytes. This project will examine the effect of graphene chemistry on electrochemical activity and utilizing specific bio-active decoration of the graphene sheets to optimize electrochemical properties and allow for the efficient design and optimal working performance of the biosensor. The proposed technology is anticipated to exhibit a combination of outstanding beneficial properties, such as high electroactivity, good biocompatibility, and versatility in many different sensing tasks.
The broader impact/commercial potential of this project is the availability of a biosensor that improves the performance of existing glucose biosensors and opens opportunities for new sensor product lines for other analyte assays where the current carbon materials cannot provide the needed performance. The global biosensor market forecasted to grow by 11.5 % over the next several years, reaching $14 billion by 2016, with home diagnostics and point of care biosensor markets comprising $2.8 billion and $6.3 billion respectively of the total market share. Glucose biosensors account for 30-35 % of the world biosensor market revenues, and biosensors for other analyst detection such as cholesterol, proteins, etc, are also predicted to rapidly expand, with forecasted growth of 19 %. If successful, the anticipated electrochemical activity of the new graphene-based biosensor technology is expected to make it a compelling choice to improve sensitivity and performance of current carbon-based biosensors. Furthermore, the science and engineering aspects of this project especially with regards to electroactivity of graphene and functionalized graphene will be of broad interest within the scientific community and improve the general understanding of graphene-based electrochemical systems.
The global biosensor market is forecast to grow by more than 10% over the next several years, reaching $14 billion by 2016, with home diagnostics and point of care biosensor markets comprising $2.8 billion and $6.3 billion, respectively. A large fraction of this market relies on disposable, inexpensive, and chemically stable electrochemical sensing platforms (electrodes) that can be produced through printing approaches on ceramic or polymeric (flexible) substrates using graphite-based ink formulations. However, compared to metallic electrodes, graphite-based electrodes typically exhibit low electrochemical activity and lack selectivity and sensitivity if no additional electrode treatments are applied after basic sensor fabrication. Furthermore, they exhibit substantial inter- and intra-batch variations of their properties which are attributed to a small effective electrochemically active surface area (<50%), electrical conductivities far inferior to those of silver-based conductive inks, and hard-to-control surface morphology resulting in roughness and porosity which alter electrochemical performance. To address the overall needs of next generation biosensor products with sensitive and rapid detection of the analyte of interest and at a low cost, Vorbeck Materials is developing an electrochemical biosensor based on functionalized graphene (Vor-x®) technology. In this Phase I SBIR program, Vorbeck has evaluated the electrochemical properties of Vor-x® in detail and was able to establish a proof of concept that carbonaceous printable inks based on Vor-x® yield highly electrochemically reactive and selective electrodes, their good performance being a result of both superior electrical conductivity of the printed electrodes as well as increased intrinsic electrochemical activity of the Vor-x® compared to carbonaceous materials. Using novel types of Vor-x® as well as special binder polymers, Vorbeck has shown that functionalized graphene offers great potential for the development of electrochemical biosensors that outperform existing technologies in terms of electrochemical activity and selectivity but also in terms of mechanical stability and tunability of their electrochemical characteristics.
