Electrochemical biosensors based upon nanomaterials have recently attracted considerable attention. The electrochemical method has many advantages, such as high sensitivity, good selectivity, fast detection and low cost. Inherent benefits of electrochemical sensors include also ease of use and scope for miniaturisation, so a lot of electrochemical sensors with high sensitivity and selectivity toward many targets have been prepared. In a direct electrochemistry-based biosensor, biological molecules are integrated with electrodes, and the crucial step is the transfer of electrons to and from a biological molecule. A recent thrust has focused towards modifying the electrodes with the aim of broadening the sensing range and increasing sensitivity with reduced effect of interferents. Many kinds of nanomaterials have been used in construction of electrochemical biosensors for medical analysis, environmental monitoring, food and water quality control, etc. The exceptional properties of carbon-based nanomaterials make them compelling for electrochemical biosensor development.
The discovery of graphene in 2004, added a new dimension to electrochemical biosensor research. Being a single layer of carbon atoms in a closely packed honeycomb two-dimensional lattice, graphene is now positioned among top-ranked novel materials which potentially may thrust new perspectives into the field of miniaturized medical diagnostic devices. Because of its unique electrical (fast electron transportation), physical (excellent mechanical flexibility), and optical properties (transparency, photodetection capability), graphene has great potential to be a novel alternative to other carbon or metal alloy nanocomposites in biosensing. Graphene based biosensors are advantageous in terms of, for example, large detection area, possibilities of new sensing mechanisms, ease of effective functionalization, immobilization of other particles on its surface, and finally good biocompatibility. It is widely believed that graphene biodevices may be able to reach high sensitivities and detection limits previously unattainable with nanoscale‐based technologies.
Proper conjugation between biological molecules such as DNA, RNA, enzymes, antibodies, receptors, and aptamers needs to be developed for graphene based electrochemical sensing electrodes. A recent thrust has focused towards modifying the electrodes with the aim of broadening the sensing range and increasing sensitivity with reduced effect of interferents. Various immobilization protocols for sensing elements are used including physical adsorption, chemical linkage and entrapment in polymers. Much attention has been recently been attracted to the development of reactive biofilms on working electrodes. It was shown for instance that chitosan and graphene composite film not only acts as the role of electronic signal transduction, but also provides a shelter for the biomolecules to retain their bioactivity. So, transducer biomolecules entrapped in the graphene–chitosan composite films could retain its native structure because the graphene–chitosan film might have good biocompatibility. Appropriate functionalization of graphene and the immobilization of biomaterials on it is another concern, as functional groups can create defects on graphene surfaces and thus change its conductance.
One major challenge for many of fabricated biosensors is that so far they have only been developed in laboratory environments. For any commercial application to be successful there must exist a technology that allows rapid production of large numbers of disposable sensors, to high quality specifications and relatively inexpensively. One potential technology is that of screen or ink printed electrodes which can be produced relatively cheaply using existing technology. An alternative technique is that of complementary metal oxide semiconductor technology (CMOS) which is widely used for constructing integrated circuits.
Taking into account the above mentioned information it is suffice to say that graphene-based biosensing platforms are in the early research and development phases, but due to their exquisite properties in combination with present achievements in nanoelectronics and microfliudics, hold a great perspective for point-of-care medical diagnostics. With rational physical and/or chemical modification as well as electronic compliance, graphene sensors are capable of detecting many types of molecules, ions, microorganism or even cells. Thus, there is an urgent need for the intensification of new research and development initiatives aimed at implementing innovative graphene-nanosensor technologies in the field of medical diagnostics.
The discovery of graphene in 2004, added a new dimension to electrochemical biosensor research. Being a single layer of carbon atoms in a closely packed honeycomb two-dimensional lattice, graphene is now positioned among top-ranked novel materials which potentially may thrust new perspectives into the field of miniaturized medical diagnostic devices. Because of its unique electrical (fast electron transportation), physical (excellent mechanical flexibility), and optical properties (transparency, photodetection capability), graphene has great potential to be a novel alternative to other carbon or metal alloy nanocomposites in biosensing. Graphene based biosensors are advantageous in terms of, for example, large detection area, possibilities of new sensing mechanisms, ease of effective functionalization, immobilization of other particles on its surface, and finally good biocompatibility. It is widely believed that graphene biodevices may be able to reach high sensitivities and detection limits previously unattainable with nanoscale‐based technologies.
Proper conjugation between biological molecules such as DNA, RNA, enzymes, antibodies, receptors, and aptamers needs to be developed for graphene based electrochemical sensing electrodes. A recent thrust has focused towards modifying the electrodes with the aim of broadening the sensing range and increasing sensitivity with reduced effect of interferents. Various immobilization protocols for sensing elements are used including physical adsorption, chemical linkage and entrapment in polymers. Much attention has been recently been attracted to the development of reactive biofilms on working electrodes. It was shown for instance that chitosan and graphene composite film not only acts as the role of electronic signal transduction, but also provides a shelter for the biomolecules to retain their bioactivity. So, transducer biomolecules entrapped in the graphene–chitosan composite films could retain its native structure because the graphene–chitosan film might have good biocompatibility. Appropriate functionalization of graphene and the immobilization of biomaterials on it is another concern, as functional groups can create defects on graphene surfaces and thus change its conductance.
One major challenge for many of fabricated biosensors is that so far they have only been developed in laboratory environments. For any commercial application to be successful there must exist a technology that allows rapid production of large numbers of disposable sensors, to high quality specifications and relatively inexpensively. One potential technology is that of screen or ink printed electrodes which can be produced relatively cheaply using existing technology. An alternative technique is that of complementary metal oxide semiconductor technology (CMOS) which is widely used for constructing integrated circuits.
Taking into account the above mentioned information it is suffice to say that graphene-based biosensing platforms are in the early research and development phases, but due to their exquisite properties in combination with present achievements in nanoelectronics and microfliudics, hold a great perspective for point-of-care medical diagnostics. With rational physical and/or chemical modification as well as electronic compliance, graphene sensors are capable of detecting many types of molecules, ions, microorganism or even cells. Thus, there is an urgent need for the intensification of new research and development initiatives aimed at implementing innovative graphene-nanosensor technologies in the field of medical diagnostics.
