After 20 years of research, Graphene is considered a “material of the future”, due to its remarkable (opto)electronic, (electro)chemical, and mechanical properties. These properties make it useful in many and diverse processes and applications, ranging from components of smartphones and batteries to solar panels, wearable electronics and diagnostics, as for example biosensors of proteins for early detection and progression monitoring of health diseases.
What is Graphene
In simple terms, Graphene is a one-atom-thick layer of carbon atoms arranged in a hexagonal lattice. Its’ discovery[1] and the subsequent groundbreaking studies on this 2D material led Andre Geim and Kostya Novoselov to be awarded the 2010 Nobel Prize in Physics.
As introduced by the Graphene Flagship Initiative the following properties make graphene unique.
Graphene is …:
- … the world's thinnest material, only one atom thick, one million times thinner than a human hair, which also makes it extremely light. It is one million times thinner than a human hair whereas less than 1 g of graphene layer can cover a football/soccer field.
- … very strong, stronger than steel and diamond, offering outstanding stiffness and durability.
- … very flexible, ideal for wearable devices and foldable electronics.
- … transparent.
- … a great conductor of electricity and heat, allowing the creation of conductive materials, such as inks for electronic circuits and gels that dissipate heat.
- … selectively permeable, allowing (or not) selective passage of atoms.
Figure 1. Graphene properties [Source: Graphene Flagship Initiative]
Graphene-based biosensing
Due to its unique physical structure, as well as its chemical and electronic properties, graphene has become a cornerstone material in life sciences and other fields. It offers a simple, low-cost, highly stable and modular platform for biosensing applications, towards real-time assessment of miscellaneous biomolecular analytes (e.g., proteins).
Using these unique properties, biosensors equipped with graphene as transducer (i.e., the part of the sensor which converts chemical information into a measurable signal) enable high sensitivity and specificity, as well as stability. Point-of-Care (PoC) diagnostic devices can be developed with graphene, which can particularly enhance patient care, offering more accessible early diagnosis and progression monitoring of diseases.
Such miniaturized diagnostics do not require highly trained personnel, expensive reagents, high-precision instruments, or time-consuming quantification methods to achieve highly sensitive detection of the target biomolecules and thus diagnosis.
Graphene for Alzheimer’s Disease – The 2D-BioPAD project
Within the 2D-BioPAD project, graphene plays a pivotal role, as the project aims to develop two graphene-based biosensing technologies for early detection and progression monitoring of Alzheimer’s disease, targeting the identification of specific proteins in blood samples.
The 2D-BioPAD consortium brings together experts from academia and industry to deliver a fast, cost-effective, less-invasive, reliable PoC in-vitro diagnostics (IVD) system that will wirelessly report concentration levels of 5 protein biomarkers using a few drops of blood.
In particular, the Catalan Institute of Nanoscience and Nanotechnology (ICN2) is developing a lateral-flow electrochemical sensor, based on their print and stamp patented technology. This innovation aims to develop highly conductive graphene electrodes on paper, allowing for a low-cost solution with a higher electrical signal than other conventional methods.
In parallel, for allowing extended benchmarking, Grapheal develops advanced graphene field effect transistor (GFET) biosensors, produced by printed electronics with unprecedented sensitivity, in a more compact design for digital readout.
To further optimize the sensor operation, the functionalization of graphene will be studied to reduce the signal-to-noise ratio and increase the selectivity and sensitivity of the developed biosensors. Towards this goal, the Czech Advanced Technology and Research Institute at Palacký University (UP-CATRIN) joins forces with densely and selectively functionalized conductive graphenes, which will make it easier to conjugate with the biorecognition unit (i.e., aptamer or antibody) while boosting the electrochemical activity.
Stay tuned to learn more about these fascinating applications of graphene for cutting-edge biosensing solutions.
[1] Novoselov, K. S., et al., (2004). Electric field effect in atomically thin carbon films. Science, 306(5696), 666-669.
