Graphene’s superior utility within the fabrication of nanoscale biosensors has been explored extensively by a variety of researchers and a assessment printed within the journal, Nanotechnology Evaluations.
Research: Graphene-Primarily based Biosensors for Illness Theranostics: Growth, Purposes, and Current Developments. Picture Credit score: luchschenF/Shutterstock.com
Graphene has gathered rising consideration over current years with its use in varied functions on account of outstanding attributes, and this has additionally branched into progressive sensing platforms.
Why Novel Biosensors are Wanted
Biosensors are vital for diagnosing illness as they’ll make contact with vital biomarkers that enable for illnesses to be recognized in sufferers, permitting efficient administration and remedy.
Typical approaches to determine illnesses embody however aren’t restricted to polymerase chain response (PCR), lateral circulation immunoassay, DNA sequencing and microarrays, and enzyme-linked immunosorbent assay (ELISA).
Whereas these strategies might be efficient with correct and delicate detection of illness markers resulting in diagnoses, they maintain vital limitations that lower their use effectivity. These limitations embody requiring extremely exact and costly devices and reagents and preparations steps which might be advanced and time-consuming.
Nevertheless, progressive approaches that make the most of sensors might be extra advantageous on account of being cheap, easy with out invasive procedures, and having extremely particular strategies which might be efficient for detecting goal biomolecules. Moreover, these novel sensors can be utilized for early illness analysis additional enabling illnesses to be managed and handled successfully, in addition to being able for use in real-time for the monitoring and analysis of illness, deeming them to be extra helpful in a wider vary of functions.
Graphene Incorporation into Biosensors
The novel nanomaterial, graphene was first found by Andre Geim and Kostya Novoselov in 2004 and is a carbon allotrope nanomaterial shaped of a single layer of graphite with atoms organized in a honeycomb lattice.
Its distinctive traits consist of a giant floor space, excessive flexibility in addition to efficient digital transportation. The flexibility of graphene includes of its two-dimensional construction, which might be exploited for functionalization with linker molecules that enhance its sensitivity and selectivity properties, enhancing its use as a biosensor candidate.
Examples of graphene which were utilized for its biosensing capabilities embody graphene oxide (GO) and diminished graphene oxide (rGO). Graphene biosensors can be utilized for biomedical functions equivalent to detecting essential biomarkers to diagnose most cancers formations and cardiovascular illnesses.
The usage of real-time monitoring of illness, equivalent to using graphene-based electrochemical biosensors for implantable gadgets, can be revolutionary for detecting early biomarkers to stop illness development. This novel subject of theranostics which allows the remedy of illnesses with early diagnoses can be a key methodology of enhancing affected person care to a complicated degree.
Growth of Graphene-Primarily based Biosensors
Graphene might be produced by way of two fundamental approaches, the top-down manufacturing strategy and the bottom-up strategy.
Graphene derivatives might be sourced by way of varied carbon provides throughout the top-down strategy, together with graphite flakes or powder. Graphene might be produced after mechanical or electrochemical exfoliation and chemical oxidation-reduction reactions.
Nevertheless, the bottom-down strategy depends on producing graphene layers from carbon atom bases and might embody a lot of strategies equivalent to chemical vapor deposition or thermal pyrolysis.
The strategy to producing graphene is important as it may well have an effect on the character of the graphene consequence that’s shaped on the finish, and this may subsequently affect its traits. When graphene is created for the idea of being a biosensor, its construction can embody a graphene layer that works as a transducer in addition to biomolecules that operate as receptors, equivalent to antibodies, this may be seen within the visible diagram under.
Graphene biosensor gadget which makes use of graphene (transducer) and biomolecules (receptor). ©Alhazmi, H., et al (2021)
Biomolecules such as enzymes, proteins, DNA, and antibodies can be used for specific biorecognition in order to target analytes including biomarkers within a sample. The receptors have a very significant function in being sensitive to physicochemical changes and so can be used to produce a signal when in contact with particular therapeutic targets.
While other significant functions of graphene in various fields include electronics and healthcare with uses in sensors, quantum dots, novel drug delivery, and others, its role as a biosensor can be used to advance the field of personalized medicine.
Applications of Graphene-Based Biosensors
Conventional methods for disease diagnosis as mentioned previously are costly and require complex machinery and reagents, and most significantly, are not quantifiable in real-time.
The intriguing nature of graphene-based sensors includes a wide range of benefits to biomedical applications and with easy-to-use techniques, cost-efficient, non-toxic and high sensitivity, and selectivity characteristics, this innovation may be revolutionary for enhancing patient care.
They can be utilized for the detection of various infectious diseases from viruses and bacteria and have successfully been used in research to detect the Ebola virus, E. coli and Zika virus. Additionally, graphene biosensors which were modified with silver and gold nanoparticles were also used in the detection of Salmonella typhimurium, hepatitis-C virus (HCV) and avian influenza virus.
The ability to modify graphene biosensors can further enhance its use with other proven research illustrating the modification of these versatile biosensors with dendrimers, polymers, and cyclodextrin in order to diagnose celiac disease, human immunodeficiency virus (HIV) and cholera.
Some common noncovalent functionalization showing pyrene–graphene, glucose oxidase–graphene, and ssDNA–graphene hybrids. ©Alhazmi, H., et al (2021)
The potential of graphene-based biosensors is tremendous and with successful research in this field detecting various infectious diseases, the translation into clinical use would be revolutionary.
However, with limitations such as its ability to adsorb nontarget molecules may cause false-positive detection, especially if noncovalent functionalization methods are used. Additionally, the incorporation of biomolecules onto the graphene layer may be affected by factors such as temperature, pH, salt concentration, as well as the intrinsic properties of graphene itself.
This area of research may still have obstacles to climb, however, its significance in theranostics is promising, especially for use as potentially implantable devices for real-time monitoring of disease.
Applications of biomolecules-immobilized graphene-based biosensors in the detection of target molecules. ©Alhazmi, H., et al (2021)
Alhazmi, H., Ahsan, W., Mangla, B., Javed, S., Hassan, M., Asmari, M., Al Bratty, M. and Najmi, A., (2021) Graphene-based biosensors for disease theranostics: Development, applications, and recent advancements. Nanotechnology Reviews, 11(1), pp.96-116. Available at: https://www.degruyter.com/document/doi/10.1515/ntrev-2022-0009/html
Sekhon, S., Kaur, P., Kim, Y. and Sekhon, S., (2021) 2D graphene oxide–aptamer conjugate materials for cancer diagnosis. npj 2D Materials and Applications, 5(1). DOI: https://doi.org/10.1038/s41699-021-00202-7