Advanced biosensors have become a key priority for researchers within the field of biomedicine and nanotechnology to detect biomarkers associated with an array of diseases and disorders. This may be revolutionary as early disease detection can prevent morbidity and mortality rates, especially at a younger age, which may be helpful in patients with diabetes, cancer, and neurological disorders such as Alzheimer's disease.
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There has been an increase in the volume of patients with diseases such as diabetes, cancer, and Alzheimer's disease, as well as the associated mortality rates relating to these.
The use of nanotechnology-based biosensors for early disease detection may advance research into preventing disease progression through the identification of associated biomarkers.
Diabetes mellitus can lead to an increased level of glucose in the blood, which can cause adverse effects such as heart disease, kidney failure and blindness. The detection of glucose concentration as a biomarker can greatly impact the progression of diabetes in patients, aiding with effective disease management.
Similarly, other types of diseases, including cancer and neurodegenerative diseases such as Alzheimer's, can also be detected through biomarkers to assist with early diagnosis; this may be more useful than current disease approaches, which are ineffective due to a lack of suitable treatment.
The World Health Organization has stated cancer as the main causative agent responsible for 10 million deaths globally in 2020, while Alzheimer's statistic reports have revealed 121,499 associated deaths in 2019.
According to the European commission's recommendation in 2011, nanomaterials can be described as "a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm–100 nm".
These materials can be categorized into four key groups, including (i) carbon-based nanomaterials, such as graphene or carbon nanotubes, (ii) inorganic-based nanomaterials such as metal oxide nanoparticles, (iii) organic-based nanomaterials including liposomes, and (iv) composite-based nanomaterials including hybrid nanofibers.
Nanomaterials have remarkable physiochemical properties, as well as good electrical and optical features that allow them to be beneficial for biosensor applications.
Biosensors can be described as analytical devices based on receptors and transducers, with the former aiding detection and the latter assisting in response measurements. These devices can be used for recognizing biomarkers, including but not limited to enzymes, proteins, and antibodies.
Carbon-Based Nanomaterial Biosensors
Carbon-based nanomaterials such as one-dimensional carbon nanotubes and two-dimensional graphene have been an attractive point of research within biosensor development.
Interestingly, these electrochemical sensors can convert biological reactions, including enzyme-substrate reactions, into electrical signals. Using nanomaterials within biosensors involves surface functionalization, which can be beneficial for the precise targetability of analytes. This can also enhance the biorecognition component of these advanced biosensors, subsequently impacting other properties such as specificity and sensitivity.
Other key benefits of utilizing nanomaterial-based biosensors include the ability to reuse the device, which can influence the overall expenditure of biosensors, benefitting the commercial market for both the creators and consumers of the products.
Carbon-based nanomaterials are strong candidates for biosensor development due to their ability to function in harsh conditions while maintaining a high level of sensitivity and specificity within various temperatures. This can be applied in detecting biomarkers, including glucose concentration and protein markers for diseases, due to withstanding the human body conditions in vivo.
Graphene, a significant allotrope of carbon, has also gained traction in nanomaterial research due to critical features that have advanced applications in fields from medicine to electronics. However, limitations such as lack of quantity and its hydrophobic nature have withheld this unique nanomaterial's potential for biosensor applications.
Interestingly, these challenges have been addressed by researchers that used graphene oxide to increase the hydrophilicity of the material and improve the electrical conductivity properties. This has enabled graphene oxide to be utilized for optical biosensors, such as for photoluminescence and label-free optical biosensor development.
Gold Nanomaterial-Based Biosensors
Gold is an interesting element in nanotechnology due to its remarkable properties at the nanoscale, including higher reactivity.
Gold nanomaterials have been used in electrochemical sensor research due to benefits such as good electrical conductivity as well as a large surface ratio.
Gold nanomaterials for this application can also enable surface functionalization for higher targetability of analytes, as well as incorporation with other composites and elements; this can include poly(diallyldimethylammonium chloride)-functionalized graphene oxide and chitosan to enhance the critical biosensor properties such as specificity, sensitivity and stability of the device.
The development of optical and electrochemical biosensors with nanomaterials can advance these analytical devices, enhancing properties such as the sensitivity and specificity of analytes. These devices can also innovate the detection of biomarkers for early disease detection with the potential of developing rapid point-of-care devices that would be revolutionary for diagnostics.
Additionally, with electrodes that can be used as microchips, the potential for creating products with a higher level of sustainability may also be advantageous for both the medical and electronic fields.
However, current challenges facing researchers include the miniaturization of the devices, as well as integrating them with fluid systems and multichip systems. Further research into these areas can provide potential solutions for the detection of novel viruses, such as the SARS-CoV-2 virus, responsible for the COVID-19 pandemic, as well as many other infectious diseases from diabetes to neurodegenerative diseases that impact world health.
Further Reading and References
Alzheimer's & Dementia, (2021) Alzheimer's disease facts and figures. 17(3), pp.327-406. Available at: https://doi.org/10.1002/alz.12328
Fahmy, H., Abu Serea, E., Salah-Eldin, R., Al-Hafiry, S., Ali, M., Shalan, A. and Lanceros-Méndez, S., (2022) Recent Progress in Graphene- and Related Carbon-Nanomaterial-based Electrochemical Biosensors for Early Disease Detection. ACS Biomaterials Science & Engineering, 8(3), pp.964-1000. Available at: https://doi.org/10.1021/acsbiomaterials.1c00710
Sheikhzadeh, E., Beni, V. and Zourob, M., (2021) Nanomaterial application in bio/sensors for the detection of infectious diseases. Talanta, 230, p.122026. Available at: 10.1016/j.talanta.2020.122026
Who.int. (2022) Cancer. [online] Available at: https://www.who.int/news-room/fact-sheets/detail/cancer