Tell us a little about why you developed a graphene sensing electrode in Gii-Sens?
MC: Screen-printed electrodes and screen-printed electrochemical sensors (devices containing more electrodes on the same printed platform) offer a significant opportunity to develop more accessible portable analytical devices. Today, there are a variety of biosensors and bioassays which relate to the screen-printed electrodes respective electrochemical sensors outcoming from the electrodes. One of the most well-known examples of this is the glucose biosensors containing glucose oxidase, devices also called personal glucometers, are the most commercially relevant biosensors based on screen-printed electrodes. Despite the great success and deployment of glucometers, there are still so many more opportunities for new devices to be developed and central to this will be the development of screen-printed electrochemical technology.
Fundamental to the development in this area is drive and necessity for improvements in measurement methods, lowering of costs and making analysis more accessible. There is a universal requirement for smaller and affordable diagnostics that removes the requirement for the dependency on a laboratory. Thankfully through the deployment and progression of technologies that leverage materials such as magnetic particles and nanoparticles, quantum dots, metal nanoparticles, and piezoelectric detectors are all exciting and offer promise and opportunity to develop solutions ready to be utilised for routine analyses outside laboratories.
Screen-printed electrodes are one of the emerging technologies that are readily available for practical applications in the field of biosensors and bioassays. They are a commercially available platform serving multiple analytical applications to determine the biological origin. Owing to nanomaterials' (in this case graphene’s) very good catalytic features and conductivity, we can use them for enhancing the electron transfer between the electrode surface and target analyte. Moreover, they can be used as the catalyst for increasing the electrochemical reaction to excellent effect.
However, not all SPEs are created equal. In our experience, we look at a lot of the graphene-based electrodes on the market today are composite, for example like graphene oxide (GO). The main issue when composite variants of graphene are used, the extraordinary properties of graphene are lost because of the requirement of binders, additives or stabilizers, which serve to mask those properties. This is where Gii-Sens is different, our patented process produces near pure graphene (>98% carbon), whereas other GSPE must use as additives as they start from powder.
This is why we are different, our purity. Gii (Integrated Graphene’s 3D Graphene Foam) exhibits the same performance or even better than gold or other noble based metals, at the price of carbon. This opens up other opportunities as we have better electrochemical performance – we’ve yet to see another company in the market match our performance levels at our price point. Cost is important as moving to carbon means there is a reduction in performance. There is now a viable alternative to gold as a sensing material. Furthermore, as a company, we can only offer this new solution to everyone as well as the service business (all in a one-stop-shop). Using 3DG because of the cost of gold there now is an alternative.
The problem with graphene is that providers are making claims that are not true, i.e. inks are not what they purport to be with graphene products with less than 23% graphene contents, it is these products that are used to make the composites for a good proportion of SPGE on the market presently. As a consequence, there are issues with reproducibility creating variation issues batch to batch.
Where are your biggest opportunities for Gii-Sens?
MC: In terms of market opportunities for us, our expertise lies with the medical device industry, biomedical device and veterinarian diagnostics but this technology opens up so many opportunities beyond our current scope. Applications of graphene biosensors that would be of interest for further exploration would be opportunities like gas sensing, drug detection, heavy metal ions amongst many others.
Nanomaterials created new opportunities especially in biotechnology, with their easy modification advantage, especially in the field of diagnosis, and they offer significant advantages over traditional diagnostic methods in terms of sensitivity and selectivity. Diagnosis is the most important step in terms of developing health technologies. The correct diagnosis brings with it the rightful treatment, the right prognosis, the well-being of the patient, and the decrease in health expenditures. The important parameters in the exact diagnosis are sensitivity and accuracy.
How do you feel about competing nanomaterials that can offer other improvements on incumbent sensing materials like noble metals?
MC: Nanomaterials possess unique features which make them particularly attractive for biosensing applications. In particular, carbon nanotubes (CNTs) can serve as scaffolds for immobilisation of biomolecules at their surface, and combine several exceptional physical, chemical, electrical, and optical characteristics properties which make them one of the best-suited materials for the transduction of signals associated with the recognition of analytes, metabolites, or disease biomarkers. However, CNTs are expensive and have issues with screen printing.
Similarly, fullerene holds a lot of potential in a similar respect due to in suitability for immobilisation materials for recognition analyte molecules. Fullerenes, like Gii, provide an extremely large surface area. Therefore, it provides more biological or non-biological recognition receptors immobilised on this surface area. However, it is slightly more academic and not widely accessible in a commercial context. The development and study of fullerenes for biosensing has somewhat diminished in recent years with the rise of CNTs and graphene, which are more scalable and practical carbon nanomaterials.