FIELD

The described embodiments relate generally to sensors, and more particularly to coal-based graphene biosensors.

BACKGROUND

Biosensors may be used in life sciences, clinical diagnostics, environmental monitoring, and medical research for affinity-based sensing, such as hybridization between complementary single strand DNA in a microarray or affinity binding of a matched sensitive biological element-antigen pair. Biosensors may include a biological recognition element and a transducer that converts a recognition event into a measurable electronic signal. While graphene has desirable electrical properties that can allow for its use in converting a biological recognition event into a measurable electronic signal, it can be expensive to produce and difficult to effectively functionalize or incorporate into usable technologies.

Accordingly, it may be desirable to provide a more economical method for producing graphene to allow for the production of less expensive sensors at a large scale. Further, unique properties of coal-based graphene as compared to other forms of graphene can enhance the functionality of biosensors and biosensor arrays.

SUMMARY

Embodiments disclosed herein relate to methods of forming graphene from coal for one or more life science devices, methods of forming the one or more life science devices that include graphene formed from coal, and the related life science devices. An example method includes providing coal and extracting the graphene from the coal. The graphene may be extracted using any suitable technique, such as the Hummers method, a modified Hummers method, or exfoliation of graphite. The method may further include forming a life science device from the graphene. The life science device may include, for example, a biosensor or a drug delivery system.

In an embodiment, a method to form a life science device is disclosed. The method includes providing graphene formed from coal and forming a life science device from the graphene.

In some embodiments, forming the life science device from the graphene includes disposing at least one graphene layer that includes the graphene on a substrate to form a biosensor. The at least one graphene layer includes one or more binding sites configured to bind or otherwise react with one or more targets.

In some embodiments, disposing the at least one graphene layer on the substrate includes disposing at least one first graphene layer on the substrate to form at least one first subsensor and at least one second graphene layer on the substrate to form at least one second subsensor that is spaced from the at least one first subsensor. The at least one first graphene layer includes one or more first binding sites and the at least one second graphene layer includes one or more second binding sites that are different than the one or more first binding sites.

In some embodiments, the method includes forming one or more electrical contacts on at least one of the at least one graphene layer or the substrate.

In some embodiments, the method includes functionalizing the graphene to form the one or more binding sites.

In some embodiments, the method includes attaching, either directly or indirectly, one or more sensitive biological elements to the at least one graphene layer.

In some embodiments, forming the life science device from the graphene includes rolling the graphene into a carbon nanotube to form a drug delivery system.

In some embodiments, providing the graphene formed from coal includes providing the coal and extracting the graphene from the coal.

In an embodiment, a method of forming graphene from coal that is suitable for use in one or more life science devices is disclosed. The method includes providing the coal and extracting the graphene from the coal.

In some embodiments, extracting the graphene from the coal includes extracting the graphene from the coal using the Hummers method or a modified Hummers method.

In some embodiments, extracting the graphene from the coal includes exfoliating graphite that is present in the coal.

In some embodiments, the method includes evaluating the coal to determine one or more characteristics of the coal.

In some embodiments, the one or more characteristics include at least one of a carbon, aromaticity, heavy metal, or ash content of the coal.

In some embodiments, one or more parameters of an extraction technique that is used to extract the graphene from the coal is selected at least in part in response to analyzing the coal.

In some embodiments, the method includes, after extracting the graphene from the coal, evaluating the graphene to determine one or more characteristics of the graphene.

In some embodiments, the one or more characteristics includes at least one of average flake size, graphene purity, average number of carbon layers, presence of impurities, composition of the impurities, electrical properties, or thermal properties.

In some embodiments, the method includes selecting graphene exhibiting one or more selected characteristics for use in the one or more life science devices.

In some embodiments, the method further includes functionalizing the graphene.

In some embodiments, the method includes forming the graphene into one or more life science devices.

In an embodiment, a biosensor is disclosed. The biosensor includes a substrate, at least one graphene layer disposed on the substrate, and one or more binding sites on the graphene that is configured to bind or otherwise react with one or more targets. The at least one graphene layer includes graphene formed from coal.

In some embodiments, the biosensor includes at least one first subsensor and at least one second subsensor spaced from the at least one first subsensor. The at least one first subsensor including one or more first binding sites and the at least one second subsensor includes one or more second binding sites that are different than the one or more first binding sites.

In some embodiments, the biosensor is at least one of an amperometric biosensor, a conductometric biosensor, a potentiometric biosensor, impedimetric biosensor or a field-effect transistor biosensor.

In some embodiments, wherein the biosensor is at least one of a rapid diagnostic biosensor, a sequencing biosensor, a cancer detection biosensor, or a biosensor for personalized medicine.

In some embodiments, the biosensor is an enzyme-linked immunosorbent assay.

