After scrolling through many articles in Materials Today, I eventually found an interesting title, “Biodegradable nanocomposite-based sensors are on the menu.” So, the researchers used a seaweed capsule and used a graphene ink as the filling / core. It consists of a shell made from solid seaweed gel layer and a core made from Graphene ink.

So, the researchers used a seaweed capsule and used a graphene ink as the filling / core. It consists of a shell made from solid seaweed gel layer and a core made from Graphene ink.

A drop-by-drop method with the help of CaCl2 solution is used in the synthesis process, which is shown in the following picture. Calcium ion will interact with the guluronic acid, which is the component of alginate, driving the gelation process. Gelation is possible through cross linking or formation of 3D networks from guluronic acid monomer. The calcium ion will be surrounded by guluronic acid and form a spherical capsule. The solution of Calcium Chloride, Alginate, and Graphene form a Graphene Capsule.

The graphene capsule can be used for biosensor application due to its very low electrical resistivity, which is on the order of 10-8 Ωm. When the capsule undergoes stress and strain, it undergoes deformation, making the geometrical shape of the capsule change. The geometrical change causes electromechanical response, which is the generation of electric field or current that is caused by stress/strain. These tiny capsules are then assembled into networks.

This device can have potential applications for internal body sensors due to its biocompatibility, such as blood pressure sensor, muscular and breathing pulse measurements as written in the article. It can also be used on skin as epidermal sensor. I can’t wait to see when the nanocomposite material can be used as electronic textile for sensors/wearables placed on skin replacing old epidermal sensors that are not environmentally friendly.