Biosensors and Wearable Sensors Based on Graphene Composites for Lab-on-Skin

A highly-sensitive wearable sensor based on Graphene (G) - Hexagonal boron nitride (h-BN) composite with various organic additives ((poly (3,4-ethylenedioxythiophene): polystyrene sulfonate composite (PEDOT:PSS), glucose oxidase enzyme (GOx or GOD), ethylene glycol (EG)) has been developed. The effect of the substrate on the sensitive abilities of sensors of various compositions has been studied. It has been shown that when the G+PEDOT:PSS composite is exposed to glucose solutions of various concentrations, a different change in the electrical resistance of the samples on the PET substrate is observed. The addition of h-BN to the composite creates a mesa-porous structure, due to which there is an increase in the sensor response on the PET substrate by an order of magnitude. On a paper substrate, there is an increase in the current response of the sensor by (4–5) orders, depending on the active material. Preliminary modification of the sensor with GOD can further increase the response of the sensor to exposure to glucose solutions. This is true for both PET and paper substrates. In vivo experiments have shown that there is a relationship between the electrical current through the sample and the concentration of glucose in the blood when wearing samples on the wrist. With an increase in the number of layers during printing, the current response increases. The mechanism of conductivity of composite films was investigated. It turned out to be the Schottky emission mechanism. The mechanism of conductivity does not depend on the addition of organics.