Reduced graphene oxide modified smart conducting paper for cancer biosensor.

ABSTRACT

We report results of the studies relating to the fabrication of a paper based sensor comprising of poly (3,4-ethylenedioxythiophene)poly(styrenesulfonate) ( PEDOT PSS) and reduced graphene oxide (RGO) composite. The effect of various solvents like methanol, ethylene glycol and H2SO4 on the electrical conductivity of PEDOT PSS coated Whatman paper has been investigated. The conductivity of this solution processed conducting paper significantly increases from ~1.16×10(-4) S cm(-1) up to ~3.57×10(-2) S cm(-1) (~300 times) on treatment with ethylene glycol. The observed significant increase in electrical conductivity is due to conformational rearrangement in the polymer and is due to strong non-covalent cooperative interaction between PEDOT and the cellulose molecules. Further, incorporation of RGO into the conducting paper results in improved electrochemical performance and signal stability. This paper electrode is a promising alternative over the expensive conventional electrodes (ITO, gold and glassy carbon), that are known to have limited application in smart point-of-care (POC) devices. This low cost, flexible and environment friendly conducting paper based biosensor utilized for cancer biomarker (carcinoembryonic antigen, CEA) detection reveals high sensitivity of 25.8 µA ng(-1) mL cm(-2) in the physiological range, 1-10 ng mL(-1).