Crumpled graphene induced by commercial Heat-Shrinkable material for chemiresistive biosensors toward cancer biomarker detection

Chemiresistive biosensors have revolutionized the field of biomedical diagnosis owing to the novel properties of graphene layered materials that can enhance their sensitivity. We propose a commercial heat-shrinkable material (polystyrene) induced crumpled graphene for cancer biomarker detection. After heating polystyrene, the thermally induced transformation causes the shrinkage and deformation of graphene, resulting in the graphene structure becoming crumpled and thus increasing the surface area. Low-damage plasma treatment is used to oxidize the surface of crumpled graphene with high controllability, forming the bioactive graphene oxide. The DNA probe is then immobilized on graphene oxide via a chemical covalent-amide bond to facilitate hybridization with the biological target miRNA-21. Because the attachment of the miRNA-21 on the oxidized crumpled graphene alters the conductivity, we measure its electrical resistance change rate as a sensor response. The results demonstrate that the sensor response linearity increases with miRNA-21 concentration (10 nM to 1 pM) with the linearity of 0.988 and the limit of detection of 1.74 pM. The results of the real-time applicability test reveal a very high performance with low interference. Therefore, a crumpled graphene-based chemiresistive biosensor has good sensitivity with valuable selectivity, and its biomarker detection raises the possibility of using these sensors for real-time cancer determination and other screening applications in the future.