Graphene quantum dots-polyfluorene hybrid nanobiosensor for mitomycin C-DNA interaction sensing

A novel graphene quantum dots (GQD) / polyfluorene (PF) nanocomposite was deposited on the disposable pencil tip graphite electrode (PGE) and proven to be an efficient nanosensor for analysis of the electrochemical interaction between the antitumor compound mitomycin C (MC) with double stranded DNA (ds-DNA). This modified electrode (GQD@PF-PGE) was prepared in four steps: hydrothermal, chemical oxidation, ultrasonication and electro-oxidation processes. GQD, PF, GQD@PF and GQD@PF-PGE have been characterized by different analytical techniques such as SEM, TEM, XRD, FTIR, UV–Vis, EIS. Compared to bare PGE, GQD@PF modified PGE performed approximately 56 times more sensitive analysis when evaluating the guanine oxidation signals measured by DPV. CV and EIS measurements also showed that GQD@PF-PGE possesses a fast electron transfer as compared to bare electrode and exhibit a remarkable electrocatalytic activity towards both guanine and MC electrooxidation. Comprehensive optimization studies have also been carried out for the developed new nanobiosensor.