Stretched graphene tented by polycaprolactone and polypyrrole net–bracket for neurotransmitter detection

A net-bracket built out from the core@shell structure of chemically oxidized polypyrrole (PPy) coated electrospun polycaprolactone (PCL) nanofibers, and the following surface modification of a thin layer of positively charged poly(dimethyl diallyl ammonium chloride) (PDDA) has been applied for stretching the reduced graphene oxide (RGO) sheets to some extent with the electrochemical deposition method. The as-formed RGO/PDDA/PCL@PPy nanocomposites were investigated by using scanning electron microscopy, transmission electron microscope, X-ray diffraction and Raman spectroscopy. The graphene tented by the net-bracket showed remarkable electrocatalytic properties in detecting the neurotransmitter dopamine (DA). Low detection limit of 0.34   μM (S/N   =   3) with the wide linear detection range from 4   μM to 690   μM was obtained. The successful determination of DA in real urine samples and DA injection were achieved. Such attractive fabrication strategy can be extended to make other graphene sheet-based sensors.