A poly (propylene imine) dendrimer – Carbon nanofiber based aptasensor for bisphenol A in water

Abstract

• An aptasensor route not susceptible to BPA electro-oxidation fouling is developed. • A carbon nanofibre-dendrimer nanocomposite is prepared for aptamer immobilisation. • The aptasensor detected BPA in a sub-nanomolar concentration by EIS and DPV. • BPA was detected in real water sample and the results were validated with GC. We report a poly (propylene imine) dendrimer-carbon nanofiber nanocomposite (CNFs-PPI) immobilisation platform based aptasensor for bisphenol A (BPA). Amino modified aptamers were immobilised on the CNFs-PPI platform on a glassy carbon electrode (GCE) by covalent bonding using glutaraldehyde as a cross-linker. The interfacial changes on the surface of the electrode during the biosensor fabrication and operation were investigated using electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The proposed aptasensor (GCE/CNFs-PPI/NH-Apt) was able to detect BPA in the range of 1–10 nM, with limits of detection of 0.03 and 0.06 nM obtained from DPV and EIS respectively. The biosensor stability was investigated. Furthermore, the biosensor had good selectivity towards the BPA molecule in the presence of interfering species and exhibited repeatability with a relative standard deviation of 3.8% with good stability. Real sample application of the proposed aptasensor in water samples was investigated and recoveries between 91.8% and 100.3% were obtained.