An efficiently engineered electrochemical biosensor as a novel and user-friendly electronic device for biosensing of Streptococcus Pneumoniae bacteria

We have constructed a novel electrochemical biosensor for detection and quantification of the Streptococcus Pneumoniae bacteria (SPB) based on change in electrochemical impedance spectroscopic (EIS) responses of the biosensing system. A glassy carbon electrode (GCE) was chosen as the platform of the biosensor and it was modified with lead nanoparticles (Pb NPs) and then, DNA-[FAM]CGC AAT CTA GCA GAT GAA GCA GGA AAA AAA AAA [Thiol] (DNA-FAM-S) was loaded onto Pb NPs as a selective probe for sensitive and selective determination of the SPB. After electrochemical and microscopic characterization of the modifications applied to the GCE, analytical characterization of the biosensor was performed. The biosensor had a limit of detection of 0.0022 ng/ml ~ 622 SPBs and a sensitivity of 3432.9 Ω (ng/ml)−1 or 3432.9 Ω (2.9 × 105 SPBs)−1. The biosensor response was selective, sensitive, stable, repeatable and reproducible in determination of the SPB. The biosensor performance for determination of the SPB was comparable with the NanoDrop method which encouraged us to recommend it for practical purposes. •A novel impedimetric biosensor was developed based on modification of a GCE.•Structure of the biosensor was characterized by the use of microscopic and electrochemical methods.•Performance of the biosensor towards detection of Streptococcus Pneumoniae bacteria was verified.•By an interesting procedure number of the bacteria was determined based on electrochemical response of the biosensor.•The biosensor showed an admirable performance for detection and determination if the bacteria.