Low-power microwave-induced fabrication of functionalised few-layer black phosphorus electrodes: A novel route towards Haemophilus Influenzae pathogen biosensing devices

In this paper, various passivation schemes were applied at few-layer black phosphorus (FLBP) to achieve covalent functionalisation with 4-azidobenzoic acid, improving its electrochemical response intended for analytical and biosensing applications. The thermal and microwave assisted modification procedures in toluene and dimethylformamide resulted in high reversibility of reactions on functionalised FLBP using a ferricyanide/ferrocyanide redox probe. The lowest peak-to-peak separation of 91 mV, and high kinetics were obtained by thermal synthesis in dimethylformamide. Attachment of a = N-phenylene-COOH moiety to the FLBP limits its degradation under ambient conditions delivering a linker for a peptide bond with proteins in the -NH2 groups. The functionalised FLBP was applied for impedimetric detection of the Haemophilus Influenzae (HI) bacterial protein with a low limit of detection (LOD) of 5.82 mu g mL(-1) along with high sensitivity equal to 1.267% mu g(-1) mL. The proposed strategy delivers a novel phosphorene-based electrode for sensitive detection of various bacterial pathogens.