A highly sensitive peptide-based biosensor using NiCo2O4 nanosheets and g-C3N4 nanocomposite to construct amplified strategy for trypsin detection

Here, a simple electrochemical biosensor was proposed based on the specific recognition between trypsin and peptide. Initially, NiCo2O4-PAMAM nanocomposite was casted on the bare electrode to achieve the electrochemical signal amplification in 0.1 mM [Ru(NH3)(6)](3+) solution owing to the great electronic conductivity and high electrochemical activity induced by the special structure of NiCo2O4 nanosheets (Ni3+ cations in octachedral sites of the Co3O4). Subsequently, a declined electrochemical signal was obtained when g-C3N4 labeled peptide composites were anchored on the electrode. However, after trypsin was added into solution and incubated with the biosensor, the electrochemical signal was re-promoted. Therefore, the as-synthesized biosensor could realize the sensitive detection of trypsin by virtue of the specific recognition between trypsin and peptide. As a result, the developed peptide-based exhibited a linear range from 10(-10) to 10(-4) mg mL(-1) with an ultralow detection limit of 10(-10) mg mL(-1), providing sensitive analytical performance and acceptable application potential in clinical test and disease diagnosis due to its high stability, excellent selectivity, acceptable reproducibility and accurate signal output. (c) 2018 Elsevier B.V. All rights reserved.