Development of an electrochemical DNA biosensor for detection of specific Mycobacterium tuberculosis sequence based on poly(L-glutamic acid) modified electrode

摘要

An electrochemical DNA biosensor was developed by avidin-biotin interaction of a biotinylated probe and avidin-attached, poly(L-glutamic) acid coated pencil graphite electrode (PGA/PGE) for detection of specific Mycobacterium tuberculosis DNA sequence. The discrimination of fully complementary hybridization and mismatch hybridization was carried out by electrochemical reduction current of Meldolaa€?s Blue (MDB) in square wave voltammetry (SWV). The calibration graph of the DNA biosensor was linear between 1.5a€“12.5 nM and the detection limit was calculated as 1.3 nM. The proposed biosensor successfully discriminated short andlong oligonucleotides related to DNA sequence of Mycobacterium tuberculosis in optimal condition.