Novel Redox Nanoprobes For Voltammetric Sensing Of Mycobacterium Tuberculosis Dnaand Antigen

OBJECTIVETuberculosis,caused by Mycobacterium tuberculosis complex,remains the top fatal infection continuing to threat public health,and the present detection method for MTB is facing great challenges with the global TB burden.The aim of the study is to develop novel sandwich-type electrochemical biosensors for detecting the IS6110 fragment and MPT64 antigen of Mycobacterium tuberculosis.METHODSSeveral original carbon nanocomposites of fullerene nanoparticles incorporated with graphene nanosheet and/or carbon nanotubes were synthesized in the study for the first time,which directly served as a novel redox nanoprobe to generate signal response without additional electroactive substances.After a typical sandwich recognition process,the proposed electrochemical biosensors were incubated with tetraoctylammonium bromide(TOAB),which displays high ratio surface,great conductivity,rich recognition elements and outstanding redox activity and therefore was used as a booster to arouse the inherent redox activity of the tracer labels.The electrochemical biosensors were fabricated using the carbon nanocomposites and nanomaterials(i.e.Au nanoparticles),and the biotin-avidin system was incorporated to promote target recognition.The sandwich-type recognition was realized based on an aptamer recognition system or DNA base pairing.After the sandwich-type hybridization,the proposed electrochemical DNA biosensor was treated with tetraoctylammonium bromide(TOAB)to arouse the inherent electroactivity of the tracer label,generating distinctive current response for target quantification.RESULTSThe proposed electrochemical biosensors have shown a broad linear range for Mycobacterium tuberculosis determination and a low limit of detection.In addition,the proposed biosensors have displayed excellent selectivity,stability and reproducibility.More importantly,they have been preliminarily applied in clinical detection and displayed excellent ability to distinguish tuberculosis clinical samples from non-tuberculosis ones.CONCLUSIONNovel sandwich-type electrochemical biosensors for detecting the IS6110 fragment and MPT64 antigen of Mycobacterium tuberculosis have been successfully developed,and there is great potential for the developedmethod to be used in early diagnosis and monitor of tuberculosis.