An ultrasensitive label free nanobiosensor platform for the detection of cardiac biomarkers

We report the fabrication of a label free nano biosensor platform comprising single nanofiber that is derived out of multi-walled carbon nanotubes (MWCNTs) embedded SU-8 photoresist, for the detection of three important human cardiac biomarkers viz., myoglobin (Myo), cardiac Troponin I (cTn I) and Creatine Kinase-MB (CK-MB). These composite nanofibers were synthesized using electrospinning process. Single nanofibers were aligned between pairs of electrodes in-situ during the electrospinning process. The target proteins were detected using chemiresistive detection methodology. Each biomarker was detected using a specific, single, aligned nanofiber, functionalized with its corresponding monoclonal antibody. Chemiresistive detection involves measuring the change in conductance of the functionalized nanofibers upon the binding of the targeted antigen. The minimum detection limits of Myo, CK-MB and cTn I were experimentally found out to be as low as 6, 20 and 50 fg/ml respectively. No response was observed when the nanofibers were exposed to a non-specific protein, demonstrating excellent specificity to the targeted detection. These MWCNTs embedded SU-8 nanofibers based nanobiosensor platform shows great promise in the detection of cardiac markers and other proteins as they have fast response time, high sensitivity and good specificity.