Graphene-CNT nanohybrid aptasensor for label free detection of cardiac biomarker myoglobin

• Label free Mb detection on aptamer functionalized rGO/CNT nanostructured electrodes.
• The generated anti-Mb aptamer showed high senstivity (KD ~ 65 pM).
• Direct electron transfer monitored specifically on apt/rGO/CNT electrodes.
• Mb Assay demonstrated LOD ~0.34 ng/mL with linear range between 1 to 4000 ng/mL.
• Developed platform has potential in routine screening of Mb in patient's samples.

We report a label free electrochemical detection of cardiac bio-marker myoglobin (Mb) on aptamer functionalized rGO/CNT nanostructured electrodes by measuring its direct electron transfer (DET). Configured as a highly responsive aptasensor, the newly developed biosensing platform exhibits synergistic effect of the nano-hybrid functional construct by combining good electrical properties and the facile chemical functionality of nanohybrid for the compatible bio-interface development. The specific anti-Mb aptamer was generated by five iterative SELEX (Systematic evolution of ligands by exponential enrichment) rounds, showing high senstivity (KD ~65 pM). The aptamer functionalized rGO/CNT nanostructured electrodes demonstrated a significant increase in signal response with a detection limit of ~0.34 ng/mL in the dynamic response range between 1 ng/mL and 4 µg/mL for Mb. The newly developed DET assay format presents a promising candidate in point-of-care diagnosis for routine screening of Mb in patient's samples.