Ru(bpy)32+ encapsulated cyclodextrin based metal organic framework with improved biocompatibility for sensitive electrochemiluminescence detection of CYFRA21-1 in cell.

Metal-organic frameworks (MOFs) have attracted strong interest from researchers. Here, for the first time, we report a sandwich-type electrochemiluminescent biosensor as a signal probe prepared from cyclodextrin-based MOF (CD-MOF)-encapsulated Ru(bpy)32+. Due to the combination of the two materials, the obtained CD-MOF@Ru(bpy)32+ nanocomposites exhibited excellent biocompatibility and electrochemical performance. At the same time, CD-MOF@Ru(bpy)32+ adhered to the electrode surface closely because Ru(bpy)32+ was successfully encapsulated by the CD-MOF. In this paper, CD-MOF@Ru(bpy)32+ and glutaraldehyde were modified on a glassy carbon electrode (GCE) surface to provide excellent conductivity and to immobilize primary antibodies. Under the optimal experimental conditions, the established biosensor exhibited high sensitivity, a low limit of detection and a great linear range for cytokeratin 19 fragment antigen 21-1 (CYFRA21-1). Finally, this designed biosensor was further applied to the determination of CYFRA21-1 in A549 lung cancer cells. According to the results of the toxicity test, CD-MOF@Ru(bpy)32+ exhibited hypotoxicity to living bodies. These results all indicate that this biosensor has great potential for a promising approach to the evaluation of biomarkers.