Application of RNA Aptamers as Recognition Layers for the Electrochemical Analysis of C-Reactive Protein

C-reactive protein (CRP) is one of the crucial biomarkers of inflammation, as well as cardiovascular and cancer diseases. Hence, the development of a sensitive and selective technique for CRP detection is of special importance. One of the possibilities is the application of biosensors containing receptor elements formed of RNA aptamers, as they exhibit high affinity towards C-reactive protein. Herein, the capability of utilization of thiolated RNA aptamers as sensing layers was verified. The occurrence of aptamer - C-reactive protein interaction was confirmed by quartz crystal microbalance experiments. The voltammetric measurements performed in the presence of methylene blue redox indicator showed a linear current decrease within 1-100pmolL(-1) range of protein concentration. The interaction between surface-tethered aptamer and CRP was distinguished with dissociation constant of 25.9pmolL(-1). The developed assay demonstrated a pronounced selectivity to CRP over interfering proteins as well as capability of CRP analysis in serum sample.