Comparison of the Performances of Two RNA-Based Geno- Sensing Principles for the Detection of lncPCA3 Biomarker †

The most common prostate cancer (PCa) diagnostics which is based on detection of prostate-specific antigen (PSA) in blood has specificity limitations often resulting in both false-positive and false-negative results; therefore, improvement in PCa diagnostics using more specific PCa biomarkers is of high importance. Studies have shown that the long noncoding RNA Prostate Cancer Antigen 3 (lncPCA3) over-expressed in the urine of prostate cancer patients is an ideal biomarker for non-invasive early diagnostics of PCa. Geno-sensors based on aptamer bioreceptors (apta-sensors) offer costand time-effective, and precise diagnostic tools for detection PCa biomarker. In this study, we report on further development of RNA-based aptasensors exploiting two different detection strategies, i.e., electrochemical (CV and IS) and optical (spectroscopic ellipsometry) measurements. These sensors were made by immobilization of thiolated CG-3 RNA aptamers on the surface of gold. Aptamer labelled with redox group (ferrocene) was used in electrochemical measurements, while non-labelled aptamer was used in total internal reflection ellipsometry (TIRE) measurements. The results obtained by these two methods were compared; the sensitivity in sub-pM level of concentration was achieved, and the required selectivity is provided by high affinity of PCA3-to-aptamer binding with KD in 10-9 M range. The spectroscopic ellipsometry measurements provided additional information on the processes PCA3 to aptamer binding of proposed detection approaches allow the reliable detection of PCA3 at low concentrations, thus providing a background for future development of novel, highly sensitive and cost-effective diagnostic methodologies for prostate can-