Enhanced Performance Electrochemical Biosensor for Detection of Prostate Cancer Biomarker PCA3 Using Specific Aptamer

Abstract

In the quest for the development of accurate, reliable, and cost-effective biosensing technology for early diagnostics of prostate cancer, we describe here an electrochemical biosensor combining a simple transducing method of differential pulse voltammetry (DPV) with an RNA-based aptamer labelled with a methylene blue redox group acting as a highly specific bioreceptor to the prostate cancer biomarker PCA3. A series of DPV measurements on screen-printed gold electrodes is functionalised with a redox-labelled aptamer in solutions (either buffer or synthetic urine) containing PCA3 in a wide range of concentrations from 0.1 picomolar (pM) to 10 nanomolar (nM). In these measurements, the current peak values correlate with the concentration of PCA3 and yield a low detection limit (LDL) of 0.1 pM. Furthermore, the binding kinetics study revealed the high affinity of the aptamer to the target PCA3 with the affinity constants KD of about 3.0 × 10−8 molar. In addition, the AFM study showed the increase in the molecular layer roughness caused by the binding of PCA3, which is a large RNA molecular fragment.

An Electrochemical Aptasensor for the Detection of Freshwater Cyanobacteria

“…Due to the immobilization of the APS9 on the SPEs, the redox probe, MB, which is tagged at the 3 ′ end of the APS9, is brought closer to the surface of the electrode, resulting in the production of an electrochemical signal from MB (red line, Figure 2c). Also, in other studies, MB was chosen as a redox mediator for the development of aptasensors [26,31,32,37,38]. Several strategies employing MB as a redox mediator in aptasensors as well as DNA sensors have been applied: the MB can either electrostatically interact with the DNA or intercalate in the DNA double helix between the G-C sequence [39].…”

Designing a Simple Electrochemical Genosensor for the Detection of Urinary PCA3, a Prostate Cancer Biomarker

“…In the case of PCA3, the literature reported the design of electrochemical genosensors labeled with enzymes [41], redox indicators like methylene blue [42] and ferrocene [43], or nanomaterials for signal amplification [44,45]. Despite its interest, the labeling increases the process's complexity and cost, necessitating additional time and effort due to intermediate functionalization steps.…”