Electrochemical aptamer-based biosensor developed to monitor PSA and VEGF released by prostate cancer cells

Abstract

Early prostate cancer (PCa) diagnostic is crucial to enhance patient survival rates; besides, non-invasive platforms have been developed worldwide in order to precisely detect PCa biomarkers. Therefore, the aim of the present study is to develop a new aptamer-based biosensor through the self-assembling of thiolated aptamers for PSA and VEGF on the top of gold electrodes. This biosensor was tested in three prostate cell lines (RWPE-1, LNCaP and PC3). The results evidenced a stable and sensitive sensor presenting wide linear detection ranges (0.08-100 ng/mL for PSA and 0.15 ng-100 ng/mL for VEGF). Therefore, the aptasensor was able to detect the patterns of PSA and VEGF released in vitro by PCa cells, which gave new insights about the prostate cancer protein dynamics. Thus, it could be used as a non-invasive PCa clinical diagnosis instrument in the near future. Graphical Abstract Overview of the experimental design applied to the aptamer-based electrochemical sensor self-assembled on the thiolated hairpin structure. A filter membrane was added on top of working electrode to provide the cell-attachment surface after aptamer incubation, without compromising the aptamer layer. The pore membrane allowed target proteins to pass to the aptamer surface; the MCH backfilling avoided unspecific protein binding to the gold electrode surface.

Using an Electrochemical Aptasensor to Early Detect Prostate Specific and Free Prostate Specific Antigens Released by Cancer Cells

“…Figure A shows the stability of the developed sensor over time: background signal was very stable and it did not cause significant loss in the peak current (around 10 % signal loss) as shown in Figure B. This outcome is similar to results recorded for a whole range of new electrochemical aptamer‐based biosensors .…”

“…MB redox tag selection lied on the easy anchoring of the tag to the hairpin structure of the aptamers (Figure A and B). The MB redox tag is widely used for the development of electrochemical‐based aptamers . Stability of the aptasensor was assessed through SWV in a buffer for 2 hours, before PSA detection.…”

“…The calibration of PSA aptasensor was published in previous paper with a detection limit of 1.1 ng/mL and a linear range of 0–100 ng/mL . The developed aptasensor for PSA and fPSA is suitable to detect PSA and fPSA, respectively, because the protein range in PCa is higher than 4 mg/mL .…”

“…PCa is the most common cancer type among men – it corresponds to approximately 20 % of all tumors affecting the male population. Estimates assume that 15 % of the global male population will be diagnosed with PCa throughout life . The prostate specific antigen (PSA) is the most usual biomarker for PCa; therefore, it is widely used for PCa detection and diagnosis.…”

“…Such demand increases the time to get to an accurate diagnosis, as well as increases costs with the assay. Consequently, a faster, portable and easy‐to‐handle method capable of generating a highly specific response is strongly recommended for disease diagnosis and monitoring . A method encompassing all these features depends on the participation of biosensors .…”