Detection of the Prostate Cancer Biomarker PCA3 with Electrochemical and Impedance-Based Biosensors

Diagnosis of prostate cancer via PCA3 biomarker detection is promising to be much more efficient than with the prostatic specific antigens currently used. In this study, we present the first electrochemical and impedance-based biosensors that are capable of detecting PCA3 down to 0.128 nmol/L. The biosensors were made with a layer of PCA3-complementary single-stranded DNA (ssDNA) probe, immobilized on a layer-by-layer (LbL) film of chitosan (CHT) and carbon nanotubes (MWCNT). They are highly selective to PCA3, which was confirmed in impedance measurements and with polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). Using information visualization methods, we could also distinguish between cell lines expressing the endogenous PCA3 long noncoding RNA (lncRNA) from cells that did not contain detectable levels of this biomarker. Since the methods involved in fabrication the biosensors are potentially low cost, one may hope to deploy PCA3 tests in any laboratory of clinical analyses and even for point-of-care diagnostics.
This work had financial support from CNPq (Grant #164356/2015-0 and #113757/2018-2), FAPESP (Grant #2013/14262-7) and Barretos Cancer Hospital (Brazil). Andrey Soares thanks to Grant #2018/18953-8, São Paulo Research Foundation (FAPESP). The authors are also thankful to Maria Helena de Oliveira Piazzetta and Angelo Luiz Gobbi for the use of the Microfabrication Laboratory (LMF/LNNano/CNPEM) to manufacture interdigitated electrodes.