Electrochemical and optical detection and machine learning applied to images of genosensors for diagnosis of prostate cancer with the biomarker PCA3.

The development of simple detection methods aimed at widespread screening and testing is crucial for many infections and diseases, including prostate cancer where early diagnosis increases the chances of cure considerably. In this paper, we report on genosensors with different detection principles for a prostate cancer specific DNA sequence (PCA3). The genosensors were made with carbon printed electrodes or quartz coated with layer-by-layer (LbL) films containing gold nanoparticles and chondroitin sulfate and a layer of a complementary DNA sequence (PCA3 probe). The highest sensitivity was reached with electrochemical impedance spectroscopy with the detection limit of 83 pM in solutions of PCA3, while the limits of detection were 2000 pM and 900 pM for cyclic voltammetry and UV-vis spectroscopy, respectively. That detection could be performed with an optical method is encouraging, as one may envisage extending it to colorimetric tests. Since the morphology of sensing units is known to be affected in detection experiments, we applied machine learning algorithms to classify scanning electron microscopy images of the genosensors and managed to distinguish those exposed to PCA3-containing solutions from control measurements with an accuracy of 99.9%. The performance in distinguishing each individual PCA3 concentration in a multiclass task was lower, with an accuracy of 88.3%, which means that further developments in image analysis are required for this innovative approach.

Talanta. 2020 Aug 07 [Epub]

Valquiria C Rodrigues, Juliana C Soares, Andrey C Soares, Daniel C Braz, Matias Eliseo Melendez, Lucas C Ribas, Leonardo F S Scabini, Odemir M Bruno, Andre Lopes Carvalho, Rui Manuel Reis, Rafaela C Sanfelice, Osvaldo N Oliveira

Department of Materials Engineering, Sao Carlos School of Engineering, University of Sao Paulo, São Carlos, SP, 13563-120, Brazil; Sao Carlos Institute of Physics, University of Sao Paulo, 13566-590, São Carlos, Brazil., Sao Carlos Institute of Physics, University of Sao Paulo, 13566-590, São Carlos, Brazil., Nanotechnology National Laboratory for Agriculture (LNNA), Embrapa Instrumentação, 13560-970, São Carlos, Brazil., Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil; Pelé Little Prince Research Institute, Little Prince College, Little Prince Complex Curitiba, 80250-060, Curitiba, PR, Brazil., Institute of Mathematics and Computer Science, University of Sao Paulo, Sao Carlos, Brazil., Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil., Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400, Barretos, Brazil; Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal., Department of Chemical Engineering, Federal University of the Triângulo Mineiro, Uberaba-MG, Brazil., Sao Carlos Institute of Physics, University of Sao Paulo, 13566-590, São Carlos, Brazil. Electronic address: .