Multiplex biomarker detection platform based on zinc protoporphyrin-modified gold electrodes: Application potential for early diagnosis and postoperative monitoring of prostate cancer.

Early detection and treatment of prostate cancer are essential for improving outcomes. Blood tests measuring prostate-specific antigen (PSA) are commonly used to assess cancer risk. However, PSA levels can be affected by non-cancer conditions, leading to possible misdiagnosis and stress for patients. To improve accuracy, a new detection system using gold electrodes modified with zinc protoporphyrin (Au/ZnPP) was developed. This system detects proteins in blood by using the interaction between zinc ions and protein groups, combined with differential pulse voltammetry. Three electrochemical sensors were made to detect PSA, free PSA (fPSA), and C-reactive protein (CRP). These sensors worked well in diluted human blood, detecting PSA from 0.01 to 50 ng/mL, fPSA from 5x10-3-50 ng/mL, and CRP from 5x10-3-500 μg/mL. The sensitivities of the PSA, fPSA and CRP sensors were 383.4 μA/log(ng/mL)-cm2, 406.2 μA/log(ng/mL)-cm2, and 252.7 μA/log(μg/mL)-cm2, respectively. All three markers can be measured within 3 min using this method. Furthermore, the clinical applicability of the proposed biosensor was validated using serum samples from 14 human subjects, including patients with benign prostatic hyperplasia (BPH) and stage I prostate cancer (PCa). The quantification results showed strong agreement with those obtained from conventional enzyme-linked immunosorbent assay (ELISA), confirming the accuracy and reliability of the proposed method in complex biological samples. This platform shows strong potential for early prostate cancer screening and post-surgery monitoring.