Prostate specific antigen

Ammonium molybdate tetrahydrate (99.98%, Sigma-Aldrich, Burlington, MA, USA), thiourea (AMRESCO, Solon, OH, USA), and polyvinylpyrrolidone (Sigma-Aldrich, Burlington, MA, USA) were used to synthesize the MoS₂ NPs. Potassium hexacyanoferrate (III) (K₃Fe(CN)₆) (approx. 99.0%, Sigma-Aldrich, Burlington, MA, USA) and potassium hexacyanoferrate (II) trihydrate (K₄Fe(CN)₆) (≥99.0%, Sigma-Aldrich, Burlington, MA, USA) solution in phosphate-buffered saline (PBS) (Sigma-Aldrich, Burlington, MA, USA) was used as the electrolyte in this study. EDC and NHS were purchased from Thermo Scientific (≥99.0%, Waltham, MA, USA). Human serum (Sigma-Aldrich, Burlington, MA, USA), cysteamine (Cys) (≥98.0%, Sigma-Aldrich, Burlington, MA, USA), gp120 antibody (Sino biological, Wayne, PA, USA), and gp120 antigen (ACRO Biosystem, Newark, DE, USA) were used to fabricate the biosensor. All aqueous solutions were prepared using deionized (DI) water from a Millipore Milli-Q water purifier operating at a resistance of 18 MΩ·cm. Myoglobin (Mb) (≥90.0%, Sigma-Aldrich, Burlington, MA, USA), hemoglobin (Hb) (Sigma-Aldrich, Burlington, MA, USA), thioredoxin (Trx) (Sino biological, Wayne, PA, USA), and prostate-specific antigen (PSA) (Abcam, Cambridge, UK) were used to investigate the selectivity of the fabricated biosensor.