Prolactin (PRL) is produced by the pituitary gland and plays a vital role in the production of milk after a baby is born. PRL levels are normally elevated in pregnant and nursing women, and high levels of PRL in the human body cause hyperprolactinemia, infertility, galactorrhea, infrequent or irregular periods, amenorrhea, breast pain, and loss of libido. Accordingly, herein, a novel label-free immunosensor using a bismuth sulfide/polypyrrole (Bi₂S₃/PPy)-modified screen-printed electrode (SPE) for the fast and facile detection of the peptide hormone PRL. Bi₂S₃ nanorods were synthesized via a facile hydrothermal technique, and PPy was prepared by chemical polymerization method. Subsequently, the Bi₂S₃/PPy/ SPE was modified with 3-mercaptopropionic acid (MPA) and EDC/NHS. Owing to the cross-linking effect of EDC/NHS, antibody-PRL (anti-PRL) was firmly stabilized on the modified SPE surface. These layer-by-layer modifications enhanced the conducting properties, anti-PRL loading capacity, and sensitivity of the developed immunosensor. Under optimized conditions, the PRL immunosensor demonstrated a broad linear range of approximately 1–250 ng/mL, a low detection limit of approximately 0.130 ng/mL (3 × SD/b), good specificity, reproducibility, and stability. PRL was successfully evaluated in human and mouse serum samples, and the corresponding outcomes were compared with those of the electrochemical and ELISA methods.

催乳素 (PRL) 由垂体产生，在婴儿出生后的乳汁分泌中发挥着至关重要的作用。孕妇和哺乳期妇女的PRL水平通常升高，人体内PRL水平过高会导致高泌乳素血症、不孕、溢乳、月经稀少或不规律、闭经、乳房疼痛和性欲减退。因此，本文提出了一种新型无标记免疫传感器，其使用硫化铋/聚吡咯(Bi ₂ S ₃ /PPy)修饰的丝网印刷电极(SPE)来快速且简便地检测肽激素PRL。通过简便的水热技术合成了Bi ₂ S ₃纳米棒，并通过化学聚合方法制备了PPy。随后，用3-巯基丙酸(MPA)和EDC/NHS对Bi ₂ S ₃ /PPy/SPE进行修饰。由于EDC/NHS的交联作用，抗体-PRL（抗PRL）牢固地稳定在修饰的SPE表面上。这些逐层修饰增强了所开发的免疫传感器的导电特性、抗 PRL 负载能力和灵敏度。在优化条件下，PRL 免疫传感器表现出约 1–250 ng/mL 的宽线性范围、约 0.130 ng/mL (3 × SD/b) 的低检测限、良好的特异性、重现性和稳定性。在人和小鼠血清样本中成功评估了 PRL，并将相应的结果与电化学和 ELISA 方法的结果进行了比较。