Sensitive and specific detection of β-hCG in women's serum and cervical secretions is of great significance for early pregnancy evaluation. However, the accurate detection of trace amounts of β-hCG in cervical secretions remains challenging because of its low level. Herein, we report a unique strategy for β-hCG detection in a heterogeneous sandwich-type bioassay by using LiLuF₄:Ce,Tb nanoparticles as time-resolved photoluminescence (PL) nanoprobes. By taking advantage of the intense and long-lived PL of the nanoprobes, the short-lived background autofluorescence can be completely eliminated, which enables the sensitive detection of β-hCG with a linear range of 0–10 ng mL⁻¹ and a detection limit down to 6.1 pg mL⁻¹, approximately two orders of magnitude improvement relative to that of a commercial β-hCG assay kit. Furthermore, we demonstrate the application of the nanoprobes for accurate detection of β-hCG in clinical serum and cervical secretion samples and unveil that the ratio of β-hCG levels in cervical secretions and serum can be a good indicator of early pregnancy viability in unknown locations. These findings bring new opportunities in perinatal medicine by employing luminescent lanthanide nanoprobes, thus laying a foundation for future development of luminescent nanoprobes for versatile biomedical applications.

中文翻译：

---

基于时间分辨的发光镧系元素纳米探针，准确检测女性血清和宫颈分泌物中的β-hCG，以预测早孕能力

女性血清和宫颈分泌物中β-hCG的敏感和特异性检测对于早期妊娠评估具有重要意义。然而，由于其水平低，准确检测宫颈分泌物中痕量的β-hCG仍然具有挑战性。在这里，我们报告了一种独特的策略，通过使用LiLuF ₄：Ce，Tb纳米粒子作为时间分辨的光致发光（PL）纳米探针，在异质夹心式生物测定中检测β-hCG 。通过利用纳米探针的高强度和长寿命PL，可以完全消除短寿命的背景自发荧光，从而可以灵敏地检测线性范围为0–10 ng mL ^-1的β-hCG并进行检测限量低至6.1 pg mL ^-1与商用β-hCG检测试剂盒相比，可提高约两个数量级。此外，我们证明了纳米探针在临床血清和宫颈分泌物样品中准确检测β-hCG的应用，并揭示了宫颈分泌物和血清中β-hCG水平的比率可以作为未知位置早期妊娠存活率的良好指标。这些发现通过使用发光镧系元素纳米探针为围产期医学带来了新的机遇，从而为将来开发用于多功能生物医学应用的发光纳米探针奠定了基础。