The apurinic/apyrimidinic (AP) site is one of the most common DNA lesions and a critical intermediate during the base excision repair pathway. Therefore, AP sites are essential in clinical diagnosis, treatment and detection. However, the existing detection methods are complicated in design and synthesis and have high instrument requirements, limiting their wide application. Therefore, there is an urgent need for a sensitive and straightforward detection method without time-consuming and heterogeneous reactions. Herein, we developed two compatible detection methods for AP sites in long and short dsDNA. For long and short dsDNA, the background signal was successfully suppressed by the affinity difference of Terminal deoxynucleotidyl transferase (TdT) and 3’ -end blocking, respectively, thus achieving high detectability and specificity. The detection limit was 13 pM in 20 μL, meaning that the LOD was 0.26 fmol for AP site amount and 0.05% for AP site abundance. The method has been successfully applied to detect AP sites in various biological samples quickly. Therefore, it has broad clinical application prospects, catering for the need for a point of care.

脱嘌呤/脱嘧啶 (AP) 位点是最常见的 DNA 损伤之一，也是碱基切除修复途径中的关键中间体。因此，AP位点在临床诊断、治疗和检测中至关重要。然而，现有的检测方法设计合成复杂，仪器要求高，限制了其广泛应用。因此，迫切需要一种灵敏且直接的检测方法，无需耗时且不均匀的反应。在此，我们针对长短 dsDNA 中的 AP 位点开发了两种兼容的检测方法。对于长和短 dsDNA，背景信号分别被末端脱氧核苷酸转移酶 (TdT) 和 3'-末端封闭的亲和力差异成功抑制，从而实现了高可检测性和特异性。检测限为 20 μL 中的 13 pM，这意味着 AP 位点数量的 LOD 为 0.26 fmol，AP 位点丰度的 LOD 为 0.05%。该方法已成功应用于快速检测各种生物样品中的AP位点。因此，它具有广阔的临床应用前景，满足了床位护理的需要。