In this article we describe a sensitive exonuclease III detection method using a DNB nanoarray from a BGISEQ-500 sequencing kit and demonstrate a detection limit as low as 0.001 U/mL. The flow cell of the sequencing kit was loaded with billions of DNA nanoballs (DNBs) to form the DNB nanoarray and initially used for massively parallel sequencing. The 3′-end recessed dsDNA structure formed by sequencing was shown to be a perfect substrate for exonuclease III, but not for other nucleases such as exonuclease I, RecJf and nuclease P1. We developed an exonuclease III assay using the DNB nanoarray, together with other reagents within the BGISEQ-500 sequencing kit, which only required one additional cycle of sequencing. The DNB nanoarray can be reused for the exonuclease III assay at least five times. This method demonstrated superior sensitivity, selectivity, and reusability compared with other assay methods and is accompanied by low cost and simple setup.

在本文中，我们描述了一种使用 BGISEQ-500 测序试剂盒中的 DNB 纳米阵列的灵敏外切核酸酶 III 检测方法，并证明检测限低至 0.001 U/mL。测序试剂盒的流动池装有数十亿个 DNA 纳米球 (DNB)，形成 DNB 纳米阵列，最初用于大规模并行测序。通过测序形成的 3' 端凹陷 dsDNA 结构被证明是外切酶 III 的完美底物，但不是外切酶 I、RecJf 和核酸酶 P1 等其他核酸酶的完美底物。我们使用 DNB 纳米阵列以及 BGISEQ-500 测序试剂盒中的其他试剂开发了一种外切核酸酶 III 检测，只需要一个额外的测序循环。DNB 纳米阵列可重复用于核酸外切酶 III 测定至少五次。该方法表现出卓越的灵敏度，