Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA.
Molecules. 2020 Feb 20;25(4):947. doi: 10.3390/molecules25040947.
Isothermal, enzyme-free amplification methods based on DNA strand-displacement reactions show great promise for applications in biosensing and disease diagnostics but operating such systems within biological environments remains extremely challenging due to the susceptibility of DNA to nuclease degradation. Here, we report a catalytic hairpin assembly (CHA) circuit constructed from nuclease-resistant l-DNA that is capable of unimpeded signal amplification in the presence of 10% fetal bovine serum (FBS). The superior biostability of the l-DNA CHA circuit relative to its native d-DNA counterpart was clearly demonstrated through a direct comparison of the two systems (d versus l) under various conditions. Importantly, we show that the l-CHA circuit can be sequence-specifically interfaced with an endogenous d-nucleic acid biomarker via an achiral peptide nucleic acid (PNA) intermediary, enabling catalytic detection of the target in FBS. Overall, this work establishes a blueprint for the detection of low-abundance nucleic acids in harsh biological environments and provides further impetus for the construction of DNA nanotechnology using l-oligonucleotides.
基于 DNA 链置换反应的等温、无酶扩增方法在生物传感和疾病诊断应用中具有很大的应用前景，但由于 DNA 易被核酸酶降解，在生物环境中运行这些系统仍然极具挑战性。在这里，我们报告了一种由耐核酸酶的 l-DNA 构建的催化发夹组装 (CHA) 电路，它能够在存在 10%胎牛血清 (FBS) 的情况下不受阻碍地进行信号放大。通过在各种条件下直接比较两种系统 (d 与 l)，明显证明了 l-DNA CHA 电路相对于其天然 d-DNA 对应物具有更高的生物稳定性。重要的是，我们表明，l-CHA 电路可以通过非手性肽核酸 (PNA) 中间体与内源性 d-核酸生物标志物进行序列特异性接口，从而能够在 FBS 中催化检测靶标。总的来说，这项工作为在恶劣的生物环境中检测低丰度核酸奠定了基础，并为使用 l-寡核苷酸构建 DNA 纳米技术提供了进一步的动力。
