The false-negative result of nucleic acid testing is an important cause of continued spread of COVID-19, while SARS-CoV-2 RNA degradation during transportation and nucleic acid extraction can lead to false-negative results. Here, we investigated that single-walled carbon nanotubes (SCNTs) could protect RNA from degradation for at least 4 days at room temperature. By constructing magnetism-functionalized SCNTs (MSCNTs), we developed a method that enabled protection and simple extraction of SARS-CoV-2 RNA, and the RNA-bound MSCNTs can be directly used for reverse transcription polymerase chain reaction (RT-qPCR) detection. The experimental results showed that one microgram of MSCNTs adsorbed up to 24 ng of RNA. Notably, the MSCNTs-based method for extracting SARS-CoV-2 RNA from simulated nasopharyngeal swabs and saliva samples with mean recovery rates of 103% and 106% improved the sensitivity of RT-qPCR detection by 8–32 fold in comparison to current common methods. This improvement was largely attributable to the protection of RNA, enabling increased RNA load for downstream assays.

核酸检测的假阴性结果是COVID-19持续传播的重要原因，而SARS-CoV-2 RNA在运输和核酸提取过程中的降解会导致假阴性结果。在这里，我们研究了单壁碳纳米管 (SCNT) 可以在室温下保护 RNA 至少 4 天不被降解。通过构建磁性功能化的 SCNTs (MSCNTs)，我们开发了一种能够保护和简单提取 SARS-CoV-2 RNA 的方法，RNA 结合的 MSCNTs 可直接用于逆转录聚合酶链反应 (RT-qPCR) 检测. 实验结果表明，1 微克的 MSCNTs 最多可吸附 24 ng 的 RNA。尤其，基于 MSCNT 的方法从模拟鼻咽拭子和唾液样本中提取 SARS-CoV-2 RNA，平均回收率为 103% 和 106%，与目前常用的方法相比，RT-qPCR 检测的灵敏度提高了 8-32 倍。这种改进主要归因于 RNA 的保护，从而增加了下游分析的 RNA 载量。