A simple magnetic nanoparticles-based viral RNA extraction method for efficient detection of SARS-CoV-2

Zhen Zhao; Haodong Cui; Wenxing Song; Xiaoling Ru; Wenhua Zhou; Xuefeng Yu

Quantitative extraction of nucleic acids with high purity from complex samples are the prerequisite for efficient RT-PCR assays. Low extraction efficiency might give poor signals during exponential amplification and thus result in false negative results. [11] [12] Low extraction quality, on the other hand, may contain a variety of PCR inhibitors, which gives unreliable readouts during amplification. [13] [14] In the control and diagnosis towards SARS-CoV-2 currently, silica-based spin column RNA extraction methods are widely used, in which a silica membrane or glass fiber is applied to bind nucleic acids. In these traditional methods, the samples need pre-lysis in an appropriate buffer to release nucleic acids from viral particles before binding to the column membrane and multiple centrifugation steps are required to enable binding, washing and elution of extracted nucleic acids. Additionally, as various corrosive chaotropic salts and toxic organic solvents are involved in the lysis and binding steps, several sequential washing steps are required to eliminate possible PCR inhibitory effects in the eluted products. The whole process comprises multiple centrifuging and column-transferring steps, which is laborious, time-consuming, and vulnerable to contamination or column clogging. More importantly, spin column-based approaches are not suitable for a high-throughput, automated operation. In the monitoring and control of sudden outbreaks, such as SARS-CoV-2, these traditional methods consume a large number of operators, but giving low diagnosis efficiency and high risk of cross infection. Thus, fast, convenient and automated nucleic acids extraction methods are highly desirable not just in the molecular diagnosis of SARS-CoV-2, but also in the monitoring and prevention of other infectious diseases.