Reversible superhydrophobicity unyielding magnetic beads of flipping-triggered (SYMBOL) regulate the binding and unbinding of nucleic acids for ultra-sensitive detection

Present molecular biology procedures often include extraction and purification of nucleic acids (NAs) based on centrifuge-and column-based methods, which involve the usage of specialized apparatus and toxic chemicals. These restrict its usage in large scale high-throughput settings. Magnetic beads (MBs) may provide an ideal approach to extracting and purifying DNA or RNA instead of them. However, the low separation rate of NAs (DNA or RNA) on MBs limits its NAs' detection. Here, we developed a reversible superhydrophobicity unyielding magnetic-beads of flipping-triggered (SYMBOL) system which can regulate the binding and unbinding capacity of NAs via the buffers due to the flipping of -COO- on the surface of SYMBOL. Compared to other MBs examined in this study, SYMBOL exhibited similar binding properties and far enhanced separation properties. In fact, the DNA separation rate rose from about 79% to nearly 96%, whereas, the RNA separation rate increased from roughly 75% to 97%. When it applied to SARS-CoV-2 detection, the SYMBOL, coupled with Simulation Digital RT-LAMP (a previously developed system), could further increase the sensitivity of the detection, thereby achieving a detection threshold of 5 copies/mL. The SYMBOL showed excellent extraction capability in a variety of tissues and can be used in a wide range of nucleic acid related technologies such as PCR, sequencing, etc.

Automated summary

This study presents a magnetic beads system called SYMBOL, which can regulate the binding and unbinding capacity of nucleic acids by flipping the -COO- on the surface of the beads. The SYMBOL system showed enhanced separation properties compared to other magnetic beads, leading to higher DNA and RNA separation rates. When combined with a previously developed system, SYMBOL could increase the sensitivity of SARS-CoV-2 detection, achieving a detection threshold of 5 copies/mL. The SYMBOL system also demonstrated excellent extraction capability in various tissues and could be used in a wide range of nucleic acid related technologies.