RNase-free RNA removal and DNA purification by functionalized magnetic particles

Isolation of high-quality DNA is one of the essential steps in the field of molecular biology. Before DNA isolation, ribonuclease A (RNase) has to be introduced to degrade RNA. However, RNase needs to be stored at low temperature, and the conditions for the degradation of RNA need to be strictly controlled. In the study, graphene oxide functionalized magnetic particles (GO-MPs) were prepared and used for RNA removal. GO-MPs demonstrate good environmental stability. The RNA removing process by GO-MPs can be finished in 10 min at room temperature. Also, GO-MPs exhibit good selectivity toward RNA over double-stranded DNA. Next, the spherical and core–shell structure poly(3,4-dihydroxy-L-phenylalanine) functionalized MPs (polyDOPA-MPs) were prepared and used for the purification of DNA. The DNA adsorption and release can be realized by adjusting the pH value of solutions. It is worth emphasizing that the condition for RNA removal by GO-MPs is the same as that for DNA adsorption by polyDOPA-MPs, which ensures the effective connection between the two steps. The feasibility of the MPs-based protocol was verified by the successful extraction of genomic DNA from Escherichia coli DH5α and genetically modified corn. The results suggest that the protocol would provide a promising platform for RNase-free RNA removal and DNA purification from bacteria and plant seeds.