Reduced Graphene Oxide-Based Solid-Phase Extraction for the Enrichment and Detection of microRNA

MicroRNAs (miRNAs) are endogenous molecules with regulatory functions. The purification and enrichment of miRNA are essential for its precise and sensitive detection. miRNA isolated using commercial kits contains abundant interfering RNAs, and the concentration of miRNA may not be adequate for detection. Herein, we prepared a reduced graphene oxide (rGO)-based magnetic solid-phase extraction material for the enrichment and ultrasensitive detection of miRNA from intricate nucleic acid solutions. In situ reverse transcription (RT) was developed as the most efficient approach to desorb miRNA from rGO among the methods that are compatible for the subsequent amplification reported thus far. Additionally, rolling circle amplification and qPCR were used to detect let-7a with a decrease of the limit of detection by 24.7- and 31.3-fold, respectively. This material was also successfully used to extract and detect miRNA from total RNA isolated from human plasma. Our results show that the material prepared in this study has the potential for cancer biopsy in clinics and the discovery of new miRNAs in scientific research.