Graphene Oxide-Based Suppression of Nonspecificity in Loop-Mediated Isothermal Amplification Enabling the Sensitive Detection of Cyclooxygenase-2 mRNA in Colorectal Cancer.

Cyclooxygenase-2 (COX2) mRNA represents a key biomarker for identifying subjects with colorectal cancer (CRC), while there is still no rapid and sensitive detection method for COX2 mRNA. Loop-mediated isothermal amplification (LAMP) is extensively developed for the amplification of nucleic acids; however, its application is frequently hindered by serious nonspecific amplification. Herein, this work reported a graphene oxide (GO)-based LAMP method to enable the one-step detection of COX2 mRNA in cancer cells and serum samples. We found that GO greatly enhanced the specificity of LAMP through decreasing nonspecific hybridization and the fluorescence background signal because of the simultaneous adsorption of single-stranded primers and DNA staining dyes on GO. The detection limit of developed GO-based LAMP was 2 orders of magnitude more sensitive compared to that of classical LAMP. Then a GO-based reverse transcription (RT)-LAMP strategy was further developed and applied to detect COX2 mRNA in CRC cancer cells and serum samples with high specificity. The GO-based LAMP platform with advantages of low cost, simplicity, high specificity, and sensitivity holds considerable potential for real-time fluorescence monitoring of nucleic acid amplification in a wide range of fields.