Portable and sensitive detection of miRNA in cerebral infarction through the DSN enzyme assisted dual signal recycles by using personal glucose meters (PGMs)

Development of a portable and sensitive microRNAs (miRNAs) detection approach is crucial for the fundamental research and early-diagnosis of many diseases. Herein, we propose a novel miRNA detection strategy by using duplex-specfic nuclease (DSN enzyme) and DNAzyme to form dual signal amplification, and using PGMs to read the detection result. In this method, a hairpin structure catch probe is designed to specifically recognize target miRNA to generate a DNA-RNA complex. Under the assistance of DSN enzyme, the binding section which is complementary with target miRNA is digested, and the miRNA is released from the duplex. The liberated miRNA unfolds a next catch probe to form the first signal amplification. Meanwhile, the DNAzyme section in catch probe forms its active structure under the assistance of Mg2+ and substrate to cut the complementary sequence in substrate and to generate the linker. The linker sequence assists the formation of SMBs-ssDNA-sucrase complex through mediating conjugation of sucrase-ssDNA and streptavidin magnetic beads (SMBs)-ssDNA, generating. After magnet based removal of unbound linker sequences, the complex is then utilized to catalyze sucrose to glucose, which could be detected by using PGMs. Based on this, the approach exhibits a favorable detection sensitivity with a low limit of detection (LOD). This new approach is an essential step toward the portable and reliable detection of miRNA for diagnostic purposes.