Design of oligonucleotide-capped mesoporous silica nanoparticles for the detection of miRNA-145 by duplex and triplex formation

•A new biosensor for the detection of miRNA-145 has been developed.•The system consists on a gated material capped with several oligonucleotide probes.•The system has shown high sensitivity, selectivity and rapidity.•The method was successfully applied in competitive serum samples. The development of new strategies to detect microRNAs (miRNAS) has become an important challenge in the biomedical field. We report herein the use of oligonucleotide-gated silica nanoparticles for the detection of miRNA-145. In the proposed design, mesoporous silica nanoparticles (MSNs) are loaded with a fluorescent reporter (rhodamine B) and pores are blocked by specific DNA oligonucleotides. The opening of the gated system and dye delivery is selectively controlled by DNA-miRNA recognition. Moreover, the use of DNA capture probes able to form duplex or triplex structures between target miRNA and the complementary oligonucleotides has been studied. By this simple procedure a limit of detection as low as 0.25 pM was found for miRNA. The method was successfully applied to detect miRNA-145 in serum samples, which demonstrates the high potential of these capped materials to detect miRNA for diagnostic purposes.