Herein, we report the development of a highly sensitive nanotechnology-based system—silicon-on-insulator nanowire biosensor for the revelation of microRNAs (miRNAs), associated with the development of glioma in the human. In this system, a sensor chip, bearing an array of silicon nanowire structures, is employed. The sensor chip is fabricated using a top-down technology. In our experiments reported herein, we demonstrated the detection of DNA oligonucleotide (oDNA), which represents a synthetic analogue of microRNA-363 associated with the development of glioma. To provide biospecific detection of the target oligonucleotides, the surface of the nanowire structures is modified with oligonucleotide probes; the latter are complementary to the target ones. The concentration limit of the target oligonucleotide detection, attained using our nanowire biosensor, is at the level of DL~10−17 M. The revelation of the elevated level of glioma-associated miRNA in plasma is also demonstrated.

The detection of CA 125 protein in a solution using a silicon-on-insulator (SOI)-nanowire biosensor with n-type chip has been experimentally demonstrated. The surface of nanowires was modified by covalent immobilization of antibodies against CA 125 in order to provide the biospecificity of the target protein detection. We have demonstrated that the biosensor signal, which results from the biospecific interaction between CA 125 and the covalently immobilized antibodies, increases with the increase in the protein concentration. At that, the minimum concentration, at which the target protein was detectable with the SOI-nanowire biosensor, amounted to 1.5 × 10−16 M.

Nanoribbon chips, based on “silicon-on-insulator” structures (SOI-NR chips), have been fabricated. These SOI-NR chips, whose surface was sensitized with covalently immobilized oligonucleotide molecular probes (oDNA probes), have been employed for the nanoribbon biosensor-based detection of a circular ribonucleic acid (circRNA) molecular marker of glioma in humans. The nucleotide sequence of the oDNA probes was complimentary to the sequence of the target oDNA. The latter represents a synthetic analogue of a glioma marker—NFIX circular RNA. In this way, the detection of target oDNA molecules in a pure buffer has been performed. The lowest concentration of the target biomolecules, detectable in our experiments, was of the order of ~10−17 M. The SOI-NR sensor chips proposed herein have allowed us to reveal an elevated level of the NFIX circular RNA in the blood of a glioma patient.