RESUMO
A method for detection of cancer-associated protein D-NFATc1 in serum using nanowire (NW) biosensor based on field-effect nanotransistor is developed. Field-effect nanotransistor was fabricated on the basis of «silicon-on-insulator¼ structures. For the biospecific detection of target protein, the NW surface was modified with aptamers against the target protein. Using the 3 um-NW enabled to obtain stable source-drain characteristics and to register D-NFATc1 in serum at concentration of 2.5 x 1014 M in the mode of drain-source current vs. gate voltage characteristics measurements. Data collection in the mode of drain-source current vs. gate voltage characteristics measurements was carried out with the use of high-speed data collection system running TURBO NBS software.
Assuntos
Técnicas Biossensoriais , Fatores de Transcrição NFATC/sangue , Nanofios , Proteínas de Neoplasias/sangue , Software , Transistores Eletrônicos , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Humanos , Sensibilidade e EspecificidadeRESUMO
The nanowire (NW) detection is one of fast-acting and high-sensitive methods allowing to reveal potentially relevant protein molecules. A NW biosensor based on the silicon-on-insulator (SOI)-structures was used for biospecific label-free detection of NFAT 1 (D-NFAT 1) oncomarker in real time. For this purpose, SOI-nanowires (NWs) were modified with aptamers against NFAT 1 used as molecular probes. It was shown that using this biosensor it is possible to reach the sensitivity of ~10(-15) M. This sensitivity was comparable with that of the NW biosensor with immobilized antibodies used as macromolecular probes. The results demonstrate promising approaches used to form the sensor elements for high-sensitive disease diagnostics.
Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/instrumentação , Fatores de Transcrição NFATC/análise , Nanofios/química , Proteínas de Neoplasias/análise , Anticorpos Monoclonais/química , Aptâmeros de Nucleotídeos/síntese química , Técnicas Biossensoriais/economia , Técnicas Eletroquímicas , Humanos , Limite de Detecção , Dióxido de Silício/química , Soluções , Succinimidas/químicaRESUMO
A superconductor in a magnetic field acquires a finite electrical resistance caused by vortex motion. A quest to immobilize vortices and recover zero resistance at high fields made intense studies of vortex pinning one of the mainstreams of superconducting research. Yet, the decades of efforts resulted in a realization that even promising nanostructures, utilizing vortex matching, cannot withstand high vortex density at large magnetic fields. Here, we report a giant reentrance of vortex pinning induced by increasing magnetic field in a W-based nanowire and a TiN-perforated film densely populated with vortices. We find an extended range of zero resistance with vortex motion arrested by self-induced collective traps. The latter emerge due to order parameter suppression by vortices confined in narrow constrictions by surface superconductivity. Our findings show that geometric restrictions can radically change magnetic properties of superconductors and reverse detrimental effects of magnetic field.