RESUMEN
AIM: A new type of surface modification of SOI-FET sensors with ultrathin sensor-probe transition layer and uncharged probes for highly specific detection of short RNA (saRNA) was suggested. MATERIALS & METHODS: Carbonyldiimidazole (CDI) or glycidoxypropyltrimethoxysilane were used as precursors of sensor-probe interface layers, together with peptide nucleic acids and new NA analogues - phosphoryl guanidine oligo(2'-OMe)ribonucleotides (PGO) as probes for RNA hybridization. RNA sequences corresponding to mRNA NELFA (NM_005663) and microRNA-29a (cancer markers) were used as saRNA targets. Real-time saRNA detection by SOI-FET sensors and fluorescence analysis were applied. RESULTS: Highly specific response with femtomolar sensitivity to saRNA was demonstrated for CDI-PGO-modified sensors fabricated by optical lithography. CONCLUSION: The proposed CDI-PGO protocol of modification of Si sensor surface is a promising procedure for biomedical applications.
Asunto(s)
Técnicas Biosensibles/métodos , Hibridación de Ácido Nucleico/métodos , ARN Interferente Pequeño/análisis , Secuencia de Bases , Técnicas Biosensibles/instrumentación , Diseño de Equipo , Humanos , Imidazoles/química , MicroARNs/genética , Sondas de Oligonucleótidos/química , Ácidos Nucleicos de Péptidos/química , ARN Mensajero/genética , ARN Interferente Pequeño/genética , Silanos/química , Propiedades de Superficie , Factores de Elongación Transcripcional/genéticaRESUMEN
Silicon-on-isolator-nanowires (SOI-NWs) were used for the label-free, real-time biospecific detection of the hepatitis B marker HBsAg and cancer marker α-fetoprotein (AFP). Specific protein-protein recognition was carried out using individual NWs that were functionalized with antibodies. To solve the problem of non-specific binding of target protein molecules to the sensor element the use of a reference NW with immobilized antibodies against non-target proteins was proposed. Using individual SOI-NW surface functionalization allowed the fabrication of a NW array, containing working NWs and reference NWs within one chip. It was shown that this approach allows us to reach a detection limit up to 10(-14) and 10(-15) M for HBsAg and AFP, respectively. Our investigations also allowed us to reveal the influence of the charged state of the target protein molecules and antibodies in solutions with various pH values on the target protein detection limit. A high sensitivity NW-detector is of interest for the creation of diagnosticums for hepatitis B and for the early stages of cancer diseases.