Gold nanoparticle enhanced surface plasmon resonance imaging of microRNA-155 using a functional nucleic acid-based amplification machine

MicroRNAs (miRNAs) are considered as being promising biomarkers for hematological malignancies, their aging, progression and prognosis. The authors have developed a method for the detection of miRNA155 by using surface plasmon resonance (SPR) imaging coupled to a nucleic acid-based amplification strategy using gold nanoparticles (AuNPs). The target miRNA155 is captured by surface-bound DNA probes. After hybridization, DNA-AuNP are employed for signal amplification via DNA sandwich assembly, resulting in a large increase in the SPR signal. This method can detect miRNA-155 in concentrations down to 45 pM and over dynamic that extends from 50 pM to 5 nM. The assay is highly specific and can discriminate even a single base mismatch. It also is reproducible, precise, and was successfully applied to the determination of miRNA-155 in spiked real samples where it gave recoveries in the range between 86% and 98%. This biosensor provides an alternative approach for miRNA detection in biomedical research and clinical diagnosis, which is highly effective and efficient.