Biomarkers P53 And Mirna Surface Plasmon Resonance Detection

Surface plasmon resonance (SPR) is an optical technique capable of measuring the tiny changes occurring at the metal films. As one of the most powerful techniques, SPR can monitor the biomolecular interactions in a real-time, highly sensitive, and label-free way. In this paper, two important biomarkers, p53 protein and miRNA, have been determined by SPR.First of all, ultrasensitive determination of wild-type and total p53 proteins (wild-type and mutant combined) present in cancer cell lysates has been performed with a dual-channel surface plasmon resonance instrument. To achieve specificity, each channel of the SPR chip was modified with a consensus double-stranded (ds-) DNA and a monoclonal antibody. The high affinity of the consensus ds-DNA to the wild-type p53 and the antibody to total p53 results in remarkably low detection levels (10.6 and 1.06 pM for the wild-type and total p53, respectively). The difference between the SPR signals reveals the extent of p53 mutation, which is indicative of cancer development. In comparison with enzyme-linked immunosorbant assay (ELISA), SPR obviates the need of a second antibody labeled with an enzyme in the "sandwich enzyme immunoassay" format and is capable of real-time monitoring the binding events. Thus, SPR could potentially serve as an attractive technique for rapid, sensitive, reliable, and label-free cancer diagnoses.miRNAs are a family of endogenous, small (approximately 19-25 nucleotides in length), noncoding, fucitonal RNAs. Sensitive, specific, and label-free miRNA detection has been carried out using SPR. First, the capture RNA probe was immobilized onto the SPR sensor chip. This was followed by the competition reaction between target miRNA and biotinylated miRNA with the capture probe. Thanks to the specific binding of SA-gold to biotinylated RNA, quantification of miRNA in real samples has been achived using SPR. According to the competition mode, with the increase of the concentration of target miRNA, the SPR signals decrease accordingly. The feasibility of the method for miRNA determination has been demonstrated.