Multiplexed Surface Plasmon Imaging of Circulating Biomarkers

In vitro diagnosis is a rapidly growing research field to meet the unmet needs of early disease prediction, treatment, and prevention. Among many target analytes, circulating biomarkers facilitate a minimally invasive diagnostic approach. Biomarkers are molecular indicators that can vary widely in concentrations between normal and abnormal conditions (either up or down regulated). Nevertheless, they are typically present at very low levels in complex clinical matrices (e.g., whole blood, serum, saliva, and urine). Hence, bioassays that are selective, sensitive, and offering a wide dynamic range of detection are ideal. Furthermore, multiplex assay platforms are expected to increase the probability of in vitro diagnostics for specific and successful identification of desired abnormalities. We present herein a multiplex surface plasmon resonance imaging microarray that employs citrate-stabilized Fe3O4@Au core/shell nanoparticles as the plasmon signal amplification label for ultra-low detection of serum proteins and microRNA markers.