Browsing by Subject "Surface Plasmon Resonance"

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    Highly specific plasmonic biosensors for ultrasensitive microRNA detection in plasma from pancreatic cancer patients
    (American Chemical Society, 2014-12-10) Joshi, Gayatri K.; Deitz-McElyea, Samantha; Johnson, Merrell; Mali, Sonali; Korc, Murray; Sardar, Rajesh; Department of Chemistry & Chemical Biology, School of Science
    MicroRNAs (miRs) are small noncoding RNAs that regulate mRNA stability and/or translation. Because of their release into the circulation and their remarkable stability, miR levels in plasma and other biological fluids can serve as diagnostic and prognostic disease biomarkers. However, quantifying miRs in the circulation is challenging due to issues with sensitivity and specificity. This Letter describes for the first time the design and characterization of a regenerative, solid-state localized surface plasmon resonance (LSPR) sensor based on highly sensitive nanostructures (gold nanoprisms) that obviates the need for labels or amplification of the miRs. Our direct hybridization approach has enabled the detection of subfemtomolar concentration of miR-X (X = 21 and 10b) in human plasma in pancreatic cancer patients. Our LSPR-based measurements showed that the miR levels measured directly in patient plasma were at least 2-fold higher than following RNA extraction and quantification by reverse transcriptase-polymerase chain reaction. Through LSPR-based measurements we have shown nearly 4-fold higher concentrations of miR-10b than miR-21 in plasma of pancreatic cancer patients. We propose that our highly sensitive and selective detection approach for assaying miRs in plasma can be applied to many cancer types and disease states and should allow a rational approach for testing the utility of miRs as markers for early disease diagnosis and prognosis, which could allow for the design of effective individualized therapeutic approaches.
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    Naturally occurring autoantibodies against beta-amyloid: investigating their role in transgenic animal and in vitro models of Alzheimer's disease
    (Society for Neuroscience, 2011-04-13) Dodel, Richard; Balakrishnan, Karthikeyan; Keyvani, Kathy; Deuster, Oliver; Neff, Frauke; Andrei-Selmer, Luminita-Cornelia; Röskam, Stephan; Stüer, Carsten; Al-Abed, Yousef; Noelker, Carmen; Balzer-Geldsetzer, Monika; Oertel, Wolfgang; Du, Yansheng; Bacher, Michael; Neurology, IU School of Medicine
    Alzheimer's disease (AD) is a neurodegenerative disorder primarily affecting regions of the brain responsible for higher cognitive functions. Immunization against β-amyloid (Aβ) in animal models of AD has been shown to be effective on the molecular level but also on the behavioral level. Recently, we reported naturally occurring autoantibodies against Aβ (NAbs-Aβ) being reduced in Alzheimer's disease patients. Here, we further investigated their physiological role: in epitope mapping studies, NAbs-Aβ recognized the mid-/C-terminal end of Aβ and preferentially bound to oligomers but failed to bind to monomers/fibrils. NAbs-Aβ were able to interfere with Aβ peptide toxicity, but NAbs-Aβ did not readily clear senile plaques although early fleecy-like plaques were reduced. Administration of NAbs-Aβ in transgenic mice improved the object location memory significantly, almost reaching performance levels of wild-type control mice. These findings suggest a novel physiological mechanism involving NAbs-Aβ to dispose of proteins or peptides that are prone to forming toxic aggregates.