Showing papers by "Hye Jin Lee published in 2007"
TL;DR: A methodology for the detection of protein biomarkers at picomolar concentrations that utilizes surface plasmon resonance imaging (SPRI) measurements of RNA aptamer microarrays is developed.
Abstract: A methodology for the detection of protein biomarkers at picomolar concentrations that utilizes surface plasmon resonance imaging (SPRI) measurements of RNA aptamer microarrays is developed. The adsorption of proteins onto the RNA microarray is detected by the formation of a surface aptamer-protein-antibody complex. The SPRI response signal is then amplified using a localized precipitation reaction catalyzed by the enzyme horseradish peroxidase that is conjugated to the antibody. This enzymatically amplified SPRI methodology is first characterized by the detection of human thrombin at a concentration of 500 fM; the appropriate thrombin aptamer for the sandwich assay is identified from a microarray of three potential thrombin aptamer candidates. The SPRI method is then used to detect the protein vascular endothelial growth factor (VEGF) at a biologically relevant concentration of 1 pM. VEGF is a signaling protein that has been used as a serum biomarker for rheumatoid arthritis, breast cancer, lung cancer, and colorectal cancer and is also associated with age-related macular degeneration.
282 citations
TL;DR: Ultrasensitive surface bioaffinity sensors are created by the adsorption of gold nanoparticles onto gold diffraction gratings and are employed to detect unmodified DNA at a concentration of 10 fM.
Abstract: Ultrasensitive surface bioaffinity sensors are created by the adsorption of gold nanoparticles onto gold diffraction gratings. An enhanced diffraction obtained in a surface plasmon resonance geometry is observed due to the optical coupling of the planar surface plasmons in the grating to the localized surface plasmons in the gold nanoparticles. As a first example, these nanoparticle grating biosensors are employed to detect unmodified DNA at a concentration of 10 fM.
88 citations
TL;DR: In this paper, the molecular structure and thickness of polyelectrolyte multilayers were determined using a combination of polarization modulation FT-IR reflection-absorption spectroscopy (PM-FTIRRAS) and FT-surface plasmon resonance (FT-SPR) thickness measurements.
Abstract: Alternating electrostatic multilayer adsorption of poly-L-lysine (pLys) and DNA is used to create well-defined biopolymer multilayers for use as an ultrathin aqueous phase in liquid–liquid interfacial measurements. The molecular structure and thickness of the polyelectrolyte multilayers are determined using a combination of polarization modulation FT-IR reflection-absorption spectroscopy (PM-FTIRRAS) and FT-surface plasmon resonance (FT-SPR) thickness measurements. Electroactive species such as ferri/ferrocyanide ions can be incorporated into the DNA/pLys polyelectrolyte multilayers. The ion transport activity of these electroactive films when in contact with 1,2-dichoroethane is verified by electrochemical measurements. Micron-sized patterns of these multilayers are created by either photopatterning, vapour-deposited spot patterning or microfluidic stencil processing, and are used in conjunction with fluorescence and surface plasmon resonance imaging (SPRI) to monitor (i) the intercalation of dye molecules into DNA/pLys ultrathin films, (ii) the electrostatic adsorption of gold nanoparticles onto DNA/pLys multilayers and (iii) the spatially controlled incorporation and reaction of enzymes into patterned biopolymer multilayers.
7 citations