Improving the sensitivity of immunoassays by reducing non-specific binding of poly(acrylic acid) coated upconverting nanoparticles by adding free poly(acrylic acid).

Upconverting nanoparticles (UCNPs) are attractive reporters in immunoassays because of their outstanding detectability. However, non-specific binding of antibody-UCNP conjugates on protein coated solid support results in background, which limits the immunoassay sensitivity. Thus, the full potential of UCNPs as reporters cannot be fully exploited.

Upconverting nanophosphors as reporters in a highly sensitive heterogeneous immunoassay for cardiac troponin I.

Photon upconverting nanophosphors (UCNPs) have a unique capability to produce anti-Stokes emission at visible wavelengths via sequential multiphoton absorption upon infrared excitation. Since the anti-Stokes emission can be easily spectrally resolved from the Stokes' shifted autofluorescence, the upconversion luminescence (UCL) is a highly attractive reporter technology for optical biosensors and biomolecular binding assays - potentially enabling unprecedented sensitivity in separation-based solid-phase immunoassays. UCL technology has not previously been applied in sensitive detection of cardiac troponin I (cTnI), which requires highly sensitive detection to enable accurate and timely diagnosis of myocardial infarction.

Spectrally and Spatially Multiplexed Serological Array-in-Well Assay Utilizing Two-Color Upconversion Luminescence Imaging.

We demonstrate a simple dual-mode multiplexed array-in-well immunoassay for simultaneous classification and detection of serum IgG and IgM antibodies against influenza A and human adenoviruses based on the color and position of the upconversion luminescence on the array. Biotinylated influenza A/H1N1 and A/H5N1 as well as adenovirus serotype 2 and 5 hexon antigens along with positive and negative controls were printed in an array format onto the bottom of streptavidin-coated microtiter wells. The anti-influenza A and antiadenovirus antibodies present in the sample were captured to the array and detected with antihuman antibody-coated upconverting nanophosphors (UCNPs).

Identification and analysis of anti-HDL scFv-antibodies obtained from phage display based synthetic antibody library.

Objective: In epidemiological studies plasma high density lipoprotein cholesterol (HDL-C) levels are found to correlate inversely with atherosclerotic cardiovascular events. HDL consists of different subpopulations and they vary in their anti-atherogenic properties. The aim of this study is to isolate coronary artery disease (CAD) specific anti-HDL scFv-antibodies.