Enhancing Sensitivity of Immunomagnetic Detection of Alzheimer’s Disease Biomarkers with Magnetic Nanoparticles and Anti‐Biofouling Coating

Immunomagnetic capturing/detection of biomarkers, including immunoprecipitation‐mass‐spectrometry (IP‐MS) and single molecule array (Simoa®), is a key technology in biofluidic‐based in vitro diagnosis of Alzheimer’s disease (AD). However, proteins and other biomolecules in samples can non‐specifically absorb on the surface of biomarker‐targeting ligand functionalized capturing agents, such as commercial magnetic beads (Dynabeads®). Such “biofouling” effect leads to the formation of a “protein corona” that not only attenuates the detection specificity, sensitivity and reproducibility by blocking the binding of targeted biomarkers, but also creates strong “contaminating” background signals. This report introduces a polyethylene glycol‐block‐allyl glycidyl ether (PEG‐b‐AGE) polymer coated magnetic iron oxide nanoparticle (IONP) rendering anti‐biofouling capability to improve the sensitivity of blood‐sample‐based AD biomarker detection.