Polymer functionalized magnetic nanoconstructs for immunomagnetic separation of analytes†
Abstract
Magnetic nanoparticles are promising materials for immunomagnetic separation of various proteinaceous and genetic entities, and are used in the field of biosensing. In this paper, we have reported the synthesis and evaluation of novel terpolymeric functionalized magnetic nanoconstructs (PFMNCs) as an effective immunomagnetic separator and sensing platform. A multistep strategy was adopted to prepare the functionalized magnetic nanoconstructs. An iron oxide dispersion was synthesized by coprecipitation method followed by stabilization using sodium oleate as surfactant (IONPs). Finally, encapsulation of preformed IONPs was done by in situ emulsion polymerization of styrene, methyl methacrylate and acetoacetoxy ethyl methacrylate in the presence of varied amounts (3–21% w/w) of surfactant stabilized IONPs. Nanoconstructs were characterized by spectral, morphological and various analytical techniques. Polymeric nanoconstructs with 6% IONPs exhibited good dispersion stability, superparamagnetic properties and well defined core–shell morphology with a 123 nm magnetic core and 54 nm shell thickness. PFMNCs were evaluated as an immunomagnetic matrix for the detection of analyte by sandwich ELISA. Amino groups of antibodies (GAR-IgG) were covalently attached to pendant di-ketonic functionalities of nanoconstructs with high immobilization efficiency of 85%. Polymeric magnetic nanoconstructs can efficiently separate the target entities from the aqueous solution, which leads to the lower detection limit of 0.39 ng mL−1 of analyte, RAG-IgG. The developed nanoconstructs demonstrate dual capabilities of working as an immunomatrix as well as magnetic separator and thus have a strong potential for use in clinical diagnostics.