Hot spot-localized artificial antibodies for label-free plasmonic biosensing

The development of biomolecular imprinting over the last decade has raised promising perspectives in replacing natural antibodies with artificial antibodies. A significant number of reports have been dedicated to imprinting of organic and inorganic nanostructures, but very few were performed on nanomaterials with a transduction function. Herein, a relatively fast and efficient plasmonic hot spot-localized surface imprinting of gold nanorods using reversible template immobilization and siloxane copolymerization is described. The technique enables a fine control of the imprinting process at the nanometer scale and provides a nanobiosensor with high selectivity and reusability. Proof of concept is established by the detection of neutrophil gelatinase-associated lipocalin (NGAL), a biomarker for acute kidney injury, using localized surface plasmon resonance spectroscopy. The work represents a valuable step towards plasmonic nanobiosensors with synthetic antibodies for label-free and cost-efficient diagnostic assays. It is expected that this novel class of surface imprinted plasmonic nanomaterials will open up new possibilities in advancing biomedical applications of plasmonic nanostructures. Macromolecular imprinting of gold nanorods is achieved using reversible template immobilization and siloxane copolymerization. The anisotropic capping of the nanorods is used to selectively localize the protein imprints at the nanorod plasmonic hot-spots. This configuration represents the first protein-imprinted localized surface plasmon resonance nanosensor dedicated to the detection of biomarkers at clinically relevant concentrations.