Chiroplasmon-active optical fiber probe for environment chirality estimation

The utilization of chiroplasmonic effects provides unique feasibility in the fields of enantioselective detection and recognition. In this work, the chiroplasmonic fiber probes were created through the coupling of a highly optically active dielectric medium with intrinsically non-chiral plasmon-active nanostructures. The specifically designed enantiomers of helicenes with a huge optical rotation were selectively immobilized to thin gold and silver layers deposited on an optical fiber core. The chirality transfer from helicene enantiomers to closed plasmon active noble metals films results in excitation of chiral plasmon waves with opposite rotation on gold or silver surfaces. The created chiroplasmon-active optical fiber probes were used for environmental chirality monitoring and found to be sensitive to the presence of left- or right-handed molecules (glucose enantiomers) or biomolecules conformation (beta-Lactoglobulin) in surrounding solutions. Control experiments confirmed that observed chiralityrelated plasmon band shift can be attributed to the interaction of chiral plasmon waves with the external environment, but not to the immobilization of probing molecules on the fiber surface. Created structures allow us to simultaneously estimate the presence of optically active molecules, with both, point or conformation chirality, and provides the ability to studying chiral macromolecular structure of proteins.

Automated summary

The study successfully created chiroplasmonic fiber probes for environmental chirality monitoring, where the selective immobilization and transfer of enantiomers led to the excitation of chiral plasmon waves, enabling sensitive detection of left- or right-handed molecules as well as biomolecular conformations.